1. Adipose tissue lipoprotein lipase (EC 18.104.22.168; AT-LPL), a rate-limiting enzyme in triglyceride storage in adipose tissue, is hormonally regulated and may be important in the maintenance of obesity.
2. In twelve obese women, AT-LPL activity was measured before weight loss, during weight loss and after 1 and 2 weeks of weight maintenance on either a high-carbohydrate or a high-protein diet.
3. When related to tissue weight, AT-LPL activity during the 2 weeks of weight maintenance was higher than the initial AT-LPL activity; there was no difference when activity was expressed per cell.
4. Changes in AT-LPL activity were not affected by diet composition. AT-LPL activity correlated with insulin levels and a change in the insulin sensitivity of AT-LPL was observed after weight loss.