What do the kidneys do under normal conditions? The kidney is not only the main excretory organ of the body, but also an important endocrine organ, which plays a rather important role in maintaining the stability of the internal environment of the body. Its daily work is as follows: 1. excrete metabolites such as urea, creatinine, uric acid, etc. 2.Maintain the water balance by the amount of urine. 3.Maintain the balance of electrolytes. 4.Maintain the balance of acid-base. 5, endocrine function: secretion of vasoactive hormones (such as renin, angiotensin, prostaglandins, etc.) and non-vascular hormones (such as erythropoietin, 1-hydroxylase).