Renal oligopeptide reabsorption

Renal oligopeptide reabsorption is the part of renal physiology that deals with the retrieval of filtered oligopeptides, preventing them from disappearing from the body through the urine.

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Almost all reabsorption takes place in the proximal tubule. Practically nothing is left in the final urine. Longer oligopeptides, such as angiotensin^[1] and glutathione^[1] are degraded by enzymes on the brush border, while shorter ones, such as carnosine^[1], are transported across the apical membrane as a whole by the PepT 1 transporter, and degraded inside the proximal tubule cell.

Overview table

Characteristics of oligopeptide reabsorption
Characteristic	proximal tubule			loop of Henle	Distal convoluted tubule	Collecting duct system
Characteristic	S1	S2	S3	loop of Henle	Distal convoluted tubule	Collecting duct system
reabsorption (%)	99^[1]			Beyond the proximal tubule: 1%^[1]
reabsorption (mmoles/day)
Concentration
apical transport proteins	sodium-amino acid symporter^[1] PepT 1 (for short peptides, n=2 to 4)^[1]
basolateral transport proteins	amino acid transporter^[1]
Other reabsorption features

References

^ ^a ^b ^c ^d ^e ^f ^g ^h Walter F., PhD. Boron. Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders. ISBN 1-4160-2328-3. Page 798

v • d • e Urinary system, physiology: renal physiology and acid base physiology
Filtration	Renal blood flow - Ultrafiltration - Countercurrent exchange
Hormones affecting filtration	Antidiuretic hormone (ADH) - Aldosterone - Atrial natriuretic peptide
Secretion/clearance	Pharmacokinetics - Clearance of medications
Reabsorption	Solvent drag -Na⁺ - Cl^- -urea -glucose -oligopeptides -protein
Endocrine	Renin - Erythropoietin (EPO) - Calcitriol (Active vitamin D) - Prostaglandins
Assessing Renal function / Measures of dialysis	Glomerular filtration rate - Creatinine clearance - Renal clearance ratio - Urea reduction ratio - Kt/V - Standardized Kt/V - Hemodialysis product - PAH clearance (Effective renal plasma flow - Extraction ratio)
Acid base physiology	Fluid balance - Darrow Yannet diagram - Body water - Interstitial fluid - Extracellular fluid - Intracellular fluid/Cytosol - Plasma - Transcellular fluid - Base excess - Davenport diagram - Anion gap - Arterial blood gas
Buffering/compensation	Bicarbonate buffering system - Respiratory compensation - Renal compensation