[Glutamate decarboxylase activity in the hypophysis after changes in corticotropin levels in rats]

It was shown that glutamate decarboxylase is present in the whole hypophyses and its anterior pituitary lobe of experimental rats. Single and repeated hydrocortisone- and/or multiple desoxycorticosterone injections to intact rats led to a decrease in the hypophyseal glutamate decarboxylase activity. The enzyme activity remained unchanged after cyproheptadine use and lowered following nacom administration (the drugs, blocking corticotropin secretion). Adrenalectomy induced a sharp fall of the glutamate decarboxylase activity in the rat hypophyses. The enzyme activity returned completely to normal after cyproheptadine use and was partially stabilized following a single hydrocortisone injection in the hypophyses of adrenalectomized rats.