Effect of xylazine on some endocrinological and hematological parameters in heifers under thermoneutral or heat stress conditions

A study was performed to assess the effect of xylazine HCl [0.1 mg/kg of body weight, i.v.] in heifers maintained at thermoneutral [TN, 18C, 42% RH] or heat stress [HS, 33C, 63% RH] conditions. Xylazine injection resulted in a sharp increase [P <0.05] in serum cortisol levels after 15 minutes in both groups. However, cortisol levels gradually declined and reached basal levels after 45 minutes and 3 hours in heifers maintained under TN and HS conditions, respectively. Xylazine administration increased [P <0.05] serum T3 concentrations after 15 and 30 minutes in the thermoneutral and heat-stressed animals, respectively. Serum T3, however, gradually decreased and reached basal values after 3 hours in both groups. The xylazine- treated heifers had lower [P <0.05] red blood cells, hemoglobin and packed cell volume under TN conditions, while higher [P <0.05] values were observed under HS conditions. All the above parameters were greater [P <0.05] in the thermoneutral animals than in the heat- stressed ones either before or after xylazine administration. It is possible than an undesirable interaction occurred between xylazine and the hot environment, thus it is suggested that xylazine should be used cautiously in hyperthermic animals

Morphine role against cadmium-induced testicular damage in rats

The effects of cadmium upon the testis, kidney and spleen were investigated in rats which injected subcutaneously with cadmium chloride [7 mg/kg b. wt]. Twenty-four hours post injection, the animals were sacrificed and the testes, kidneys and spleens were removed and weighed. The extent of hemorrhage was estimated by determining the absorbance of hemoglobin at 414 nanometer in the soluble fraction of organ homogenates. Exposure to cadmium increased the hemoglobin absorbance of the tests from 0.18 +/- 0.03 to 0.71 +/- 0.08. Intraperitoneal pretreatment with morphine sulphate [20 mg/kg b. wt.] greatly provoked the cadmium-induced testicular hemorrhage. Cadmium induced a moderate leucocytosis, while the hemoglobin%, PCV and RBCs count were not affected. It was concluded that morphine can protect against certain toxic effects of cadmium

Antifertility effects of melatonin in male rats

The effects of melatonin on the reproductive organs and testosterone concentration were investigated in adult male rats. Melatonin administration, intraperitoneal [0.5 mg/rat], for successive 14 days resulted in a significant decrease in the testes, epididymis seminal vesicle and fat body weight. Varying degrees of degeneration and necrosis of seminiferous tubules associated with marked interstitial and subcapsular oedema were observed. Plasma testosterone concentration was significantly decreased [1.76 ng/ml] in melatonin treated rats as compared to the control [2.75 ng/ml]