title: Post-prandial decrease of human plasma ghrelin in the absence of insulin.
abstract: Ghrelin is the most powerful orexigenic hormone in mammalian physiology. Ghrelin plasma concentrations increase prior to meal onset, but decrease post-prandially. We and others reported previously that insulin reduces circulating ghrelin levels and might therefore be a driving force for post-prandial suppression of ghrelin. To test the influence of insulin on post-prandial ghrelin regulation, a patient with Type I diabetes with complete insulin deficiency received a low glycemic index meal and subsequently an additional high glycemic index meal in the absence of insulin substitution. Subsequently, a sc injection of 0.08 IU Lispro insulin per kg body weight was given. Results were compared to those of a healthy control subject matched for sex, age and body mass index, which was undergoing the same test series (without Lispro bolus) in the presence of endogenous post-prandial insulin secretion. A substantial decrease of plasma ghrelin levels was observed in the insulin-deficient patient following low glycemic index carbohydrate load (27% plasma ghrelin decrease). The subsequent exposure to a high glycemic index meal resulted in a slight additional reduction of ghrelin levels (32% from baseline), while Lispro bolus did not induce further changes in circulating ghrelin (27% of baseline at termination). This post-prandial response was comparable to that of the healthy control subject (33% reduction after the first meal, 40% after the second meal). These data tentatively suggest that post-prandial secretion of ghrelin is not exclusively regulated by plasma insulin or plasma glucose but may depend on other metabolic factors yet to be identified.
authors.affiliation: Department of Clinical Nutrition, German Institute of Human Nutrition Potsdam-Rehbrücke, Bergholz-Rehbrücke, Germany. spranger@mail.dife.de
authors.forename: J
authors.initials: J
authors.lastname: Spranger
authors.forename: M
authors.initials: M
authors.lastname: Ristow
authors.forename: B
authors.initials: B
authors.lastname: Otto
authors.forename: W
authors.initials: W
authors.lastname: Heldwein
authors.forename: M
authors.initials: M
authors.lastname: Tschöp
authors.forename: A F H
authors.initials: AF
authors.lastname: Pfeiffer
authors.forename: M
authors.initials: M
authors.lastname: Möhlig
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D054439:Ghrelin; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007328:Insulin / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology / Q000502:physiology*; D061268:Insulin Lispro; D008297:Male; D036361:Peptide Hormones / Q000097:blood*; D019518:Postprandial Period / Q000502:physiology*
chemical_list: D001786:Blood Glucose; D054439:Ghrelin; D007004:Hypoglycemic Agents; D007328:Insulin; D061268:Insulin Lispro; D036361:Peptide Hormones