ATP content of isolated fat cells effects of insulin, ouabain, and lipolytic agents
1970; Elsevier BV; Volume: 202; Issue: 3 Linguagem: Inglês
10.1016/0005-2760(70)90120-7
ISSN1879-145X
Autores Tópico(s)Pancreatic function and diabetes
Resumo1. The ATP content of isolated fat cells was measured by a luminescence assay. 2. The depression of ATP content induced by oligomycin was partly prevented by the addition of glucose to the incubation medium and more so by the further addition of insulin or ouabain, agents known to increase glucose uptake. 3. Lipolytic agents (adrenaline, caffeine) markedly depressed the ATP levels. The magnitude of this effect was dependent on the concentrations used and on the duration of incubation. 4. The addition of octanoate to the incubation medium or the reduction in the albumin concentrations in the medium mimicked lipolytic agents in decreasing the ATP levels. These effects were ascribed to an increase in intracellular free fatty acids brought about by these procedures. 5. In the absence of added glucose, insulin, ouabain or omission of K+ partly prevented the depression in ATP levels induced by lipolytic agents. 6. Two main mechanisms are suggested for the effect of lipolysis on ATP levels: increased utilization, e.g. for cyclic AMP formation, and decreased formation. This second effect may be due to interference with phosphorylating respiration by free fatty acids or their derivatives or some other product (s) of lipolysis. 7. Insulin appears to regulate ATP levels: (a) by its effect on glucose entry and further metabolism; (b) by its antilipolytic action. The complexity of the latter is illustrated by the observation that insulin counteracted the depression in ATP levels induced not only by adrenaline but by caffeine as well.
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