[An ultrastructural and cytochemical study of human corpora lutea (author's transl)]

Human luteal cells have characteristic organelles, such as well developed smooth endoplasmic reticulum (sER), large mitochondria with tubular cristae, lysosome like granules and lipid droplets. To investigate possible roles of these characteristic organelles, 21 human active corpora lutea, obtained from women aged 32-46, were studied cytochemically on 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), cytochrome c oxidase (CY-O), NADPH diaphorase (NP-DP) and acid phosphatase (ACP) activities, using the methods by Benkoël et al., Ogawa et al., Ago et Ogawa and Barka et Anderson. Subcellular localization of 3 beta-sterol were also examined using the 3 beta-sterol digitonin complex method by Mizuhira et al., 3 beta-HSD and NP-DP activities were demonstrated in the intercrystal and outer space of mitochondria and sER. CY-O activities were demonstrated in mitochondria. ACP activities were demonstrated in lysosomes and Golgi apparatus. Some lipid droplets contained the crystals of 3 beta-sterol digitonin complex. These data suggest that human luteal mitochondria can synthetize progesterone from cholesterol, and that mitochondrial respiratory chain activities in human luteal cells is highly elevated. Human luteal cells probably require much oxygen. Elevated ACP activities indicate that lysosomes play a role in the steroidogenesis. Some lipid droplets may contain cholesterol and other 3 beta-sterols.