The effect of diet during development on cholesterol metabolism

Abstract

Developing Sprague-Dawley rates fed a semipurified diet or commercial rat feed were found to have the same major developmental features of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase activity from 4 days following weaning after which time the activity decreased to a minimum plateau. However, the enzyme level was significantly (P<0.05) higher in the commercial rat feed group from weaning (21 days of age) to 100 days of age. Also, the animals fed the semipurified diet reached their normal adult level at 35 days of age (0.166 moles mevalonic acid formed/min/mg protein), while the level in the commercial rat feed group did not become constant until 60 days of age(0.55 moles). Normal diurnal rhythm was found to be independent of dietary constituents. There was no difference in growth rate, liver size, liver cholesterol or liver lipids due to diet. No inhibitor was found in either the microsomal or cytosol fractions. Insulin gave a normal response in both dietary groups. Rate which had access to the semipurified diet from day 12 to 60 or 80 days of age and then changed to commercial rat feed for 20 days, exhibited permanently low HMG CoA reductase activities. Rats fed semipurified diets until only 30 or 40 days of age did not maintain the low levels but returned to the high levels of the commercial rat feed group..