LACK OF INHIBITION OF ANTERIOR-PITUITARY HORMONE-RELEASE DURING CHRONIC TREATMENT WITH CALCIUM-ANTAGONISTS

Ca antagonists are widely used for the treatment of cardiovascular disorders, especially ischemic heart disease. These drugs, either in vitro or acutely administered in humans, inhibited the basal and stimulated secretion of pituitary hormones by blocking Ca influx through slow Ca channels. To see if a similar effect could be detected after their chronic administration, the basal, TRH- and LHRH-stimulated TSH, PRL [prolactin], LH [luteinizing hormone] and FSH release in 18 male subjects with chronic stable angina before and on the 30th day of oral treatment with verapamil (n = 8; 80 mg 3 times a day) or with nifedipine (n = 10; 10 mg 3 times a day). Neither drug had any effect on basal TSH, PRL, LH and FSH values or on their response to the specific hypothalamic-releasing hormones. The chronic administration of Ca antagonists, at the usual therapeutic doses, does not affect the process of stimulus-secretion coupling of anterior pituitary hormones, ruling out any impairment of the related target glands which have been expected on the basis of previous studies.