Abstract
Oral glucose tolerance test with 50g glucose was carried out with and without simultaneous oral administration of 3g calcium lactate. Blood sugar and serum immunoreactive insulin (IRI) were measured before and 30, 60, 90 and 120min after glucose load in 11 diabetics and 11 non-diabetics. Similar oral glucose tolerance test was performed with and without intravenous administration of 10ml 8.5% calcium gluconate in 6 diabetics and 6 non-diabetics. Maximum serum level after glucose load (Max IRI), maximum rise of serum IRI following glucose load (Max ΔIRI), maximumΔIRI/ΔBS following oralglu cose load (Max ΔIRI/ΔBS), the area surrounded by the ΔIRI curve and the abscissa (ΣΔIRI) and the area surrounded by the ΔIRI/ΔBS curve and the atscissa (ΣΔIRI/ΔBS) significantly increased in diabetics but not in non-diabetics after oral calcium load, whereas intravenous calcium load failed to influence any of these values. Oral calcium load thus appears to augment glucose-induced insulin secretion only in diabetics, suggesting some abnormality in the mechanism of insulin secretion with reference to calcium in diabetes mellitus.
