Hormones secreted by the kidney
The kidney secretes a variety of hormones. They are:
- Erythropoietin
- It is produced by the peritubular capillary endothelial cells in response to hypoxia
- It acts on the bone marrow to stimulate erythropoiesis
- 1,25-Dihydroxycholecalciferol
- It is also known as calcitriol – the active form of Vitamin D
- It is formed by hydroxylation of 25-hydroxycholecalciferol by the enzyme 25-hydroxyvitamin D3 1-alpha-hydroxylase located in the proximal tubules of the nephron
- The activity of the enzyme is under the control of PTH (Parathyroid hormone)
- It stimulates calcium absorption from the intestine and reabsorption of calcium and phosphate from the kidneys
- Renin
- It is secreted by the juxtaglomerular apparatus of the kidney
- It is secreted in response to a decrease in arterial blood pressure or sodium chloride content in blood
- It plays an important role in electrolyte balance by mediating the conversion of angiotensinogen to angiotensin I
