بررسی تأثیر هیپوترمی متوسط بر محور رنین ـ آنژیوتنسین آلدوسترون در موشهای بزرگ آزمایشگاهی نر

Hypothermia in nature occurs in hibernating animals. It has applications&nbsp;in medicine in open heart surgery,organ and connective tissue preserving,&nbsp;altitude medicine and geriatrics. Despite the vastness of studies on&nbsp;hypothermia many of its biologic and physiologic effects including&nbsp;endocrine system alterations are still poorly recognized. In this study the&nbsp;effect of hypothermia on renin- angiotensin-aldosterone axis was explored. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Ten male wistar albino rats (mean age 5 months) were anesthetized by&nbsp;intraperitoneal&nbsp;injection of chloralhydrat (0.5 m1/100gr body weight). Then&nbsp;animals were placed in hypothermia apparatus . Their body temperature&nbsp;were reduced to 250 C. AngiotensinI(ANGI) and aldosterone (ALD) levels of&nbsp;serum were measured by radioimmunoassay before and after hypothermia &nbsp;&nbsp; induction and once every 24 hours for three days. Plasma renin activity&nbsp;(PRA) was also measured by using the standard formula of angiotensin&nbsp;determinates at two temperatures of 40C and 370C . &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; The results showed that PRA,ANGI and ALD increased significantly&nbsp;immedietly after hypothermia (p<0.03).&nbsp;Later changes were followed as&nbsp; these factors decreased to basal level, except in the case of aldosterone&nbsp;which maintained its increased level significantly for 24 hours (p<0.05). &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; It seems that moderate hypothermia have stimulatory effect on&nbsp;PRA,ANGI and ALD that results of this study confirm it.