Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-09T05:55:57.286Z Has data issue: false hasContentIssue false

PROGESTERONE AND THE CONTROL OF HUMAN PREGNANCY AND PARTURITION

Published online by Cambridge University Press:  01 May 2009

SAM MESIANO*
Affiliation:
Department of Reproductive Biology, Case Western Reserve University and Department of Ob/Gyn, University Hospitals Case, Medical Center, 11100 Euclid Ave, Cleveland OH 44106-5034.
TONI WELSH
Affiliation:
Department of Reproductive Biology, Case Western Reserve University and Department of Ob/Gyn, University Hospitals Case, Medical Center, 11100 Euclid Ave, Cleveland OH 44106-5034.
*
Sam Mesiano, Department of Reproductive Biology, Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OHIO 44106-5034.

Extract

Almost 80 years ago George Corner and colleagues provided the first evidence that progesterone maintains pregnancy and that it does so, at least in part, by promoting myometrial relaxation. In the 1950s, Arpad Csapo proposed the “progesterone block hypothesis”, which posits that progesterone maintains pregnancy by promoting myometrial relaxation and that its withdrawal initiates a cascade of hormonal interactions that transforms the myometrium to a highly contractile state leading to the onset of labour. Csapo later proposed that contractility of the pregnant myometrium is determined by the balance between relaxation induced by progesterone and contraction induced by a cohort of signals including oestrogens, uterine distention and stimulatory uterotonins such as prostaglandins (PGs) and oxytocin (OT). According to this “seesaw” hypothesis, progesterone promotes myometrial relaxation by directly inducing relaxation and/or by inhibiting the production of, or myometrial responsiveness to, stimulatory uterotonins. These landmark concepts, though derived from studies of experimental animals, form the foundation for current understanding of progesterone's role in the physiology of human pregnancy. Remarkable progress has been made over the last 20–30 years in understanding the signal transduction pathways through which steroid hormones affect target cells. This knowledge has broadened the scope of Csapo's original paradigms and we are now beginning to unravel the specific signaling pathways and molecular interactions by which progesterone affects human myometrium and how its actions are controlled at the functional level. This is important for the development of progestin-based therapeutics for the prevention or suppression of preterm labour and preterm birth. Here we review recent progress in understanding the mechanisms by which progesterone sustains pregnancy and in particular how it promotes myometrial relaxation, how its relaxatory actions are nullified at parturition, and the hormonal interactions that induce progesterone withdrawal to determine the timing of human birth.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Corner, GW. The hormones in human reproduction. London: Princton University Press; 1946.Google Scholar
2Csapo, A. Progesterone block. Am J Anat 1956; 98: 273–91.CrossRefGoogle ScholarPubMed
3Csapo, A. The “seesaw” theory of the regulatory mechanism of pregnancy. Am J Obstet Gynecol 1975; 121: 578–81.CrossRefGoogle Scholar
4Avrech, OM, Golan, A, Weinraub, Z, Bukovsky, I, Caspi, E. Mifepristone (RU486) alone or in combination with a prostaglandin analogue for termination of early pregnancy: a review. Fertil Steril 1991; 56: 385–93.CrossRefGoogle ScholarPubMed
5Chwalisz, K, Stockemann, K, Fuhrmann, U, Fritzemeier, KH, Einspanier, A, Garfield, RE. Mechanism of action of antiprogestins in the pregnant uterus. Ann N Y Acad Sci 1995; 761: 202–23.CrossRefGoogle ScholarPubMed
6Chwalisz, K. The use of progesterone antagonists for cervical ripening and as an adjunct to labour and delivery. Hum Reprod 1994; 9 Suppl 1: 131–61.CrossRefGoogle ScholarPubMed
7Chwalisz, K, Garfield, RE. Antiprogestins in the induction of labor. Ann N Y Acad Sci 1994; 734: 387413.CrossRefGoogle ScholarPubMed
8Horwitz, KB, Alexander, PS. In situ photolinked nuclear progesterone receptor of human breast cancer cells: subunit molecular weights after transformation and translocation. Endocrinology 1983; 113: 2195–201.CrossRefGoogle ScholarPubMed
9Wei, LL, Krett, NL, Francis, MD, Gordon, DF, Wood, WM, O'Malley, BW, et al. Multiple human progesterone receptor messenger ribonucleic acids and their autoregulation by progestin agonists and antagonists in breast cancer cells. Mol Endocrinol 1988; 2: 6272.CrossRefGoogle ScholarPubMed
10Kastner, P, Krust, A, Turcotte, B, Stropp, U, Tora, L, Gronemeyer, H et al. Two distinct estrogen-regulated promoters generate transcripts encoding the two functionally different human progesterone receptor forms A and B. EMBO J 1990; 9: 1603–614.CrossRefGoogle ScholarPubMed
11Hirata, S, Shoda, T, Kato, J, Hoshi, K. Isoform/variant mRNAs for sex steroid hormone receptors in humans. Trends Endocrinol Metab 2003; 14: 124–29.CrossRefGoogle ScholarPubMed
12Giangrande, PH, Kimbrel, EA, Edwards, DP, McDonnell, DP. The opposing transcriptional activities of the two isoforms of the human progesterone receptor are due to differential cofactor binding. Mol Cell Biol 2000; 20: 3102–15.CrossRefGoogle ScholarPubMed
13Tung, L, Mohamed, MK, Hoeffler, JP, Takimoto, GS, Horwitz, KB. Antagonist-occupied human progesterone B-receptors activate transcription without binding to progesterone response elements and are dominantly inhibited by A-receptors. Mol Endocrinol 1993; 7: 1256–65.Google ScholarPubMed
14Vegeto, E, Shahbaz, MM, Wen, DX, Goldman, ME, O'Malley, BW, McDonnell, DP. Human progesterone receptor A form is a cell- and promoter-specific repressor of human progesterone receptor B function. Mol Endocrinol 1993; 7: 1244–55.Google ScholarPubMed
15Mulac-Jericevic, B, Mullinax, RA, DeMayo, FJ, Lydon, JP, Conneely, OM. Subgroup of reproductive functions of progesterone mediated by progesterone receptor-B isoform. Science 2000; 289: 1751–754.CrossRefGoogle ScholarPubMed
16Shyamala, G, Yang, X, Silberstein, G, Barcellos-Hoff, MH, Dale, E. Transgenic mice carrying an imbalance in the native ratio of A to B forms of progesterone receptor exhibit developmental abnormalities in mammary glands. Proc Natl Acad Sci USA 1998; 95: 696701.CrossRefGoogle Scholar
17Brodt-Eppley, J, Myatt, L. Changes in expression of contractile FP and relaxatory EP2 receptors in pregnant rat myometrium during late gestation, at labor, and postpartum. Biol Reprod 1998; 59: 878–83.CrossRefGoogle ScholarPubMed
18Cook, JL, Shallow, MC, Zaragoza, DB, Anderson, KI, Olson, DM. Mouse placental prostaglandins are associated with uterine activation and the timing of birth. Biol Reprod 2003; 68: 579–87.CrossRefGoogle ScholarPubMed
19Dong, YL, Yallampalli, C. Pregnancy and exogenous steroid treatments modulate the expression of relaxant EP(2) and contractile FP receptors in the rat uterus. Biol Reprod 2000; 62: 533–39.CrossRefGoogle ScholarPubMed
20Fang, X, Wong, S, Mitchell, BF. Effects of RU486 on estrogen, progesterone, oxytocin, and their receptors in the rat uterus during late gestation. Endocrinology 1997; 138: 2763–768.CrossRefGoogle ScholarPubMed
21Ou, CW, Chen, ZQ, Qi, S, Lye, SJ. Expression and regulation of the messenger ribonucleic acid encoding the prostaglandin F(2alpha) receptor in the rat myometrium during pregnancy and labor. Am J Obstet Gynecol 2000; 182: 919–25.CrossRefGoogle ScholarPubMed
22Swahn, ML, Bygdeman, M. The effect of the antiprogestin RU 486 on uterine contractility and sensitivity to prostaglandin and oxytocin. Br J Obstet Gynaecol 1988; 95: 126–34.CrossRefGoogle ScholarPubMed
23Selinger, M, MacKenzie, IZ, Gillmer, MD, Phipps, SL, Ferguson, J. Progesterone inhibition in mid-trimester termination of pregnancy: Physiological and clinical effects. Br J Obstet Gynaecol 1987; 94: 1218–222).CrossRefGoogle ScholarPubMed
24Webster, MA, Phipps, SL, Gillmer, MD. Interruption of first trimester human pregnancy following Epostane therapy. Effect of prostaglandin E2 pessaries. Br J Obstet Gynaecol 1985; 92: 963–68.CrossRefGoogle ScholarPubMed
25Challis, JR, Patel, FA, Pomini, F. Prostaglandin dehydrogenase and the initiation of labor. J Perinat Med 1999; 27: 2634.CrossRefGoogle ScholarPubMed
26Patel, FA, Challis, JR. Cortisol/progesterone antagonism in regulation of 15-hydroxysteroid dehydrogenase activity and mRNA levels in human chorion and placental trophoblast cells at term. J Clin Endocrinol Metab 2002; 87: 700708.CrossRefGoogle ScholarPubMed
27Patel, FA, Funder, JW, Challis, JR. Mechanism of cortisol/progesterone antagonism in the regulation of 15-hydroxyprostaglandin dehydrogenase activity and messenger ribonucleic acid levels in human chorion and placental trophoblast cells at term. J Clin Endocrinol Metab 2003; 88: 2922–933.CrossRefGoogle ScholarPubMed
28Patel, FA, Sun, K, Challis, JR. Local modulation by 11beta-hydroxysteroid dehydrogenase of glucocorticoid effects on the activity of 15-hydroxyprostaglandin dehydrogenase in human chorion and placental trophoblast cells. J Clin Endocrinol Metab 1999; 84; 395400.Google ScholarPubMed
29Hendrix, EM, Myatt, L, Sellers, S, Russell, PT, Larsen, WJ. Steroid hormone regulation of rat myometrial gap junction formation: effects on cx43 levels and trafficking. Biol Reprod 1995; 52: 547–60.CrossRefGoogle ScholarPubMed
30Garfield, RE, Hayashi, RH. Appearance of gap junctions in the myometrium of women during labor. Am J Obstet Gynecol 1981; 140: 254–60.CrossRefGoogle ScholarPubMed
31Di, WL, Lachelin, GC, McGarrigle, HH, Thomas, NS, Becker, DL. Oestriol and oestradiol increase cell to cell communication and connexin43 protein expression in human myometrium. Mol Hum Reprod 2001; 7: 671–79.CrossRefGoogle ScholarPubMed
32Zhao, K, Kuperman, L, Geimonen, E, Andersen, J. Progestin represses human connexin43 gene expression similarly in primary cultures of myometrial and uterine leiomyoma cells. Biol Reprod 1996; 54: 607–15.CrossRefGoogle ScholarPubMed
33Soloff, MS, Fernstrom, MA, Periyasamy, S, Soloff, S, Baldwin, S, Wieder, M. Regulation of oxytocin receptor concentration in rat uterine explants by estrogen and progesterone. Can J Biochem Cell Biol 1983; 61: 625–30.CrossRefGoogle ScholarPubMed
34Adachi, S, Oku, M. The regulation of oxytocin receptor expression in human myometrial monolayer culture. J Smooth Muscle Res 1995; 31: 175–87.CrossRefGoogle ScholarPubMed
35Fuchs, AR, Periyasamy, S, Soloff, MS. Systemic and local regulation of oxytocin receptors in the rat uterus, and their functional significance. Can J Biochem Cell Biol 1983; 61: 615–24.CrossRefGoogle ScholarPubMed
36Ou, CW, Chen, ZQ, Qi, S, Lye, SJ. Increased expression of the rat myometrial oxytocin receptor messenger ribonucleic acid during labor requires both mechanical and hormonal signals. Biol Reprod 1998; 59: 1055–61.CrossRefGoogle ScholarPubMed
37Haluska, GJ, West, NB, Novy, MJ, Brenner, RM. Uterine estrogen receptors are increased by RU486 in late pregnant rhesus macaques but not after spontaneous labor. J Clin Endocrinol Metab 1990; 70: 181–86.CrossRefGoogle Scholar
38Mesiano, S, Chan, EC, Fitter, JT, Kwek, K, Yeo, G, Smith, R. Progesterone withdrawal and estrogen activation in human parturition are coordinated by progesterone receptor A expression in the myometrium. J Clin Endocrinol Metab 2002; 87: 2924–930.CrossRefGoogle ScholarPubMed
39Sanborn, BM, Ku, CY, Shlykov, S, Babich, L. Molecular signaling through G-protein-coupled receptors and the control of intracellular calcium in myometrium. J Soc Gynecol Investig 2005; 12: 479–87.CrossRefGoogle ScholarPubMed
40Colledge, M, Scott, JD. AKAPs: from structure to function. Trends Cell Biol 1999; 9: 216–21.CrossRefGoogle ScholarPubMed
41Edwards, AS, Scott, JD. A-kinase anchoring proteins: protein kinase A and beyond. Curr Opin Cell Biol 2000; 12: 217–21.CrossRefGoogle ScholarPubMed
42Feliciello, A, Gottesman, ME, Avvedimento, EV. The biological functions of A-kinase anchor proteins. J Mol Biol 2001; 308: 99114.CrossRefGoogle ScholarPubMed
43Ku, CY, Word, RA, Sanborn, BM. Differential expression of protein kinase A, AKAP79, and PP2B in pregnant human myometrial membranes prior to and during labor. J Soc Gynecol Investig 2005; 12: 421–27.CrossRefGoogle ScholarPubMed
44Ku, CY, Sanborn, BM. Progesterone prevents the pregnancy-related decline in protein kinase A association with rat myometrial plasma membrane and A-kinase anchoring protein. Biol Reprod 2002; 67: 605609.CrossRefGoogle ScholarPubMed
45Perusquia, M. Nongenomic action of steroids in myometrial contractility. Endocrine 2001; 15: 6372.CrossRefGoogle ScholarPubMed
46Chanrachakul, B, Pipkin, FB, Warren, AY, Arulkumaran, S, Khan, RN. Progesterone enhances the tocolytic effect of ritodrine in isolated pregnant human myometrium. Am J Obstet Gynecol 2005; 192: 458–63.CrossRefGoogle ScholarPubMed
47Lofgren, M, Holst, J, Backstrom, T. Effects in vitro of progesterone and two 5 alpha-reduced progestins, 5 alpha-pregnane-3,20-dione and 5 alpha-pregnane-3 alpha-ol-20-one, on contracting human myometrium at term. Acta Obstet Gynecol Scand 1992; 71: 2833.CrossRefGoogle ScholarPubMed
48Perusquia, M, Garcia-Yanez, E, Ibanez, R, Kubli-Garfias, C. Non-genomic mechanism of action of delta-4 and 5-reduced androgens and progestins on the contractility of the isolated rat myometrium. Life Sci 1990; 47: 1547–53.CrossRefGoogle ScholarPubMed
49Perusquia, M, Jasso-Kamel, J. Influence of 5alpha- and 5beta-reduced progestins on the contractility of isolated human myometrium at term. Life Sci 2001; 68: 2933–944.CrossRefGoogle ScholarPubMed
50Pinto, RM, Lerner, U, Pontelli, H. The effect of progesterone on oxytocin-induced contraction of the three separate layers of human gestational myometrium in the uterine body and lower segment. Am J Obstet Gynecol 1967; 98: 547–54.CrossRefGoogle ScholarPubMed
51Fu, X, Rezapour, M, Lofgren, M, Ulmsten, U, Backstrom, T. Unexpected stimulatory effect of progesterone on human myometrial contractile activity in vitro. Obstet Gynecol 1993; 82: 2328.Google ScholarPubMed
52Fu, X, Rezapour, M, Lofgren, M, Ulmsten, U, Backstrom, T. Antitachyphylactic effects of progesterone and oxytocin on term human myometrial contractile activity in vitro. Obstet Gynecol 1993; 82: 532–8.Google ScholarPubMed
53Rezapour, M, Hongpaisan, J, Fu, X, Backstrom, T, Roomans, GM, Ulmsten, U. Effects of progesterone and oxytocin on intracellular elemental composition of term human myometrium in vitro. Eur J Obstet Gynecol Reprod Biol 1996; 68: 191–97.CrossRefGoogle ScholarPubMed
54Hendricks, CH, Brenner, WE, Gabel, RA, Kerenyi, T, (eds). The effect of progesterone administered intra-amniotically in late human pregnancy. Brook Lodge Symposium: Progesterone; 1961; Augusta, Michigan: The Upjohn Company.Google Scholar
55Pinto, RM, Montuori, E, Lerner, U, Baleiron, H, Glauberman, M, Nemirovsky, H. Effect Of Progesterone On The Oxytocic Action Of Estradiol-17-Beta. Am J Obstet Gynecol 1965; 91: 1084–89.CrossRefGoogle ScholarPubMed
56Zhu, Y, Bond, J, Thomas, P. Identification, classification, and partial characterization of genes in humans and other vertebrates homologous to a fish membrane progestin receptor. Proc Natl Acad Sci USA 2003; 100: 2237–242.CrossRefGoogle ScholarPubMed
57Zhu, Y, Rice, CD, Pang, Y, Pace, M, Thomas, P. Cloning, expression, and characterization of a membrane progestin receptor and evidence it is an intermediary in meiotic maturation of fish oocytes. Proc Natl Acad Sci USA 2003; 100: 2231–36.CrossRefGoogle ScholarPubMed
58Falkenstein, E, Heck, M, Gerdes, D, Grube, D, Christ, M, Weigel, M, et al. Specific progesterone binding to a membrane protein and related nongenomic effects on Ca2+-fluxes in sperm. Endocrinology 1999; 140: 59996002.CrossRefGoogle ScholarPubMed
59Falkenstein, E, Schmieding, K, Lange, A, Meyer, C, Gerdes, D, Welsch, U, et al. Localization of a putative progesterone membrane binding protein in porcine hepatocytes. Cell Mol Biol. 1998; 44: 571–78.Google ScholarPubMed
60Gerdes, D, Wehling, M, Leube, B, Falkenstein, E. Cloning and tissue expression of two putative steroid membrane receptors. Biol Chem 1998; 379: 907–11.Google ScholarPubMed
61Mifsud, W, Bateman, A. Membrane-bound progesterone receptors contain a cytochrome b5-like ligand-binding domain. Genome Biol 2002; RESEARCH0068. Epub; 3: Nov 12.CrossRefGoogle ScholarPubMed
62Mourot, B, Nguyen, T, Fostier, A, Bobe, J. Two unrelated putative membrane-bound progestin receptors, progesterone membrane receptor component 1 (PGMRC1) and membrane progestin receptor (mPR) beta, are expressed in the rainbow trout oocyte and exhibit similar ovarian expression patterns. Reprod Biol Endocrinol 2006; 4: 6.CrossRefGoogle ScholarPubMed
63Peluso, JJ, Pappalardo, A, Fernandez, G, Wu, CA. Involvement of an unnamed protein, RDA288, in the mechanism through which progesterone mediates its antiapoptotic action in spontaneously immortalized granulosa cells. Endocrinology 2004; 145: 3014–22.CrossRefGoogle ScholarPubMed
64Peluso, JJ, Pappalardo, A, Losel, R, Wehling, M. Expression and function of PAIRBP1 within gonadotropin-primed immature rat ovaries: PAIRBP1 regulation of granulosa and luteal cell viability. Biol Reprod 2005; 73: 261–70.CrossRefGoogle ScholarPubMed
65Grazzini, E, Guillon, G, Mouillac, B, Zingg, HH. Inhibition of oxytocin receptor function by direct binding of progesterone. Nature 1998; 392: 509–12.CrossRefGoogle ScholarPubMed
66Putnam, CD, Brann, DW, Kolbeck, RC, Mahesh, VB. Inhibition of uterine contractility by progesterone and progesterone metabolites: mediation by progesterone and gamma amino butyric acid A receptor systems. Biol Reprod 1991; 45: 266–72.CrossRefGoogle Scholar
67Chapman, NR, Kennelly, MM, Harper, KA, Europe-Finner, GN, Robson, SC. Examining the spatio-temporal expression of mRNA encoding the membrane-bound progesterone receptor-alpha isoform in human cervix and myometrium during pregnancy and labour. Mol Hum Reprod 2006; 12: 1924.CrossRefGoogle ScholarPubMed
68Fernandes, MS, Pierron, V, Michalovich, D, Astle, S, Thornton, S, Peltoketo, H et al. Regulated expression of putative membrane progestin receptor homologues in human endometrium and gestational tissues. J Endocrinol 2005; 187: 89101.CrossRefGoogle ScholarPubMed
69Karteris, E, Zervou, S, Pang, Y, Dong, J, Hillhouse, EW, Randeva, HS, et al. Progesterone signaling in human myometrium through two novel membrane G protein coupled receptors: potential role in functional progesterone withdrawal at term. Mol Endocrinol 2006; 20: 1519–34. Epub 2006; Feb 16.CrossRefGoogle ScholarPubMed
70Krietsch, T, Fernandes, MS, Kero, J, Losel, R, Heyens, M, Lam, EW, et al. Human homologs of the putative G protein-coupled membrane progestin receptors (mPRalpha, beta, and gamma) localize to the endoplasmic reticulum and are not activated by progesterone. Mol Endocrinol 2006; 20: 3146–164.CrossRefGoogle Scholar
71Bogacki, M, Silvia, WJ, Rekawiecki, R, Kotwica, J. Direct inhibitory effect of progesterone on oxytocin-induced secretion of prostaglandin F(2alpha) from bovine endometrial tissue. Biol Reprod 2002; 67: 184–88.CrossRefGoogle ScholarPubMed
72Dunlap, KA, Stormshak, F. Nongenomic inhibition of oxytocin binding by progesterone in the ovine uterus. Biol Reprod 2004; 70: 6569.CrossRefGoogle ScholarPubMed
73Kubli-Garfias, C, Hoyo-Vadillo, C, Lopez-Nieto, E, Ponce-Monter, H. Inhibition of spontaneous contractions of the rat pregnant uterus by progesterone metabolites. Proc West Pharmacol Soc 1983; 26: 115–18.Google ScholarPubMed
74Kubli-Garfias, C, Medrano-Conde, L, Beyer, C, Bondani, A. In vitro inhibition of rat uterine contractility induced by 5 alpha and 5 beta progestins. Steroids 1979; 34: 609–17.CrossRefGoogle ScholarPubMed
75Thornton, S, Terzidou, V, Clark, A, Blanks, A. Progesterone metabolite and spontaneous myometrial contractions in vitro. Lancet 1999; 353: 1327–29.CrossRefGoogle ScholarPubMed
76Sheehan, PM, Rice, GE, Moses, EK, Brennecke, SP. 5 Beta-dihydroprogesterone and steroid 5 beta-reductase decrease in association with human parturition at term. Mol Hum Reprod 2005; 11: 495501.CrossRefGoogle ScholarPubMed
77Mitchell, BF, Mitchell, JM, Chowdhury, J, Tougas, M, Engelen, SM, Senff, N, et al. Metabolites of progesterone and the pregnane X receptor: a novel pathway regulating uterine contractility in pregnancy? Am J Obstet Gynecol 2005; 192: 1304–13.CrossRefGoogle ScholarPubMed
78Astle, S, Khan, RN, Thornton, S. The effects of a progesterone metabolite, 5 beta-dihydroprogesterone, on oxytocin receptor binding in human myometrial membranes. BJOG 2003; 110: 589–92.Google ScholarPubMed
79Burger, K, Fahrenholz, F, Gimpl, G. Non-genomic effects of progesterone on the signaling function of G protein-coupled receptors. FEBS Lett 1999; 464: 2529.CrossRefGoogle ScholarPubMed
80Mellon, SH, Griffin, LD. Neurosteroids: biochemistry and clinical significance. Trends Endocrinol Metab 2002; 13: 3543.CrossRefGoogle ScholarPubMed
81Sergeev, PV, Sizov, PI, Dukhanin, AS, Mineeva, EN. Study of the GABA-benzodiazepine receptor system of the human myometrium. Biull Eksp Biol Med 1990; 110: 382–84.CrossRefGoogle ScholarPubMed
82Edwards, DP. Regulation of signal transduction pathways by estrogen and progesterone. Annu Rev Physiol 2005; 67: 335–76.CrossRefGoogle ScholarPubMed
83Leonhardt, SA, Boonyaratanakornkit, V, Edwards, DP. Progesterone receptor transcription and non-transcription signaling mechanisms. Steroids 2003; 68: 761–70.CrossRefGoogle ScholarPubMed
84Yoon, S, Seger, R. The extracellular signal-regulated kinase: multiple substrates regulate diverse cellular functions. Growth Factors 2006; 24: 2144.CrossRefGoogle ScholarPubMed
85Sooranna, SR, Engineer, N, Loudon, JA, Terzidou, V, Bennett, PR, Johnson, MR. The mitogen-activated protein kinase dependent expression of prostaglandin H synthase-2 and interleukin-8 messenger ribonucleic acid by myometrial cells: the differential effect of stretch and interleukin-1β. J Clin Endocrinol Metab 2005; 90: 3517–27.CrossRefGoogle Scholar
86Li, Y, Je, HD, Malek, S, Morgan, KG. Role of ERK1/2 in uterine contractility and preterm labor in rats. Am J Physiol Regul Integr Comp Physiol 2004; 287: R32835.CrossRefGoogle ScholarPubMed
87Kordowska, J, Huang, R, Wang, CL. Phosphorylation of caldesmon during smooth muscle contraction and cell migration or proliferation. J Biomed Sci 2006; 13: 159–72.CrossRefGoogle ScholarPubMed
88Morgan, KG, Gangopadhyay, SS. Invited review: cross-bridge regulation by thin filament-associated proteins. J Appl Physiol 2001; 91: 953–62.CrossRefGoogle ScholarPubMed
89Boroditsky, RS, Reyes, FI, Winter, JS, Faiman, C. Maternal serum estrogen and progesterone concentrations preceding normal labor. Obstet Gynecol 1978; 51: 686–91.Google ScholarPubMed
90Tulchinsky, D, Hobel, CJ, Yeager, E, Marshall, JR. Plasma estrone, estradiol, estriol, progesterone, and 17-hydroxyprogesterone in human pregnancy. I. Normal pregnancy. Am J Obstet Gynecol 1972; 112: 1095–100.CrossRefGoogle ScholarPubMed
91Walsh, SW, Stanczyk, FZ, Novy, MJ. Daily hormonal changes in the maternal, fetal, and amniotic fluid compartments before parturition in a primate species. J Clin Endocrinol Metab 1984; 58: 629–39.CrossRefGoogle Scholar
92Merlino, AA, Welsh, TN, Tan, H, Yi, LJ, Cannon, V, Mercer, BM, et al. Nuclear progesterone receptors in the human pregnancy myometrium: evidence that parturition involves functional progesterone withdrawal mediated by increased expression of progesterone receptor-A. J Clin Endocrinol Metab 2007; 92: 1927–33.CrossRefGoogle ScholarPubMed
93Haluska, GJ, Wells, TR, Hirst, JJ, Brenner, RM, Sadowsky, DW, Novy, MJ. Progesterone receptor localization and isoforms in myometrium, decidua, and fetal membranes from rhesus macaques: evidence for functional progesterone withdrawal at parturition. J Soc Gynecol Investig 2002; 9: 125–36.Google ScholarPubMed
94Condon, JC, Hardy, DB, Kovaric, K, Mendelson, CR. Up-regulation of the progesterone receptor (PR)-C isoform in laboring myometrium by activation of nuclear factor-kappaB may contribute to the onset of labor through inhibition of PR function. Mol Endocrinol 2006; 20: 764–75.CrossRefGoogle Scholar
95Henderson, D, Wilson, T. Reduced binding of progesterone receptor to its nuclear response element after human labor onset. Am J Obstet Gynecol 2001; 185: 579–85.CrossRefGoogle ScholarPubMed
96Condon, JC, Jeyasuria, P, Faust, JM, Wilson, JW, Mendelson, CR. A decline in the levels of progesterone receptor coactivators in the pregnant uterus at term may antagonize progesterone receptor function and contribute to the initiation of parturition. Proc Natl Acad Sci USA. 2003; 100: 9518–23.CrossRefGoogle Scholar
97Dong, X, Shylnova, O, Challis, JR, Lye, SJ. Identification and characterization of the protein-associated splicing factor as a negative co-regulator of the progesterone receptor. J Biol Chem 2005; 280: 13329–340.CrossRefGoogle ScholarPubMed
98Young, IR. The comparative physiology of parturition in mammals. Front Horm Res. 2001; 27: 1030.CrossRefGoogle ScholarPubMed
99Madsen, G, Zakar, T, Ku, CY, Sanborn, BM, Smith, R, Mesiano, S. Prostaglandins differentially modulate progesterone receptor-A and -B expression in human myometrial cells: evidence for prostaglandin-induced functional progesterone withdrawal. J Clin Endocrinol Metab 2004; 89: 1010–13.CrossRefGoogle Scholar
100Takimoto, GS, Tung, L, Abdel-Hafiz, H, Abel, MG, Sartorius, CA, Richer, JK, et al. Functional properties of the N-terminal region of progesterone receptors and their mechanistic relationship to structure. J Steroid Biochem Mol Biol 2003; 85: 209–19.CrossRefGoogle ScholarPubMed
101Thiery, J. Induction of labor with prostaglandins. In: Keirse M, Anderson A, Benebroek-Gravenhorst J, (eds.) Human Parturition The Hague: Martinus Nijhoff; 1979; 155–64.CrossRefGoogle Scholar
102Jain, JK, MishellDR, Jr DR, Jr. A comparison of intravaginal misoprostol with prostaglandin E2 for termination of second-trimester pregnancy. N Engl J Med 1994; 331: 290–93.CrossRefGoogle ScholarPubMed
103Robins, J, Mann, LI. Midtrimester pregnancy termination by intramuscular injection of a 15-methyl analogue of prostaglandin F2 alpha. Am J Obstet Gynecol 1975; 123: 625–31.CrossRefGoogle ScholarPubMed
104Mitchell, MD, Romero, RJ, Edwin, SS, Trautman, MS. Prostaglandins and parturition. Reprod Fertil Dev 1995; 7: 623–32.CrossRefGoogle ScholarPubMed
105Boggess, KA. Pathophysiology of preterm birth: emerging concepts of maternal infection. Clin Perinatol 2005; 32: 561–69.CrossRefGoogle ScholarPubMed
106Klein, LL, Gibbs, RS. Infection and preterm birth. Obstet Gynecol Clin North Am 2005; 32: 397410.CrossRefGoogle ScholarPubMed
107Kelly, RW. Inflammatory mediators and parturition. Rev Reprod 1996; 1: 8996.CrossRefGoogle ScholarPubMed
108Bowen, JM, Chamley, L, Keelan, JA, Mitchell, MD. Cytokines of the placenta and extra-placental membranes: roles and regulation during human pregnancy and parturition. Placenta 2002; 23: 257–73.CrossRefGoogle ScholarPubMed
109Bowen, JM, Chamley, L, Mitchell, MD, Keelan, JA. Cytokines of the placenta and extra-placental membranes: biosynthesis, secretion and roles in establishment of pregnancy in women. Placenta 2002; 23: 239–56.CrossRefGoogle ScholarPubMed
110Gravett, MG, Witkin, SS, Haluska, GJ, Edwards, JL, Cook, MJ, Novy, MJ. An experimental model for intraamniotic infection and preterm labor in rhesus monkeys. Am J Obstet Gynecol 1994; 171: 1660–67.CrossRefGoogle ScholarPubMed
111Romero, R, Mazor, M, Tartakovsky, B. Systemic administration of interleukin-1 induces preterm parturition in mice. Am J Obstet Gynecol 1991; 165: 969–71.CrossRefGoogle ScholarPubMed
112Hardy, DB, Janowski, BA, Corey, DR, Mendelson, CR. Progesterone receptor plays a major antiinflammatory role in human myometrial cells by antagonism of nuclear factor-kappaB activation of cyclooxygenase 2 expression. Mol Endocrinol 2006; 20: 2724–733.CrossRefGoogle Scholar
113Kalkhoven, E, Wissink, S, van der Saag, PT, van der Burg, B. Negative interaction between the RelA(p65) subunit of NF-kappaB and the progesterone receptor. J Biol Chem 1996; 271: 6217–224.CrossRefGoogle ScholarPubMed
114Hartikainen-Sorri, AL, Kauppila, A, Tuimala, R. Inefficacy of 17 alpha-hydroxyprogesterone caproate in the prevention of prematurity in twin pregnancy. Obstet Gynecol 1980; 56: 692–95.Google ScholarPubMed
115Hauth, JC, Gilstrap, LC 3rd, Brekken, AL, Hauth, JM. The effect of 17 alpha-hydroxyprogesterone caproate on pregnancy outcome in an active-duty military population. Am J Obstet Gynecol 1983; 146: 187–90.CrossRefGoogle Scholar
116Johnson, JW, Austin, KL, Jones, GS, Davis, GH, King, TM. Efficacy of 17alpha-hydroxyprogesterone caproate in the prevention of premature labor. N Engl J Med 1975; 293: 675–80.CrossRefGoogle ScholarPubMed
117Yemini, M, Borenstein, R, Dreazen, E, Apelman, Z, Mogilner, BM, Kessler, I, et al. Prevention of premature labor by 17 alpha-hydroxyprogesterone caproate. Am J Obstet Gynecol 1985; 151: 574–77.CrossRefGoogle ScholarPubMed
118Keirse, MJ. Progestogen administration in pregnancy may prevent preterm delivery. Br J Obstet Gynaecol 1990; 97: 149–54.CrossRefGoogle ScholarPubMed
119da Fonseca, EB, Bittar, RE, Carvalho, MH, Zugaib, M. Prophylactic administration of progesterone by vaginal suppository to reduce the incidence of spontaneous preterm birth in women at increased risk: a randomized placebo-controlled double-blind study. Am J Obstet Gynecol 2003; 188: 419–24.CrossRefGoogle Scholar
120Meis, PJ, Aleman, A. Progesterone treatment to prevent preterm birth. Drugs 2004; 64: 2463–74.CrossRefGoogle ScholarPubMed
121O'Brien, JM, Adair, CD, Lewis, DF, Hall, DR, Defranco, EA, Fusey, S, et al. Progesterone vaginal gel for the reduction of recurrent preterm birth: primary results from a randomized, double-blind, placebo-controlled trial. Ultrasound Obstet Gynecol 2007; 30: 687–96.CrossRefGoogle ScholarPubMed
122Rouse, DJ, Caritis, SN, Peaceman, AM, Sciscione, A, Thom, EA, Spong, CY, et al. A trial of 17 alpha-hydroxyprogesterone caproate to prevent prematurity in twins. N Engl J Med 2007; 357: 454–61.CrossRefGoogle ScholarPubMed
123DeFranco, EA, O'Brien, JM, Adair, CD, Lewis, DF, Hall, DR, Fusey, S, et al. Vaginal progesterone is associated with a decrease in risk for early preterm birth and improved neonatal outcome in women with a short cervix: a secondary analysis from a randomized, double-blind, placebo-controlled trial. Ultrasound Obstet Gynecol 2007; 30: 697705.CrossRefGoogle Scholar
124Fonseca, EB, Celik, E, Parra, M, Singh, M, Nicolaides, KH. Progesterone and the risk of preterm birth among women with a short cervix. N Engl J Med 2007; 357: 462–69.CrossRefGoogle ScholarPubMed
125Klebanoff, MA, Meis, PJ, Dombrowski, MP, Zhao, Y, Moawad, AH, Northen, A, et al. Salivary progesterone and estriol among pregnant women treated with 17-alpha-hydroxyprogesterone caproate or placebo. Am J Obstet Gynecol 2008; 199: 506. e 17.CrossRefGoogle ScholarPubMed
126Mesiano, S, Katz, SL, Lee, JY, Jaffe, RB. Phytoestrogens alter adrenocortical function: genistein and daidzein suppress glucocorticoid and stimulate androgen production by cultured adrenal cortical cells. J Clin Endocrinol Metab 1999; 84: 2443–448.Google ScholarPubMed
127Sexton, DJ, O'Reilly, MW, Friel, AM, Morrison, JJ. Functional effects of 17alpha-hydroxyprogesterone caproate (17P) on human myometrial contractility in vitro. Reprod Biol Endocrinol 2004; 2: 80.CrossRefGoogle ScholarPubMed
128Rosenberg, K, Trevathan, W. Birth, obstetrics and human evolution. BJOG 2002; 109: 1199–206.CrossRefGoogle ScholarPubMed
129Rosenberg, KR, Trevathan, WR. The evolution of human birth. Sci Am 2001; 285: 7277.CrossRefGoogle ScholarPubMed
130Trevathan, WR. Human birth. An evolutionary perspective. Hawthorne, NY: Aldine De Gryter; 1987.Google Scholar
131Simpson, SW, Quade, J, Levin, NE, Butler, R, Dupont-Nivet, G, Everett, M et al. A female Homo erectus pelvis from Gona, Ethiopia. Science 2008; 322: 1089–92.CrossRefGoogle ScholarPubMed
132Gould, S. Ever Since Darwin: Reflections in Natural History. New York: Penguin; 1977.Google Scholar
133Dorus, S, Vallender, EJ, Evans, PD, Anderson, JR, Gilbert, SL, Mahowald, M, et al. Accelerated evolution of nervous system genes in the origin of Homo sapiens. Cell 2004; 119: 1027–40.CrossRefGoogle ScholarPubMed
134Clark, AG, Glanowski, S, Nielsen, R, Thomas, P, Kejariwal, A, Todd, MJ, et al. Positive selection in the human genome inferred from human-chimp-mouse orthologous gene alignments. Cold Spring Harb Symp Quant Biol 2003; 68: 471–77.CrossRefGoogle ScholarPubMed
135Chen, C, Opazo, JC, Erez, O, Uddin, M, Santolaya-Forgas, J, Goodman, M, et al. The human progesterone receptor shows evidence of adaptive evolution associated with its ability to act as a transcription factor. Mol Phylogenet Evol 2008; 47: 637–49.CrossRefGoogle ScholarPubMed