The importance of GLP-1 and PYY in resistant starch's effect on body fat in mice

Resistant starch (RS) is a dietary fermentable fiber that decreases body fat accumulation, and stimulates the secretion of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) in rodents. GLP-1 and PYY are gut-secreted hormones with antiobesity effect. Thus, blocking the signals of increased GLP-1 and PYY may also block the effect of dietary RS on body fat. In a 10-week study, C57BL/6J and GLP-1 receptor null (GLP-1R KO) mice were fed control or 30% RS diet, and received daily intraperitoneal injection of either saline or PYY receptor antagonist (BIIE0246, 20 μg/kg body weight). Dietary RS significantly decreased body fat accumulation only in wild-type mice that has saline injection, but not in GLP-1R KO mice. PYY receptor antagonist diminished RS action on body fat in wild-type mice, but did not interfere with GLP-1R KO mice response to RS. Regardless of genotype and injection received, all RS-fed mice had increased cumulative food intake, cecal fermentation, and mRNA expression of proglucagon and PYY. Thus, our results suggest that increased GLP-1 and PYY is important in RS effects on body fat accumulation.