Murashita Koji, Fukada Haruhisa, Hosokawa Hidetsuyo, Masumoto Toshiro
Faculty of Agriculture, Kochi University, B200 Monobe, Nankoku, Kochi 783-8502, Japan.
Comp Biochem Physiol B Biochem Mol Biol. 2007 Mar;146(3):318-25. doi: 10.1016/j.cbpb.2006.11.009. Epub 2006 Nov 24.
In fish, the regulation of digestive enzyme secretion by hormonal control such as cholecystokinin (CCK) and neuropeptide Y (NPY)-related peptide is not well understood. To investigate the roles of fish CCK and peptide Y (PY) in digestive enzyme secretion, mRNA levels of CCK and PY, pyloric caeca enzyme activities and mRNA levels of pancreatic digestive enzymes (lipase, trypsin and amylase) were measured at pre- and post-prandial stages in yellowtail. Pyloric caeca were sampled at 0, 0.5, 1.5, 3, 6, 12, 24 and 48 h after feeding. The mRNA levels of trypsin and amylase increased after feeding, suggesting that transcription was induced by feed ingestion. Digestive enzyme activities decreased in exocrine pancreas after feeding, suggesting the stored enzyme was secreted from pancreas post-prandially. mRNA levels for CCK displayed a time-dependent increase, peaking between 1.5 and 3 h after-feeding followed by a rapid decrease 3 to 6 h after feeding. The mRNA expression pattern of PY was inverse to the pattern of CCK, decreasing until 1.5 h after feeding and then rising to initial levels by 12 h after feeding. These results suggest that CCK and PY work antagonistically in the exocrine pancreas of yellowtail.
在鱼类中，激素控制（如胆囊收缩素（CCK）和神经肽Y（NPY）相关肽）对消化酶分泌的调节作用尚未完全明确。为了研究鱼类CCK和肽Y（PY）在消化酶分泌中的作用，测定了黄尾鱼在摄食前和摄食后的CCK和PY的mRNA水平、幽门盲囊酶活性以及胰腺消化酶（脂肪酶、胰蛋白酶和淀粉酶）的mRNA水平。在喂食后0、0.5、1.5、3、6、12、24和48小时采集幽门盲囊样本。摄食后胰蛋白酶和淀粉酶的mRNA水平升高，表明转录是由摄食诱导的。摄食后外分泌胰腺中的消化酶活性降低，表明储存的酶在摄食后从胰腺分泌。CCK的mRNA水平呈现出随时间增加的趋势，在喂食后1.5至3小时达到峰值，随后在喂食后3至6小时迅速下降。PY的mRNA表达模式与CCK相反，在喂食后1.5小时之前下降，然后在喂食后12小时回升至初始水平。这些结果表明，CCK和PY在黄尾鱼的外分泌胰腺中起拮抗作用。
