Erratum to: Decreased glucagon levels and decreased insulin secretion after sitagliptin versus mitiglinide administration with similar glycemic levels following an oral glucose load: a randomized crossover pharmaceutical mechanistic study.

[This corrects the article DOI: 10.1007/s13340-015-0207-1.].

Decreased glucagon levels and decreased insulin secretion after sitagliptin versus mitiglinide administration with similar glycemic levels following an oral glucose load: a randomized crossover pharmaceutical mechanistic study.

AIMS: Both sitagliptin (SIT) and mitiglinide (MIT) can lower postprandial hyperglycemia. The purpose of this study was to examine differences in insulin and glucagon secretion after SIT or MIT administration when similar levels of plasma glucose (PG) were achieved for both agents following an oral glucose load. PATIENTS AND METHODS: We directly compared the effects of these two agents in 16 type-2 diabetic patients (M/F = 10/6, age 66 ± 3 years old, HbA1c 6.6 ± 0.5 %). Patients received SIT (50 mg qd for 1 week and 100 mg qd for an additional week) or MIT (10 mg tid for 2 weeks). After 2 weeks, patients crossed over to the other treatment. 75-g oral glucose tolerance tests were conducted before the study and after interventions. RESULTS: The area under the curve (AUC) up to 180 min for the PG response was similar for both agents. While basal insulin secretion rates (ISR) were similar, incremental AUC of ISR was significantly lower in the SIT treatment (522 ± 108 vs 702 ± 288 pmol/min min, p < 0.01), although the difference between the SIT and MIT treatments in the Matsuda index-which reflects insulin sensitivity-remained nonsignificant. Glucose-stimulated insulin secretion was similarly increased by the MIT and SIT treatments. Suppression of the AUC for glucagon was observed in the SIT treatment, while MIT treatment failed to suppress the glucagon concentration (-432 ± 2322 vs MIT 1116 ± 2520 pg/ml min, p < 0.05). The basal proinsulin/insulin ratio was lower in the SIT treatment (0.23 ± 0.04 vs MIT 0.26 ± 0.36, p < 0.05). CONCLUSIONS: Although either SIT or MIT can be employed to reduce postprandial hyperglycemia, SIT induces changes in hormonal profiles that are more favorable to islet functions than MIT does.

Effect of troglitazone on serum gamma-glutamyltransferase activity and plasma t-PA/PAI-1 complex in type 2 diabetic patients.

BACKGROUND: This study was conducted to determine whether troglitazone (CAS 97322-87-7, Noscal), a thiazolidinedione with alpha-tocopherol in the side chain, had an antioxidant effect in patients with Type 2 diabetes. METHODS: In 46 Type 2 diabetic outpatients aged 64 +/- 7 years (male/female: 33/13), with a body mass index of 23.4 +/-2.8 kg/m2, a 2-year prospective study was performed. Patients were given troglitazone tablet (200 mg) twice a day. After treatment for 4 months, troglitazone was withheld for one month (washout period). Then troglitazone was resumed for a further 19 months. RESULTS: The study was completed in 28 patients. In 18 patients, it was not completed because of side effects in 4 female patients and because of withdrawal of troglitazone from the Japanese market in 14 patients. Fasting plasma glucose was decreased by troglitazone treatment from 170.2 +/- 38.2 mg/dl to 151.6 +/- 34.5 mg/dl (ANOVA: F = 8.054, p < 0.001). Washout caused it to return to the pre-treatment level (170.9 +/- 38.0 mg/dl), but it decreased again to 145.4 +/- 33.4 mg/dl with the resumption of treatment (F = 3.845, p < 0.001). Glycated hemoglobin was decreased by treatment from 8.2 +/- 1.6 % to 7.9 +/- 1.6 % (F = 7.558, D < 0.001). Washout caused it to return to the pre-treatment level (8.0 +/- 1.6 %), but it decreased again to 7.6 +/- 1.2 % with the resumption of treatment (F = 1.985, p = 0.041). Fasting serum immunoreactive insulin was decreased by treatment from 5.5 +/- 3.4 pU/ml to 4.0 +/- 2.2 pU/ml (F = 9.098, p < 0.001). Washout caused it to return to near the pre-treatment level (4.6 +/- 2.4 pU/ml). After resumption of treatment, it remained unchanged. Serum n-glutamyltransferase (gamma-GT) activity was decreased by treatment from 37.5 +/- 25.7 U/I to 25.6 +/- 12.3 U/I (F = 19.406, p < 0.001). Washout caused it to return to the pre-treatment level (36.5 +/- 25.1 U/I), but it decreased again to 24.2 +/- 10.1 U/l with the resumption of treatment (F = 7.931, p < 0.001). Plasma tissue plasminogen activator(t-PA)/plasminogen activator inhibitor-1 (PAI-1) complex was decreased by treatment from 21.7 + 8.6 ng/ml to 19.0 +/- 6.6 ng/ml (F = 8.784, p < 0.001). Washout caused it to return to the pretreatment level (21.9 +/- 7.4 ng/ml), but it decreased again to 14.3 +/- 4.3 ng/ml after the resumption of treatment (F = 12.341, p < 0.001). CONCLUSION: Decreases in serum gamma-GT activity and plasma t-PA/PAI-1 complex were closely related with antioxidant action of troglitazone.