Differential effects of choline administration on liver microsomes of female and male rats

Choline was administered for 3 weeks, twice daily, in the amount of $\text{50}\text{mg}\text{100}\text{g}$ body weight to male and female rats. The content of phosphatidyl cholines (PC) and the enzymatic activities related to the smooth endoplasmic reticulum were increased in the female rats receiving choline but not in males. Such changes were accompanied by an increase in surface of smooth membranes, evaluated by stereological analyses. Both enzymatic activities and values of surface and volume densities of the endoplasmic reticulum were lower in the untreated females than in the corresponding group of males. Morphological electron microscopic findings well agree with the increased biogenesis of smooth surfaced membranes in the hepatocytes of the liver of female rats receiving choline.