Kidney roles

Fowler BA, DuVal G. 1991. Effects of lead on the kidney Roles of high-affinity lead-binding proteins. Environ Health Perspectives 91 77-89. 

Lasker IM, Chen WB, Wolf I, Bloswick BP, Wilson PD, et al. 2000. Formation of 20-hydroxyeicosatetraenoic acid, a vasoactive and natriuretic eicosanoid, in human kidney. Role of Cyp4F2 and Cyp4All. J Biol Chem 275 4118-4126. 

Kohn, M. C., and Melnick, R. L. (1999). A physiological model for ligand-induced accumulation of alpha 2u globulin in male rat kidney Roles of protein synthesis and lysosomal degradation in the renal dosimetry of 2,4,4-trimethyl-2-pentanol. Toxicology 136, 89-105. 

Zitting A et al., Acute toxic effects of trinitrotoluene on rat brain, liver, and kidney Role of radical production, Arch. Toxicol., 51, 53, 1982. 

In subsequent studies attempting to find a correlation of physicochemical properties and antimicrobial activity, other parameters have been employed, such as Hammett O values, electronic distribution calculated by molecular orbital methods, spectral characteristics, and hydrophobicity constants. No new insight on the role of physiochemical properties of the sulfonamides has resulted. Acid dissociation appears to play a predominant role, since it affects aqueous solubiUty, partition coefficient and transport across membranes, protein binding, tubular secretion, and reabsorption in the kidneys. An exhaustive discussion of these studies has been provided (10). 

Kidney Function. Prostanoids influence a variety of kidney functions including renal blood flow, secretion of renin, glomerular filtration rate, and salt and water excretion. They do not have a critical role in modulating normal kidney function but play an important role when the kidney is under stress. Eor example, PGE2 and -I2 are renal vasodilators (70,71) and both are released as a result of various vasoconstrictor stimuli. They thus counterbalance the vasoconstrictor effects of the stimulus and prevent renal ischemia. The renal side effects of NSAIDS are primarily observed when normal kidney function is compromised. 

Although it is being found that vitamin D metaboUtes play a role ia many different biological functions, metaboHsm primarily occurs to maintain the calcium homeostasis of the body. When calcium semm levels fall below the normal range, 1 a,25-dihydroxy-vitainin is made when calcium levels are at or above this level, 24,25-dihydroxycholecalciferol is made, and 1 a-hydroxylase activity is discontiaued. The calcium homeostasis mechanism iavolves a hypocalcemic stimulus, which iaduces the secretion of parathyroid hormone. This causes phosphate diuresis ia the kidney, which stimulates the 1 a-hydroxylase activity and causes the hydroxylation of 25-hydroxy-vitamin D to 1 a,25-dihydroxycholecalciferol. Parathyroid hormone and 1,25-dihydroxycholecalciferol act at the bone site cooperatively to stimulate calcium mobilization from the bone (see Hormones). Calcium blood levels are also iafluenced by the effects of the metaboUte on intestinal absorption and renal resorption. 

The integrity of mammalian kidneys is vital to body homeostasis, because the kidneys play the principal role in the excretion of metabolic wastes and the regulation of extracellular fluid volume, electrolyte balance, and acid-base... 

Eder, M., Krantle, R, Dong, Y, et al., 1997. Characterization of human and pig kidney long-chain-acyl-CoA dehydrogena.se.s and dieir role in beta-oxidation. European Journal of Biochemistry 245 600—607. 

AQP6 is expressed in the intercalated cells of the kidney collecting duct. This channel is hardly permeable to water, but capable of transporting anions, including chloride, and is therefore thought to play a role in maintenance of body acid-base balance or in intracellular vesicle acidification. 

AQP10 has only been identified in the small intestine so far and is thought to play a role in hormonal secretion. AQP11 is expressed in kidney, liver, testis and brain, but no function has been found so far. AQP12 has been identified in pancreatic acinar cells, where it is thought to facilitate the release of digestive enzymes into the pancreatic duct. 

CNG channels are expressed in retinal photoreceptors and olfactory neurons, and play a key role in visual and olfactory signal transduction. In addition, CNG channels are found at low density in some other cell types and tissues such as brain, testis, and kidney. While the function of CNG channels in sensory neurons has been unequivocally demonstrated, the role of these channels in other cell types, where expression has been observed, remains to be established. Based on their phylogenetic relationship, the six CNG channels... 

Endothelins comprise a family of three vasoactive isopeptides of 21 amino acids that have an essential role in the regulation of the vascular and bronchiolar tone and the control of natriuresis in the kidney. Endothelin peptides are also involved in nociception and have a critical role in the progression of prostate and ovarian cancer. 

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