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J Tannenbaum

Publications and source records attributed to J Tannenbaum.

42 records · Page 3Linked to original sources

Subcellular localization of binding sites for cytochalasin D: evidence from activation energies.

The activation energies for binding of tritiated cytochalasin D to HEp-2 cells and isolated plasma membrane were determined by Arrhenius plots. The higher value for intact cells (24 kcal/mol) compared to the plasma membrane fraction (4 kcal/mol at greater than 11.5 degrees C, 18 kcal/mol at less than 11.5 degrees C) was taken as evidence that [3H]cytochalasin D must penetrate the plasma membrane in order to reach its binding sites. The data support the conclusion that binding sites for [3H]cytochalasin D are intracellular, on the cytoplasmic face of the plasma membrane (rather than within the lipid bilayer), and on microsomes (endomembranes).

Binding Sites↗

Enhanced renal prostaglandin production in the dog. I. Effects on renal function.

The changes in renal function produced by endogenous synthesis of prostaglandins by the kidney were evaluated by infusing sodium arachidonate, the prescursor of the prostaglandins, into one renal artery of the dog. These changes were compared with those produced by similar infusions on performed prostaglandin (PG) E2 and F2alpha.PGE2given at 0.01-0.3 mug/kg min--1 produced dose-related increases in urine flow, sodium and potassium excretion, free water clearance, and renal blood flow. The glomerular filtration rage increased only at the lowest dose and the calculated filtration fraction fell. Arachidonic acid at 1.0-30.0 mug/kg min--1 similarly produced dose-related increases in electrolyte excretion, but the increase in renal blood flow was much less than that produced by PGE2 and there were no changes in glomerular filtration rate, filtration fraction, or free water clearances. PGF2alpha had essentially no effects at infusion rates of 0.03-1.0 mug/kg min--1. All renal effects of arachidonic acid were inhibited by simultaneous infusions of an inhibitor of prostaglandin synthetase, 5, 8, 11,14-eicosatetraynoic acid (20:4). None of the effects produced by PGE2 were inhibited by 20:4. These results indicate that enhanced endogenous renal prostaglandin synthesis, which can be produced by arachidonate infusion, results in significant alterations of renal function. This finding strengthens the hypothesis that renal prostaglandins formed in vivo have physiological importance as regulators of renal function.

Animals↗