Synthesis of ovulating hormone in organ culture.

Abstract

Adult female rat medial basal hypothalami (MBH) from the first and second days of diestrus, early and late proestrus and estrus of the estrous cycle were incubated with 25-day-old female rat pituitary explants in organ culture. At the end of 5 days the pituitary tissue was homogenized in the culture medium and the supernatant bioassayed for ovulating hormone (OH) activity in the PMS-primed immature female rat. The number of ova released was considered an index of OH potency. The pituitarytissue plus media from cultures containing MBH of adult female rats in the second day of diestrus and early and late proestrus induced the release of significantly more ova per rat than media from 25-day pituitary cultured alone or noncultured pituitary. It is concluded that the MBH of the adult female rat in the second day of diestrus and early and late proestrus of the estrous cycle is capable of stimulating synthesis of OH by the 25-day female rat anterior pituitary in organ culture. (Endocrinology 84: 778, 1969)