Mori J, Satoh Y, Hashimoto M, Honda F
Jpn J Pharmacol. 1979 Dec;29(6):899-911. doi: 10.1254/jjp.29.899.
The acinar cells of the exocrine pancreas have the capacity of efficiently take up and metabolize L-dopa. In the present study, the metabolism of L-dopa by the exocrine pancreas of the rat and effects of receptor blockers on the metabolism were studied by fluorescent histochemical and chemical methods. After i.v. administration of L-dopa (50 mg/kg), a large amount of dopamine (DA) was detected in the exocrine pancreas, and in the pancreatic juice large amounts of DA and its metabolites. DA-blockers (haloperidol, sulpiride, and pimozide) and alpha-blockers (phenoxybenzamine, and phentolamine) produced a significant increase in the accumulation of DA after administration of L-dopa. On the other hand, beta-blockers (propranolol, and oxprenolol) were without effects. The excretion of DA into the pancreatic juice appeared to be associated with the secretion of zymogen granules, thus DA serves as an indicator of pancreatic secretory activity, especially of enzyme secretion. Because DA- and alpha-blockers produced an increase in the accumulation of DA, dopaminergic and/or alpha-adrenergic mechanisms probably exist in the exocrine pancreas of the rat and these mechanisms modify the enzyme secretion.
外分泌胰腺的腺泡细胞具有高效摄取和代谢左旋多巴的能力。在本研究中，采用荧光组织化学和化学方法研究了大鼠外分泌胰腺对左旋多巴的代谢以及受体阻滞剂对该代谢的影响。静脉注射左旋多巴（50mg/kg）后，在外分泌胰腺中检测到大量多巴胺（DA），并且在胰液中检测到大量的DA及其代谢产物。多巴胺受体阻滞剂（氟哌啶醇、舒必利和匹莫齐特）和α受体阻滞剂（酚苄明和酚妥拉明）在给予左旋多巴后使DA的蓄积显著增加。另一方面，β受体阻滞剂（普萘洛尔和氧烯洛尔）则无此作用。DA排入胰液似乎与酶原颗粒的分泌有关，因此DA可作为胰腺分泌活动尤其是酶分泌的指标。由于多巴胺受体阻滞剂和α受体阻滞剂使DA的蓄积增加，大鼠外分泌胰腺中可能存在多巴胺能和/或α肾上腺素能机制，并且这些机制可调节酶的分泌。
