AJP - Regulatory, Integrative and Comparative Physiology, Vol 260, Issue 1 153-R158, Copyright © 1991 by American Physiological Society
Effects of pregnancy and ovarian steroids on fatty acid synthesis and uptake in Syrian hamsters
A. J. Bhatia and G. N. Wade
Neuroscience and Behavior Program, University of Massachusetts, Amherst 01003.
The effects of pregnancy and ovarian steroids on the in vivo distribution
of newly synthesized fatty acids (incorporation of tritium from 3H2O into
fatty acid) in Syrian hamsters (Mesocricetus auratus) were examined. During
late, but not early, gestation hamsters had reduced levels of newly
synthesized fatty acids in heart, liver, uterus, and white adipose tissues
(parametrial and inguinal fat pads). Treatment of ovariectomized hamsters
with estradiol + progesterone significantly decreased fatty acid
synthesis-uptake in heart, liver, and inguinal white adipose tissue.
Treatment with either estradiol or progesterone alone was without
significant effect in any tissue. Pretreatment of hamsters with Triton
WR-1339 (tyloxapol), an inhibitor of lipoprotein lipase activity and tissue
triglyceride uptake, abolished the effects of estradiol + progesterone in
white adipose tissue and heart but not in liver. Thus hamsters lose body
fat during pregnancy in part because of decreased de novo lipogenesis. The
effect of pregnancy on lipogenesis is mimicked by treatment with estradiol
+ progesterone but not by either hormone alone. Furthermore, it appears
that the liver is the principal site of estradiol + progesterone action on
lipogenesis in Syrian hamsters.
