Major Functions of the Kidneys Regulation of body fluid osmolarity and volume electrolyte balance acid-base balance blood pressure 2. Excretion of metabolic products foreign substances(pesticides, chemicals etc. excess substance(water, etc) 3. Secretion of erythropoitin 1, 25-dihydroxy vitamin D3(vitamin D activation) renin prostaglandinMajor Functions of the Kidneys 1. Regulation of: body fluid osmolarity and volume electrolyte balance acid-base balance blood pressure 2. Excretion of metabolic products foreign substances (pesticides, chemicals etc.) excess substance (water, etc) 3. Secretion of erythropoitin 1,25-dihydroxy vitamin D3 (vitamin D activation) renin prostaglandin