Glucose-stimulated insulin secretion in rats with normal plasma calcium levels: effects of calcium deficiency.
Weanling Wistar rats were pair-fed for 9 days a control or a calcium-deficient diet. After a 12-hour fast the rats were injected intraperitoneally with glucose (250 mg/100 g body weight), and blood was collected 15, 30 and 60 minutes after the injection. Before injection, calcium (9.7 +/- 0.2 mg/100 ml), glucose and insulin plasma levels were identical in the control and deficient animals, although calcium-deficient animals showed a small but significant increase in blood plasma magnesium levels. Blood glucose levels were higher in the calcium-deficient rats than in control rats 15 to 30 minutes after the glucose injection (15.4 +/- 1.4 vs. 9.7 +/- 0.4 mM, P less than 0.01, 30 minutes after). Plasma insulin levels were significantly lower 15 minutes after the glucose injection (24 +/- 4 vs. 73 +/- 8 microU/ml; P less than 0.01). Calcium deficiency is therefore associated with a decreased response to the glucose tolerance test in the absence of any change in the blood plasma calcium levels.
D000818:Animals; D002118:Calcium / Q000097:blood / Q000172:deficiency / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology*; D005951:Glucose Tolerance Test; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D008274:Magnesium / Q000097:blood; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D007328:Insulin; D008274:Magnesium; D005947:Glucose; D002118:Calcium