老年大鼠糖负荷时激素的应激性调节变化

Changes of hormonal stressful regulation of older rats in glucose-tolerance

目的探讨老年和成年大鼠、雌性和雄性大鼠葡萄糖耐量实验过程中,血糖、胰岛素、皮质酮激素水平的应激性调节变化。方法将大鼠分为成年雄性、成年雄性、老年雄性、老年雌性组,在葡萄糖耐量实验过程中,分别于0、30、60、120 min采血,测定血糖值、胰岛素、皮质酮水平。计算胰岛β细胞功能指数(HOMAβ)和I30/G30。实验结束后处死所有大鼠,测定脏器指数、胰岛素、皮质酮水平。结果相比较成年雄性大鼠,老年雌性大鼠各时间点血糖水平升高,30 min胰岛素水平显著降低(P<0.01),0、30 min皮质酮水平降低(P<0.01),60、120 min胰岛素减少、皮质酮水平升高、脏器指数下降。相比较成年雌性大鼠,老年雌性大鼠的30、60、120 min血糖水平升高(P<0.05)、胰岛素减少,各时间点皮质酮均显著升高(P<0.05),脏器指数均下降(P<0.05)。基础胰岛素分泌功能强弱顺序:成年雌性大鼠>老年雌性大鼠>成年雌性大鼠>老年雄性大鼠。早期胰岛素分泌功能强弱顺序:成年雄性大鼠>成年雌性大鼠>老年雄性大鼠>老年雌性大鼠。结论老年大鼠胰岛素发挥作用具有延时或胰岛素敏感性下降的特点,尤其是老年雌性大鼠。不同性别老年大鼠皮质酮反应性不同,机体脏器均有萎缩,基础和早期胰岛素分泌功能均较差。

Objective To investigate the blood glucose,insulin level and corticosterone levels variation in glucose tolerance test between older and younger rats,male and female rats,to explore the stressful regulation changes of these hormones. Methods Rats were divided into four groups:adults male,adults female,older male,older female. The glucose tolerance test was conducted,the rat’s blood was collected at 0,30,60,120 min each point,the levels of glucose,insulin and corticosterone were measured. After experiment,all rats were decapitated,the levels of insulin and corticosterone were measured,and the organ indexes were assayed. Then the HOMAβ and △I30/ △G30were accounted. Results In glucose tolerance test,compared with that of adults male rats,older male rats’ blood glucose levels was raised at each time point,its insulin levels at 30 min was significantly decreased( P < 0. 01),while at 60 and 120 min also decreased,the corticosterone levels was reduced notably at 0 and 30 min( P < 0. 01),while increased at 60 and 120 min,organ index lowered in different degree. Compared with those of adults female rats,older female rats’ blood glucose level was raised significantly at 30,60,120 min( P < 0. 05),its insulin level at 30 min was significantly decreased( P < 0. 01),while at 60 and 120 min also decreased,the corticosterone level was increased notably at each time point( P < 0. 05). After death,the corticosterone level was higher than that of other groups( P < 0. 01),the organ indexes were decreased notably( P < 0. 05). The order of basal insulin secretion function:adult male > older female > adult female > older male. The order of prophase insulin secretion function:adult male > adult female > older male > older female. Conclusions Insulin is delayed to produce a marked effect or the sensitivity is declined in older rats,especially the older female rats. The corticosterone levels variation in different gender,the organ indexes are atrophy,and the insulin secretion function in basal and prophase is declined.