Steroid production by the isolated rabbit ovarian follicle

Graafian follicles from New Zealand white rabbits were incubated at 37 degrees C for various periods of time with air as the gas phase. Media were changed every 15 min and stored at -15 degrees C until analysed for progestins, 17 beta-hydroxyandrogens and oestrogens using established radioimmunoassay procedures. At fixed times after the start of the incubations, media containing various test substances were added with subsequent replacement by medium alone. Addition of 5 mug LH/ml for 1 sec caused a dramatic increase in the synthesis and secretion of androgen with lesser increases in progestin and oestrogen. Puromycin and cycloheximide but not actinomycin D, inhibited LH-induced steroidogenesis. Cycli AMP, dibutyryl cycli AMP, cyclic CMP, 5'-AMP, and theophylline also caused an increase in androgen production which rapidly ceased when media without nucleotides were added. Sodium fluoride had no effect on steroidogenesis. From these data it was concluded that (i) the rabbit follicle is the major source of ovarian androgen; (ii) the binding of LH to the follicular cells is a rapid process; (iii) the events following LH binding do not require the presence of LH in the medium; (iv) cyclic nucleotides which may act as second messengers also stimulate steroidogenesis; (v) the effects of LH and cyclic nucleotides on steroidogenesis are different; and (vi) the action of LH on follicular steroidogenesis probably occurs in the translational level.