Insulin-like actions of nickel and other transition-metal ions in rat fat-cells

NiCl₂ (1-6mM) decreased adrenaline and glucagon-stimulated lipolysis in rat fat-cells, and also considerably stimulated [U-¹⁴C]glucose incorporation into fat-cell lipids. 2. These insulin-like effects were also observed with CuCl, CuCl₂, CoCl₂ and (to a lesser extent) with MnCl₂. 3. NiCl₂ was less effective in mimicking insulin effects on [U-¹⁴C]fructose metabolism than on glucose utilization. 4. It is tentatively suggested that these transition-metal ions may mimic actions of insulin at the fat-cell plasma membrane which decrease lipolysis and stimulate glucose transport, but do not mimic certain other effects of the hormone on intracellular metabolic processes. 5. These results are discussed with reference to suggestions that redistributions of cellular Ca²⁺ are associated with insulin action in fat-cells.