Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-19T23:53:56.503Z Has data issue: false hasContentIssue false
  • English
  • Français

Effect of progesterone priming on gonadotropin secretion and luteal function in GnRH-treated seasonally anoestrous ewes

Published online by Cambridge University Press:  02 September 2010

W. Haresign ,
G. F. Basiouni  and
M. Khalid
W. Haresign
Affiliation:
Faculty of Agricultural and Food Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough LEU 5RD
G. F. Basiouni
Affiliation:
Faculty of Agricultural and Food Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough LEU 5RD
M. Khalid
Affiliation:
Faculty of Agricultural and Food Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough LEU 5RD
Get access

Abstract

The main objective of the experiment was to investigate the mechanism by which progesterone priming eliminates defective luteal function in anoestrous ewes induced to ovulate with GnRH. Animals in group 1 (no. = 10) were primed with a single i.m. injection of progesterone in corn oil 3 days before the start of GnRH treatment, while ewes in group 2 (no. = 10) received corn oil alone and served as untreated controls. Ewes in group 3 (no. = 10), which served as positive controls, were treated with an intra-vaginal progestagen sponge for 7 days, and this was removed just before the start of GnRH treatment. Ewes in all three groups were induced to ovulate by administration of 2-h injections of GnRH (250 ng per injection) for 54 h. Frequent blood samples for LH, FSH and progesterone analysis were taken around the time of both progesterone injection and GnRH treatment, as well as daily thereafter to monitor luteal function, and laparoscopy was performed 3 and 7 days after GnRH treatment.

The incidence of ovulation was similar for all the three groups (8/10, 7/10 and 9/10 for groups 1, 2 and 3 respectively). Hoioever, both laparoscopic examination and plasma progesterone concentrations revealed that the incidence of normal luteal function was significantly higher in progesterone-primed animals group 1:7/8; group 3:9/9) compared ivith controls (group 2:0/7), P < 0-05) with no difference between groups 1 and 3. Injection of progesterone on day −3 significantly suppressed mean LH concentrations (P < 0·05), but mean FSH concentrations were not altered. However, there were no significant differences between groups in LH and FSH concentrations over the period of GnRH treatment, nor in the timing, duration and height of pre-ovulatory LH and FSH surges. These results suggest that progesterone priming may eliminate defective luteal function either by changing LH concentrations at the time of progesterone administration or through mechanisms not involving gonadotropin secretion.

Keywords

ewesGnRHgonadotropinsluteal functionprogesterone
Type
Research Article
Information
Animal Science , Volume 62 , Issue 1 , February 1996 , pp. 97 - 103
Copyright
Copyright © British Society of Animal Science 1996

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

Clarke, I. J. and Cummins, J. 1984. Direct pituitary effects of estrogen and progesterone on gonadotropin secretion in the ovariectomized ewe. Neuroendocrinology 39: 267–274.CrossRefGoogle ScholarPubMed
Foster, J. P. and Crighton, D. B. 1974. Luteinizing hormone (LH) release after single injections of a synthetic LH-releasing hormone (LH-RH) in the ewe at three different reproductive stages and comparison with natural LH release at oestrus. Theriogenalogy 2: 87–100.CrossRefGoogle ScholarPubMed
Haresign, W., Cooper, A. C., Khalid, M. and Hanrahan, J. P. 1995. Patterns of gonadotropins secretion in cyclic Finn ewes selected for and against high ovulation rate. Animal Science 61: 251–257.CrossRefGoogle Scholar
Haresign, W., Foster, J. P., Haynes, N. B., Crighton, D. B. and Lamming, G. E. L. 1975. Progesterone levels following treatment of seasonally anoestrous ewes with synthetic LH-releasing hormone. Journal of Reproduction and Fertility 43: 269–279.CrossRefGoogle ScholarPubMed
Hauger, R. L., Karsch, F. J. and Foster, D. L. 1977. A new concept for control of estrous cycle in the ewe based on the temporal relationships between luteinizing hormone, estradiol and progesterone in peripheral serum and evidence that progesterone inhibits tonic LH secretion. Endocrinology 101: 807–817.CrossRefGoogle ScholarPubMed
Hunter, M. G., Southee, J. A., McLeod, B. J. and Haresign, W. 1986. Progesterone pretreatment has a direct effect on GnRH-induced preovulatory follicle to determine their ability to develop into normal corpora lutea in anoestrous ewes. Journal of Reproduction and Fertility 76: 349–363.CrossRefGoogle Scholar
Karsch, F. J., Bittman, E. L., Foster, D. L., Goodman, R. L., Legan, S. J. and Robinson, J. E. 1984. Neuroendocrine basis of seasonal reproduction. Recent Progress in Hormone Research 40: 185–225.Google ScholarPubMed
Karsch, F. J., Legan, S. J., Hauger, R. L. and Foster, D. L. 1977. Negative feedback action of progesterone on tonic luteinizing hormone secretion in the ewe: dependence on the ovaries. Endocrinology 101: 800–806.CrossRefGoogle ScholarPubMed
Legan, S. J. and Saelinger, H. T. 1985. Serum FSH levels in GnRH-treated anoestrous ewes: effect of progesterone pretreatment on mean levels and pulsatile release. Biology of Reproduction 32: suppl., abstr. 152.Google Scholar
Martin, G. B., Wallace, J. M., Taylor, P. L., Fraser, H. M., Tsonis, C. G. and McNeilly, A. S. 1986. The roles of inhibin and gonadotrophin secretion in the ewe. Journal of Endocrinology 111: 287–296.CrossRefGoogle ScholarPubMed
McLeod, B. J. and Haresign, W. 1984. Evidence that progesterone may influence subsequent luteal function in the ewe by modulating preovulatory follicle development. Journal of Reproduction and Fertility 71: 381–386.CrossRefGoogle ScholarPubMed
McLeod, B. J. and Haresign, W. 1987. Plasma FSH concentrations in seasonally anoestrous ewes induced to ovulate with repeated injections or continuous infusion of CnRH. Animal Reproduction Science 14: 53–63.CrossRefGoogle Scholar
McLeod, B. J., Haresign, W. and Lamming, G. E. 1982a. The induction of ovulation and luteal function in seasonally anoestrous ewes treated with small-dose multiple injections of GnRH. Journal of Reproduction and Fertility 65: 215–221.CrossRefGoogle ScholarPubMed
McLeod, B. J., Haresign, W. and Lamming, G. E. 1982b. Response of seasonally anoestrous ewes to small-dose multiple injections of GnRH with and without progesterone pretreatment. Journal of Reproduction and Fertility 65: 223–230.CrossRefGoogle ScholarPubMed
Pearce, D. T., Oldham, C. M., Haresign, W. and Gray, S. J. 1987. Effects of duration and timing of progesterone priming on the incidence of corpora lutea with a normal life-span in Merino ewes induced to ovulate by the introduction of rams. Animal Reproduction Science 13: 81–89.CrossRefGoogle Scholar
Rush, M. E. 1986. Follicle-stimulating hormone secretion in monosodium glutamate-lesioned rats: response to unilateral gonadectomy or porcine follicular fluid (inhibin). Life Science 38:1941–1949.CrossRefGoogle ScholarPubMed
Southee, J. A., Hunter, M. G. and Haresign, W. 1988. Function of abnormal corpora lutea in vivo after GnRH-induced ovulation in the anoestrous ewe. Journal of Reproduction and Fertility 84: 131–137.CrossRefGoogle ScholarPubMed