The levels of 5α-dihydrotestosterone in follicular fluid in healthy and atretic ovine follicles
| Autor: | C.D. Nancarrow, Masa Tetsuka |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
endocrine system
medicine.medical_specialty medicine.drug_class Follicular Atresia Luteal phase Biology urologic and male genital diseases Endocrinology Ovarian Follicle Food Animals Internal medicine Follicular phase medicine Animals Testosterone Ovarian follicle Progesterone Estrous cycle Sheep Estradiol urogenital system Follicular atresia Androstenedione Dihydrotestosterone Androgen Follicular fluid Follicular Fluid medicine.anatomical_structure Female Animal Science and Zoology hormones hormone substitutes and hormone antagonists medicine.drug |
| Zdroj: | Domestic Animal Endocrinology. 33:347-357 |
| ISSN: | 0739-7240 |
| Popis: | Dihydrotestosterone (DHT) induces follicular atresia under experimental conditions. However, whether it causes any antagonistic effect under natural condition is not known. In the present study, we investigated concentrations of DHT in follicular fluid and correlated them with concentrations of estradiol-17beta (E2) and its androgen substrates, androstenedione (A4) and testosterone (T), in healthy and atretic follicles of sheep. Merino ewes were treated twice with PGF2alpha (PG) to synchronize estrus. The ovaries were recovered at 14 days after the second PG (luteal phase) or 24h after the third PG given 14 days after the second PG (follicular phase). Follicles were dissected and their size and appearance were recorded. Follicular fluid was collected from follicles larger than 3.5mm and concentrations of E2, progesterone (P4), A4, T and DHT were determined by RIA. The inhibitory effect of DHT on conversion of T to E2 was tested in cultured granulosa cells. Appreciable levels of DHT were observed in the follicular fluid of ovine preovulatory follicles. The levels of DHT were much lower than those of E2, A4 and T, irrespective of physiological conditions of follicles. No difference was found in DHT concentration between healthy and atretic follicles. Dihydrotestosterone marginally inhibited aromatization of T in granulosa cells but this effect was only observed when the levels of DHT were 10 times higher than that of T in culture medium. These results indicate that DHT is present in ovine preovulatory follicles but its levels are not sufficient to exert any antagonistic effect on follicular development. |
| Databáze: | OpenAIRE |
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