Summary
The influence of the medium collected from cultured rat Sertoli cells on the spontaneous and LHRH-stimulated release of gonadotropins by incubated rat pituitary halves was examined. The homogeneity of the cultured population of Sertoli cells taken from 20-day-old rats ranged up to 98%. The cells in culture responded to FSH stimulation with characteristic morphological changes and with increased secretion of estradiol-17β. The hemi-pituitaries obtained from sexually mature male rats were incubated for 5 hours in the presence of Sertoli cell culture medium (SCCM) or its fractions obtained by use of ultrafiltration. The SCCM fraction deprived of MW < 10 kD compounds exhibited a typical inhibin-like activity, whereas crude SCCM as well as its low-molecular-weight fraction stimulated the basal FSH release to about 150% and 175% of the control values, respectively. These fractions exerted an inhibitory effect on the LHRH-stimulated secretion of both LH and FSH.
It is concluded that Sertoli cells cultured in chemically defined medium release, apart from inhibin, a non-steroidal, heat-labile substance of MW < 10 kD which stimulates the basal secretion of FSH and LH and inhibits the LHRH-stimulated secretion of both gonadotropins from incubated rat hemi-pituitaries.
Key-Words:
Sertoli Cells
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Pituitary Halves
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Gonadotropin Release
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Stimulatory Effect
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Inhibin
