Soloff M S, Wieder M H
Can J Biochem Cell Biol. 1983 Jul;61(7):631-5. doi: 10.1139/o83-079.
Oxytocin-receptor concentrations in the rat mammary gland were determined by Scatchard analyses with [3H]oxytocin. There was about a 100-fold increase in the number of receptors per mammary gland between the 1st day of pregnancy and late lactation. The number of receptors then fell markedly during postweaning mammary regression, but rose again during a second pregnancy and lactation cycle. The changes in oxytocin-receptor number corresponded to changes in alkaline phosphatase activity per mammary gland. These results strongly support data suggesting that alkaline phosphatase, like oxytocin receptors, is a specific marker for mammary myoepithelial cells. Despite the fall in oxytocin-receptor number per mammary gland during postweaning regression, the concentration of receptors, expressed per milligram of protein, increased 10-fold over lactating levels on the 6th day of regression. Thereafter, receptor concentrations declined, but were still elevated about fivefold over lactating levels on the 15th day of regression. It is likely that the increased concentration of receptors was due to a decrease in the relative amount of nontarget secretory cells. The factors that regulate the concentration of oxytocin receptors on mammary myoepithelial cells are presently unknown; however, the involuting mammary system may be practical for obtaining enriched populations of oxytocin-sensitive myoepithelial cells.
采用[3H]催产素通过Scatchard分析测定大鼠乳腺中催产素受体的浓度。在妊娠第1天和泌乳后期之间，每个乳腺的受体数量增加了约100倍。断奶后乳腺退化期间，受体数量显著下降，但在第二次妊娠和泌乳周期中又再次上升。催产素受体数量的变化与每个乳腺中碱性磷酸酶活性的变化相对应。这些结果有力地支持了以下数据，即碱性磷酸酶与催产素受体一样，是乳腺肌上皮细胞的特异性标志物。尽管断奶后退化期间每个乳腺中催产素受体数量下降，但以每毫克蛋白质表示的受体浓度在退化第6天时比泌乳水平增加了10倍。此后，受体浓度下降，但在退化第15天时仍比泌乳水平高约5倍。受体浓度增加可能是由于非靶分泌细胞相对数量减少所致。目前尚不清楚调节乳腺肌上皮细胞上催产素受体浓度的因素；然而，退化的乳腺系统可能是获取催产素敏感肌上皮细胞富集群体的实用方法。
