Effect of Excess Dietary L-Histidine on Plasma Cholesterol Levels in Weanling Rats

Abstract

Supplementation of a closed formula, cereal based stock diet with excess L-histidine at a 5% or 8% level for 4 days reduced growth and induced hepatomegaly and an increase in plasma cholesterole levels in weanling rats. The enlargement of the liver was in part due to glycogen accumulation; plasma glucose concentration was unchanged. Feeding four different amino acids (L-phenylalanine, L-glutamic acid, glycine and L-tryptophan), at levels which caused reduction of growth comparable to the 5% and 8% L-histidine supplementation, did not effect liver weight or plasma cholesterol levels. L-Threonine added, at a 2% level, to the 8% L-histidine diet did not alleviate any of the histidine effects. Rats fed a diet containing 5% urocanic acid, the first metabolite of the histidine degradative pathway, grew at a normal rate but had higher plasma cholesterol levels compared to rats fed stock diet. When rats fed L-histidine-or urocanic acid-supplemented diets were returned to stock diet, a normal growth rate was resumed immediately and plasma cholesterol levels returned to normal within 6 days. These results suggest that L-histidine and/or urocanic acid induce a hypercholesterolemia which disappears several days after the supplementation ceases.

Effects of Feeding a Histidine-excess Diet and Subsequent Starvation on Liver and Muscle Glycogen, and on Serum Glucose

“…It follows from these observations that the decrease in serum glucose might have been due to the accumulation of glycogen in the liver. 3 ) Thus, the response of serum glucose in young rats to excess histidine under the non-starved state was different from that in adult rats. We have no adequate explanation for the reason why liver glycogen accumulates in rats fed with a histidine-exce~s diet.…”

Effects of dietary tyrosine on serum cholesterol fractions in rats

“…It seems likely that cholesterol metabolism is quite different in rats fed higher doses of tyrosine from those of rats fed cholesterol-containing diet. Many investigators have already suggested that the hypercholesterolemia seen in feeding dietary tyrosine (Qureshi et al, 1978;Solomon and Geison, 1978) was mediated by enhancement of of cholesterol synthesis in the liver.…”

Effect on Liver and Serum Lipids in Rats of Dietary Additions of Fibers and Ionexchangers to a Histidine-excess Diet

“…2 Katayama Chemical Industries Co., Ltd., Osaka, Japan. 3 Tokyo Chemical Industry Co., Ltd., Tokyo, Japan. 4 Avicel, Funakoshi Pharmaceutical Co., Ltd., Tokyo, Japan.…”

“…Geison and Waisman 2 ) showed the increase in plasma cholesterol of rabbits fed a histidine-excess diet. Furthermore, Solomon and Geison 3 ) and Harvey et al 4 ) reported that feeding a diet supplemented with excess histidine, but not with other excess amino acids tested, resulted in hypercholesterolemia and hepatomegaly in rats.…”