Effects of Sex Hormones on Vascular Reactivity in Boys With Hypospadias.

ABSTRACT

BACKGROUND: Arteries from boys with hypospadias demonstrate hypercontractility and impaired vasorelaxation. The role of sex hormones in these responses in unclear. AIMS: We compared effects of sex steroids on vascular reactivity in healthy boys and boys with hypospadias. METHODS: Excess foreskin tissue was obtained from 11 boys undergoing hypospadias repair (cases) and 12 undergoing routine circumcision (controls) (median age [range], 1.5 [1.2-2.7] years) and small resistance arteries were isolated. Vessels were mounted on wire myographs and vascular reactivity was assessed in the absence/presence of 17ß-estradiol, dihydrotestosterone (DHT), and testosterone. RESULTS: In controls, testosterone and 17ß-estradiol increased contraction (percent of maximum contraction [Emax] 83.74 basal vs 125.4 after testosterone, P < .0002; and 83.74 vs 110.2 after estradiol, P = .02). 17ß-estradiol reduced vasorelaxation in arteries from controls (Emax 10.6 vs 15.6 to acetylcholine, P < .0001; and Emax 14.6 vs 20.5 to sodium nitroprusside, P < .0001). In hypospadias, testosterone (Emax 137.9 vs 107.2, P = .01) and 17ß-estradiol (Emax 156.9 vs 23.6, P < .0001) reduced contraction. Androgens, but not 17ß-estradiol, increased endothelium-dependent and endothelium-independent vasorelaxation in cases (Emax 77.3 vs 51.7 with testosterone, P = .02; and vs 48.2 with DHT to acetylcholine, P = .0001; Emax 43.0 vs 39.5 with testosterone, P = .02; and 39.6 vs 37.5 with DHT to sodium nitroprusside, P = .04). CONCLUSION: In healthy boys, testosterone and 17ß-estradiol promote a vasoconstrictor phenotype, whereas in boys with hypospadias, these sex hormones reduce vasoconstriction, with androgens promoting vasorelaxation. Differences in baseline artery function may therefore be sex hormone-independent and the impact of early-life variations in androgen exposure on vascular function needs further study.