Pharmacologic inhibition of serotonin htr2b ameliorates hyperglycemia and the altered expression of hepatic FGF21, Sdf2l1, and htr2a in db/db mice and KKA mice.

Plasma fibroblast growth factor 21 (FGF21) levels and hepatic FGF21, serotonin 2a receptor (htr2a), and stromal cell-derived factor 2 like 1 (Sdf2l1) expression are increased in insulin-resistant C57BL6J mice fed a high-fat diet. Here we show that plasma FGF21 levels and hepatic FGF21, Sdf2l1, and htr2a expression were decreased in 6-week-old db/db mice compared with C57BL6J mice, whereas they were increased in 6-week-old KKA mice compared with KK mice. Expression of hepatic htr2b was increased in db/db mice and KKA mice compared with controls. Treatment with the selective htr2b antagonist SB204741 suppressed the hyperglycemia in either db/db mice or KKA mice. Treatment with SB20471 reversed the decreases in plasma FGF21 levels and hepatic FGF21, Sdf2l1, and htr2a expression in db/db mice, whereas it suppressed the increases in plasma FGF21 levels and hepatic FGF21, Sdf2l1, and htr2a expression in KKA mice. Moreover, treatment with SB204741 increased plasma FGF21 levels and expression of hepatic FGF21, htr2a, and Sdf2l1 in C57BL6J mice, whereas it decreased plasma FGF21 levels and hepatic FGF21 expression in KK mice. These findings suggest that pharmacologic inhibition of htr2b ameliorates the hyperglycemia and altered expression of hepatic FGF21, Sdf2l1 and htr2a in obese and diabetic db/db and KKA mice.