PLASMA PROLACTIN LEVELS AFTER TRH AND CHLORPROMAZINE IN NORMAL SUBJECTS AND PATIENTS WITH IMPAIRED PITUITARY FUNCTION

ABSTRACT Basal plasma prolactin levels and values after stimulation with TRH and chlorpromazine respectively were measured. TRH tests were performed in 50 healthy subjects (25 women and 25 men). The basal prolactin levels and the maximum increment were found to be as follows in women 22.02 ng/ml ± 5.02 sem and 100.0 ng/ml ± 11.3 sem respectively, in men 16.62 ng/ml ± 2.46 sem and 45.26 ng/ml ± 5.70 sem respectively. The maximum prolactin increase after chlorpromazine in 6 men amounted to 64.77 ng/ml ± 8.28 sem respectively and in 12 women, 6 of them taking hormonal contraceptives, 81.0 ng/ml ± 16.53 sem. There was no significant difference between the 2 groups of women. The behaviour of plasma prolactin under stimulation in patients with impaired pituitary function was compared with the other trophic pituitary functions before therapy, in 7 patients before and after hypophysectomy and 15 patients only after therapy. In addition 6 patients with tumours adjacent to the pituitary and 3 women with Sheehan's syndrome were investigated. Plasma prolactin before and after stimulation was not pathologically changed in all cases. After surgery the prolactin levels were also normal in many patients. In most of them slight or marked elevation of prolactin levels were found. There was no good correlation between the trophic pituitary functions in most cases. It seems that prolactin measurement under stimulation conditions is the most sensitive indicator of a residual pituitary function.