Lipid metabolising enzymes in isolated rat testicular germ cells and changes associated with meiosis.

To assess the lipid metabolising potential of testicular germ cells undergoing meiosis, spermatocytes and spermatids were isolated from adult rat testis and purified by centrifugal elutriation followed by density gradient centrifugation. Seven key enzymes of lipid metabolism (namely beta-hydroxybutyrate dehydrogenase, carnitine acetyl transferase, ATP citrate lyase, hydroxyacyl-CoA dehydrogenase, glycerol 3-phosphate dehydrogenase, acetyl-CoA carboxylase and long chain acyl-CoA synthetase) were assayed in cell homogenates. The results indicated that germ cells possess the key enzymes for de novo synthesis and oxidation of fatty acids. The significant increase in activities of anabolic enzymes and decrease in activities of catabolic enzymes in post-meiotic germ cells indicated a shift in lipid metabolism towards fatty acid synthesis during meiosis. Long chain acyl-CoA synthetase activity was not detected in the two cell types. The study indicates a major reorganization of fatty acid turnover during meiosis with equilibrium shifting in favour of synthesis.