Hirata Y, Takata S, Takagi Y, Matsubara H, Omae T
Biochem Biophys Res Commun. 1986 Jul 16;138(1):405-12. doi: 10.1016/0006-291x(86)90296-2.
To elucidate the regulation of vascular receptors for atrial natriuretic peptide (ANP), we have studied the binding capacity of 125I-labeled rat (r) ANP using cultured vascular smooth muscle cells from rat aorta. After preincubation with 3.2 X 10(-8) M rANP at 37 degrees C, the binding capacity decreased as a function of time; the maximal receptor loss (70-75%) occurred after 4 hrs and persisted for 24 hrs. Pretreatment with cycloheximide (20 micrograms/ml) and actinomycin D (2 micrograms/ml) similarly caused a dramatic reduction (approximately 80%) of the binding capacity after 24 hrs; the half-life (t1/2) of the receptor loss was approximately 7-8 hrs. Following removal of rANP, the "down-regulated" ANP receptors fully recovered in the presence of 10% fetal calf serum, but not in combination with either actinomycin D or cycloheximide. Concanavalin A dose-dependently inhibited the binding. The binding capacity also decreased with time in the presence of tunicamycin (1 microgram/ml) with t1/2 of approximately 30 hrs. These data indicate that protein and carbohydrate moieties are essential for the functional integrity of the vascular receptor binding sites for ANP, and suggest that the recovery of the receptor loss by "down-regulation" requires concomitant RNA and protein synthesis.
为阐明心房利钠肽（ANP）血管受体的调节机制，我们利用大鼠主动脉培养的血管平滑肌细胞，研究了125I标记的大鼠（r）ANP的结合能力。在37℃下与3.2×10(-8)M的rANP预孵育后，结合能力随时间下降；4小时后出现最大受体丢失（70 - 75%），并持续24小时。用环己酰亚胺（20微克/毫升）和放线菌素D（2微克/毫升）预处理同样在24小时后导致结合能力显著降低（约80%）；受体丢失的半衰期（t1/2）约为7 - 8小时。去除rANP后，“下调”的ANP受体在10%胎牛血清存在下完全恢复，但在与放线菌素D或环己酰亚胺联合使用时则不能恢复。伴刀豆球蛋白A剂量依赖性地抑制结合。在衣霉素（1微克/毫升）存在下，结合能力也随时间下降，t1/2约为30小时。这些数据表明蛋白质和碳水化合物部分对于ANP血管受体结合位点的功能完整性至关重要，并表明通过“下调”导致的受体丢失的恢复需要伴随RNA和蛋白质合成。
