Regulation of Lipid Transport and Deposition: Role of Prostaglandin E sub 1

摘要

Three series of experiments were performed to clarify the role of the prostaglandins in regulating the mobilization of free fatty acids (FFA) from adipose tissue. In the first series, epididymal fat pads were stimulated by faradic current in a medium with or without added prostaglandin E sub 1 (PGE sub 1). Even very low concentrations of PGE sub 1 inhibited release of FFA; this inhibition was even more pronounced when electrical stimulation was used to increase release of FFA into the medium. In the second series of experiments, PGE sub 1 was infused in vivo into normal rats and guinea pigs and into medullectomized rats. PGE sub 1 caused a simultaneous decrease in plasma FAA levels and an increase in blood glucose levels in both normal and demedullated animals. In the third series of experiments, mast cells were incubated in vitro with PGE sub 1. Results showed that PGE sub 1 caused release of granules, of histamine (indicated by release of H3-histamine), and of heparin (shown by release of S35-heparin) from mast cells. These experiments suggested that the role of PGE sub 1 on lipid transport includes limiting of FFA mobilization from adipose tissue, lowering of serum FFA levels, and stimulation of the release of heparin, thereby increasing lipoprotein lipase activity. These studies provide further evidence of the important role of the prostaglandins in regulating lipid mobilization and transport. (Author)