AJP - Endocrinology and Metabolism, Vol 249, Issue 1 1-E5, Copyright © 1985 by American Physiological Society
Binding protein for vitamin D and its metabolites in rat mesenteric lymph
S. Dueland, R. Bouillon, H. Van Baelen, J. I. Pedersen, P. Helgerud and C. A. Drevon
A protein with high affinity for vitamin D3 and 25-hydroxyvitamin D3 in rat
mesenteric lymph has been studied. Mesenteric lymph was collected after
duodenal instillation of radiolabeled vitamin D3 and 25-hydroxyvitamin D3.
As previously described, approximately 10% of vitamin D3 (S. Dueland, J.I.
Pedersen, P. Helgerud, and C.A. Drevon, J. Biol. Chem. 257: 146-150, 1982)
and 95% of 25-hydroxyvitamin D3 (S. Dueland, J.I. Pedersen, P. Helgerud,
and C.A. Drevon, Am. J. Physiol. 245 (Endocrinol. Metab. 8): E463-E467,
1983) recovered in mesenteric lymph were associated with the alpha-globulin
fractions. The radioactive vitamin D3 recovered in the lymph fraction with
d greater than 1.006 (free of chylomicrons) coeluted with purified rat
serum binding protein for vitamin D and its metabolites (DBP) from an
antirat DBP column. The results obtained by immunoblotting after sodium
dodecyl sulfate polyacrylamide gel electrophoresis showed that this protein
in mesenteric lymph had molecular weight and immunological properties
identical with purified serum DBP. Purified serum DBP labeled with 125I was
injected intravenously and mesenteric lymph was collected. in lymph,
suggesting that DBP may be transferred from blood to mesenteric lymph and
that plasma and lymph DBP may have a similar origin.
