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. 1997 Apr 29;94(9):4782–4787. doi: 10.1073/pnas.94.9.4782

Figure 4.

Figure 4

Expression and glucose-dependent regulation of MIF mRNA in pancreatic β cell lines and in isolated rat pancreatic islets. (A) Northern blot analysis of MIF mRNA and β-actin mRNA expression by INS-1 cells incubated with 0, 5, 10, and 20 mM glucose in RPMI 1640 medium for 24 hr. (B) Time course of MIF mRNA expression by INS-1 cells incubated with 20 mM glucose. Total RNA was extracted at intervals, and MIF mRNA was analyzed by Northern blotting as described in the Methods. (C) Islets of Langerhans were isolated from Sprague–Dawley rats, total RNA was extracted from 100 and 200 islets and analyzed by Northern blotting using MIF and rat proinsulin II cDNA probes. (D) Western blot analysis of the MIF content of INS-1 cells or isolated islets of Langerhans. Protein extracts (40 μg) obtained from INS-1 cells or islets of Langerhans were size-fractionated on an SDS/18% polyacrylamide gel, transferred to nitrocellulose, and blotted with an anti-MIF antiserum. rMIF (50 ng) served as a positive control and size marker. (E) Northern blot analysis of MIF, GLUT-2, and β-actin mRNA expression by 400 pancreatic islets incubated for 12 hr in RPMI 1640 medium containing 2.8 or 30 mM glucose. Normalized to β-actin, MIF and GLUT2 mRNA increased 4-fold when the glucose concentration was raised from 2.8 to 30 mM.