Effects of three prostaglandin analogues on lysosomal enzyme activities and ultrastructural morphology of luteal cells in the chacma baboon.

The effects were studied of three different prostaglandin analogues on lysosomal cathepsin D and acid phosphatase activities in the corpus luteum of the chacma baboon (Papio ursinus). Lysosomal latency was found to be increased by these agents, as well as the total particulate activities of both enzymes. A comparison of total post-treatment cathepsin D values with control values showed a significant increase in activity with time; this did not apply to acid phosphatase. Concomitant electron microscopic studies showed a higher cellular content of lysosomes, consistent with the greater particulate activities recorded. Definitive evidence of progressive ultrastructural changes was consistently found in corpora lutea from prostaglandin analogue-treated baboons. It is proposed that the mechanism of luteolysis induced by prostaglandin analogues in this primate species is based on induction of the formation of primary lysosomes which cause cellular degeneration through autosegregation and enzymatic digestion of cell organelles in secondary lysosomes.