1,25 - 二羟胆钙化醇在佝偻病雏鸡骨细胞核中的定位。

The localization of 1,25-dihydroxycholecalciferol in bone cell nuclei of rachitic chicks.

作者信息

Weber J C, Pons V, Kodicek E

出版信息

Biochem J. 1971 Nov;125(1):147-53. doi: 10.1042/bj1250147.

DOI:10.1042/bj1250147

PMID:4333933

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1178034/

Abstract

A simple technique has been developed to obtain subcellular fractions of chick bone. The method yielded 60-70% of total DNA in the nuclear debris fraction and 80-90% of total (14)C recovered in bone after a dose of radioactive vitamin D. 2. After a dose of [4-(14)C,1,2-(3)H(2)]cholecalciferol (0.5mug) was given to vitamin D-deficient chicks, the time-course of total (14)C radioactivity in the epiphysis, metaphysis and diaphysis of proximal tibiae was measured. The maximum concentrations were reached at 6h, corresponding to a similar peak of radioactivity in blood, decreasing until 24h and indicating the dependence on the circulating (14)C and on the blood supply of the three bone components. 3. The (14)C radioactivity of cholecalciferol and 25-hydroxycholecalciferol (expressed per mg of DNA) followed the pattern of incorporation of total (14)C radioactivity in all three bone components. The more polar metabolite fraction reached a peak of radioactivity at 6-9h and maintained its concentration over the 24h period studied in all anatomical bone components. 4. After a dose of [4-(14)C,1-(3)H]cholecalciferol (0.5mug) was given to vitamin D-deficient chicks, the subcellular distribution was studied. At 24h after dosing, the nuclear fraction contained 27% and the supernatant fraction had 67% of total (14)C recovered in the bone filtrate. When the (14)C in the residual bone fragments was included, the nuclear fraction contained up to 35% of the total radioactivity in the bone. 5. The subcellular distribution pattern of individual vitamin D metabolites indicated that the purified nuclear fraction concentrated the polar metabolite, which lost (3)H at C-1, so that 77% of the radioactivity could be accounted for by 1,25-dihydroxycholecalciferol. The supernatant fraction contained smaller amounts of 1,25-dihydroxycholecalciferol (9%), with 66% of 25-hydroxycholecalciferol forming the major metabolite, corresponding to its concentration found in blood at 24h. 6. The preferential accumulation of 1,25-dihydroxycholecalciferol in the nuclear fraction and the overall pattern of other metabolites, found previously in intestinal tissue, suggests a similar mechanism of action in bone to that postulated for the intestinal cell in calcium translocation.

摘要

已开发出一种简单技术来获取鸡骨的亚细胞组分。该方法在核碎片组分中得到了总DNA的60 - 70%，在给予放射性维生素D剂量后，骨中回收的总（14）C的80 - 90%。2. 给维生素D缺乏的雏鸡给予一剂[4 - （14）C，1，2 - （3）H2]胆钙化醇（0.5微克）后，测量近端胫骨骨骺、干骺端和骨干中总（14）C放射性的时间进程。在6小时达到最大浓度，这与血液中放射性的类似峰值相对应，直至24小时下降，表明这三个骨成分对循环（14）C和血液供应的依赖性。3. 胆钙化醇和25 - 羟基胆钙化醇的（14）C放射性（以每毫克DNA表示）遵循了所有三个骨成分中总（14）C放射性的掺入模式。极性更强的代谢物组分在6 - 9小时达到放射性峰值，并在所有解剖学骨成分研究的24小时期间保持其浓度。4. 给维生素D缺乏的雏鸡给予一剂[4 - （14）C，1 - （3）H]胆钙化醇（0.5微克）后，研究亚细胞分布。给药后24小时，核组分含有回收于骨滤液中总（14）C的27%，上清液组分含有67%。当包括残余骨碎片中的（14）C时，核组分含有骨中总放射性的高达35%。5. 单个维生素D代谢物的亚细胞分布模式表明，纯化的核组分浓缩了在C - 1位失去（3）H的极性代谢物，因此77%的放射性可由1，25 - 二羟基胆钙化醇解释。上清液组分含有较少量的1，25 - 二羟基胆钙化醇（9%），66%的25 - 羟基胆钙化醇构成主要代谢物，这与24小时时血液中发现的其浓度相对应。6. 1，25 - 二羟基胆钙化醇在核组分中的优先积累以及其他代谢物的总体模式，先前在肠道组织中发现，提示在骨中的作用机制与在肠道细胞钙转运中假设的机制相似。