Species differences between chicks and rats in inhibition of lipoprotein hydrolysis by Triton WR-1339.

To identify the species differences in lipoprotein hydrolysis, plasma lipoproteins and lipoprotein lipase (LPLase) prepared from both rats and chicks were incubated in vitro in the presence of Triton WR-1339 at concentrations up to 500 micrograms/ml. Rate of lipoprotein hydrolysis by LPLase declined gradually with an increase of Triton concentration irrespective of differences in sources in the lipoprotein and LPLase. At 250 micrograms/ml Triton, the lipoprotein hydrolysis was inhibited by 90% in rats but was only inhibited by < 20% in chicks. Lipoprotein hydrolysis inhibited by Triton was partly recovered by an increase of LPLase concentration, and extents of the recovery were prominent either when rat lipoprotein was provided in place of chick lipoprotein and when rat LPLase rather than chick LPLase was used as the enzyme source for each lipoprotein. These results suggest species differences between chicks and rats with regard to the affinity of Triton to LPLase and lipoprotein and/or the chemical characteristics of both LPLase and lipoprotein.