PLASMA-LEVELS OF LUTEINIZING AND FOLLICLE-STIMULATING HORMONES IN NALOXONE-TREATED SUBESTRUS BUFFALOS

To stude the effects of an antiopiate naloxane on hypophysial gonadotr ophins; luteinizing hormone (LH) and follicle stimulating hormone (FSH ) and estrus behaviour in subestrous buffaloes naloxone hydrochloride (1.5 mg/kg wt) dissolved in saline was infused into the jugular vein c ontinuously for 4 hr through a catheter at a rate of 0.66 ml/min. Simi larly, saline was infused 2 days before naloxone treatment. Blood samp ling was done at 1.5 min interval during the infusion period and at ho urly interval for 4 hr post-infusion in both the treatments. Mean LH l evels measured showed a significant (P <0.05) increase during naloxone infusion compared to the levels observed during saline infusion. The pulse frequency and magnitude of LH observed during the naloxone treat ment were also significantly high (P <0.05 and P <0.01 respectively) c ompared to those in saline treatment. Mean LH levels post-infusion did not differ between treatments. Mean FSH levels measured in plasma sam ples did not show and significant difference between treatments during both infusion and post-infusion. Buffaloes though exhibited estrus af ter naloxone treatment, the cycle lengths were longer. The results sho wed that naloxone can increase LH levels for short periods and its eff ects on estrus need further investigation.