AJP - Endocrinology and Metabolism, Vol 244, Issue 5 442-E446, Copyright © 1983 by American Physiological Society
Progestin increases cathepsin D synthesis in uterine luminal epithelial cells
B. C. Moulton and B. B. Koenig
Early in blastocyst implantation, cells of the uterine luminal epithelium
deteriorate and die in response to the presence of the blastocyst.
Destruction of the epithelial cells appears to depend on control of the
autophagic activity and enzyme content of lysosomes in these cells.
Concentrations of the lysosomal proteinase, cathepsin D, have been
identified in luminal epithelial cells, and these studies examined changes
in epithelial cathepsin D activity and their hormonal control during early
pseudopregnancy in the rat. Cathepsin D activity in luminal epithelial
cells increases during early pseudopregnancy to maximal levels at the time
of sensitivity to deciduogenic stimuli. Rates of cathepsin D synthesis in
luminal epithelial cells also increase during early pseudopregnancy, but
neither enzyme activity nor rates of synthesis increase in
stromal-myometrial tissues. In ovariectomized rats, progestins rather than
estradiol increase cathepsin D activity and rates of synthesis in luminal
epithelial cells. These studies suggest that cell death in the luminal
epithelium during blastocyst implantation may depend in part on the
accumulation of lysosomal cathepsin D in these cells in response to
progesterone secretion during early pregnancy.
