Anemia in renal failure

Patients with severe chronic renal failure almost always develop anemia. The most important cause of this is decreased renal secretion of erythropoietin, which stimulates the bone marrow to produce red blood cells. If the kidneys are seriously damaged they are unable to form adequate quantities of erythropoietin, which leads to diminished red blood cell production and consequent anemia.

Hormones acts on kidney

A. Aldosterone

·        Increase NaCl and H₂O reabsorbtion

·        Increase K⁺ excreation

·        Increase proton excretion

B. ADH

·        Increase water reabsorption from DCT and CD by making them permeable to H₂O

·        Vasoconstriction

·        Potentiate the pressor effects of catecholamines

C. ANP

·        Decreased NaCl and water reabsorption from CD

·        Antagonizes sympathetic nervous system activity

·        Antagonizes renin-angiotensin-aldosterone system

·        Increase GFR by dilatation of afferent arteriole

·        Inhibits ADH release

D. Angiotensin II

·        Increases NaCl and water reabsorption from PCT

·        Increase aldosterone secretion from adrenal cortex to increase NaCl and water reabsorption from DCT and CD

·        Causes constriction of efferent arteriole at physiological concentration but at high concentration it causes constriction of both afferent and efferent arterioles and reduces RBF and GFR

·        Enhances ADH release and stimulates thirst center

·        Generalized vasoconstriction

E. Dopamine

·        Increases RBF and decreases NaCl reabsorption from PCT

·        Causes natriuresis and diuresis

F.  PTH

·        Increase calcium reabsorption from PCT

·        Decreases phosphate reabsorption from PCT

G. Prostaglandin

·        Regulates renal hemodynamics and maintains RBF and GFR

·        Antagonizes SNS activity, ADH and angeotensin-II

·        Net effect is renal vasodilatation, natriuresis and diuresis

H. Catecholamine

·        Renal vasoconstriction

·        Stimulation of RAAS and increases rennin secretion

·        Renal NaCl and H_2­O retention

Synthesis and release of hormone from kidney

1.      Rennin

2.      Erythropoietin

3.      1,25 dihydroxy cholecalciferol

4.      Prostaglandins

EDRF