Effect of maternal insulin deficiency on vitamin D metabolite concentrations in normoglycemic pregnant rats and their fetuses

Summary The effects on vitamin D metabolite concentrations of insulin deficiency, not accompanied by hyperglycemia, were investigated in pregnant rats and in their fetuses injected with 75 mg/kg BW streptozotocin (SZ). These concentrations were measured in maternal plasma and whole fetal body. In the insulinopenic mothers, the 25OHD concentration was found to rise compared with that of control pregnant rats (7.00±1.66 ng/ml, n=16, versus control 4.50±1.60, n=10, 0.0012D, which was previously found to decrease in pregnant rats that were both hypoinsulinic and hyperglycemic, was not different in our control and insulinopenic rats (107.36±38.25 pg/ml, n=11, versus control 122.90±18.20, n=8). In fetuses from our SZ-injected rats, the 24,25 (OH)₂D level diminished compared with the control level (2.12±0.70 ng/g, n=11, versus control 5.23±0.95 ng/g, n=13,P<0.001). The Ca/P ratio in fetal body also decreased (0.68 versus control 1.12). It is suggested that the placental metabolism is an important determinant of normal fetal growth.