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Corticosteroids and the Development of Intrinsic Factor-Mediated Vitamin B12 Absorption in the Rat

1972; Elsevier BV; Volume: 62; Issue: 2 Linguagem: Inglês

10.1016/s0016-5085(72)80176-8

1528-0012

N. D. Gallagher, Karen Foley,

Hormonal Regulation and Hypertension

The changes which occur in vitamin B12 absorption from birth to weaning were studied in unanesthetized rats. The absorption of an oral dose of Co57-labeled vitamin B12, decreased 15 days after birth, at the same time that intrinsic factor (IF) in the stomach rose rapidly to weanling levels. The transition to IF-mediated absorption occurred at an earlier age in rats which were treated with cortisone. Absorption of the vitamin by 12-day-old rats which had received a subcutaneous injection of cortisone 8 days after birth was similar to that in animals which had just been weaned. Saturation of the absorptive mechanism was demonstrated when the dose of vitamin was increased. IF levels increased 6-fold following cortisone treatment. Repeated injections of adrenocorticotropin also resulted in elevated IF levels and in an earlier decrease in the absorption of the vitamin. The time of onset of the IF mechanism may therefore be related to the effects of endogenous corticosterone on gastric and intestinal epithelial cell function.