Endocrinology, Vol 100, 642-647, Copyright © 1977 by Endocrine Society

ARTICLES

Ontogeny and effect of vitamin D deprivation on rat serum 25- hydroxyvitamin D binding protein

S Rojanasathit and JG Haddad
Department of Medicine, Washington University School of Medicine, Jewish Hospital, St. Louis, Missouri 63178.

Specific serum binding of 25-hydroxy-cholecalciferol (25-OHD3) was measured by saturation analysis in rats of various ages, and during vitamin D deprivation. The serum binding capacity for 25-OHD3 was observed to increase until age 6-8 weeks, then decline and remain stable thereafter at 3.7 x 10(-6) M. The 25-hydroxyvitamin D (25-OHD) concentration decreased in serum from rats fed vitamin D-free diet (t1/2 = 7 days). Rats fed 2 IU of vitamin D3/g of diet maintained stable serum levels of 25-OHD at 10-12 ng/ml. Serum binding capacity and affinity for 25-OHD3 was not affected by vitamin D deprivation or hypocalcemia. In addition, the binding affinity did not differ as a function of age (Kd = 3.3 x 10(-9) M). Since normal serum concentrations of 25-OHD in the rat are 2-5 x 10(-8) M, only 1-2% of the serum binding sites for this sterol are occupied under physiological conditions.

This article has been cited by other articles:

				M. J. Rowling, C. Gliniak, J. Welsh, and J. C. Fleet High Dietary Vitamin D Prevents Hypocalcemia and Osteomalacia in CYP27B1 Knockout Mice J. Nutr., December 1, 2007; 137(12): 2608 - 2615. [Abstract] [Full Text] [PDF]

				H. Gelbard, P. Stern, and D. U'Prichard 1 alpha, 25-Dihydroxyvitamin D3 nuclear receptors in pituitary Science, September 12, 1980; 209(4462): 1247 - 1249. [Abstract] [PDF]