06 Renal Endocrine

Renin

• JG (juxto glomerulus): modified smooth muscle cells of afferent arteriole. Sits between afferent/efferent, distal tubule and glomerulus
• macula densa: DCT

• macula densa: sense NaCl levels

• Ang: made by liver, in blood
• renin finds Ang, convert to AI

Ang II

• increase Na/H2O
• increase bicarb absorption in PCT
• harder to get blood through whole system, thus lower RPF, FF goes up

Hydrostatic effect:

• less fluid go to peritubular because of constriction
• low hydrostatic pressure in peritubular capillaries
• result: water drawn out

Oncotic effect:

• protein stay in efferent, increase oncotic pressure
• high oncotic pressure
• fluid out

• AII activate Na/H antiporter
• Na absorption, H2O absorption
• Contraction alkalosis: more H+ out to lumen, combine with bicarb to form water, absorption

Aldosterone

• adrenal makes too much aldosterone

ANP

• released by heart
• opposite of renin
• relax smooth muscle via cGMP to dilate afferent

PTH

• low Ca most important
• alcoholics very low Mg

• increase Ca absorption in DCT

Vid D

• D2 less active, not important

• 25- OH longest half life

• renal failure: increase phosphate from unable to excrete
• secondary hyper PTH from renal failure

EPO

• peritubular interstitial cells
• acts in bone marrow

• association with increased mortality