title: Changes in the lipid inclusion/Sertoli cell cytoplasm area ratio during the cycle of the human seminiferous epithelium.
abstract: The area occupied by Sertoli cell lipid inclusions--electron-lucent lipid vacuoles (LLV) and electron-dense lipid droplets (DLD)--at each stage of the cycle of the seminiferous epithelium was measured on electron micrographs in young adults and elderly men, and expressed as the ratio "area occupied by lipid inclusions/area occupied by the Sertoli cell cytoplasm". For LLV this ratio increased from stage I to stage III, and decreased from stage IV to stage VI in young adults. These results suggest that the development of LLV is synchronized with the spermatogenic process: the residual bodies released in stages I and II are phagocytized by Sertoli cells and transformed into LLV; the amounts of LLV decrease in the subsequent stages of the cycle and increase again when new residual bodies appear. In elderly men the ratio LLV/Sertoli cell cytoplasm was 1.9-2.9 times higher than in young adults at each stage of the cycle. This increase may be related to the increased germ-cell degeneration observed in ageing testes, DLD were less abundant than LLV and the DLD/Sertoli cell cytoplasm ratio did not undergo cyclic changes in young adults or elderly men.
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003593:Cytoplasm / Q000648:ultrastructure; D006801:Humans; D002479:Inclusion Bodies / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D012670:Seminiferous Epithelium / Q000502:physiology*; D012708:Sertoli Cells / Q000648:ultrastructure*; D013737:Testis / Q000502:physiology*