Some Physiological Changes Resulting from the Administration of opioid antagonists in male rats

Summary:-In order to clarify the possible physiological role of endogenous opioid peptides, the present study was carried out to study the effect of opioid antagonist administration on some reproductive parameters in adult male rats.The study was carried out at the Department of Physiology, Faculty of Veterinary Medicine, Zagazig University.Fourty mature male albino rats were divided into 4 equal groups. Group I maintained as control. Group II was subjected to restraint stress 1 hour each day for 2 weeks. Group III was injected intraperitoneal with the opioid antagonist (Naltrexone) in a dosBlood samples were collected at the time of sacrifying in tubes without anticoagulants for obtaining serum to be used for estimation of testosterone and prolactin levels.Testes were carefully exiced and mixed with physiological saline then homogenized to obtain the supernatant which is handled exactly as the semen for examination of semen picture.Furthermore, histopathological examination of testis was performed.The obtained results revealed the following:I-Serum testosterone levelThe study revealed a significant decrease in serum testosterone level in immobilization stress group either after one or 2 weeks (0.92±0.09 ng/ml and 0.93±0.33 ng/ml) comparing to the control group (4.12±0.54 ng/ml and 3.09±0.05 ng/ml after one and 2 weekII- Semen picturea- Sperm motility percentage.There was a significant reduction in motility% from control group (92.50±1.44% and 90.00±2.88% after one and 2 weeks, respectively) to (73.75±4.73% and 73.33±3.33% after one and 2 weeks, respectively) in immobilization stress group. While the decrease in b- Sperm cell concentration.Sperm cell concentration showed decrease in immobilization stress group either after one or 2 weeks (40.25±3.19/ml x 125 x 104 and 35.00±2.88/ml x 125 x 104) as compared to the control group (47.50±3.17/ml x125 x 104 and 82.67±23.05/ml x 125 x 104). NTX ac- Sperm abnormalities percentage.The immobilization stress group showed a significant increase in abnormalities % after one week (26.25± 3.66%) as compared to the control group after the first week (9.25 ± 1.93% ) and this percentage showed more increase after 2 weeks in stress group (32III- Serum prolactin levelThe study revealed a significant increase in serum prolactin level after the first week in immobilization stress group (0.391±0.07 ng/ml) when compared to the control group (0.109±0.01 ng/ml) while NTX was capable of attenuation of the increase in serum pIV- Histopathological examination of testesThere was normal histopathological picture of testis in control group. While in immobilization stress group, the testis showed severe necrosis of large number of seminiferous tubules with desquamated spermatogenic cells inside the lumen. In NTX+stress gro