Introduction
Kidney function analysis is one of the best tests conducted to assess the level of toxicological damage to the organ. Urine has been proved to be an essential sample in urinalysis and toxicology because, in diseased states, it contains abnormal molecules at elevated or reduced levels. Urine tests are carried out to test for altered renal function when nephrotoxicants are introduced to the kidney (Fowler 1982). Urinalysis tests are concerned with determining molecular weights of substances, identifying substances in urine and quantifying them. Toxicologists also use isoenzymes to test for enzymes found in urine.
Body
The interference of the renal tubules leads to altered renal function which is of interest in toxicological experiments (Fowler 1982). It has been proved that toxic chemical substances can alter the fluid components of the substances that get filtered by the renal tubules. Dysfunctional kidney can be assessed by measuring the amounts of plasma creatinine and urea (Smith & Hook 1982). The levels of these two substances give a reflection of the ultrafiltration activities of the renal tubules. The volume of urine (it can either be oligonuria, polynuria or anuria) is used to test for nephrotoxicity (Smith & Hook 1982). Sometimes, oligonuria might be caused by renal failure that is induced by chemicals. In such cases, polynuria translates to anuria in a dose-response manner. Consistent polynuria may indicate altered renal function which leads to reduced ability of the renal tubules to concentrate urine. Chemicals have been demonstrated to be the main causes of changes in volume of urine in animals. Toxicologists assess the amount of urine produced by a person suspected to be poisoned. Depending on the amount of urine the person is found to void through the renal tubules, toxicologists can make generalised and specific conclusions on the identity and amount of chemicals in the organ systems of the victim.
Measuring the amounts of macromolecules is a sure way of examining renal function in man. The status of the glomerulus is assessed by determining the amounts of protein in the urine. Healthy kidney excretes small amounts of proteins in urine. However, in diseased state the amount of proteins excreted is below or above the normal limits. For example, in healthy persons with normal functioning kidneys the creatinine levels should range between 0.5 to 1.1 mg/ml. Hence, amounts above or below these limits indicate disease states. Human beings exposed to cadmium excrete high amounts of β2 microglobulin in urine.
Examination of the amount of enzymes excreted in urine provides a quick and particular way of assessing nephron function (Smith & Hook 1982). It has been demonstrated that elevated levels of GOT, ALP and GPT indicated early stages of renal injury
Enzymuria tests utilise the knowledge that nephrotoxicants affect particular regions within nephron. Therefore, the order of excretion of enzymes indicates the type of enzymes and the regions affected in nephron during toxicological assessments (Smith & Hook 1982).
Conclusion
Urinalysis helps assess renal damage and dysfunction in toxicological studies. The kidney plays an essential role in ultrafiltration of body fluids to excrete urine in concentrated form. Nephrotoxic agents alter the functioning of the kidney by damaging the tubules or the rate at which the kidney tubules filter fluids. Measuring of macromolecules in urine is used to assess the state of the renal tubules. Enzymuria test is a quick way and specific way of testing for chemically altered nephron.
References
Fowler, JSL, 1982, “Micro-, middle and macromolecules in blood and urine”, Proceedings-Nephrotoxicity (Assessment and Pathogenesis), John Wiley & Sons Publishers, Chister UK, 66.
Smith, JH & Hook, JB, 1982, “Experimental nephrotoxicity in vivo. Nephrotoxicity. Assessment and pathogenesis”, Proceedings of the international symposium on Nephrotoxicity, John Wiley & sons, UK, 117-127.