Use
of naltrexone in postmenopausal women with exaggerated
insulin secretion: a pilot study .
F. Cucinelli,
L. Soranna, C. Perri, A. Barini, R.M. Cento,S. Mancuso, A. Lanzone.
Fertil
Steril 2004;81:1047-54. 2004. |
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. Patient(s):
Forty-one healthy normoinsulinemic or hyperinsulinemic postmenopausal
women. Intervention(s): 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 Measure(s): Glucose, insulin,
and C-peptide plasma levels assessed in fasting condition and during
the OGTT. Insulin sensitivity was calculated as total body glucose
utilization. Result(s): 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
normoin¬sulinemic and hyperinsulinemic subjects. Conclusion(s):
Similar to that reported in premenopausal women, endogenous opioid
peptides are involved in the modulation of glycoinsulinemic metabolism
in postmenopause. Through a prevalent action on liver insulin metabolism,
without any clear improvement of insulin resistance and pancreatic
/3-cell function, the chronic administration of naltrexone appears
to reduce the hyperinsulinemia in those women with an exaggerated
insulin response to the OGTT. (by American Society for Reproductive
Medicine.).
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