| Autor: |
Hillier, S. G., Wickings, E. J., Saunders, P. T. K., Dixson, A. F., Shimasaki, S., Swanston, I. A., Reichert, L. E., McNeilly, A. S. |
| Zdroj: |
Journal of Endocrinology; October 1989, Vol. 123 Issue: 1 p65-73, 9p |
| Abstrakt: |
In-vitro data from experiments on rats implicate granulosa cells as primary sites of hormone-dependent ovarian inhibin biosynthesis, but no equivalent data exist for primates. We have used the common marmoset (Callithrix jacchus) to investigate inhibin biosynthesis in primate granulosa cells in vitroand to determine its relationship to preovulatory follicular development. To relate the production of immunoactive inhibin to follicular maturity, we studied primary granulosa cell cultures from follicles at progressive stages of preovulatory development. Granulosa cells from 'large' (≥2·0 mm diameter) follicles expressed high rates of inhibin production and steroidogenesis (progesterone), and were positively regulated by human (h)LH in vitro. Less mature granulosa cells from 'medium' (1·1–1·9 mm) and 'small' (≤ 1·0 mm) follicles expressed proportionately lower rates of inhibin production and steroidogenesis, but each parameter was stimulated in a dose- and time-dependent manner by hFSH in vitro. The stimulatory action of hFSH on immunoactive inhibin was augmented by the presence of testosterone or oestradiol; testosterone (but not oestradiol) also augmented the steroidogenic response to hFSH. Marmoset luteal tissue also produced inhibin in vitroand expressed an ∼1·5 kb inhibin α-subunit mRNA, confirming the corpus luteum as a source of ovarian inhibin in primates.These results provide direct experimental evidence that primate granulosa cells produce inhibin. They suggest that production of inhibin by immature granulosa cells is initially induced by FSH and subject to modulation by follicular steroids. During advanced preovulatory development, granulosa cell inhibin production becomes directly responsive to LH, thereby indicating a role for LH in the control of peri- and postovulatory inhibin secretion by the primate ovary.Journal of Endocrinology(1989) 123,65–73 |
| Databáze: |
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