The effects of serial bathing (10 minutes bathing in a city water or hot spring in Misasa, 40℃, once daily for 1-4 weeks) on fatty acid composition of cholesterol ester of the adrenal glands and serum was studied in both normal
and hypercholesteremic rats. Although the adrenal cholesterol ester levels were relatively unaffected in rats treated with serial bathing as well as non-treated rats, the proportion of 18 : 2 was increased in rats treated with hot spring bathing for 3-4 weeks. The serum cholesterol ester levels in both normal and hypercholesteremic rats tended to decrease after serial bathing for 3-4 weeks compared with non-treated rats. The fatty acid composition of serum cholesterol ester in normal
rats was unaffected. The composition in hypercholesteremic rats showed an increase in the proportion of 16 : 1 and 18 : 1 and a decrease of 18 : 2 and 20: 4 compared with normal rats. When those of hypercholesteremic rats were treated with serial bathing for 3 weeks, particularly with hot spring bathing, the proportion of 16 : 1, 18: 2 and 20 : 4 showed a tendency to approach that in tormal rats. The findings indicate that serial hot spring bathing for 3-4 weeks, unlike city water bathing, exerts an influence on the fatty acid composition of cholesterol ester of the rat adrenal glands and it also improves the fatty acid compsition of serum cholesterolester of hypercholesteremic rats.