Role of Endocrine Systems on Changes of Kidney Function during Aging

Wistar/Tw系雄性大鼠在16月龄后出现多饮和多尿，而雌性大鼠在20月龄后出现多饮和多尿。目前的研究表明，该品系是水和电解质代谢和肾功能加速老化的模型，这对动物的稳态控制很重要。本研究以该亚系大鼠为研究对象，探讨肾功能随年龄的变化及内分泌系统在其中的作用.对衰老过程中的肾功能进行了研究，并在雌性大鼠中观察到血清磷脂和甘油三酯的年龄相关性增加。这些变化与人体肾功能不全时血清指标的变化相一致。2.血清心钠素（ANP）浓度在增龄过程中无明显变化。用非肥胖糖尿病（NOD）小鼠研究了ANP随糖尿病发生的变化，因为糖尿病动物也显示多聚 ...更多信息 口渴。血清ANP浓度显著降低，心房ANP含量显著升高。3. Wistar/Tw品系在衰老过程中血清醛固酮浓度和血浆肾素活性降低（1 ~ 10倍）。这可能是由于肾组织病理改变导致肾组织中肾素释放减少所致。据报道，在衰老过程中血清加压素浓度增加。阐明了该亚系与水电解质代谢有关的血清激素的变化。4.雌性大鼠24小时尿钙排泄量随年龄增长而显著增加（10倍）。X线片显示骨质减少，股骨干重和钙含量显著降低，尾椎干重和机械强度显著降低。这些变化提示该雌性大鼠可能是自发性骨质疏松症的模型大鼠。6.血清降钙素浓度无明显变化，钙代谢在增龄过程中发生变化的机制有待进一步研究。少

Wistar/Tw strain male rats show polydipsia and polyuria after 16 months of age, while after 20 months of age in female rats. Current studies have suggested that this strain is a model for accelerated aging in water and electrolyte metabolism and kidney function, which are important for the control of homeostasis of animals. In the present study, age-related changes of kidney function and role of endocrine systems on the changes were investigated using this substrain rats.1. Kidney function during aging was studied and age-related increases of serum phospholipids and triglyceride were observed in female rats. These changes are considered to agree with the changes of serum parameters with dysfunction of kidney in human. 2. No significant change on serum atrial natriuretic peptide(ANP)concentration was observed during aging of this strain. Changes on ANP with the occurrence of diabetes mellitus were studied using non-obese diabetic(NOD)mice, as the diabetes mellitus animals also show poly … More dipsia. Significant reduction of serum ANP concentration and significant enhancement of atrial ANP content were observed. 3. Reduction of serum aldosterone concentration and plasma renin activity(1 to 10 fold)during aging of Wistar/Tw strain was observed. These results may be explained by the reduction of release of renin with the pathological changes of kidney. Increase of serum vasopressin concentration during aging has reported. Thus, changes of serum hormones which related to water and electrolyte metabolism have clarified in this substrain. 4. Furthermore, marked increase(10 fold)of urinary excretion of calcium in 24 hours with aging of female rats was found. 5. Reduction of bone materials in X-ray photograph, significant reductions of dry weight and calcium content in the femur, significant reductions of dry weight and mechanical strength of tail vertebrae were observed. These changes suggest that this female rats may be a model rat for spontaneous osteoporosis. 6. Serum calcitonin concentration showed no significant change.Further studies are necessary to clarify the mechanism of such changes in calcium metabolism during aging. Less