Daniel R. Kapusta, Ph.D.Department of Pharmacology, LSUHSC
MEB Rm 7106568-3940; [email protected]
Renal Transport of Sodium, Chloride and other Solutes
Total Body Sodium Balance:Input = Output
Renal excretion of sodiumRenal excretion of sodium
Renal handling of water, electrolytes and solutesRenal handling of water, electrolytes and solutes
Renal handling of sodium
Renal process involved in the production of urineRenal process involved in the production of urine
1) Glomerular filtration1) Glomerular filtration
2) Renal tubular secretion2) Renal tubular secretion
3) Renal tubular reabsorption3) Renal tubular reabsorption
Glomerular filtration
Tubular secretion
PCT organic acid secretory transport system
PCT organic base secretory transport system
Tubular filtration and reabsorption Tubular filtration and reabsorption
Average Values for Several Substances Handled by Filtration and Reabsorption
AmountFiltered Amount %
Substance per Day Excreted Reabsorbed Water, L 180 1.8 99.0 Sodium, g 630 3.2 99.5 Glucose, g 180 0 100 Urea, g 56 28 50
Segmental renal tubular sodium reabsorption
Tuboglomerular feedback regulation of sodium chloride excretion
Juxtaglomerular apparatus (JGA)
Regulation of sodium excretion –Glomerulotubular balance
Glomerulotubular balance
Transport pathways across tubular cells
Sodium, glucose and bicarbonate reabsorption in the proximal convoluted tubule
Renal tubular reabsorption of glucoseRenal tubular reabsorption of glucose
- The increase in sodium loss in the urine, a ‘natriuresis’, causes water to follow and thus produce diuresis
- Diuretics increase the rate of urine formation by interfering with the reabsorption of sodium by the nephron
- Diuretics are drugs that increase the net excretion of water from the body
“Mannitol”
CarbonicAnhydrase
CarbonicAnhydrase
Electrolyte transport pathways in the TALH
Sodium and chloride reabsorption in theearly distal convoluted tubule
Sodium - potassium exchange in the late distal convoluted tubule
AVP-dependent water permeability in the distal nephron
Vasopressin – mediated water reabsorption