Rivard N, Rydzewska G, Lods J S, Morisset J
Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Quebec, Canada.
Am J Physiol. 1995 Sep;269(3 Pt 1):G352-62. doi: 10.1152/ajpgi.1995.269.3.G352.
Cholecystokinin (CCK) is the major pancreatic secretagogue and acinar cell mitogen. This study was performed to determine by which effector systems CCK regulates tyrosine kinases, phosphatidylinositol (PtdIns) 3-kinase, and phospholipase D (PLD) activities. Pancreatic acini loaded with [3H]myristic acid or [3H]inositol were used to assay PLD and PtdIns 3-kinase. G protein activation with NaF increased particulate and crude cytosolic tyrosine kinase and PLD activities. PLD activation was pertussis toxin sensitive. Inhibition of phospholipase C (PLC) slightly reduced caerulein-stimulated particulate tyrosine kinase and blocked crude cytosolic tyrosine kinase activity without affecting caerulein-induced PLD activity. Ca2+ is an important factor in caerulein stimulation of tyrosine kinase and PLD activities. Protein kinase C and tyrosine kinase inhibition abolished caerulein-activated particulate and crude cytosolic tyrosine kinase and PtdIns 3-kinase activities without any effect on PLD. Wortmannin inhibited PLD and PtdIns 3-kinase activation. Caerulein-induced amylase secretion was partially reduced by tyrosine kinase inhibition, with no effect from wortmannin. Caerulein can stimulate a pertussis toxin-insensitive G protein, leading to particulate tyrosine kinase activation and a Ca(2+)-sensitive cytosolic tyrosine kinase through PLC activation. However, PLD activation by caerulein is pertussis toxin sensitive, cytosolic Ca2+ sensitive, and independent of previous PLC and tyrosine kinase activation.
胆囊收缩素（CCK）是主要的胰腺促分泌素和腺泡细胞有丝分裂原。本研究旨在确定CCK通过哪些效应系统调节酪氨酸激酶、磷脂酰肌醇（PtdIns）3激酶和磷脂酶D（PLD）的活性。用负载[3H]肉豆蔻酸或[3H]肌醇的胰腺腺泡来检测PLD和PtdIns 3激酶。用氟化钠激活G蛋白可增加颗粒性和粗提胞质酪氨酸激酶以及PLD的活性。PLD的激活对百日咳毒素敏感。抑制磷脂酶C（PLC）可轻微降低蛙皮素刺激的颗粒性酪氨酸激酶活性，并阻断粗提胞质酪氨酸激酶活性，但不影响蛙皮素诱导的PLD活性。Ca2+是蛙皮素刺激酪氨酸激酶和PLD活性的重要因素。蛋白激酶C和酪氨酸激酶抑制可消除蛙皮素激活的颗粒性和粗提胞质酪氨酸激酶以及PtdIns 3激酶活性，但对PLD无任何影响。渥曼青霉素抑制PLD和PtdIns 3激酶的激活。酪氨酸激酶抑制可部分降低蛙皮素诱导的淀粉酶分泌，渥曼青霉素则无此作用。蛙皮素可刺激一种对百日咳毒素不敏感的G蛋白，通过激活PLC导致颗粒性酪氨酸激酶激活和一种对Ca(2+)敏感的胞质酪氨酸激酶激活。然而，蛙皮素对PLD的激活对百日咳毒素敏感、对胞质Ca2+敏感，且独立于先前的PLC和酪氨酸激酶激活。
