Effect of opioid antagonists on sex hormone secretion

From Pharmacology to Physiology: Endocrine Functions of μ-Opioid Receptor Networks

The steady rise in opioid users and abusers has uncovered multiple detrimental health consequences of perturbed opioid receptor signaling, thereby creating the need to better understand the biology of these systems. Among endogenous opioid networks, μ-receptors have received special attention due to their unprecedented biological complexity and broad implications in homeostatic functions. Here, we review the origin, molecular biology, and physiology of endogenous opioids with a special focus on μ-opioid receptor networks within the endocrine system. Moreover, we summarize the current evidence supporting an involvement of the latter in regulating distinct endocrine functions. Finally, we combine these insights to present an integrated perspective on μ-opioid receptor biology and provide an outlook on future studies and unresolved questions in this field.

Cigarette Smoking Is Significantly Linked to Sexual Dissatisfaction in Chinese Heroin-Dependent Patients Receiving Methadone Maintenance Treatment

Background: Cigarette smoking is associated with sexual dysfunction in the general population. Both smoking and sexual dysfunction are common in heroin-dependent patients (HDPs) receiving methadone maintenance treatment (MMT), but their association in MMT HDPs is rarely studied. This study examined the association between smoking and sexual dissatisfaction in Chinese HDPs receiving MMT. Methods: In total, 480 Chinese HDPs, who had sex with their regular or irregular sex partners within one month prior to the study, were included from three MMT clinics in Wuhan, China. Sexual dissatisfaction was assessed with one single question. Socio-demographic and clinical data and smoking characteristics were collected with a standardized questionnaire. Multiple binary logistic regression was used to analyze the association between smoking and sexual dissatisfaction, as well as the associations between levels of smoking and nicotine dependence and sexual dissatisfaction. Results: The prevalence of current smoking was 95.6% in HDPs receiving MMT. Rates of sexual dissatisfaction were higher in current smokers than non-smokers (32.9% vs. 14.3%) with a borderline significant P value of 0.074. After adjusting potential socio-demographic and clinical confounders, current smoking was significantly linked to sexual dissatisfaction (OR = 1.95, P = 0.026), and heavy smoking and severe nicotine dependence were significantly linked to sexual dissatisfaction (OR = 1.80, P = 0.025; OR = 3.27, P < 0.001). Conclusion: Smoking is significantly associated with sexual dysfunction in HDPs receiving MMT. It deserves further investigation as to whether quitting smoking can improve the sexual function of methadone-maintained patients.

Sexual life satisfaction of methadone-maintained Chinese patients: individuals with pain are dissatisfied with their sex lives

Purpose

Pain is potentially associated with sexual dysfunction. Both sexual dysfunction and pain are common in methadone-maintained patients, but the association of pain with sexual dysfunction in methadone-maintained patients is rarely studied. This study examined the association between pain and sexual life satisfaction (SLS) in Chinese patients receiving methadone maintenance treatment (MMT).

Patients and methods

A total of 477 methadone-maintained patients who recently had sex with their sex partners were recruited from three MMT clinics in Wuhan, China. SLS was assessed with a single question, and the sociodemographic, psychological, and clinical data were collected with standardized questionnaires. Pain intensity was assessed with the 5-point verbal rating scale. Multiple ordinary logistic regression was used to control for potential confounders that may bias the pain–SLS relationship.

Results

The prevalence of self-reported dissatisfaction with one’s sexual life was significantly higher in patients with clinically significant pain (CSP) than those without CSP (41.5% vs 19.4%, χ² =23.567, P<0.001). After controlling for potential sociodemographic, psychological, and clinical confounders, CSP was still significantly and independently associated with an increase in sexual life dissatisfaction (OR =1.89, P=0.011).

Conclusion

Pain is significantly associated with low SLS in methadone-maintained patients. Appropriate pain management might improve SLS of patients receiving MMT.

Effect of Withania somnifera (L.) Dunal on Sex Hormone and Gonadotropin Levels in Addicted Male Rats

Background

Opioid consumption has been widely increasing across the globe; how- ever, it can cause adverse effects on the body. Morphine, an opioid, can reduce sex hor- mones and fertility. Withania somnifera (WS) is a traditional herb used to improve sexual activities. This study strives to investigate the effect of WS on sex hormones and gonado- tropins in addicted male rats.

Materials and Methods

In this experimental study, forty-eight male National Maritime Research Institute (NMRI) rats were randomly divided into four groups: i. Control group, ii. WS-treated control group, iii. Addicted group, and iv. WS-treated addicted group. Wa- ter-soluble morphine was given to rats for 21 days to induce addiction, concurrently the treated groups (2 and 4) also received WS plant-mixed pelleted food (6.25%). At the end of the treatment, the sex hormone and gonadotropin levels of the rats’ sera were deter- mined in all the groups.

Results

Except for follicle-stimulating hormone (FSH), morphine reduced most of the gonadotropin and sex hormone levels. Whereas WS caused a considerable increase in the hormones in the treated addicted group, there was only a slight increase in the treated control group.

Conclusion

WS increased sex hormones and gonadotropins-especially testosterone, es- trogen, and luteinizing hormone-in the addicted male rats and even increased the proges- terone level, a stimulant of most sex hormones in addicted male rats.

Methadone-induced hypoglycemia

To determine if recent observations of hypoglycemia in patients receiving high-dose methadone extended to an animal model, we explored the effects of methadone and other mu-opioids on blood glucose levels in mice. Methadone lowered blood glucose in a dose-dependent manner with 20 mg/kg yielding a nadir in average glucose levels to 55 ± 6 mg/dL from a baseline of 172 ± 7 mg/dL, an effect that was antagonized by naloxone and mu selective antagonists β-funaltrexamine and naloxonazine. The effect was stereoselective and limited to only the l-isomer, while the d-isomer was ineffective. Despite the robust decrease in blood glucose produced by methadone, a series of other mu-opioids, including morphine, fentanyl, levorphanol, oxycodone or morphine-6β-glucuronide failed to lower blood glucose levels. Similar differences among mu-opioid agonists have been observed in other systems, suggesting the possible role of selected splice variants of the mu-opioid receptor gene Oprm1. This mouse model recapitulates our clinical observations and emphasizes the need to carefully monitor glucose levels when using high methadone doses, particularly intravenously, and the need for controlled clinical trials.