The effects of temperature and glucose on protein biosynthesis by immature (round) spermatids from rat testes

A method is described for the preparation of highly purified fractions (>80% pure) of immature spermatids (round, steps 1-8) from rat testes by centrifugal elutriation in sufficient yields for biochemical studies when four rat testes are used. Electron microscopy established the identity of the cells and demonstrated that the cell membrane is intact. Some cells develop nuclear and cytoplasmic vacuoles during the 2 h required for preparation. Immature spermatids prepared by this method use glucose with an increase in oxygen consumption, lactate production, and protein synthesis over control levels (no glucose). The testicular cell suspension from which spermatids are separated, like whole testis and spermatids themselves, show higher incorporation of amino acids into TCA-precipitable material at 34°C than at 38°C and in the presence of glucose. A subcellular system prepared from immature spermatids with excess ATP shows greater incorporation of amino acids into TCA-precipitable material at 34°C than at 38°C. This difference does not result from increased breakdown of protein. It is concluded that body temperature (38°C) inhibits some aspect(s) of protein synthesis in addition to previously reported effects on amino acid transport and production of ATP.