EVIDENCE FOR INHIBITION OF STEROID-HORMONE SECRETION BY ARGININE VASOTOCIN (AVT) IN TISSUE-CULTURE OF ISOLATED OVARIAN FOLLICULAR CELLS

Two follicular compartments, granulosa (G) and theca interna (T) cells isolated from porcine ovaries were cultured alone or in co-culture (G T). Cells were grown as monolayers in a control medium without hormone and in a media supplemented with arginine-vasotocin (AVT) at a concen tration of either 10(-7)M or 2x10(-7)M. Progesterone (P4), estrogen (E 2) and androgen (A) concentrations in the culture media were taken as measures of the effect of AVT on the function of follicular cells. Ste roids were analysed by radioimmunoassay. AVT action in this culture sy stem was expressed as a decrease in progesterone secretion by cultures of granulosa cells alone, and especially as a change in the pattern o f estradiol and androgen secretion by co-cultures. Control T and G cel ls cultured alone secreted small amounts of A (238.0pg/10(5) cells, 27 .3pg/10(5) cells, respectively), and E2 (272.5pg/10(5) cells, 10.6pg/1 0(5) cells, respectively) while in co-culture these two cell types int eracted and the result of this positive interaction was a significant increase in secretion of these two steroids (941.0pg/10(5) cells andro gen secretion and 854.1pg/10(5) cells estradiol secretion). This pheno menon is similar to that observed in the intact follicle in vivo. AVT introduced to the culture medium impaired the effect of this positive interaction of mixed G and T cells on the production of high levels of E2 and A by untreated co-cultures.