AJP - Gastrointestinal and Liver Physiology, Vol 249, Issue 2 203-G208, Copyright © 1985 by American Physiological Society
Effect of lactation on cholesterol synthesis in rats
K. R. Feingold and A. H. Moser
Lactation induces a variety of morphological and functional changes in the
gastrointestinal tract. In the present study we employed tritiated water as
the substrate to demonstrate that in the intact rat lactation results in a
twofold increase in cholesterol synthesis in the small intestine. Feeding a
high-cholesterol diet did not markedly inhibit small intestinal cholesterol
synthesis in either control or lactating animals, and the difference in
cholesterol synthesis between the two groups persisted. In the large
intestine, cholesterol synthesis is increased threefold in the lactating
animals, and feeding a high-cholesterol diet did not affect synthesis in
either the control or lactating animals. In the liver, lactation stimulated
cholesterol synthesis, and quantitatively this increase in hepatic
cholesterol synthesis is much greater than the increase observed in the
intestines. Feeding the rats a high-cholesterol diet markedly inhibited
hepatic cholesterol synthesis in both control and lactating animals, a
finding that demonstrates that the feedback inhibition of cholesterol
synthesis in the liver is not impaired by lactation. In the lactating
animals, the quantity of labeled cholesterol in 1 ml of serum is 2.4 times
greater than observed in controls. Feeding the rats a high-cholesterol diet
markedly decreased the quantity of labeled cholesterol in the serum in both
groups and obliterated the difference between control and lactating
animals. This suggests that the increased hepatic cholesterol synthesis in
the lactating animals is responsible for the differences in labeled
cholesterol in the serum. Cholesterol feeding also reduced the quantity of
labeled cholesterol localized to the mammary glands in lactating
animals.(ABSTRACT TRUNCATED AT 250 WORDS)
