Effect of Testosterone on Natriuretic Peptide Levels

BACKGROUND Circulating natriuretic peptide (NP) levels are markedly lower in healthy men than women. A relative NP deficiency in men could contribute to their higher risk of hypertension and cardiovascular disease. Epidemiological studies suggest testosterone may contribute to sex-specific NP differences. OBJECTIVES This study aimed to determine the effect of testosterone administration on NP levels using a randomized, placebo-controlled design. METHODS One hundred and fifty-one healthy men (20 to 50 years of age) received goserelin acetate to suppress endogenous production of gonadal steroids, and anastrazole to suppress conversion of testosterone to estradiol. Subjects were randomized to placebo gel or 4 different doses of testosterone (1%) gel for 12 weeks. Serum N-terminal-pro-B-type natriuretic peptide (NT-proBNP) and total testosterone levels were measured at baseline and follow-up. RESULTS Men who did not receive testosterone replacement (placebo gel group) after suppression of endogenous gonadal steroid production experienced a profound decrease in serum testosterone (median 540 to 36 ng/dl; p < 0.0001). This was accompanied by an increase in median NT-proBNP (+8 pg/ml; p = 0.02). Each 1-g increase in testosterone dose was associated with a 4.3% lower NT-proBNP at follow-up (95% confidence interval: similar to 7.9% to similar to 0.45%; p = 0.029). An individual whose serum testosterone decreased by 500 ng/dl had a 26% higher predicted follow-up NT-proBNP than someone whose serum testosterone remained constant. CONCLUSIONS Suppression of testosterone production in men led to increases in circulating NT-proBNP, which were attenuated by testosterone replacement. Inhibition of NP production by testosterone may partly explain the lower NP levels in men. (Dose-Response of Gonadal Steroids and Bone Turnover in Men; NCT00114114) Published by Elsevier on behalf of the American College of Cardiology Foundation.