Is there a role for the adrenals in the development of hypercholesterolemia in Zucker fatty rats?

We tested the hypothesis that hypercorticosteronemia causes the hypercholesterolemia in young developing "fatty" rats. Obesity induced increases in corticosterone. Insulin, glucose, body weight, average daily food intake, plasma triglyceride, plasma phospholipids, liver weight, liver trigl...

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Published inThe American journal of physiology Vol. 263; no. 2 Pt 1; p. E287
Main Authors Alarrayed, F, Hartman, A D, Porter, J R
Format Journal Article
LanguageEnglish
Published United States 01.08.1992
Subjects
Adipose Tissue - pathology
Adrenal Glands - physiopathology
Adrenalectomy
Animals
Body Weight
Corticosterone - blood
Eating
Hypercholesterolemia - etiology
Lipid Metabolism
Lipids - blood
Liver - enzymology
Liver - metabolism
Obesity - blood
Obesity - complications
Obesity - physiopathology
Organ Size
Rats
Rats, Zucker - blood
Rats, Zucker - physiology
Reference Values
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Summary:We tested the hypothesis that hypercorticosteronemia causes the hypercholesterolemia in young developing "fatty" rats. Obesity induced increases in corticosterone. Insulin, glucose, body weight, average daily food intake, plasma triglyceride, plasma phospholipids, liver weight, liver triglyceride, various adipose tissue parameters, and liver hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase activity were all ameliorated by adrenalectomy. Adrenalectomy exacerbated the hypercholesterolemia in obese animals and induced it in lean rats. Changes or lack of change in hepatic microsomal cholesterol, HMG-CoA reductase, and 7 alpha-hydroxylase, combined with the adrenalectomy-induced curtailment of tissue storage of cholesterol in adipose tissue, all contribute to the hypercholesterolemia caused by adrenalectomy. We suggest a mechanism whereby this may be related to elevated hepatic very low-density lipoprotein secretion rates. The elevated HMG-CoA reductase activity in obese rats results from the lower liver microsomal free cholesterol content. We conclude that the absence of glucocorticoids does not directly reduce plasma cholesterol in obese Zucker rats. The surprising elevation of cholesterol by adrenalectomy is due to other prevailing mechanisms in liver and adipose tissue, which curtail their capacity to store cholesterol.
ISSN:0002-9513
DOI:10.1152/ajpendo.1992.263.2.e287