TY - JOUR
T1 - [63] A Sensitive Radioreceptor Assay for 1α,25-Dihydroxyvitamin D in Biological Fluid
AU - Chandler, John S.
AU - Wesley Pike, J.
AU - Hagan, Laura A.
AU - Haussler, Mark R.
PY - 1980/1/1
Y1 - 1980/1/1
N2 - This chapter discusses a sensitive radioreceptor assay for lα,25-dihydroxyvitamin D in biological fluids. Vitamin D has been recognized as a principal regulator of calcium and phosphate homeostasis in a variety of animal species, including humans. Some studies describe 1α,25-dihydroxyvitamin D [lα,25-(OH)2D] as the hormonal metabolite responsible for mediating intestinal transport of these minerals and hence necessitate development of a precise method for quantitating this sterol in biological fluids, particularly serum. It has been demonstrated that chick intestinal mucosa contained a cytosolic protein that rapidly and specifically bound lα,25-(OH)2D3 both in vivo and in vitro with high affinity. Furthermore, the sterol–protein complex was rapidly translocated to the intestinal cell nucleus, suggesting a classic steroid hormone action. The ligand affinity and specificity of this cytosolic receptor has been exploited to develop a sensitive competitive protein binding assay for lα,25-(OH)2D. This radioreceptor assay has been instrumental in the phosphate-related disease states, as well as in characterizing the physiological regulation of lα,25-(OH)2D. Specific components for the radioreceptor assay are described in the chapter. Procedures for hormone extraction, purification, preparation, and reconstitution of cytosol-chromatin, etc, are also discussed in detail.
AB - This chapter discusses a sensitive radioreceptor assay for lα,25-dihydroxyvitamin D in biological fluids. Vitamin D has been recognized as a principal regulator of calcium and phosphate homeostasis in a variety of animal species, including humans. Some studies describe 1α,25-dihydroxyvitamin D [lα,25-(OH)2D] as the hormonal metabolite responsible for mediating intestinal transport of these minerals and hence necessitate development of a precise method for quantitating this sterol in biological fluids, particularly serum. It has been demonstrated that chick intestinal mucosa contained a cytosolic protein that rapidly and specifically bound lα,25-(OH)2D3 both in vivo and in vitro with high affinity. Furthermore, the sterol–protein complex was rapidly translocated to the intestinal cell nucleus, suggesting a classic steroid hormone action. The ligand affinity and specificity of this cytosolic receptor has been exploited to develop a sensitive competitive protein binding assay for lα,25-(OH)2D. This radioreceptor assay has been instrumental in the phosphate-related disease states, as well as in characterizing the physiological regulation of lα,25-(OH)2D. Specific components for the radioreceptor assay are described in the chapter. Procedures for hormone extraction, purification, preparation, and reconstitution of cytosol-chromatin, etc, are also discussed in detail.
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U2 - 10.1016/S0076-6879(80)67065-7
DO - 10.1016/S0076-6879(80)67065-7
M3 - Article
C2 - 6892721
AN - SCOPUS:0018861037
SN - 0076-6879
VL - 67
SP - 522
EP - 528
JO - Methods in Enzymology
JF - Methods in Enzymology
IS - C
ER -