Species differences in the activity of a serum triglyceride transferring factor.
Atherosclerosis, 1979/6;33(2):165-9.
Barter PJ, Gooden JM, Rajaram OV
PMID: 224889
Impact factor: 6.847
Abstract
Low density lipoproteins (LDL), endogenously labelled with 3H in the triglyceride moiety, were isolated from rabbit serum and subsequently incubated in vitro at 37 degrees C with unlabelled preparations of rabbit high density lipoproteins (HDL) or very low density lipoproteins (VLDL). In incubations performed in the presence of phosphate buffer, there was no significant transfer of [3H]triglyceride from LDL to either HDL or VLDL; but when rabbit lipoprotein-free serum (the dialysed 1.21 g/ml infranatant) was added, transfer was apparent to both HDL and VLDL. The triglyceride transferring activity of the lipoprotein-free serum was abolished by heating at 85 degrees C for 10 min; all the transferring activity was found in the fraction which precipitated with ammonium sulphate at a concentration of less than 50% saturation. In direct contrast to the rabbit studies, rat serum failed to show a comparable process of triglyceride transfer. In subsequent experiments, mixtures of labelled LDL and unlabelled VLDL isolated either from rabbits or from rats were incubated with lipoprotein-free rabbit, rat or human serum. The lipoprotein-free serum of both the rabbit and man was effective in promoting transfer of 30--50% of LDL [3H]triglyceride into VLDL, regardless of the species origin of the lipoproteins. By contrast the lipoprotein-free serum of rats was only slightly more effective than buffer alone in promoting such transfers. It has been concluded that rabbit and human serum contains a triglyceride transferring factor of far greater activity than that in rat serum.
MeSH terms
Adolescent; Adult; Animals; Humans; Lipoproteins, HDL; Lipoproteins, LDL; Lipoproteins, VLDL; Male; Rabbits; Rats; Species Specificity; Transfer Factor; Triglycerides
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