Reversibility of the insulin-stimulated phosphorylation of ATP citrate lyase and a cytoplasmic protein of subunit Mr 22000 in adipose tissue

Exposure of rat epididymal adipose tissue to insulin leads to a 2-fold increase in incorporation of [32P]phosphate into ATP citrate lyase and a cytoplasmic protein of Mr 22000. A smaller increase and decrease in incorporation into cytoplasmic proteins of Mr 63000 and 20000 respectively were also observed. Subsequent addition of anti-insulin serum largely reversed these changes within 15 min, indicating that the alterations in 32P incorporation represented changes in net phosphate content of the proteins.