Involvement of multiple pathways in the protection of liver against high-fat diet-induced steatosis by betaine

•Betaine supplement to high-fat diet (HF) prevents induction of fatty liver in rats.•Phosphorylation of AMPK/ACC is enhanced and LXRα/nSREBP-1c is depressed by betaine.•Betaine administration up-regulates BHMT and decreases homocysteine levels in liver.•Betaine feeding elevates hepatic ApoB and serum PC levels decreased by HF intake.•Betaine alleviates steatosis by inhibiting lipid synthesis and enhancing its secretion. The mechanism of lipotropic action provided by betaine in early diet-induced liver steatosis was investigated. Male rats received a high-fat liquid diet (HF) for 3 wk. HF intake resulted in a significant accumulation of triacyglycerol and cholesterol in the liver. Phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) was decreased, while protein expression of liver-X-receptor α (LXRα) and nuclear sterol regulatory element binding protein-1c (nSREBP-1c) was enhanced. Betaine supplement at 1% in HF inhibited hepatic triacyglycerol accumulation, but elevated serum cholesterol and triacyglycerol levels. Phosphorylation of AMPK and ACC was normalized, and induction of LXRα and nSREBP-1c was prevented. HF intake down-regulated betaine–homocysteine methyltransferase and increased homocysteine levels, both of which were blocked by betaine. Betaine supplementation elevated hepatic apolipoprotein B and serum phosphatidylcholine levels. The results suggest that both inhibition of lipid synthesis and enhancement of its secretion are involved in the anti-steatotic activity of betaine.