Table 1.

Evaluation of insulin secretion in the proband and her mother

	Proband	Mother
Oral glucose tolerance test
C‐peptide (ng/mL)
Pre	0.85
30 min	2.53
60 min	2.77
120 min	1.79
Glucose (mg/dL)
Pre	121
30 min	199
60 min	321
120 min	323
ΣCPR (ng/mL)	8.6
Arginine challenge test
C‐peptide (ng/mL)
Pre	0.85
30 min	2.53
60 min	2.77
120 min	1.79
Glucagon (pg/mL)
Pre	113
30 min	521
60 min	365
120 min	134
Glucagon challenge test
Glucose (mg/dL)
Pre	98	94
Post	131	105
C‐peptide (ng/mL)
Pre	1.0	1.8
Post	2.2	2.6

Plasma glucose or glucagon as well as serum C‐peptide concentrations before and 30, 60 or 120 min after the oral administration of glucose (75 g) or intravenous administration of arginine (0.5 g/kg) were measured. Plasma glucagon was measured with a radioimmunoassay (BML, Tokyo, Japan). For the glucagon challenge test, glucagon (1 mg) was injected intravenously after the participants had been deprived of food overnight, with plasma glucose and serum C‐peptide being measured before (pre) and 6 min after (post) the injection. ΣCPR, sum of serum C‐peptide immunoreactivity.