Naloxone effects on post-prandial glucose, insulin and C-peptide levels in obese subjects.
In order to investigate the relationships between glucose metabolism, insulin secretion and endogenous opioids in obese patients, we have studied the effects of a naloxone infusion on insulin and C-peptide release after a normal meal (800 kcal) eaten at 12.00 hr in 16 obese women, aged 20-61 yr, with a BMI ranging from 25 to 37.2 kg/m2, with normal glucose tolerance (Group 1) and with NIDDM (Group 2). Naloxone was administered in a bolus of 1.6 mg i.v., followed by a continuous infusion of 4 mg in 2 hr starting immediately after feeding. In Group 1 naloxone infusion significantly increased the glucose levels, but insulin secretion was unaffected. In Group 2, naloxone infusion failed to modify significantly the postprandial levels of glucose, insulin and C-peptide. Therefore, in our study naloxone infusion seems to have beta-endorphin-like effects in non-diabetic obese subjects by increasing their glycemic levels, with no evidence of expected insulin decrease. In diabetic obese patients we observed a trend towards decrease in glycemic values during naloxone infusion, as expected, due to insulin plasma levels increase. By these data we can hypothesise a complex regulatory role of opioids in metabolic balance in obesity. In diabetic patients, naloxone can improve the surviving insulin secretion with better glucose tolerance. In non-diabetic subjects naloxone exerts its effects, probably, on peripheral organs.
De Marinis
L
L
Institute of Endocrinology, Catholic University School of Medicine, Rome, Italy.
Mancini
A
A
De Luca
A M
AM
Fiumara
C
C
Zuppi
P
P
Sammartano
L
L
Valle
D
D
D000328:Adult; D000704:Analysis of Variance; D001786:Blood Glucose / Q000378:metabolism*; D002096:C-Peptide / Q000097:blood* / Q000187:drug effects; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000097:blood*; D008875:Middle Aged; D009270:Naloxone / Q000494:pharmacology*; D009765:Obesity / Q000097:blood* / Q000188:drug therapy
D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D009270:Naloxone