Ovarian inhibin: a hormone with potential to increase ovulation rate in sheep

K.M. Henderson, P. Franchimont, M.J. Lecomte-Yerna, Ch. Charlet- Renard, N. Hudson, K. Ball, K.P. McNatty

Wallaceville Animal Research Centre, Ministry of Agriculture and Fisheries, Upper Hutt and Laboratoire de Radioimmunologie, Universite de Liege, Belgium

Proceedings of the New Zealand Society of Animal Production. 1984, 44: 29-32

There is increasing evidence that a non-steroidal compound, inhibin, produced by the ovary is involved in the regulation of follicle stimulating hormone (FSH) production by the pituitary. Our studies have shown that ovarian inhibin is present in follicular fluid, that it is synthesised exclusively by follicular granulosa cells, that androgens regulate its synthesis and that it is predominantly a product of healthy follicles, i.e. follicles with the potential to attain ovulatory granulosa cell inhibin production which then suppresses pituitary FSH secretion thereby limiting the number of follicles that can be stimulated to develop to ovulatory maturity. Ovulation rates of Romney ewes actively immunised with a semi-purified preparation of inhibin derived from bovine follicular fluid were significantly higher than those of control ewes (2.06 ą 0.16 v 1.31 ą 0.06 ovulations/ewe).

Keywords: NZSAPAB; Inhibin; granulosa cells; theca; androgens; sheep; cow; ovulation rate

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Last Updated 03-05-1997