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Vitamin D and Bone Mineral Homeostasis during Pregnancy in the Diabetic BB Rat*

1986; Oxford University Press; Volume: 118; Issue: 3 Linguagem: Inglês

10.1210/endo-118-3-1019

1945-7170

Johan Verhaeghe, R. Bouillon, B. L. Grégoire Nyomba, Willy Lissens, Frans André Van Assche,

Birth, Development, and Health

Vitamin D and bone mineral metabolism during pregnancy were studied in 17 diabetic and 13 control BB rats. Oh day 21 of pregnancy, reduced mean levels of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3; 56.9 vs. 97.9 pg/ml; P < 0.0001] and vitamin D-binding protein (304 vs. 482 μg/ml; P < 0.0001) were found in the diabetic rats, while the free 1,25-(OH)2D3 concentration was not different from the control level. Total plasma calcium and total plasma protein concentrations were also significantly decreased in the diabetic group, but the calculated diffusible calcium was not significantly lower. Calcium and phosphorus urinary excretion were increased in the diabetic rats. There was no difference in bone mineral content. The fetuses of the diabetic BB rat had a lower body weight and were hypoinsuliriemic. Both 1,25-(OH)2D3 (41.3 vs. 54.7 pg/ml; P < 0.01) and vitamin D-binding protein (80 vs. 123 μg/ml; P < 0.001) were decreased in the fetuses of diabetic rats, but the free 1,25-(OH)2D3 concentration was slightly but significantly (6.96 vs. 5.54; P < 0.05) increased. We observed that the fetuses of diabetic rats had fewer ossification centers, counted with the Alizarin Red S staining method. The fetal ash weight was lower in the diabetic group (16.7 vs. 26.9 mg; P < 0.0001). In addition, the relative calcium and phosphorus, but not magnesium, content of ash was lower in the fetuses of diabetic rats. This reduced mineral content in fetuses of diabetic mothers could be implicated in the pathogenesis of early neonatal hypocalcemia in infants of diabetic mothers. (Endocrinology118: 1019–1025, 1986)