Pyridoxal 5'-phosphate in whole blood, plasma and blood cells of postpartum nonlactating and lactating rats and their pups.

Pregnant rats were fed either a diet containing 20.2 mg pyridoxine/kg (control) or a diet containing 1,430 mg/kg (high vitamin B-6). At the time of delivery, pups were removed from half of the dams fed each diet. This resulted in four treatment groups: lactating and nonlactating dams fed the control diet and lactating and nonlactating dams fed the high vitamin B-6 diet. At delivery and at weeks 1, 2, and 3 postpartum, groups of dams and pups were killed and the content of pyridoxal 5'-phosphate (PLP) in whole blood, plasma and blood cells was measured. The PLP content in the whole blood of dams and pups was increased significantly by the high vitamin B-6 diet. Lactation had no effect on the PLP in whole blood of dams. Diet increased the PLP content in the plasma of dams and pups only slightly, whereas lactation greatly depressed PLP in the dams' plasma. In the blood cells, the PLP content was increased by diet and decreased by lactation.