Gestational changes in hamster adrenal cortex: stereologic and functional studies

Abstract

Pregnancy in hamsters evoked a prompt increase in adrenal weight, with the highest value at day 5 and a subsequent fall toward the end of gestation. The surface densities of mitochondrial cristae and smooth endoplasmic reticulum did not display significant changes in the course of gestation, while lll3-hydroxylase and 313-hydroxysteroid dehydrogenase/isomerase activity (two enzymes located in these two organelles) underwent significant increases at day 5 and day 10 of pregnancy, respectively. Neither the adrenal content of cortisot nor cortisol output by adrenal homogenates changed, but cortisol production measured in adrenal slices gradually rose during the course of pregnancy. Blood cortisol concentration increased about ten-fold toward the end of gestation, whereas the plasma ACTH level remained unchanged and plasma aldosterone concentration was significantly lowered. The conclusion is drawn that the pregnant hamster's adrenal glands possess an enhanced capacity to secrete cortisol, but the factor(s) involved remain unknown.