FIGURE 7.
Expression of gastric and non-gastric H+-K+ pumps. A, RT-PCR on mRNA extracted from whole rat pancreas (P), stomach (S), or colon (C). Samples were run with primers for α-subunits of the gastric H+-K+ pump (HKα1), non-gastric H+-K+ pump (HKα2) and β-subunit for the gastric H+-K+ pump (HKβ). The expected transcripts were 476, 486, and 373 bp, respectively. B, nested PCR on single isolated pancreatic ducts showing transcripts for HKα1, HKα2, and HKβ subunits. The expected transcripts were 350, 307, and 276 bp, respectively. Purity of duct preparations was checked (see “Experimental Procedures”). Primer sets are given in Table 1. Identity of all products was confirmed by sequencing. C–E, Western blot on membrane fraction proteins extracted and from pancreas (P), stomach (S), kidney (K), and colon (C). C, gastric H+-K+ antibody (Calbiochem 119101) was used. D, non-gastric antibody HKα2 antibody (C384-M79) (17) was used. E, antibody directed against gastric HKβ (Sigma A2749) was used. See supplemental Figs. S1–3 for controls.