Use of naltrexone in postmenopausal women with exaggerated insulin secretion:
a pilot study
Cucinelli F, Soranna L, Perri C, Barini A, Cento RM, Mancuso S, Lanzone A.
Fertil Steril. 2004 Apr;81(4):1047-54.
Objective: To determine the effect of naltrexone (an opiate
receptor blocker) on insulin metabolism in postmenopausal women with
different insulinemic patterns. Design: Randomized placebo-controlled
study. Setting: Academic research environment. Patients:
Forty-one healthy normoinsulinemic or hyperinsulinemic postmenopausal
women. Interventions :Oral glucose tolerance test (OGTT)
before and after 5 weeks of the opioid antagonist (naltrexone, 50
mg/d orally) or the placebo administration; euglycemic-hyperinsulinemic
glucose clamp. Main outcome measures: Glucose, insulin, and
C-peptide plasma levels assessed in fasting condition and during the
OGTT. Insulin sensitivity was calculated as total body glucose utilization.
Results: Naltrexone reduced fasting and stimulated insulin
response to the glucose load while inducing a significant improvement
of the hepatic extraction, only in the hyperinsulinemic patients.
No differences were found in the C-peptide pancreatic secretion and
in the peripheral insulin sensitivity. No net change in the glycoinsulinemic
metabolism was observed in normoinsulinemic patients or in placebo-controlled
normoinsulinemic and hyperinsulinemic subjects. Conclusions:
Similar to that reported in premenopausal women, endogenous opioid
peptides are involved in the modulation