Acute effects of intravenous and rectal acetate on glucagon-like peptide-1, peptide YY, ghrelin, adiponectin and tumour necrosis factor-α

Abstract

In animals, colonic infusion of SCFA does not affect glucagon-like peptide-1 (GLP-1) release whereas intravenous infusion does and SCFA may directly stimulate peptide YY (PYY) release. It is unknown whether SCFA and their route of administration affect human blood concentrations of GLP-1 and PYY. Our aim was to conduct a pilot study to determine the effects of intravenous and rectal acetate on blood concentrations of GLP-1, PYY, ghrelin, adiponectin and TNF-in hyperinsulinaemic human subjects. Six hyperinsulinaemic female subjects were given 20mmol sodium acetate intravenously, 60mmol acetate rectally, or normal saline rectally or intravenously on four separate occasions in randomised order, with blood samples collected at 0, 10, 15, 30, 45 and 60min. Change in plasma PYY was significantly higher after acetate and rectal infusions (969 and 1378pg/ml) compared with saline and intravenous (060 and 31pg/ml; P<001), respectively. Change in plasma GLP-1 was increased by rectal and acetate infusions (025 and 023mmol/l) v. intravenous and saline (026 and 019mmol/l; P<001). Acetate decreased TNF-v. saline (08 and 015pg/ml; P<005). Rectal infusions increased TNF-and ghrelin (02 and 9827pg/ml) v. intravenous (09 and 40pg/ml; P<001). There was no effect of treatment on plasma adiponectin. These preliminary results suggest that acetate raises plasma PYY and GLP-1, and suppresses TNF-. Also, distending the rectum increases PYY, GLP-1, TNF-and ghrelin in hyperinsulinaemic females. Increasing colonic fermentation products, particularly acetate, could yield a new mechanism for modifying weight gain.