Time dependent effect of Diapin on blood glucose level in <i>KKay</i> diabetic mice.

<p>Male <i>KKay</i> diabetic mice were randomly divided into control and treated groups. In control group (•), the mice were fed with regular chaw diet. The mice in the treated groups were fed with regular chow diet containing 6 (Δ) and 12 g/kg Diapin (▪), respectively. The casual blood glucose levels were monitored weekly. n = 10, *<i>p</i><0.05, compared with the control.</p

Effect of Diapin on blood glucose levels in C57BL/6J mice during OGTT.

<p><b>A.</b> Effect of Diapin on blood glucose. The mice were fasted overnight and orally loaded with glucose (2 mg/g, bw) in the control (n = 10) and glucose (2 mg/g) plus Diapin (4 µmol/g, equal to 1 mg/g) in the treated group (n = 10). <b>B.</b> Effect of the amino acids of Diapin on blood glucose. In the treated group (n = 10), the mice were loaded with glucose and mixture of amino acids of Diapin (G, G, L; 4 µmol/g for each amino acid). <b>C.</b> Effect of the dipeptides on blood glucose. In the treated groups, the mice were loaded with glucose and dipeptides (GG or GL, 4 µmol/g). <b>D.</b> Effect of a control peptide on blood glucose. In the treated group (n = 10), the mice were loaded with glucose and a tripeptide (4 µmol/g). Blood glucose levels were measured every 30 min after glucose loading. *<i>P</i><0.05, compared with the controls.</p

Effect of Diapin on blood glucose levels in diabetic mice.

<p>After oral loading of Diapin (Δ, 0.5 mg/g; ▪, 1 mg/g) by gavage, OGTT was performed in male (<b>A</b>) <i>ob/ob</i> (n = 10), (<b>B</b>) <i>db/db</i> (n = 10) diabetic mice, (<b>C</b>) <i>KKay</i> (n = 9), and (<b>D</b>) the high fat diet-induced obesity mice (n = 10), in which the wild type male C57BL/6J mice were fed with high fat diet for ten weeks. *<i>p</i><0.05, compared with the controls.</p

Effect of Diapin on non-fasting blood glucose levels in <i>KKay</i> diabetic mice.

<p>(A) Male <i>KKay</i> diabetic mice and (<b>B</b>) adult male C57BL/6J mice under non-fasting condition were given either vehicle in control groups or Diapin (1 mg/g bw, n = 9/group) in the treated groups. After Diapin loading, the blood glucose levels were measured every 30 min. *<i>P</i><0.05, compared with the controls.</p

Effect of Diapin on plasma GLP-1 levels in <i>KKay</i> diabetic mice.

<p><b>A.</b> GLP-1 levels in mouse plasma. The male <i>KKay</i> mice (n = 10/group) were treated as in Fig. 6A. Blood samples were collected 30 min after administration of glucose and plasma GLP-1 levels were measured. <b>B.</b> GLP-1 secretion by STC-1 cells. STC-1 cells were treated with various concentration of Diapin for 2 hours and the supernatants were collected for GLP-1 measurement. *<i>P</i><0.05, compared with that in the absence of Diapin.</p

Effect of Diapin on blood glucose in C57BL/6J mice during IPGTT.

<p>The mice were orally given vehicle in the control group (n = 10) and Diapin (1 mg/g, n = 10) in the treated group and followed by IPGTT. *<i>P</i><0.05, compared with the controls.</p

Effect of Diapin on plasma insulin levels in <i>KKay</i> diabetic mice.

<p><b>A.</b> Insulin levels in mouse plasma. The fasted male <i>KKay</i> mice were randomly divided into two groups (n = 11/group) and orally given glucose or glucose plus Diapin, respectively. Blood samples were collected 30 min after administration of glucose and plasma insulin levels were measured. <b>B.</b> Diapin concentration in mouse plasma. The fasted male C57BL/6J mice were orally loaded with Diapin at 1 mg/g bw plus glucose 2 mg/g. Blood samples were collected at different time points and Diapin in plasma was measured by LC-MS/MS system (n = 5). <b>C.</b> Insulin secretion by INS-1 cells. INS-1 cells were treated with various concentration of Diapin for 1 hour and the supernatants were collected for insulin measurement. *<i>P</i><0.05, compared with that in the absence of Diapin.</p