Inhibin-B levels in healthy young adult men and prepubertal boys: is obesity the cause for the contemporary decline in sperm count because of fewer Sertoli cells?

Inhibin-B is a heterodimeric glycoprotein produced by Sertoli cells. Although inhibin-B levels are low when seminiferous tubules are damaged, studies in normal monkeys reveal that inhibin-B levels also correlate positively with Sertoli cell number. In this study, we measured inhibin-B levels in healthy young adult men aged 18-24 years and in prepubertal boys aged 5-9 years in relation to body mass index (BMI).