In vivo, ex vivo and in vitro evidence for atropine-mediated attenuation of glucagon-like peptide-1 secretion: findings from a systematic review.

Glucagon-like peptide-1 (GLP-1) is involved in postprandial glucose homeostasis. Secretion of which involves a cholinergic pathway. Anticholinergic agent like atropine could act as a competitive antagonist of acetylcholine at muscarinic receptors. This review explores studies that assess the role of atropine in GLP-1 secretion. We selected published original articles from PubMed, Science Direct, The Cochrane Library, Trip, Google and the reference lists of the selected articles. Reporting was done according to the PRISMA statement. Relevant standard and previously published tools were used to assess the risk of bias of the selected articles. Twelve articles out of 185 search results fulfilled the review criteria. Eight were in vivo studies (six animal and two human studies), three were ex vivo studies and one was an in vitro study. Animal studies had rats, mice, pigs and monkeys as the subjects. Human studies involved healthy men and women. Majority of the studies reported an atropine-mediated attenuation of GLP-1 secretion and postprandial secretion of GLP-1 was mainly affected. However, atropine failed to significantly affect GLP-1 secretion when dipeptidyl peptidase-4 (DPP-4) enzyme was inhibited.