Calcium antagonists and hormone release. V. Effects of a calcium-antagonist (verapamil) on pituitary hormone release in hypersecretory states.
Twenty-five patients with various syndromes of pituitary hyperfunction, of tumoral and nontumoral origin, were infused with verapamil (VE), a Ca2+-channel blocker (5 mg/h X 3 h) to assess the calcium dependence of the augmented hormone secretion. In 5 hypogonadal women with elevated gonadotropin secretion, VE produced a marked inhibition of LH (54.6%) and FSH (49.4%) release, comparable to that observed in normal subjects who were infused with VE. In 5 patients with latent or mild hypothyroidism, TSH levels decreased during the VE infusion, and the magnitude of the decrease was directly correlated with the basal levels (r = 0.986, p less than 0.01). In patients harboring a pituitary tumor, differential effects of VE infusion were observed: it induced an inhibition (28.5%) of ACTH secretion in patients with Cushing's disease; in acromegalic patients, no alterations in HGH levels were noted; on the contrary, in prolactinoma patients, a clear PRL increment (47.2%) was present. These experiments confirm that the need for extracellular Ca2+ varies from hormone to hormone and that VE infusion can modify the secretion of pituitary hormone in a hypersecretory state, as well as those hormones which are unaffected by VE infusion in basal condition.
D000172:Acromegaly / Q000503:physiopathology; D000293:Adolescent; D000328:Adult; D003480:Cushing Syndrome / Q000503:physiopathology; D005260:Female; D006801:Humans; D007006:Hypogonadism / Q000503:physiopathology; D007037:Hypothyroidism / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010900:Pituitary Diseases / Q000503:physiopathology*; D010907:Pituitary Hormones / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000378:metabolism; D011388:Prolactin / Q000378:metabolism; D014700:Verapamil / Q000494:pharmacology*
D010907:Pituitary Hormones; D011388:Prolactin; D014700:Verapamil