What is implied, if a drug has more renal clearance than the GFR :
Ans. is 'b' i.e. Drug is secreted in the tubules Logically, if a drug is more in renal clearance than the amount filtered by glomerulus, it has to be secreted in the kidney tubules." Tubular secretion - is the active transfer of organic acids and bases by two separate nonspecific mechanism which operate in the proximal tubules. If renal clearance of a drug is greater than 120 ml/min (g.f.r.), additional tubular secretion can be assumed to be occuring "Soif renal clearance is more than G.F.R.* - Tubular secretionIf renal clearance is less than G.F.R. * - Tubular reabsorption.If renal clearance is equal to G.F.R.* - The drug does not undergo either tubular sec. or tub. reabsorption.
Drug is reabsorbed in the tubules
Drug is secreted in the tubules
Drug is excreted in bile
Drug is neither secreted, nor resorbed.
Glomerular Filtration, Renal Blood Flow, and Their Control