PYY STIMULATES SYNTHESIS AND SECRETION OF INTESTINAL APOLIPOPROTEIN AIV WITHOUT AFFECTING MESSENGER-RNA EXPRESSION

We tested whether exogenous peptide YY (PYY) can stimulate synthesis a nd lymphatic secretion of intestinal apolipoprotein AIV (apo ATV). Rat s with mesenteric lymph fistulas and right atrial cannulas were given continuous intravenous infusions of central vehicle or PYY at 25, 50, 75, 100, or 200 pmol . kg(-1) . h(-1). PYY (75-200 pmol . kg(-1) . h(- 1)) stimulated lymphatic apo AIV output from 1.5- to 3.5-fold higher t han basal output. In separate experiments, PW (100 pmol kg(-1) . h(-1) ) produced a 60% increase in jejunal mucosal apo AIV synthesis but had no effect on mucosal apo AIV mRNA levels at doses up to 200 pmol . kg (-1) . h(-1). Finally, exogenous PW infusion (100 pmol . kg(-1) . h(-1 )) produced a plasma PW increment of 30 pM compared with an increment of 18.7 pM in response to ileal infusion of Lipid. These results suppo rt the hypothesis that PYY may he an endocrine mediator of the effects of distal gut Lipid on production and release of intestinal apo ATV, likely via a posttranscriptional mechanism of action.