Changes in Testis Specific Lactate Dehydrogenase Isoenzymes during the Seasonal Spermatogenic Cycle of the Marsupial Schoinobates volans (Petauridae)

Abstract

Histological examination of the testes of Schoinobates volans revealed an annual cycle with spermatogenic activity commencing in December and continuing until July, with peak sperm production in March. Starch gel electrophoretic patterns of LDH isoenzymes in regressed and prepubertal testes and epididymides contained only the five anodally migrating bands present in somatic tissues. Testes and epididymides collected from December until July contained two additional LDH isoenzymes (X and X′). These were absent from the somatic tissues and migrated toward the cathode. Immunochemical and kinetic analyses of the isolated LDH isoenzymes show that the subunit compositions of X and X′ are C₄ and C₃A, respectively. Two anodally migrating testes-specific LDH isoenzymes (X″ and X‴) were present in samples collected during July. On the basis of their electrophoretic mobilities, it is proposed that X″ and X‴ are C-B subunit hybrids. These data indicate the cyclic expression of LDH genes during seasonal spermatogenesis in a marsupial.