Ito H, Baum B J, Roth G S
Mech Ageing Dev. 1981 Feb;15(2):177-88. doi: 10.1016/0047-6374(81)90073-7.
beta-Adrenergic regulation of exocrine protein secretion from the parotid gland was studied over the adult rat life span. Enzymatically dispersed cell aggregates were prepared from 3-, 6-, 12-, and 24-month-old rats and exocrine protein secretion (amylase release) measured. No age differences were seen in the time course of amylase release following (-)-isoproterenol stimulation or in the (-)-isoproterenol dose-response curve. the beta-adrenergic antagonist (+/-)-propanolol inhibited (-)-isoproterenol-stimulated protein secretion from parotid cell aggregates of young and old animals equally. Similarly dibutyryl cyclic AMP induced comparable rates of protein secretion from cells of different aged rats. Direct examination of beta-adrenergic receptor characteristics in parotid gland membranes from 3- to 24-month-old rats revealed no differences in the equilibrium dissociation constant (Kd) or maximum specific ligand binding capacity (receptor number). These results suggest that the rat parotid beta-adrenergic system remains functionally intact throughout the animals' lifetime.
在成年大鼠的整个生命周期中，研究了β-肾上腺素能对腮腺外分泌蛋白分泌的调节作用。从3个月、6个月、12个月和24个月大的大鼠中制备酶分散的细胞聚集体，并测量外分泌蛋白分泌（淀粉酶释放）。在（-）-异丙肾上腺素刺激后淀粉酶释放的时间过程或（-）-异丙肾上腺素剂量反应曲线中未观察到年龄差异。β-肾上腺素能拮抗剂（±）-普萘洛尔同样抑制年轻和老年动物腮腺细胞聚集体中（-）-异丙肾上腺素刺激的蛋白分泌。同样，二丁酰环磷酸腺苷诱导不同年龄大鼠细胞的蛋白分泌速率相当。对3至24个月大大鼠腮腺膜中β-肾上腺素能受体特征的直接检查显示，平衡解离常数（Kd）或最大特异性配体结合能力（受体数量）没有差异。这些结果表明，大鼠腮腺β-肾上腺素能系统在动物的整个生命周期中功能保持完整。
