Lerner U H, Mellström D
Department of Oral Cell Biology, University of Umeå, Sweden.
Calcif Tissue Int. 1992 Dec;51(6):424-8. doi: 10.1007/BF00296675.
In view of the possible association between ingestion of caffeine (a constituent of coffee, tea, and several beverages) and osteoporosis, we have studied the effect of caffeine on bone resorption in vitro. Caffeine caused a dose-dependent increase of the spontaneous release of 45Ca from neonatal mouse calvarial bones. The effect of caffeine was less pronounced than that of parathyroid hormone (PTH), but of the same magnitude as that of theophylline, a structurally related methylxanthine. The enhancement of 45Ca release induced by caffeine and PTH was observed in 5 days culture. In 2 days culture, however, only PTH stimulated mineral mobilization. The delayed stimulatory effect of caffeine in long-term cultures was abolished by indomethacin and flurbiprofen. In indomethacin-treated bones, however, caffeine potentiated the stimulatory effect on 45Ca release induced by choleratoxin and forskolin. In contrast, caffeine did not potentiate 45Ca release stimulated by PTH. These data show that caffeine can stimulate calcium release from bone in vitro and that this effect is due to potentiation of a stimulatory action of a bone resorptive agonist acting via the adenylate cyclase-cyclic AMP system.
鉴于摄入咖啡因（咖啡、茶及多种饮品的一种成分）与骨质疏松症之间可能存在关联，我们研究了咖啡因对体外骨吸收的影响。咖啡因导致新生小鼠颅骨中45Ca的自发释放呈剂量依赖性增加。咖啡因的作用不如甲状旁腺激素（PTH）明显，但与结构相关的甲基黄嘌呤茶碱的作用强度相当。在5天的培养中观察到咖啡因和PTH诱导的45Ca释放增强。然而，在2天的培养中，只有PTH刺激矿物质动员。吲哚美辛和氟比洛芬消除了咖啡因在长期培养中的延迟刺激作用。然而，在吲哚美辛处理的骨骼中，咖啡因增强了霍乱毒素和福斯高林诱导的45Ca释放的刺激作用。相比之下，咖啡因并未增强PTH刺激的45Ca释放。这些数据表明，咖啡因可在体外刺激骨钙释放，且这种作用是由于增强了通过腺苷酸环化酶 - 环磷酸腺苷系统起作用的骨吸收激动剂的刺激作用。
