Abstract
The testicular synthesis of sulphatoxygalactosylacylalkylglycerol (SGG) has been studied in the rat by autoradiography of frozen tissue sections following in vivo metabolic labelling. The results are consistent with the synthesis of this major mammalian germ-cell glycolipid at the zygotene and early pachytene stages of spermatogenesis. Further synthesis of SGG is prevented by the appearance of an inhibitor of galactolipid sulphotransferase activity at the mid-pachytene stage.