Transient dexamethasone loading in mice causes prolonged hyperglycemia associated with lower GLP-1 level and higher DPP-4 activity. Mice were subcutaneously implanted with dexamethasone (Dexa) pellets designed for a 21-day continuous release. Blood glucose level of Dexa-treated mice persistently increased in the ITT and OGTT. Decreased GLP-1 level and increased DPP-4 activity of Dexa-treated mice during and after Dexa-loading were revealed. (A) Schematic representation of the transient Dexa loading in the experimental mice. (B-E) Blood glucose levels of Dexa-treated mice during the ITT. (F-I) Those during the OGTT. (J-M) Plasma insulin levels of Dexa-treated mice during the OGTT. (N-Q) Plasma GLP-1 levels of Dexa-treated mice during the OGTT. (R-U) Plasma DPP-4 activity of Dexa-treated mice during the OGTT. (B, F, J, N, R) Before Dexa-loading (day 0), (C, G, K, O, S) during Dexa-loading (day 14), (D, H, L, P, T) 1 week after the completion of Dexa loading (after the completion: day 28), and (E, I, M, Q, U) 5 weeks after the completion of Dexa loading (postloading: day 56). DPP-4, dipeptidyl peptidase 4; GLP-1, glucagon-like peptide 1; ITT, insulin tolerance test; OGTT, oral glucose tolerance test. Gray lines indicate control mice; black lines represent Dexa-treated mice. *P < 0.05, **P < 0.01 vs control. N = 8 per group.