Hormone and Vitamin Regulation
The kidney contributes to the degradation of a significant number of peptide hormones, including most pituitary hormones, glucagon, and insulin. Decreased renal catabolims of insulin in patients with diabetes and renal insufficiency can lead to hypoglycemia.
Erythropoietin
The kidney is the major site of production for erythropoietin, a hormone responsible for increasing RBC production.
Vitamin D
The kidney contributes to calcium homeostasis by hydroxylating vitamin D, controlled and stimulated by PTH and low phosphate.
Glucose
The kidney regulates plasma glucose levels by using lactate, pyruvate, and amino acids through gluconeogenesis. This is important in states of prolonged starvation, when the kidneys can contribute up to 40% of plasma glucose. Absence of this pathway can contribute to hypoglycemia in people with renal failure and diabetes.