Ultraviolet light irradiation and fat metabolism in guinea pigs subjected to exogenous cholesterol feeding

Abstract

Daily UV-irradiation of male guinea pigs fed a high-cholesterol, high-saturated fat diet caused no differences in skin sterols, but the amount of cholesterol in the liver, lungs, adrenals and intestine was significantly increased in the irradiated animals. Irradiation was associated with a decrease in epididymal fat weight and diminution of esterified fatty acids in this tissue and in the liver; the level of this fraction in serum was higher. Cholesteryl esters in epididymal fat showed a shift from monoenes to saturated fatty acids. Microscopic examination of the aorta and myocardium revealed a higher degree of atherosclerotic changes in irradiated animals. Since our previous reports on irradiated rats fed a low-cholesterol diet indicated a decrease in liver cholesterol with an increase in skin sterols, it is concluded that the effect of UV-light may be dependent on the dietary fat composition, the extent of the exogenous cholesterol intake and the rate of endogenous sterol synthesis.