TOX 300 Lecture Notes - Lecture 20: Proximal Tubule, Blood Urea Nitrogen, Haloalkane
Document Summary
Urine is major excretion route for most xenobiotics. Concentrates xenobiotics in filtrate (during tubular reabsorption) Excretion of metabolic (nitrogenous) wastes: e. g. urea. Blood pressure regulation (related to fluid volume in the body) *a lipid-soluble xenobiotic will get concentrated in the filtrate when water is reabsorbed, creating a concentration gradient between the filtrate and the blood. This allows the xenobiotic to passively diffuse back into the capillaries this is why we need biotransformation to make xenobiotics water-soluble. **if a xenobiotic causes kidney toxicity and disrupts its major functions, it will cause a toxic response to the organism it is a major target organ like the liver. Increased levels of small proteins indicate loss of pct reabsorption, indicating toxicity to pct cells. Increased levels of large proteins indicate effects on glomerular cells. Glycosuria = increased glucose in urine indicates tubular dysfunction (in absence of hyperglycemia: usually no glucose is excreted in the urine, unless the person has diabetes.
