Impact of fasting time on hepatic lipid metabolism in nutritional animal studies

Abstract

Many animal studies on improvement of lipid metabolism, using dietary components, fast the animals on the final day of the feeding. Although fasting has a significant impact on lipid metabolism, its time-dependent influence is not fully understood. We examined the effects of several fasting times on lipid metabolism. Rats fed with a semisynthetic diet for 2 wk were killed after 0 (9:00 am), 6 (7:00 am–1:00 pm), 9 (0:00 am–9:00 am), and 13 h (8:00 pm–9:00 am) of fasting. Compared to the 0 h group, marked reduction of liver weight and hepatic triacylglycerol content was observed in the 9 and 13 h groups. Activities of hepatic enzymes involved in fatty acid synthesis gradually decreased during fasting. In contrast, drastic time-dependent reduction of gene expression, of the enzymes, was observed. Expression of carnitine palmitoyltransferase mRNA was higher in the fasting groups than in the 0 h group. Our study showed that fasting has a significant impact on several parameters related to lipid metabolism in rat liver.

Chronic Stress Potentiates High Fructose–Induced Lipogenesis in Rat Liver and Kidney

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Sea Cucumber Saponin Echinoside A (EA) Stimulates Hepatic Fatty Acid β-Oxidation and Suppresses Fatty Acid Biosynthesis Coupling in a Diurnal Pattern

“…For instance, triacylglycerol and cholesterol levels of liver and serum dropped after only a 6 h fasting period, accompanied by increased serum free fatty acid (FFA). Meanwhile, lipolysis and lipogenesis were enhanced and inhibited, respectively, at related genetic and enzymic levels (25,26). Moreover, the quantity of food (food intake) could also affect the activity of enzymes and gene expression involved in lipid metabolism.…”

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