Persistence of dietary suppression of 3-hydroxy-3-methylglutaryl coenzyme-A reductase during development in rats
Reiser, R.; Henderson, G.R.; O'Brien, B.
Journal of Nutrition 107(7): 1131-1138
1977
ISSN/ISBN: 0022-3166 PMID: 559726 Document Number: 116420
Young rats suckled by mothers fed on a semipurified diet or a commercial rat food showed an increase in hepatic 3-hydroxy-3-methyl-glutaryl coenzyme-A reductase (HMG-CoA reductase) [mevalonate:NADP oxidoreductase (acylating CoA) EC 1.1.1.34] activity, greatest 4 days after weaning and thereafter decreased to a low plateau. The enzyme activity was significantly greater in the group on commercial food. The rats fed on the semipurified diet reached adult activity, mevalonic acid formed 0.17 nmol/min mg protein, at 35 days of age whereas the value with commercial rat food did not become constant, 0.55 nmol/min mg protein, until 60 days of age. Times of diurnal fluctuations were independent of dietary constituents. There was no difference in growth rate, liver size, liver cholesterol or liver lipids due to diet. No inhibitor of the enzyme was found in the microsomal or 105 000 gn supernatant fractions. Insulin gave a normal response in both diet groups. Rats on the semipurified diet until 30 or 40 days old and then on the commercial rat food soon showed the greater activity of the commercial rat food group. Those given the semipurified diet until 60 or 80 days old and then on the commercial rat food for 20 days, showed the low HMG-CoA reductase activity during the entire 20 days.