The effect of chemical ovulation-inducing substances on gonadotropin secretion in incubation experiments of the anterior pituitary.

Abstract

In order to clarify the in vitro action of clomiphene, F 6066 and Lychium chinense Miller (LCM) on the pituitary, the anterior pituitary of the rat was incubated with these materials and the gonadotropin in the medium was assayed. 1) Clomiphene showed no increase of LH secretion upon its addition to the incubation medium containing the pituitary alone or in the presense of the hypothalamus. The addition of a large amount of clomiphene induced a slight increase in secretion of FSH but it was not statistically significant, while prolactin secretion was significantly stimulated by a small amount of clomiphene. Secretion of prolactin was stimulated even in the presence of the hypothalamus. 2) F 6066 acted directly on the pituitary, markedly stimulating LH secretion. No significant changes of FSH and prolactin values were observed. 3) Extracts from LCM acted directly on the pituitary to stimulate LH secretion. 4) The results described above suggest that both clomiphene and F 6066 act on the diencephalon-pituitary system. Clomiphene gives a more marked effect on prolactin, while F 6066 acts on LH secretion more strongly. The action of LCM to induce ovulation is presumably consisted of a direct action on the pituitary to induce LH secretion. Further studies are necessary to elucidate the mechanism of action of these substances.