Acute alterations of cyclo(His-Pro) levels after oral ingestion of glucose

We analyzed the response of plasma cyclo(His-Pro) (CHP) (N = 14), insulin (N = 8), and glucose (N = 8) to oral ingestion of 75 grams of glucose in normal volunteers. Mean Fasting CHP levels prior to glucose were 614 ± 112 pg/ml (±SE). After glucose ingestion there occurred an acute rise of plasma CHP within 15 minutes ( 12 14 ) followed by a fall in plasma concentrations to below baseline values (11 of 14). The mean of highest levels within the first 15 minutes after glucose ingestion was 1035 ± 300 pg/ml (±SE), significantly above baseline (p = 0.002). The mean of lowest values below baseline was 490 ± 94 pg/ml (±SE), p < 0.001. We conclude that levels of CHP are acutely and reversibly altered by the ingestion of glucose. The possible significance of these perturbations in CHP concentrations is discussed.