Metabolic and Endocrine Agents · Insulin Sensitizing Agents
Fulghesu AM et al., 1995 · Hum Reprod
A total of 17 women affected by polycystic ovarian disease (PCOD) were studied to evaluate the involvement of endogenous opioids in the pathophysiology of the hyperinsulinism in PCOD by administering naltrexone, an oral opioid antagonist. An oral glucose tolerance test (OGTT) was performed at baseline (on day 5 of the cycle) and repeated after 6 weeks of naltrexone administration. Plasma glucose, insulin and connecting peptide (c-peptide) concentrations were evaluated in all samples. Based on their insulinaemic response to OGTT, patients were classified as hyperinsulinaemic or normoinsulinaemic. Naltrexone treatment significantly (P < 0.007) reduced the insulin response to OGTT in the hyperinsulinaemic group without affecting the c-peptide incremental area; in the normoinsulinaemic group there was a slight, but not significant, increase in both c-peptide and insulin incremental areas. The two groups showed similar c-peptide incremental areas after naltrexone treatment. There was no significant difference in the c-peptide:insulin incremental areas molar ratio between the two groups; after treatment, a significant increase in this ratio was observed in both groups. When we considered the data as an expression of the fractional hepatic extraction of insulin, we found a lower value for hyperinsulinaemic in comparison with normoinsulinaemic patients (not significant), and a significant (P < 0.01) improvement of this parameter in the hyperinsulinaemic group after naltrexone administration. In conclusion, we suggest that the contribution to hyperinsulinaemia in PCOD patients may be at least in part due to both increased pancreatic secretion and reduced hepatic removal of insulin. Chronic pharmacological inhibition of opioid tone could improve the insulin plasma concentration by acting chiefly on the liver metabolism of insulin in hyperinsulinaemic patients.
Metabolic and Endocrine Agents · Insulin Sensitizing Agents
Fulghesu AM et al., 1993 · Obstet Gynecol
To evaluate the involvement of endogenous opiates in the pathophysiology of the hyperinsulinism in patients affected by polycystic ovary disease by administering naloxone and naltrexone. We also studied the hormonal status following long-term opioid antagonist administration. Twenty-one women affected by polycystic ovary disease participated in the study. An oral glucose tolerance test (GTT) was performed at baseline and repeated after short-term naloxone infusion and after 6 weeks of naltrexone administration. Plasma glucose and insulin levels were evaluated in all samples. Gonadotropins, sex hormone-binding globulin, and androgen levels were determined initially and after the naltrexone treatment. None of the patients showed any alteration of glucose tolerance. Based on the insulin response to the GTT, the patients were classified as normo- or hyperinsulinemic. Opioid antagonist administration significantly reduced the insulin response to the GTT in hyperinsulinemic patients, without affecting their glycemic levels. In normoinsulinemic patients, glucose plasma levels were increased whereas insulin levels were not modified by the treatments. Gonadotropin and androgen plasma concentrations were not modified after naltrexone administration. This work supports a role for the endogenous opiates in the regulation of exaggerated insulin secretion in patients with polycystic ovary disease. The reduction of insulin secretion failed to demonstrate any hormonal modification in such hyperandrogenized patients.
Metabolic and Endocrine Agents · Insulin Sensitizing Agents
Givens JR et al., 1987 · J Clin Endocrinol Metab
We previously reported that circulating beta-endorphin levels are increased in obese hirsute women and that plasma immunoreactive insulin (IRI) levels are increased in proportion to the degree of hyperandrogenism in women with the polycystic ovary (PCO) syndrome. We, therefore, tested the hypothesis that endogenous opiates are at least partially responsible for the hyperinsulinemia and insulin resistance in this syndrome. In the first study, acute naloxone administration significantly reduced the plasma IRI response and IRI/glucose ratio in three euglycemic obese women with PCO and acanthosis nigricans (AN) and marked insulin resistance, but did not alter the glucose response. Naloxone had no effect on these parameters in the normal weight control subjects. In the second study, nalmefene, a new, orally active opiate antagonist, reduced IRI and the IRI/glucose ratio in four women with PCO-AN and marked hyperinsulinemia in a randomized, double blind, crossover protocol. We conclude that endogenous opiates are at least partially responsible for the hyperinsulinemia and insulin resistance in PCO-AN.
Neuroendocrinology · Opioid Peptides
Villa P et al., 1999 · Fertil Steril
To investigate the involvement of opioid tone, obesity, and hyperinsulinemia in GH secretion in women with polycystic ovary syndrome (PCOS). Controlled clinical study. Catholic University of Sacred Heart School of Medicine in Rome, Italy. PATIENT(S): Twenty-two patients with PCOS and 14 healthy, normally ovulating volunteers, matched for age and body mass index. INTERVENTION(S): Patients underwent a GH-releasing hormone (GHRH) test and an oral glucose tolerance test before and after 4-5 weeks of treatment with 50 mg/d of naltrexone. MAIN OUTCOME MEASURE(S): Serum concentrations of GH, insulin, glucose, steroids, and gonadotropins, as well as the GH area under the curve (AUC-GH) and the insulin area under the curve (AUC-I), were measured before and after naltrexone treatment. RESULT(S): In patients with PCOS, the administration of naltrexone increased the GH response to the GHRH test without interfering with the insulin response to the oral glucose tolerance test. However, the GH response to the GHRH test was improved significantly only in lean patients with PCOS, whereas obese patients with PCOS did not show any improvement in GH secretion. In obese control subjects, the treatment reduced plasma basal insulin concentrations and increased the AUC-GH, whereas in lean control subjects, the treatment reduced the GHRH-induced response. In normoinsulinemic patients with PCOS, the GH response to the GHRH test increased significantly after treatment, whereas the AUC-I was not affected. In hyperinsulinemic patients with PCOS, treatment with naltrexone significantly reduced the AUC-I, whereas the AUC-GH increased only in lean hyperinsulinemic patients with PCOS. CONCLUSION(S): Naltrexone treatment improves GHRH-induced GH secretion in patients with PCOS. However, this GH response is heterogeneously represented in relation to both obesity and hyperinsulinism.
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