C. Heckemeyer, S. Solomon, J. Barker
Sep 16, 1982
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Influential Citations
8
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Quality indicators
Journal
Biochemical and biophysical research communications
Abstract
Abstract Bacitracin, an antibiotic which decreases extracellular degradation, has been used to study peptide hormone degradation in vitro . The biologic effectiveness of these hormones in the presence of bacitracin has received minimal attention. This study demonstrates inhibition of lipolysis induced by both epinephrine and glucagon in the isolated fat cell (IFC). IFC from epididymal tissue were incubated with 0.5 μM epinephrine and increasing concentrations of bacitracin. Lipolysis was inhibited in a dose-dependent fashion, with a concentration of 5.7 × 10 −4 M bacitracin suppressing lipolysis 50%. Increasing the concentration of epinephrine in the presence of a constant dose of bacitracin overcame the antilipolytic effect. Bacitracin did not increase oxidation of glucose-U-C 14 over basal. In the perifusion system, acute exposure to 5.7 × 10 −4 M bacitracin plus 5 × 10 −9 M glucagon suppressed lipolysis below unstimulated basal levels. Constant bacitracin perifusion produced no change in basal lipolysis but blunted the response to glucagon. 125 I-glucagon degradation was decreased in the presence of bacitracin. Additional studies with dibutyryl cyclic AMP demonstrated that the antilipolytic effect of bacitracin is exerted at a step beyon the second messenger. Bacitracin exerts a direct antilipolytic effect in isolated fat cells without stimulating glucose uptake and may afford a means of studying antilipolysis in the absence of other insulin-like effects.