Immunocytochemical demonstration of anterior pituitary hormones in the pars tuberalis of long-term hypophysectomized rats.

The hormone-containing cells of the pars tuberalis of the rat adenohypophysis were studied, 4--5 months after hypophysectomy, with a double bridge immunocytochemical technique and with antisera directed against the hormones of the pars distalis. Corticotropes, lactotropes, somatotropes, thyrotropes, and gonadotropes were found in the pars tuberalis of all animals. These cells are well well situated to receive blood, nerve terminals, and tanycyte processes from the median eminence and, thus, to be influenced by the chemical messengers from the hypothalamus. It is concluded that the pars tuberalis has to be regarded as a potential source of adenohypophyseal hormones in an animal model traditionally considered to be free of such hormones.