鯉魚頭腎兒茶酚胺釋放素之純化

Abstract

鯉魚頭腎為一主要生合成及釋放腎上腺素，正腎上腺素之組織．目前已知腎上腺素，正腎上腺素之合成及釋放受到許多因數的調控；對於生合成反應之調控主要對象為參與生合成反應步驟之重要酵素，對於釋放機制之調控則很可能經由與細胞內鈣離子濃度相關之步驟．雖然已知腎上腺素，正腎上腺素受到許多因數的調控，但是調控之機制及參與調控機制中間步驟的其他因數目前均不清楚． 1988 年有報告提出，發現位於老鼠腎上腺中有一蛋白質因數，具有很強的刺激腎上腺素釋放的能力，因此本實驗主要沿用該報告的實驗方法，以鯉魚頭腎為實驗材料，嘗試由其中分離純化出具有類似活性的蛋白質因數．首先利用高效液相色層分析儀配合 HP - PEI 陰離子交換樹脂管柱，分離純化頭腎中之蛋白質，將分離所得各不同部分之蛋白質利用組織灌流法及高效液相色層分析-電化學偵測法，檢驗其是否具有釋放腎上腺素，正腎上腺素之活性．利用上述實驗步驟最後純化得到一分子量約 15kDa 之蛋白質，具有很強的刺激腎上腺素，正腎上腺素釋放的能力，其作用之有效濃度可達到 uM 以下且其分子量及作用方式均不同於目前已知的兒茶酚胺釋放調節因數，因此本實驗所純化之 15kDa 蛋白質為一新的調節兒茶酚胺的刺激因數．

Adrenal gland consists of adrenal cortex and adrenal medulla. The function of adrenal medulla is synthesis and secretion of catecholamines, mainly epinephrine (EPI) and norepinephrine (NE). The synthesis and secretion of NE and EPI is highly regulated by many factors such as sympathetic nervous system, ACTH，glucocorticoids etc.. The details of regulation mechanisms are still unknown, therefore the identification of factors involving in these regulation processes is of importance. In 1988, a catecholamine—releasing factor was discovered in adrenal gland of rat and this factor plays a role in the regulation of adrenal function. This study was aimed to purify the putative catecholamine—releasing factor from carp headkidney. After the separation with HPLC HP-PEI column, a l5kDa protein was purified and this protein factor was found to be a powerful catecholamine—releasing factor in headkidney in vitro. The effective concentration was found to be submicromolar. There is significant difference in molecule weight and pattern of stimulation between l5kDa protein and other catecholamine—releasing factor. Therefore this l5kDa protein might be a novel catecholamine—releasing factor.