Junctional communication of pancreatic β cells contributes to the control of insulin secretion and glucose tolerance
J. Clin. Invest. Anne Charollais, et al. 106:235 doi:10.1172/JCI9398 [Go to this article.]

Figure 4
Transgenic mice expressing Cx32 show altered insulin secretion. (a) Insulin secretion from in situ perfused pancreas was evaluated during six 20-minute periods that consecutively tested glucose concentrations from 1.4–16 mM glucose. Control mice (open squares) showed a progressive increase in insulin output as glucose concentration increased. In contrast, transgenic mice (solid circles; heterozygous and homozygous animals pooled) were essentially unaffected by glucose concentrations up to 8 mM and poorly stimulated at higher concentrations of the sugar. Data are mean ± SEM of the indicated number of animals. (b) The cumulative insulin output of control pancreas (open bars) perfused with 8 and 16 mM glucose was 4.2- and 9-fold higher than that measured in the presence of 1.4 mM of the sugar, respectively. Heterozygous transgenic mice (gray bars) showed a reduced response to both 8 mM (P < 0.005) and 16 mM (P < 0.03) glucose, their average insulin output being only 1.9- and 5.5-fold higher than basal level in the presence of these two glucose concentrations, respectively. Compared with controls, homozygous transgenic mice (solid bars) also showed a reduced insulin output in the presence of both 8 mM (P < 0.02) and 16 mM glucose (P < 0.007), their average insulin output being similar to basal level in the presence of the two glucose concentrations. Data are mean ± SEM of the indicated number of animals. ^AP < 0.05; difference between values evaluated for successive glucose concentrations. ^BP < 0.02; difference between values evaluated for successive glucose concentrations. ^CP < 0.001; difference between values evaluated for successive glucose concentrations.