Follicular dynamics and secretion of inhibin and oestradiol-17β during the oestrous cycle of the hamster
| Autor: | Gen Watanabe, Hisashi Kishi, Kazuyoshi Taya, Shuji Sasamoto |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
endocrine system
medicine.medical_specialty medicine.drug_class Endocrinology Diabetes and Metabolism media_common.quotation_subject Radioimmunoassay Ovary Biology Endocrinology Estrus Ovarian Follicle Cricetinae Internal medicine Follicular phase medicine Animals Inhibins Testosterone Ovulation Progesterone reproductive and urinary physiology media_common Morning Estrous cycle Estradiol Mesocricetus Luteinizing Hormone medicine.anatomical_structure Pituitary Gland Biological Assay Female Follicle Stimulating Hormone Gonadotropin hormones hormone substitutes and hormone antagonists |
| Zdroj: | Journal of Endocrinology. 146:169-176 |
| ISSN: | 1479-6805 0022-0795 |
| DOI: | 10.1677/joe.0.1460169 |
| Popis: | Plasma and ovarian levels of inhibin were determined by a radioimmunoassay (RIA) at 3-h intervals throughout the 4-day oestrous cycle of hamsters. Plasma concentrations of FSH, LH, progesterone, testosterone and oestradiol-17β were also determined by RIAs. In addition, hamsters were injected at various times with human chorionic gonadotrophin (hCG) to determine the follicular development. The changes in plasma concentrations of FSH after injection of antisera to oestradiol-17β (oestradiol-AS) and inhibin (inhibin-AS) on the morning of day 2 (day 1=day of ovulation) were also determined. Plasma concentrations of inhibin showed a marked increase on the afternoon of day 1, remained at plateau levels until the morning of day 4, then increased abruptly on the afternoon of day 4 when preovulatory LH and FSH surges were initiated. A marked decrease in plasma concentrations of inhibin occurred during the process of ovulation after the preovulatory gonadotrophin surges. An inverse relationship between plasma levels of FSH and inhibin was observed when the secondary surge of FSH was in progress during the periovulatory period. Plasma concentrations of oestradiol-17β showed three increase phases and these changes differed from those of inhibin. Changes in plasma concentrations of oestradiol-17β correlated well with the maturation and regression of large antral follicles. Follicles capable of ovulating following hCG administration were first noted at 2300 h on day 1. The number of follicles capable of ovulating reached a maximum on the morning of day 3 (24·8± 0·6), and decreased by 0500 h on day 4 (15·0 ± 1·1), corresponding to the number of normal spontaneous ovulations. Plasma concentrations of FSH were dramatically increased within 6 h after inhibin-AS, though no increase in FSH levels was observed after oestradiol-AS. These findings suggest that changes in the plasma levels of inhibin during the oestrous cycle provide a precise indicator of follicular recruitment, and that the changes in plasma concentrations of oestradiol-17β are associated with follicular maturation. These findings also suggest that inhibin may play a major role in the inhibition of FSH secretion during the oestrous cycle of the hamster. Journal of Endocrinology (1995) 146, 169–176 |
| Databáze: | OpenAIRE |
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