title: Insulin is required for prandial ghrelin suppression in humans.
abstract: Accumulating evidence indicates that ghrelin plays a role in regulating food intake and energy homeostasis. In normal subjects, circulating ghrelin concentrations decrease after meal ingestion and increase progressively before meals. At present, it is not clear whether nutrients suppress the plasma ghrelin concentration directly or indirectly by stimulating insulin secretion. To test the hypothesis that insulin regulates postprandial plasma ghrelin concentrations in humans, we compared the effects of meal ingestion on plasma ghrelin levels in six C-peptide-negative subjects with type 1 diabetes and in six healthy subjects matched for age, sex, and BMI. Diabetic subjects were studied during absence of insulin (insulin withdrawal study), with intravenous infusion of basal insulin (basal insulin study) and subcutaneous administration of a prandial insulin dose (prandial insulin study). Meal intake suppressed plasma ghrelin concentrations (nadir at 105 min) by 32 +/- 4% in normal control subjects, 57 +/- 3% in diabetic patients during the prandial insulin study (P < 0.002 vs. control subjects), and 38 +/- 8% during basal insulin study (P = 0.0016 vs. hyperinsulinemia; P = NS vs. control subjects) but did not have any effect in the insulin withdrawal study (P < 0.001 vs. other studies). In conclusion, 1). insulin is essential for meal-induced plasma ghrelin suppression, 2). basal insulin availability is sufficient for postprandial ghrelin suppression in type 1 diabetic subjects, and 3). lack of meal-induced ghrelin suppression caused by severe insulin deficiency may explain hyperphagia of uncontrolled type 1 diabetic subjects.
authors.affiliation: Department of Internal Medicine, Section of Internal Medicine and Endocrine & Metabolic Sciences (IMISEM), University of Perugia, Perugia, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Murdolo
authors.forename: Paola
authors.initials: P
authors.lastname: Lucidi
authors.forename: Chiara
authors.initials: C
authors.lastname: Di Loreto
authors.forename: Natascia
authors.initials: N
authors.lastname: Parlanti
authors.forename: Arianna
authors.initials: A
authors.lastname: De Cicco
authors.forename: Cristina
authors.initials: C
authors.lastname: Fatone
authors.forename: Carmine G
authors.initials: CG
authors.lastname: Fanelli
authors.forename: Geremia B
authors.initials: GB
authors.lastname: Bolli
authors.forename: Fausto
authors.initials: F
authors.lastname: Santeusanio
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: De Feo
mesh_terms: D000328:Adult; D002096:C-Peptide / Q000172:deficiency; D016022:Case-Control Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000378:metabolism*; D004435:Eating; D005260:Female; D054439:Ghrelin; D006801:Humans; D007262:Infusions, Intravenous; D007279:Injections, Subcutaneous; D007328:Insulin / Q000008:administration & dosage / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D036361:Peptide Hormones / Q000037:antagonists & inhibitors* / Q000097:blood
chemical_list: D002096:C-Peptide; D054439:Ghrelin; D007328:Insulin; D036361:Peptide Hormones