Gorewit R C, Tucker A
J Dairy Sci. 1976 Jul;59(7):1247-53. doi: 10.3168/jds.s0022-0302(76)84353-6.
Supernatant fractions (700 X g) isolated from homogenates of mammary tissue slices from three lactating Holstein cows (slices previously incubated with [hydrogen-3] cortisol for 1 h at 37 C) were electrophoresed on 7% polyacrylamide gels. The majority of radioactivity was in a protein(s) 2.5 to 3 cm from the origin whereas bovine serum incubated with [hydrogen-3] cortisol showed the majority of radioactivity in a protein 5 to 6 cm from the origin. N,N-diethylaminoethyl cellulose chromatography of 700 X g supernatant fluids from three lactating cows revealed that [hydrogen-3] cortisol was associated with a protein component that eluted with .3 M potassium phosphate, pH 8.0. In contrast, [hydrogen-3] cortisol bound to bovine sera eluted as two protein components with .05 and .1 M potassium phosphate, pH 8.0. Approximate molecular weights determined from gel filtration (four lactating cows) and sucrose density studies (two lactating cows) were estimated to be 2.5 X 10(5) to 3 X 10(6) for the 700 X g mammary receptor of cortisol and 6 X 10)4) to 8 X 10(4) for the primary protein which binds cortisol in serum. We conclude that lactating bovine mammary tissue contains a protein(s) capable of binding tritiated cortisol which is unique from the corticosteroid binding proteins of blood.
从三头泌乳期荷斯坦奶牛的乳腺组织切片匀浆中分离得到的上清液组分（700×g）（这些切片先前在37℃下与[氢-3]皮质醇孵育1小时）在7%聚丙烯酰胺凝胶上进行电泳。大部分放射性存在于距原点2.5至3厘米处的一种或多种蛋白质中，而与[氢-3]皮质醇孵育的牛血清中，大部分放射性存在于距原点5至6厘米处的一种蛋白质中。对三头泌乳奶牛的700×g上清液进行N,N - 二乙氨基乙基纤维素层析显示，[氢-3]皮质醇与一种蛋白质组分相关联，该组分在pH 8.0的0.3 M磷酸钾中洗脱。相比之下，与牛血清结合的[氢-3]皮质醇在pH 8.0的0.05 M和0.1 M磷酸钾中作为两种蛋白质组分洗脱。通过凝胶过滤（四头泌乳奶牛）和蔗糖密度研究（两头泌乳奶牛）确定的近似分子量估计，对于皮质醇的700×g乳腺受体为2.5×10⁵至3×10⁶，对于血清中结合皮质醇的主要蛋白质为6×10⁴至8×10⁴。我们得出结论，泌乳期牛乳腺组织含有一种能够结合氚化皮质醇的蛋白质，它与血液中的皮质类固醇结合蛋白不同。
