BACKGROUND: Stanozolol and Nandrolone decanoate are the most commonly used hormones in canine medi-cine. They are mainly administered to strengthen the muscle, gain weight, treatment of anemia and stimulate the appetite. One of the effects of hormones is to enhance the erythropoietin production and eventually an increase in the number of RBCs. OBJECTIVES: Prolonged usage of hormones may be relevant to the liver and renal disorders; therefore, the pre-sent survey was aimed to evaluate the effects of stanozolol and nandrolone decanoate on liver and kidney indices, erythropoietin and testosterone serum concentrations and hematocrit changes in healthy dogs. METHODS: Sixteen dogs were randomly categorized in two groups of A (stanozolol) and B (nandrolone decano-ate). Each group was divided into two subgroups (A1, A2 and B1, B2). The second testicle was removed on day 28 in the first subgroups (A1 and B1), and day 42 in the second subgroups (A2 and B2). The first testicle was removed at time zero. Stanozolol (50 mg per dog) was administered to all dogs of group A as IM once a week for six weeks. Group B was similar to group A with the difference that nandrolone decanoate was injected (1 mg/kg) instead of stanozolol. Blood samples were collected on days 0, 3, 14, 28 and 42. RESULTS: Erythropoietin and testosterone concentrations were virtually increased in both groups A (p <0.05) and B (p <0.05). The effect of stanozolol on erythropoietin (subgroup A1) (11.35±1.31 ng/mL) was significantly higher than nandrolone decanoate (subgroup B1) (8.02±0.55 ng/mL) (p <0.05); nevertheless, the changes in testosterone levels, was not significant between groups A and B (p >0.05). The liver enzymes of ALP, ALT and AST were increased more significantly in group A than group B (p <0.05). CONCLUSIONS: Erythropoietin and testosterone levels were virtually increased in both groups A and B; how-ever, stanozolol had more significant effect than nandrolone decanoate in increment of erythropoietin; nevertheless, it had more side effects on liver indices. It is suggested that nandrolone decanoate to be administered for the thera-peutic goals.

BACKGROUND: Neuropathic pain is a chronic condition which is mediated by complex mechanisms exerted by the release of nerve neurotransmitter. A correlation exists between the sex hormones and neuropathic pain, however many aspects of this correlation still remain unclear. OBJECTIVES: The aim of the current study was to determine the anti-nociceptive activity of testosterone and its interaction with the opioidergic, GABAergic, and dopaminergic receptors in sciatic nerve-ligated male rats. METHODS: In this study, 170 adult male rats were randomly allocated into the 4 experimental groups following the sciatic nerve ligation. In the experimental group 1, the animals were injected intraperitoneally (i.p.) with saline, testosterone (10 and 15 mg/kg), and morphine (5 mg/kg), and 30 minutes later with formalin into the plantar surface of the right paw. In the experimental group 2, the animals were injected with saline, testosterone (15 mg/kg), nalox-one (2 mg/kg), and testosterone (15 mg/kg)+naloxone (2 mg/kg). In the groups 3 and 4, flumazenil (5 mg/kg) and yohimbine (2 mg/kg) were injected instead of naloxone. Then, the time spent for paw licking was monitored for the first and second phases after the formalin injection. RESULTS: According to the results, the injection of testosterone in a dose dependent manner decreased the time of licking and biting in the injected paw compared to the control group (P<0.05). Likewise, pretreatment with na-loxone or flumazenil significantly decreased the anti-nociceptive effect of testosterone (P<0.05). While pretreatment with yohimbine significantly increased the anti-nociceptive effect of testosterone (P<0.05). CONCLUSIONS: These results suggested testosterone has an anti-nociceptive activity and this effect is mediated by the opioidergic, GABAergic, and dopaminergic receptors in the sciatic nerve-ligated male rat.