Acute Cold / Restraint Stress in Castrated Rats

Objective: the present study aimed to determine whether castration altered osmotically stimulatedvasopressin (vp) release and urinary volume and what is the role of endocrine-stress axis in thisprocess.materials and methods: totally 108 mice were studied in two main groups of castrated (n=78) andcontrol (n=30). each group was extracted by acute cold stress (4.c for 2h/day), restraint stress (bysyringes 60cc 2h/day) and cold/restraint stress. the castrated group was treated in sub groups oftestosterone, control (sesame oil as vehicle of testosterone). propranolol as blocker of sympatheticnervous system was given to both groups of castrated mice and main control.results: our results showed that, there is interactions between testosterone and sympathetic nervoussystem on vasopressin, because urine volume was decreased only in testoctomized mice withcold/restraint and cold stress (p<0.001); propranolol as the antagonist of sympathetic nervous systemcould block and increase urine volume in castrated mice. this increased volume of urine was due toacute cold stress, not restraint stress (p<0.001). the role of testosterone, noradrenalin (na) andvasopressin (vp) in the acute cold stress is confirmed, because testosterone could return the effect ofdecreased urine volume in control group (p<0.001).conclusion: considering the effect of cold/restraint stress on urinary volume in castrated mice showsthat there is interaction between sex hormone (testosterone), vasopressin and adrenergic systems.