Collins M K, Rozengurt E
Proc Natl Acad Sci U S A. 1983 Apr;80(7):1924-8. doi: 10.1073/pnas.80.7.1924.
Prior incubation of quiescent cultures of Swiss 3T3 cells with vasopressin leads to loss of mitogenic stimulation on its subsequent addition in the presence of a synergistic growth factor. This desensitization is selective for vasopressin, requires prolonged incubation (half-maximal desensitization after 12 hr of treatment) for its induction, and is reversed after a 48-hr incubation in the absence of vasopressin. It is elicited by concentrations of vasopressin, and several analogues, similar to those required for stimulation of DNA synthesis. Inhibition of 125I-labeled epidermal growth factor binding and stimulation of 86Rb+ uptake by vasopressin are also selectively decreased in the refractory cells. The vasopressin receptors that mediate mitogenesis in Swiss 3T3 cells are of the pressor type, not coupled to adenylate cyclase. These cells bind [3H]vasopressin in a specific and saturable (Kd = 1 X 10(-8) M) manner. The receptors are down-regulated after prolonged vasopressin treatment; however, this cannot provide a complete explanation of desensitization because cells that are completely refractory to vasopressin retain 60% of their [3H]vasopressin binding sites. Vasopressin refractoriness must therefore occur partly at a post-receptor locus.
预先将静止的瑞士3T3细胞培养物与加压素一起孵育,会导致在随后添加协同生长因子时丝裂原刺激作用丧失。这种脱敏作用对加压素具有选择性,诱导需要长时间孵育(处理12小时后达到半数最大脱敏),并且在无加压素的情况下孵育48小时后可逆转。它由与刺激DNA合成所需浓度相似的加压素及几种类似物引发。在不应期细胞中,加压素对125I标记的表皮生长因子结合的抑制作用和对86Rb+摄取的刺激作用也选择性降低。在瑞士3T3细胞中介导有丝分裂的加压素受体属于升压型,不与腺苷酸环化酶偶联。这些细胞以特异性且可饱和的方式(解离常数Kd = 1×10⁻⁸M)结合[³H]加压素。长时间加压素处理后受体下调;然而,这并不能完全解释脱敏现象,因为对加压素完全不应期的细胞仍保留其60%的[³H]加压素结合位点。因此,加压素不应期必定部分发生在受体后位点。