HYPERTROPHY OF LIVER CELL SMOOTH SURFACED RETICULUM FOLLOWING PROGESTERONE ADMINISTRATION

Progesterone given daily for several days to male golden hamsters was shown to promote an increase in liver weight and a striking increase in hepatic smooth endoplasmic reticulum. This increase in smooth reticulum observed by electron microscopy was confirmed biochemically through microsomal phospholipid measurements. The alterations in liver structure brought about by administration of progesterone are comparable to those induced by phenobarbital. Hypertrophy of the smooth reticulum is seen in the form of a delicate system of interwoven tubules which freely anastomose and often are seen in confluence with the lamellar profiles of rough reticulum. Progesterone-induced hypertrophy of the hepatic smooth endoplasmic reticulum demonstrates that this organelle is responsive to an endogenous compound normally present in the circulation, and suggests that stimulation by steroids may be responsible in part for the maintenance of microsomal hydroxylases and smooth reticulum in the normal hepatic cell.