ZymographyによるLipase, Lipoprotein Lipase (LPL) の研究
第二報, Heparin-Releasabie LPLについて
1983 年 12 巻 1 号 p. 10-23
詳細
1983 年 12 巻 1 号 p. 10-23
As described in a preceding paper, two lipoprotein lipase bands (b-LPL and f-LPL) were separated from extracts of adipose and other tissues from mice by electrophoresis. In the present paper, some studies with respects to these two types of lipoprotein lipase were made.
It is well known that LPL activity in serum increases after heparin administration in vivo. This is considered to be originated from cell surface of fat or mugcle through a competitive binding of heparin to the cell surface.
It was demonstrated the increase in BAT (brown adipose tissue) LPL activity by the coldexposure was canceled by heparin administration in vivo, and LPL activity in PHP (Postheparin plasma) was increased more in coid-exposed mice than in control ones.On the other hand, it was Shown in zymography that the f-LPL and b-LPL bands from BAT-extracts under cold exposed-mice were strongly stained, furthermore, their bands were decreased by injection of heparin, and the decrease of b-LPL band was especially apparent.The b-LPL band in PHP was increased more in cold exposed-mice than in control ones.Here, the b-LPL band in PHP from Cold exposed-mice was stained more strongly than that from control ones.
Since the increase of LPL could not be observed in other tissues except BAT of animals stressed by the cold, most parts of the increased activity in plasma was considered to be originated from BAT.From results of studies on relationship between b-LPL band and f-LPL band, it seemed most reasonable to conclude as follows.Namely, the b-LPL band in PHP was one type of LPL which was bound to be administrated heparin, and was originated from LPL located on the cell surface.On the other hand, the b-LPL band in tissue-extracts was an extracellular LPL bound to heparin-like glycosaminoglycan on the capillary endothelial surface, so called“heparin-releasable LPL”.lt was believed to be a functional LPL.
Furthermore, the f-LPL which was an another type of LPL seemed to be a glycosaminoglycan-free, an intracellular LPL.
