Aquatic models for the study of renal transport function and pollutant toxicity
Studies of renal cell transport mechanisms and their impairment by xenobiotics are often limited by technical difficulties related to renal tubule complexity. Problems include the juxtaposition of multiple tubule segments with different transport functions and severely limited access to the tubular lumen. Some limitations can be overcome by the careful selection of an appropriate aquatic experimental system. Two aquatic models for the vertebrate proximal segment are discussed here. The first is the kidney from certain marine flounder, which offers the following advantages: long-term viability, little tissue of nonproximal origin, and easy tubule isolation. Data are presented to demonstrate how studies with flounder kidney can be used to elucidate cellular mechanisms whereby different classes of toxic pollutants may interact. Results from these experiments indicate that the excretion of certain anionic xenobiotics can be delayed (1) by other anionic xenobiotics that compete for secretory transport sites and (2) by compounds that disrupt cellular ion gradients and energy metabolism needed to drive transport. The second system is the crustacean urinary bladder, a simple, flatsheet epithelium. Bladder morphology and transport physiology closely resemble those of vertebrate proximal segment. Electron micrographs show a brush border membrane at the luminal surface, numerous mitochondria, and an infolded serosal membrane, while in vivo and in vitro transport studies show reabsorption of NaCl, nutrients and water and secretion of organic cations; organic anions are secreted in bladders from some species and reabsorbed in others. Moreover, since bladders can be mounted as flat sheets in flux chambers, studies with this tissue avoid the problems of complex renal tubule geometry and tissue heterogeneity and tissue heterogeneity that limit transport studies in proximal tubule.
- Research Organization:
- National Institute of Environmental Health Sciences, Research Triangle Park, NC
- OSTI ID:
- 6516394
- Journal Information:
- Environ. Health Perspect.; (United States), Vol. 71
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
MEMBRANE TRANSPORT
BIOLOGICAL MODELS
XENOBIOTICS
BIOLOGICAL EFFECTS
ATP-ASE
BENZOPYRENE
BLADDER
CRUSTACEANS
FISHES
KIDNEYS
MERCURY CHLORIDES
TRANSMISSION ELECTRON MICROSCOPY
WATER POLLUTION
ACID ANHYDRASES
ANIMALS
AQUATIC ORGANISMS
AROMATICS
ARTHROPODS
BODY
CHLORIDES
CHLORINE COMPOUNDS
CONDENSED AROMATICS
ELECTRON MICROSCOPY
ENZYMES
HALIDES
HALOGEN COMPOUNDS
HYDROCARBONS
HYDROLASES
INVERTEBRATES
MERCURY COMPOUNDS
MERCURY HALIDES
MICROSCOPY
ORGANIC COMPOUNDS
ORGANS
PHOSPHOHYDROLASES
POLLUTION
URINARY TRACT
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology