Insulin action and cirrhosis: insulin binding and lipogenesis in isolated adipocytes

Insulin receptors and insulin stimulation of lipogenesis were studied in adipocytes from normal and cirrhotic subjects undergoing abdominal surgery. Despite the presence of hyperinsulinemia in the cirrhotic subjects, binding to receptors was not diminished compared to controls, whether expressed per cell number or cell size. Lipogenesis per cell surface area was higher basally (17.4 +/- 5.1 versus 3.8 +/- 1.6, p less than 0.05) and during maximal insulin stimulation (31.8 +/- 6.5 versus 10.4 +/0 3.9, p less than 0.01) in the cirrhotic subjects. However, cirrhotic and control adipocytes showed a similar increase above basal rates of lipogenesis with maximal insulin stimulation. The rate of lipogenesis was not correlated with fasting insulin level but was negatively correlated, basally (r = -0.61, p less than 0.05) and during maximal insulin stimulation (r = -0.52, p less than 0.05) with cell surface area. In contrast, insulin insensitivity, as quantified by ED50 for stimulation of lipogenesis, was positively correlated with fasting insulin level (r = 0.77, p less than 0.05) but was not related to cell size. It is concluded that the in vivo insulin resistance seen in cirrhosis is not due to any diminution in insulin binding or lipogenesis in adipocytes.