Endothelin-1 Stimulates Glucose Transport in Murine 3T3 Adipocyte Lineage, But Not in Human Subcutaneous Fat Cells

Abstract

Endothelin-1 has been recently described to stimulate glucose uptake in cultured 3T3 adipocytes via an intracellular signaling cascade distinct from that activated by insulin. In this work, we investigated whether this stimulatory effect of endothelin-1 was also found in human subcutaneous fat cells obtained from nonobese nondiabetic subjects. Endothelin-1 was unable to stimulate 2-deoxyglucose uptake in human adipocyte preparations highly responsive to insulin, while it increased hexose transport in murine 3T3-L1 and 3T3-F442A differentiated adipocytes, reaching one-third of the maximal insulin effect. Under similar conditions, the insulin-like agent peroxovanadate was effective in both human isolated fat cells and murine cultured adipocytes. Even when tested up to 100 nM or when incubated on a 3-hour period, endothelin-1 neither stimulated glucose uptake nor modified lipolytic activity of human adipocytes. These observations do not allow to merely extrapolate to human adipose tissue the short-term effects of endothelin-1 previously observed on rodent adipocytes.