Vs. Mackintosh et al., VASOACTIVE MEDIATORS AFFECT THE CLEARANCE OF LIPIDS FROM EMULSION MODELS OF PLASMA-LIPOPROTEINS IN RATS, Journal of cardiovascular pharmacology, 27(3), 1996, pp. 447-454
We wished to establish whether the haemodynamic changes accompanying a
lterations in blood pressure exert a direct effect on clearance of chy
lomicron-like emulsions. N-Nitro-L-arginine (NOLA) and endothelin-1 we
re used to increase the blood pressure of normotensive rats, sodium ni
troprusside (NP) and calcitonin gene-related peptide (CORP) were used
to decrease the blood pressure of spontaneously, hypertensive rats (SH
R). The lipid emulsions contained radiolabeled triolein (TO) and chole
steryl oleate (GO) to trace plasma clearances. NP and CORP enhanced TO
clearance in the SHR but slowed the rate of CO clearance. NOLA in nor
motensive rats clearly slowed the rate of TO removal and also retarded
CO clearance, whereas with endothelin-1 TO clearance remained unaffec
ted and CO removal was markedly slowed. The effects on TO clearance ar
e consistent with changes in arteriolar resistance regulating access o
f emulsion particles to lipoprotein lipase on the endothelial cells of
capillaries in muscle and adipose tissue. The changes in CO removal r
ate are more difficult to interpret because factors determining hepati
c blood flow are complex. The results suggest that haemodynamic change
s potentially affect circulation times of various lipoprotein species
in the plasma, with probable consequences in relation to atherogenesis
.