Alterations in sperm characteristics of follicle-stimulating hormone (FSH)-immunized men are similar to those of FSH-deprived infertile male bonnet monkeys

The quality or sperm ejaculated by bonnet monkeys and normal, healthy prove n fertile volunteer men, both actively immunized with ovine follicle-stimul ating hormone (oFSH), was examined at different times of study for chromati n packaging and acrosomal glycoprotein concentration by flow cytometry. Sus ceptibility of sperm nuclear DNA to dithiothreitol (DTT)-induced decondensa tion, as measured by ethidium bromide binding, was markedly high compared w ith values at day 0 in men and monkeys during periods when FSH antibody tit er was high. Sperm chromatin structure assay yields at values, which is ano ther index of chromatin packaging. Higher at values, signifying poor packag ing, occurred in both species following immunization with heterologous pitu itary FSH. The binding of fluorosceinated pisum sativum agglutinin (PSA-FIT C) to acrosome of sperm of monkeys and men was significantly low, compared with values at day 0 (control) during periods when cross-re-active FSH anti body titer was high and endogenous FSH was not detectable. Blockade of FSH function in monkeys by active immunization with a recombinant oFSH receptor protein corresponding to a naturally occurring messenger RNA (mRNA) also r esulted in production of sperm with similar defects in chromatin packaging and reduced acrosomal glycoprotein concentration. Thus, it appears that in monkeys and men, lack of FSH signaling results in production of sperm that exhibit defective chromatin packaging and reduction in acrosomal glycoprote in content. These characteristics are similar to that exhibited by sperm of some class of infertile men. Interestingly, these alterations in sperm qua lity occur well ahead of decreased sperm counts in the ejaculate.