Collier R J, Tucker H A
J Dairy Sci. 1978 Dec;61(12):1709-14. doi: 10.3168/jds.s0022-0302(78)83792-8.
Mammary tissue explants from four nonlactating, nonpregnant cows were placed into culture with media containing various combinations of insulin, prolactin, growth hormone, 17beta-estradiol, dexamethasone, and progesterone. Combinations of insulin, prolactin, growth hormone, or 17beta-estradiol had no effect on cytoplasmic or nuclear uptake of tritiated cortisol compared with values at zero time. Combinations containing dexamethasone of progesterone reduced cytoplasmic and nuclear uptake of tritiated cortisol. To examine inhibition by progesterone of binding of tritiated cortisol, mammary tissue from each of four lactating, nonpregnant and four nonlactating, nonpregnant cows were placed in flasks containing tissue culture medium 199, tritiated cortisol (2 ng/ml), and progesterone at concentrations of 0, 10(-12), 10(-11), 10(-10), 10(-9), 10(-8), 10(-7), 10(-6), or 10(-5) X 6.4 M. Cytoplasmic uptake of tritiated cortisol into nonlactating tissue decreased linearly as progesterone increased, whereas tritiated cortisol uptake in lactating tissue did not decrease until progesterone exceeded 10(-7) M. We postulated progesterone is sequestered in milk fat of cytoplasm of lactating tissue whereas in nonlactating tissue progesterone is available to compete with cortisol at sites of cortisol binding.
将来自4头非泌乳、未怀孕奶牛的乳腺组织外植体置于含有胰岛素、催乳素、生长激素、17β-雌二醇、地塞米松和孕酮各种组合的培养基中进行培养。与零时的值相比，胰岛素、催乳素、生长激素或17β-雌二醇的组合对氚化皮质醇的细胞质或细胞核摄取没有影响。含有地塞米松或孕酮的组合降低了氚化皮质醇的细胞质和细胞核摄取。为了研究孕酮对氚化皮质醇结合的抑制作用，将4头泌乳、未怀孕奶牛和4头非泌乳、未怀孕奶牛的乳腺组织分别置于含有组织培养基199、氚化皮质醇（2 ng/ml）以及浓度为0、10⁻¹²、10⁻¹¹、10⁻¹⁰、10⁻⁹、10⁻⁸、10⁻⁷、10⁻⁶或10⁻⁵×6.4 M孕酮的烧瓶中。随着孕酮浓度增加，非泌乳组织中氚化皮质醇的细胞质摄取呈线性下降，而泌乳组织中氚化皮质醇的摄取直到孕酮超过10⁻⁷ M才下降。我们推测，孕酮在泌乳组织细胞质的乳脂肪中被隔离，而在非泌乳组织中，孕酮可在皮质醇结合位点与皮质醇竞争。
