Glucose, insulin secretion, and insulin secretory pulses were measured by deconvolution of peripheral C-peptide concentrations in 10 IDDM recipients of a combined kidney-pancreas allograft 6 mo post-transplantation and were compared with 10 matched nondiabetic control subjects. Seven of the 10 recipients were restudied 2 yr post-transplantation. To control for immunosuppressive therapy, 6 patients with a kidney allograft also were studied. Pancreatic insulin secretion rates were evaluated over a 24-h period with three mixed meals. Six months post-transplantation, fasting (5.3 ± 0.1 vs. 5.3 ± 0.1 mM), average 24-h (6.0 ± 0.1 vs. 5.7 ± 0.1 mM), and meal-related (6.1 ± 0.3 vs. 5.8 ± 0.2 mM) plasma glucose levels were not different in control subjects and recipients, respectively. Total 24-h insulin secretion rates were similar between the two groups (150 ± 15 vs. 182 ± 24 nmol · m−2 · 24 h−1). However, post-transplantation, the relationship between basal and meal-stimulated insulin secretion was altered with increased basal insulin secretion (52.2 ± 6.4 vs. 97.4 ± 12.5 pmol · m−2 · min−1P < 0.004) and reduced meal-related secretion. The proportion of total 24-h insulin secretion comprised by basal secretion was 44 ± 4% in the control subjects vs. 73 ± 5% in recipients. The number of ultradian oscillations of insulin secretion identified in each 24-h period by pulse analysis was similar in control subjects and recipients (11.9 ± 0.9 vs. 10.4 ± 0.5 oscillations/24 h). Two years post-transplantation, the glucose profiles and oscillatory insulin secretory patterns remained intact. Basal insulin secretion was 76 ± 11 pmol · m−2 · min−1 and 24-h insulin secretion was 167 ± nmol m−2 24 h−1. Six kidney-transplant recipients studied showed that 47 ± 3% of 24-h insulin secretion was basal secretion. This finding supported the idea that altered meal secretory patterns observed in the kidney-pancreas recipients were not the result of immunosuppressive therapy. After combined kidney-pancreas transplantation 1) plasma glucose profiles remain normal 2 yr post-transplantation, 2) clearance of C-peptide is reduced, 3) basal insulin secretion is increased but meal responses are reduced, and 4) the normal oscillatory pattern of insulin secretion persists.

This content is only available via PDF.