Activities of X-linked enzymes in spermatocytes of mice rendered sterile by chromosomal alterations

Spermatocytes in the late prophase of first meiotic division isolated from sterile males retain higher activities for three X-linked enzyme⁵, phosphoglycerate kinase (PGK)-1, glucose-6-phosphate dehydrogenase (G6PD), and hypoxanthine-guanine phosphoribosyl transferase (HGPRT) than those of fertile males. The sterilty of the male is presumed to be owing to the rearrangement of X-chromosome material and the possibility of abnormal meiotic X-chromosome inactivation is discussed.