Influence of Chronic Morphine Exposure on Serum Lh, Fsh, Testosterone Levels, and Body and Testicular Weights in the Developing Male Rat

Abstract

Opiate abuse has been a matter of serious concern in male adolescents. This study investigates the effects of chronic morphine administration on serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone levels, testicular histology, and body and testes weight in developing male rats. Animals were subcutaneously injected with morphine (5 mg/kg) or saline (1 mL/kg) twice daily for 30 days. Body weight determinations and injections were carried out under light ether anesthesia. At the end of the experiments, the rats were decapitated and blood samples were collected. Serum levels of LH and FSH were measured. Chronic morphine administration significantly decreased decreased serum testosterone (p < .02) and LH (p < .01) levels, but not FSH release compared to controls. Morphine exposure reduced body weight (p < .01), but had no significant effect on the testicular weight. When the testicular tissue was histologically examined, structural features of the seminiferous tubules and Leydig cells were similar in both saline and morphine-treated animals. The results suggest that opiates affect testosterone release through the hypothalamo-hypophyseal-gonadal axis rather than by a local testicular mechanism. Chronic morphine exposure during sexual maturation may have long-term endocrine disturbances in male rats.

Chorionic morphine, naltrexone and pentoxifylline effect on hypophyso-gonadal hormones of male rats

“…This idea was repeated in ovariectomized rats when LH responses to opioids were antagonized by naloxone (18,19). In contrast to their effects on LH, most opioids and their analogs appear not to affect FSH (20). Furthermore, treatment with opioid antagonists, naloxone and naltrexone, did not alter FSH concentration levels in either sex (21), suggesting that the endogenous opioids are not involved in regulation of FSH secretion.…”

Androgen Levels in Older Men Who Have or Who Are at Risk of Acquiring HIV Infection

“…Low testosterone levels have been reported in opiate addicts [16], and long-term administration of opiates to rats during sexual maturation leads to decreased testosterone levels, with more transient effects in adult animals [17,18]. Opiates may act by suppressing the hypothalamo-pituitarygonadal axis [16].…”

Socially induced morphine pseudosensitization in adolescent mice

“…An increase in aggressive behaviors is unlikely during morphine intoxication, since opioids have been demonstrated to decrease plasma testosterone levels in both adult humans (Abs et al, 2000, Rasheed and Tareen, 1995) and rodents (Budziszewska et al, 1999, Gabriel et al, 1986). Like adults, morphine was also demonstrated to decrease plasma testosterone levels in adolescent rats (Yilmaz et al, 1999, Cicero et al, 1989). Given that testosterone levels play a significant role in male aggressive behaviors, it is not surprising that morphine thus has anti-aggressive properties (Vivian and Miczek, 1993).…”