Tyrosine transport in winter flounder intestine: Interaction with Na sup + -K sup + -2Cl sup minus cotransport

Journal Article · Sat Aug 01 00:00:00 EDT 1987 · American Journal of Physiology; (USA)

OSTI ID:5084712

Musch, M W; McConnell, F M; Goldstein, L; Field, M ^[1]

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1. Brown Univ., Providence, RI (USA) Columbia Univ., New York, NY (USA) Mount Desert Island Biological Laboratory, Salsbury, ME (USA)

Tyrosine absorption across the brush border of the intestinal epithelium of the winter flounder Pseudopleuronectes americanus was studied in Ussing chambers modified to determine early rates of uptake. At 0.1 mM tyrosine, the 4-min rate of uptake (influx) of tyrosine across the brush border averaged 37.5 nmol{center dot}cm{sup {minus}2}{center dot}h{sup {minus}1}. Omission of Na decreased influx by 60%, indicting that tyrosine influx occurs, at least in part, by a Na-coupled process. Ouabain inhibited influx by 80%. Inhibition of brush border Na{sup +}-K{sup +}-2Cl{sup {minus}} cotransport by bumetanide, 8-bromo-cyclic GMP, or Cl replacement stimulated tyrosine influx 2.5- to 4-fold. However, atriopeptin III, which also inhibits Na{sup +}-K{sup +}-2Cl{sup {minus}} cotransport, did not stimulate tyrosine influx. Cyclic AMP, which does not appear to inhibit ion cotransport, did not stimulate tyrosine influx. Both cyclic GMP and bumetanide also stimulated the net mucosa-to-serosa tyrosine flux (43 and 29%, respectively) and increased the cellular concentration of tyrosine by 50%. Thus tyrosine's influx is increased to a greater extent than is its transmural flux or its cellular concentration, suggesting that the main change occurs at the brush border and represents large increases in both influx and efflux of tyrosine across this membrane.

• OSTI ID: 5084712
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 253:2; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

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59 BASIC BIOLOGICAL SCIENCES
ABSORPTION
ALKALI METAL COMPOUNDS
AMINO ACIDS
ANIMALS
AQUATIC ORGANISMS
BIOCHEMISTRY
BODY
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
DIGESTIVE SYSTEM
DRUGS
FISHES
GASTROINTESTINAL TRACT
GLYCOSIDES
HALIDES
HALOGEN COMPOUNDS
HYDROXY ACIDS
INTESTINAL ABSORPTION
INTESTINES
LABELLED COMPOUNDS
MEMBRANE PROTEINS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
OUABAIN
POTASSIUM CHLORIDES
POTASSIUM COMPOUNDS
PROTEINS
SODIUM CHLORIDES
SODIUM COMPOUNDS
STROPHANTHINS
TYROSINE
UPTAKE
VERTEBRATES