Counterregulatory responses to hypoglycemia in patients with maturity-onset diabetes of the young caused by HNF-1alpha gene mutations (MODY3).
Mutations of HNF-1alpha lead to severe beta cell dysfunction, resulting in decreased glucose-induced insulin secretion. HNF-1alpha is also expressed in liver, kidney and pancreatic alpha cells, but the functional consequences of HNF-1alpha mutations in these organs remain unknown. We therefore assessed the counterregulatory responses to hypoglycemia in six patients with HNF-1alpha mutations (MODY3), five patients with non-insulin-dependent diabetes mellitus (NIDDM) and in nine healthy controls. Plasma glucagon concentrations and endogenous glucose production were measured every 15 min during a hyperinsulinemic clamp with progressive hypoglycemia. Plasma glucagon concentrations were similar at basal glycemia (73+/-6, 69+/-5 and 69+/-7 ng/l) and reached peak values of 88+/-9, 88+/-11 and 89+/-7 ng/l at a glycemia of 3.6 mmol/l in MODY3 patients, patients with NIDDM and controls respectively (NS). Suppression of endogenous glucose production by insulin was blunted in MODY3 patients (3.3+/-1.2 micromol/kg per min) and in patients with NIDDM (4.4+/-0.6 micromol/kg per min) compared with controls (1.7+/-0.5 micromol/kg per min, P<0.05 compared with both MODY3 patients and patients with NIDDM). During hypoglycemia, endogenous glucose production increased to 8.6+/-2.1, 8.8+/-0.7 and 7.0+/-1.0 micromol/kg per min in MODY3 patients, patients with NIDDM and controls respectively (all NS). These data indicate that mutations of HNF-1alpha in MODY3 do not result in a decreased glucagon secretion or alterations of glucose production during hypoglycemia.
Guenat
E
E
Institut de Physiologie, Université de Lausanne, Switzerland.
Seematter
G
G
Philippe
J
J
Temler
E
E
Jéquier
E
E
Tappy
L
L
D001786:Blood Glucose / Q000032:analysis; D004268:DNA-Binding Proteins; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics* / Q000503:physiopathology*; D005260:Female; D005934:Glucagon / Q000097:blood; D005947:Glucose / Q000096:biosynthesis; D015309:Glucose Clamp Technique; D051537:Hepatocyte Nuclear Factor 1; D051538:Hepatocyte Nuclear Factor 1-alpha; D051539:Hepatocyte Nuclear Factor 1-beta; D006706:Homeostasis; D006801:Humans; D007003:Hypoglycemia / Q000503:physiopathology*; D007328:Insulin / Q000097:blood; D008297:Male; D009154:Mutation; D009687:Nuclear Proteins; D014157:Transcription Factors / Q000235:genetics*
D001786:Blood Glucose; D004268:DNA-Binding Proteins; C496487:HNF1A protein, human; C496495:HNF1B protein, human; D051538:Hepatocyte Nuclear Factor 1-alpha; D007328:Insulin; D009687:Nuclear Proteins; D014157:Transcription Factors; D051537:Hepatocyte Nuclear Factor 1; D051539:Hepatocyte Nuclear Factor 1-beta; D005934:Glucagon; D005947:Glucose