EFFECTS OF RAMIPRIL ON THE HORMONE CONCENTRATIONS IN SERUM OF HYPERTENSIVE PATIENTS

The effects of the angiotensin-converting enzyme inhibitor ramipril on thirteen endocrinological tests were evaluated. These tests comprised serum follitropin, lutropin, prolactin, thyrotropin, free thyroxine, total thyroxine, free triiodothyronine, parathyrin, cortisol, testoste rone, sex hormone binding globulin, androstenedione and dehydroepiandr osterone sulphate. Eleven hypertensive outpatients, 9 men and 2 women, treated at the department of internal medicine in Turku University Ce ntral Hospital, received 5 mg of ramipril once a day for the study per iod of four weeks. The above mentioned endocrinological tests were per formed before and at the end of the ramipril treatment. Ramipril decre ased the value of free thyroxine statistically significantly, p = 0.01 1, from the mean value of 17.1 pmol/l to the mean value of 16.0 pmol/l when measured with Amerlex-MAB free thyroxine kit. The mean within-s ubject difference was -1.10 pmol/l with a 95% confidence interval of - 1.87 - -0.33 pmol/l. With the AutoDELFIA(TM) free thyroxine kit and wi th the reference method dialysis+RIA no effect was detected. Other end ocrinological tests examined were not affected by ramipril. Since the decreasing effect of ramipril on free thyroxine was detected only with Amerlex-MAB but neither with AutoDELFIA(TM) nor with dialysis+RIA, t he effect was concluded to be analytical. The underlying mechanism and the component ultimately interfering with the analysis is unknown.