Electron cytochemical demonstration of four hydrolytic enzymes in the rat corpora lutea at second half of gestation.

Corpora lutea from rat ovaries at mid pregnancy were fixed by perfusion and studied by electron cytochemistry for localisation of four hydrolytic enzymes. Using the metal-salt methods for acid phosphatase and aryl sulphatases activity was localised in small and large lysosomes, multivesicular bodies, Golgi complex and within cisternae of endoplasmic reticulum. The azo-dye coupling method for Beta-glucuronidase was less satisfactory and gave positive results in lysosomes, lipids and in the globules within the mitochondrial matrix. The latter two localisation were probably associated with affinity of the naphthol AS-BI for lipid material. In addition to plasma membranes, the reaction product for alkaline phosphatase with the lead-salt method was seen in lysosomelike bodies, in smooth endoplasmic reticulum and in occasional Golgi elements of granulosa lutein and endothelial cells. Increased activity of lysosomal acid hydrolases occurs when regressive changes of lutein cells start at the end of gestation and this might probably reflect the initiation of lytic processes.