Influence of residual C-peptide secretion on the arginine vasopressin response to hypoglycaemia and metoclopramide in insulin-dependent diabetes.
Arginine vasopressin (AVP) hypersecretion in response to metoclopramide or to insulin-induced hypoglycaemia has been described in type I diabetes mellitus. In the present study, we examined whether residual endogenous insulin secretion may play a role in the control of this abnormal AVP secretory pattern. For this purpose, 21 insulin-dependent diabetic men and 10 age- and weight-matched normal men were tested with MCP (20 mg in an i.v. bolus). On a different occasion, subjects were tested with insulin (0.15 IU kg-1). The diabetic patients were subdivided into C-peptide negative patients (CpN, 11 patients without detectable endogenous pancreatic beta cell activity) (group I) and C-peptide positive patients (CpP, 10 patients with residual endogenous insulin secretion) (group II). Experiments started after optimization of the metabolic status of the diabetic men by 3 days of treatment with continuous subcutaneous insulin infusion. The basal concentrations of AVP were similar in all groups. The administration of MCP induced a striking elevation in plasma AVP levels in the normal controls and in the diabetic subjects of groups I and II. However, the AVP rise was significantly higher in group I and group II than in normal controls. Furthermore, group I diabetics showed higher AVP increments than group II. Insulin induced a similar hypoglycaemic nadir in all subjects at 30 min, even though the diabetic subjects of groups I and II had a delayed recovery in blood glucose levels. The hypoglycaemic pattern was similar in group I and II. Hypoglycaemia induced a striking AVP increase in the normal controls.(ABSTRACT TRUNCATED AT 400 WORDS)
Chiodera
P
P
Department of Internal Medicine, University of Parma, Italy.
Volpi
R
R
Capretti
L
L
Speroni
G
G
Caffarri
G
G
Colla
R
R
Caiazza
A
A
Coiro
V
V
D000328:Adult; D000932:Antiemetics / Q000494:pharmacology*; D001127:Arginine Vasopressin / Q000378:metabolism*; D002096:C-Peptide / Q000378:metabolism*; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D006801:Humans; D007003:Hypoglycemia / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology; D008297:Male; D008787:Metoclopramide / Q000494:pharmacology*
D000932:Antiemetics; D002096:C-Peptide; D007328:Insulin; D001127:Arginine Vasopressin; D008787:Metoclopramide