[Secretory activity of lactotrophs and its regulation by hypothalamic hormones in primary cultures of pituitary cells of rats of different ages].

Basal prolactin (PRL) secretion and the responses of lactotrophs to thyroliberin, dopamine and somatostatin were studied in the experiments employing primary monolayer cultures of pituitary cells obtained from developing rats of different ages. High responsiveness of PRL-secreting cells to the action of hypothalamic hormones was observed in the group of neonatal rats, although basal PRL release was about two orders lower in pituitary cultures of neonatal rats as compared to the cultures of immature, pubertal and adult animals. The investigation performed could reveal quantitative, but not qualitative differences in the reactions of lactotrophs of various age groups. It is concluded that postnatal development in the rat is coupled with significant changes of basal PRL release and to a lesser extent, with changes of lactotroph responsiveness to hypothalamic hormones.