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- Title
Pancreatic beta-cell regeneration after 48-h glucose infusion in mildly diabetic rats is not correlated with functional improvement.
- Authors
Bernard, Catherine; Thibault, Catherine; Berthault, Marie-France; Magnan, Christophe; Sauinier, Catherine; Portha, Bernard; Pralong, William F.; Penicaud, Luc; Ktorza, Alain; Bernard, C; Thibault, C; Berthault, M F; Magnan, C; Saulnier, C; Portha, B; Pralong, W F; Pénicaud, L; Ktorza, A
- Abstract
We investigated the effect of glucose infusion on beta-cell regeneration in rats made mildly diabetic by a single injection of low dosage (35 mg/kg) streptozotocin (STZ). Nondiabetic (ND) and STZ rats were submitted to a 48-h glucose infusion (hyperglycemia approximately 22 mmol/l in both groups: ND and STZ hyperglycemic-hyperinsulinemic [ND HG-HI and STZ HG-HI rats]). Before infusion, beta-cell mass was 65% lower in STZ rats than in ND rats (2.0 +/- 0.02 vs. 5.5 +/- 0.6 mg), 1.6-fold increased in ND HG-HI rats (8.7 +/- 1.7 mg), and 2.7-fold increased in STZ HG-HI rats (5.4 +/- 0.9 mg). In ND HG-HI rats, beta-cell enlargement was related to an increase in beta-cell responsiveness to nutrient secretagogues both in vivo and in vitro, whereas in STZ HG-HI rats, no significant improvement in insulin secretion could be noticed. To determine the respective role of hyperglycemia and hyperinsulinemia on beta-cell area changes, ND and STZ rats were submitted to a 48-h hyperinsulinemic-euglycemic clamp. No modification of beta-cell mass was detected in either group. In conclusion, 48-h superimposed hyperglycemia was enough to restore beta-cell mass previously reduced by STZ injection. This effect seemed to be due to hyperglycemia rather than hyperinsulinemia alone. The data stress the dissociation between beta-cell regeneration and improvement in islet function in diabetic rats. Our model seems suitable for studying factors that can improve the plasticity and function of the pancreas in NIDDM.
- Subjects
GLUCOSE; REGENERATION (Biology); DIABETES; PHYSIOLOGY
- Publication
Diabetes, 1998, Vol 47, Issue 7, p1058
- ISSN
0012-1797
- Publication type
journal article
- DOI
10.2337/diabetes.47.7.1058