Retinol is sequestered in the bone marrow of vitamin A-deficient rats.
Retinoic acid bound to the nuclear retinoic acid receptor-alpha is required for the differentiation of promyelocytes to mature neutrophils. However, severely vitamin A-deficient rats have normal numbers of neutrophils in the blood and inflamed tissues. This paradox was explored using four dietary groups of rats: 1) vitamin A-deficient rats; 2) vitamin A-deficient rats subsequently receiving vitamin A; 3) weight-matched pair-fed rats; and 4) nonrestricted, vitamin A-complete diet-fed rats. Plasma and liver retinol concentrations of the vitamin A-deficient rats were < 1 % of those of the other three groups. In contrast, the bone marrow retinol concentrations of the vitamin A-deficient rats were fourfold higher than those in the other three groups. The distribution of myeloid-derived cells in the bone marrow was similar in all four groups of rats with the exception of a significantly greater (P < 0.05) occurrence of hypersegmented neutrophils (six or more lobes) in the vitamin A-deficient rats (2. 1 %) relative to the control groups (0-0.1%). The blood of the vitamin A-deficient rats also contained significantly higher numbers (P < 0.01) of hypersegmented neutrophils (67%) relative to those in the control groups (2-7%). The hypersegmentation of the neutrophils in this group of rats was not due to a concurrent deficiency of vitamin B-12 or folate. The importance of bone marrow-derived cells to the survival of the animal is suggested by retinol sequestration in the bone marrow of vitamin A-deficient rats, allowing the differentiation of myeloid cells to neutrophils.
Twining
S S
SS
Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Schulte
D P
DP
Wilson
P M
PM
Fish
B L
BL
Moulder
J E
JE
D000818:Animals; D001853:Bone Marrow / Q000378:metabolism* / Q000648:ultrastructure; D002851:Chromatography, High Pressure Liquid; D004032:Diet; D005260:Female; D005492:Folic Acid / Q000097:blood; D008099:Liver / Q000378:metabolism; D008297:Male; D009504:Neutrophils / Q000648:ultrastructure; D051381:Rats; D014801:Vitamin A / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D014802:Vitamin A Deficiency / Q000378:metabolism* / Q000473:pathology; D014805:Vitamin B 12 / Q000097:blood
D014801:Vitamin A; D005492:Folic Acid; D014805:Vitamin B 12