Investigations of the Effect of Molecular and Intracellular Transit and Secretion of Chylomicron Lipids Using 3h Triolein Administered in Vivo As A Probe.

3h triolein was incorporated into tag in enterocytes from normal diet and pluronic acid treated over a range of times. after pluronic acid treatment, a strong significant increase in total radioactive incorporation into tag of enterocytes was observed at all time points (po.005) compared with controls. results confirm the inhibitory effect of pluronic acid on the tag transfer from enterocytes. moreover, 3h triolein was incorporated into tag of serum at all time points but in contrast to enterocytes, pluronic acid treatment significantly decreased this incorporation compared with controls (po.005). 3h triolein was incorporated into tag of microsomes and cyto-sol of both controls and pluronic acid treated. this incorporation into microsomes and cytosol was significantly increased by pluronic acid treatment (po.005) compared with controls except at 120min of administration in cytosol. increasing effects of pluronic acid on the incorporation of 3h triolein into tag of enterocytes, and in microsomes and cytosol fractions raises the question whether the accumulated tag is in the er membrane or in the lumen. accordingly microsomes were opened, and radioactivity incorporated into tag of membranes and contents was determined. the incorporation of 3h triolein into membrane tag was more than contents at all time points in both controls and pluronic acid treated. pluronic acid caused a significant increase in the incorporation of radioisotope into tag of both membranes and contents (po.05) but to a greater extent in membranes. furthermore, when pluronic acid was added to chow fed diet, the peak of radioactivity of tag in the membranes and contents was at lhr of administration.in conclusion, incorporation of 3h triolein into tag of enterocytes and serum shows digestion, and absorption of lipids are very fast and also re synthesis of tag into the enterocytes are fast. pluronic acid does not alter the synthesis of tag but caused accumulation of 3h tag in to enterocytes, microsomes, cytosol, microsomal membrane and lumenal content, in contrast, decreased 3h triolein in serum. these results confirm that appearance and accumulation of newly synthesis tag into membrane and content by pluronic acid feeding is because of inhibitory effect of pluronic acid on the fusing of tag and apob48 to make core expansion of chylomicron in lumen of microsomes.