Lysosomes in uterine involution: Distribution of acid hydrolases in luminal epithelium

Abstract

Abstract The distribution of acid hydrolytic activities in rat uterine epithelial cells during post‐partum involution was examined by light and electron microscopic cytochemistry. Acid phosphatase, β‐glucuronidase, N‐acetyl‐β‐glucosaminidase and E 600 ‐resistant esterase (cathepsin) increased during the period of involution and the electron cytochemical preparations revealed the lysosomal nature of the acid hydrolytic positive particles visualized by light microscopy. The newly formed particles included primary lysosomes, in the form of Golgi vesicles, vacuoles, and secondary lysosomes such as dense bodies and autophagic vacuoles. This apparent increase in lysosomal activity during uterine involution is in agreement with similar patterns observed in the course of tissue regression in general.