Role of Endocrine Systems on Changes of Kidney Function during Aging

Wistar/Tw系雄性大鼠在16月龄后出现多饮多尿，雌性大鼠在20月龄后出现多饮多尿。目前的研究表明，该菌株是一种加速水、电解质代谢和肾脏功能老化的模型，这对控制动物体内平衡具有重要意义。在本研究中，使用该亚株RAS研究了与年龄相关的肾功能变化以及内分泌系统在这些变化中的作用。对雌性大鼠衰老过程中的肾功能进行了研究，观察到雌性大鼠血清磷脂和甘油三酯随年龄增长而升高。这些变化被认为与人类肾功能不全时血清参数的变化相一致。2.该菌株在老化过程中，血浆心钠素(ANP)浓度无明显变化。用非肥胖糖尿病(NOD)小鼠研究了心钠素在糖尿病发生过程中的变化，因为糖尿病动物也表现出多聚…更多的酒后症状。血清ANP浓度显著降低，心房心钠素含量显著升高。3.在Wistar/Tw品系老化过程中，血清醛固酮浓度和血浆肾素活性下降1~10倍。这些结果可能与肾素释放减少与肾脏病理改变有关。据报道，在衰老过程中，血清加压素浓度升高。从而阐明了该亚株与水、电解质代谢有关的血清激素的变化。4.随着雌性大鼠年龄的增长，24小时尿钙排泄量显著增加(10倍)。5.X线片骨料减少，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鼠。6.血清降钙素浓度无明显变化，钙代谢在衰老过程中的变化机制有待进一步研究。较少

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