PMC

Gpr40 expression in β-cells cells requires Ipf1/Pdx1. A: X-gal–stained sections (top panel) of 5-week-old adult islets from Ipf1/Pdx1^+/+;Gpr40^+/lacZ and RIP/Ipf1^Δ;Gpr40^+/lacZ mice counterstained with anti-insulin antibodies (bottom panel). B: Quantitative real-time RT-PCR expression analyses of islet cDNA from Ipf1/Pdx1^+/+ (□, n = 4) and RIP/Ipf1^Δ (□, n = 6) mice. Data are means ± SE. *P < 0.05 for Ipf1/Pdx1^+/+ vs. RIP/Ipf1^Δ islets.

Reduced plasma levels of GIP and GLP-1 in Gpr40^lacZ/lacZ mice in response to fat diet. Plasma insulin, GIP (total), GLP-1 (total), and blood glucose levels (A–D) were determined in 2- to 3-month-old Gpr40^+/+ (n = 10–16, □) and Gpr40^lacZ/lacZ (n = 8–20, ) mice after oral high-fat diet administration. x-axis indicates minutes after oral gavage. Data are means ± SE. *P < 0.05 for Gpr40^+/+ vs. Gpr40^lacZ/lacZ.

Oral glucose tolerance is normal in Gpr40^lacZ/lacZ mice. Blood glucose (A and B) and plasma insulin (C and D) levels in 2- to 3-month-old Gpr40^+/+ (⋄) and Gpr40^lacZ/lacZ (▴) mice after intraperitoneal glucose injections (A and C) and oral glucose administration (B and D). Gpr40^+/+ (n = 16) and Gpr40^lacZ/lacZ (n = 16) for the intraperitoneal glucose injections. Gpr40^+/+ (n = 6) and Gpr40^lacZ/lacZ (n = 5) for the oral glucose administration test.

Gpr40 expression in enteroendocrine cells requires Ipf1/Pdx1. A: X-gal–stained sections of the pyloric sphincter and in duodenum of e17 Ipf1/Pdx1^+/+;Gpr40^+/lacZ and Ipf1/Pdx1^−/−;Gpr40^+/lacZ embryos. B: Quantitative real-time RT-PCR expression analysis of cDNA isolated from pylorus/duodenum of Ipf1/Pdx1^+/+ (□, n = 3) and Ipf1/Pdx1^−/− embryos ( , n = 3). Data are means ± SE. *P < 0.05 and ***P < 0.001 for Ipf1/Pdx1^+/+ vs. Ipf1/Pdx1^−/−. Brackets in A indicate the border of the smooth muscle layer surrounding the lumen of the gut tube. sto., stomach; int., intestine.

Gpr40 is expressed in gut enteroendocrine cells. A: X-gal staining of sections of pylorus, duodenum, jejunum, ileum, and colon in 2-month-old Gpr40^+/+ and Gpr40^+/lacZ mice. B: In situ hybridization using Gpr40-specific probes on sections of neonatal epithelium in stomach and duodenum. Arrows indicate cells expressing Gpr40 mRNA. C: Confocal sections of 2- to 3-month-old adult Gpr40^+/lacZ pylorus and duodenum stained with anti–β-gal antibodies (green) to indicate Gpr40 expression and antibodies specific for the indicated enteroendocrine hormones (red). (Please see http://dx.doi.org/10.2337/db08-0307 for a high-quality digital representation of this figure.)