EFFECT OF DIET, OF 3:5-DIIODO-D-THYRONINE AND OF 3:5-DIIODO-4(4′-HYDROXY PHENOXY) PHENYL ACETIC ACID ON THE FORMATION AND REGRESSION OF ATHEROSCLEROTIC LESIONS IN THE RAT

• Published in: Journal of endocrinology Vol. 21; no. 1; pp. 69 - 82
• Main Authors: CUTHBERTSON, W. F. J., ELCOATE, P. V., IRELAND, D. M., MILLS, D. C. B., SHEARLEY, PATRICIA
• Format: Journal Article
• Language: English
• Published: BioScientifica 01.09.1960
• ISSN: 0022-0795; 1479-6805
• DOI: 10.1677/joe.0.0210069

1. Atherosclerotic lesions can be made to develop or regress in the albino rat by treatments that, respectively, elevate or depress the serum cholesterol concentration. 2. After young rats had been given a new diet for 45–72 days, the degree of atherosclerosis attained was related to the new serum cholesterol level and was independent of the previous degree and severity of atherosclerosis. 3. Regression of lesions established for about 1 month occurred if the serum cholesterol level was lowered, either by changes in the diet or by administering 3:5-diiodo- d -thyronine (DT 2 ). The relation between serum cholesterol level and Sudan score (see p. 70) appeared to be independent of the method used for lowering the serum cholesterol level. 4. Regression of lesions established for about 6 months occurred if the serum cholesterol level was lowered either by changes in the diet or by administering DT 2 , but the rate of regression was slower than when the lesions had been present for a short time only. 5. When the serum cholesterol levels of rats given an atherogenic diet for 6 months had been reduced to normal values by feeding stock diet, the rats still had a high degree of atherosclerosis. When stock diet containing DT 2 was then fed, there was no increase in the rate of regression of lesions over that obtained on the stock diet alone. 6. Dietary administration of different amounts of 3:5-diiodo-4(4′-hydroxy phenoxy) phenyl acetic acid (DIAC) or DT 2 to groups of rats maintained on a diet containing cholesterol and cholic acid over a 9-month period resulted in a reduction of serum cholesterol levels to an extent roughly related to the dose of drug given. Liver cholesterol levels were also reduced in the older animals. Arterial atheroma was reduced by both compounds to an extent proportional to the dose administered. Both compounds, at all dose levels, increased the rate of growth of animals compared with that of controls. Both compounds depressed liver weights at all dose levels and increased the weight of the pancreas at the higher dose levels, if these weights were expressed per 100 g/body weight.