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Drugs are excreted from the kidney by glomerular filtration and by active tubular secretion following the same steps and mechanisms as the products of intermediate metabolism. Therefore, drugs that are filtered by the glomerulus are also subject to the process of passive tubular reabsorption. Glomerular filtration will only remove those drugs ...
Tubular secretion occurs simultaneously during re-absorption of filtrate. Substances, generally produced by body or the by-products of cell metabolism that can become toxic in high concentration, and some drugs (if taken). These all are secreted into the lumen of renal tubule. Tubular secretion can be either active or passive or co-transport.
Examples of approved drugs that act as renal tubular transport inhibitors include: Probenecid : This is an inhibitor of the organic anion transport system, particularly OAT1 and OAT3. [ 2 ] [ 1 ] It is used clinically to increase the systemic concentrations of certain drugs by reducing their renal excretion.
In studies of dogs, the majority of urinary excretion is through glomerular filtration with some tubular secretion. [54] There is also tubular absorption which is increased with urine acidification. [54] However the activity of nitrofurantoin is also pH dependent and mean inhibitory concentration rises sharply with increased pH above 6. [54]
The collecting duct system of the kidney consists of a series of tubules and ducts that physically connect nephrons to a minor calyx or directly to the renal pelvis.The collecting duct participates in electrolyte and fluid balance through reabsorption and excretion, processes regulated by the hormones aldosterone and vasopressin (antidiuretic hormone).
Fig.3) Secretion and reabsorption of various substances throughout the nephron. The nephron uses four mechanisms to convert blood into urine: filtration, reabsorption, secretion, and excretion. [5]: 395–396 These apply to numerous substances. The structure and function of the epithelial cells lining the lumen change during the course of the ...
The half-life of ceftolozane is 2.5–3.0 hours, and the half-life of tazobactam is approximately 1.0 hour; the clearance of both drugs is directly proportional to renal function. Tazobactam primarily undergoes renal excretion via active tubular secretion.
Osmotic diuretics (e. g., mannitol) are substances that increase osmolarity, but have limited tubular epithelial cell permeability. They work primarily by expanding extracellular fluid and plasma volume, therefore increasing blood flow to the kidney , particularly the peritubular capillaries.