Effect of luteinizing hormone on the pattern of steroid production by preovulatory follicles of pregnant mare’s serum gonadotropin-injected immature rats.
Abstract: Preovulatory follicles were explanted on the day before ovulation from immature rats given a single injection of Pregnant Mare's Serum gonadotropin (PMS) 2 days earlier. The follicles were incubated for 4 h in modified Krebs bicarbonate buffer containing glucose and albumin in absence or presence of ovine luteinizing hormone (NIH-LH-S18; 0.1-10 mug/ml). The accumulation of progresterone, androstenedione and 17beta-estradiol in the medium was determined by radioimmunoassay. As in indicator of LH exposure the meiotic stage of the follicle-enclosed oocyte was determined at recovery by interference contrast microscopy. The first group of follicles were explanted in the morning, before the endogenous gonadotrophin surge. In hormone-free medium the oocytes remained in the dictyate stage, whereas addition of LH induced oocyte maturation. These follicles, when incubated in hormone-free medium, secreted predominantly androstenedione and estradiol and only low amounts of progesterone. In the presence of LH the secretion of all steroids was enhanced. The second group of follicles were explanted in the evening, 2-4 h after the endogenous gonadotrophin surge. After incubation in hormone-free medium the follicle-enclosed oocytes had matured. The steroid secretion by the follicles was different from that of the first group. In hormone-free medium they secreted predominantly progesterone and low amounts of androstenedione and estradiol. Addition of LH to the medium caused further enhancement of progesterone secretion, but had no effect on androstenedione and estradiol secretion. The third group of follicles were explanted in the evening from rats in which the preovulatory gonadotrophin surge had been prevented by Nembutal treatment. Oocyte maturation and steroid secretion did not differ from that found for the first group of follicles explanted in the morning. The results are compatible with the hypothesis that LH, after a transitory stimulation, inhibits androgen and estrogen secretion and stimulates progesterone secretion by the preovulatory ovarian follicle.
Publication Date: 1976-10-01 PubMed ID: 987904DOI: 10.1210/endo-99-4-996Google Scholar: Lookup
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- Journal Article
Summary
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The research investigates how the luteinizing hormone influences the secretion patterns of various steroids from preovulatory follicles in immature rats. The hormones being examined include progesterone, androstenedione, and 17beta-estradiol. The study suggests that the luteinizing hormone, following a transitory stimulation, may hinder the secretion of androgens and estrogens while enhancing progesterone secretion.
Research Methodology
- Preovulatory follicles were explanted from immature rats that had received an injection of Pregnant Mare’s Serum gonadotropin (PMS) 2 days prior, on the day before ovulation.
- The follicles were incubated for 4 hours in a modified Krebs bicarbonate buffer containing glucose and albumin, in the absence or presence of ovine luteinizing hormone.
- The meiotic stage of the follicle-enclosed oocyte was determined to indicate LH exposure.
Impact of Luteinizing Hormone
- When the first group of follicles were incubated in hormone-free medium, they primarily secreted androstenedione and estradiol and a smaller amount of progesterone, but with the addition of LH, the secretion of all steroids increased.
- For the second group of follicles, in the absence of hormones, the follicles predominantly secreted progesterone and lower amounts of androstenedione and estradiol. Adding LH to the medium boosted progesterone secretion, but had no impact on androstenedione and estradiol secretion.
- For the third group of follicles – which were taken from rats whose preovulatory gonadotrophin surge was inhibited by Nembutal treatment – the oocyte maturation and steroid secretion were similar to the first group of follicles explanted in the morning.
Interpretation of the Results
- The findings suggest that the luteinizing hormone may, after a temporary stimulation, restrict the secretion of androgens and estrogens and spur the production of progesterone in the preovulatory ovarian follicle. This could have implications for understanding the hormonal processes that occur during ovulation.
Cite This Article
APA
Hillensjö T, Bauminger S, Ahrén K.
(1976).
Effect of luteinizing hormone on the pattern of steroid production by preovulatory follicles of pregnant mare’s serum gonadotropin-injected immature rats.
Endocrinology, 99(4), 996-1002.
https://doi.org/10.1210/endo-99-4-996 Publication
Researcher Affiliations
MeSH Terms
- Androstenedione / biosynthesis
- Animals
- Estradiol / biosynthesis
- Female
- Gonadotropins, Equine / pharmacology
- Luteinizing Hormone / pharmacology
- Oocytes / cytology
- Ovarian Follicle / drug effects
- Ovarian Follicle / metabolism
- Pentobarbital / pharmacology
- Progesterone / biosynthesis
- Rats
- Time Factors
Citations
This article has been cited 2 times.- Aljonaid AA, Sato A, Asahara S, Maruo T. Abundant expression of sodium-potassium-activated adenosinetriphosphatase alpha 1 subunit in corpus luteum of porcine ovary. Endocrine 2003 Aug;21(3):233-40.
- Szoltys M, Stoklosowa S, Kasten FH. Hormonal secretion of cultured rat ovarian follicles isolated at various hours of proestrus. In Vitro 1982 May;18(5):463-8.
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