Increased germ cell degeneration during postprophase of meiosis is related to increased serum follicle-stimulating hormone concentrations and reduced daily sperm production in aged men

Abstract

Aged men, known to have high serum gonadotropin levels and reduced spermatogenic potential, were used to study the relationship between serum follicle-stimulating hormone (FSH) and germ cell degeneration. Serum hormones were measured from blood obtained at autopsy. Phase-contrast cytometry was used to enumerate germ cells in homogenates of fixed testes from 13 younger (24 - 51 yr) and 14 aged (69 - 90 yr) men. The developmental steps of spermatogenesis during which germ cells degenerate were determined by comparing potential daily sperm production based on primary spermatocytes with daily sperm production based on two different types of spermatids. During spermiogenesis, there was no significant degeneration in the younger or aged men. During postprophase of meiosis, aged men had more (p<0.01) germ cell degeneration, significantly lower (p<0.05) serum testosterone, and greater (p<0.01) serum FSH than did younger men. Germ cell degeneration during postprophase of meiosis was negatively correlated (p<0.01) to daily sperm production and significantly (p<0.01) related to serum concentrations of FSH. As revealed in these aged men, meiotic germ cell degeneration has a direct effect on daily sperm production and is significantly related to serum FSH concentrations.