Ueno A, Kikuchi K, Nishino M, Kawano M, Matsumoto N, Inoue H
Department of Biochemistry, School of Dentistry, University of Tokushima, Japan.
Arch Oral Biol. 1991;36(6):415-23. doi: 10.1016/0003-9969(91)90131-d.
Both beta-adrenergic (isoproterenol) and cholinergic (carbachol) sialagogues increase amylase secretion, ornithine decarboxylase activity and DNA synthesis in murine parotid gland in vivo and in vitro. These agonists enhanced the incorporation of labelled inorganic orthophosphate into parotid proteins in rat parotid explants cultured on siliconized lens paper floating on serum-free 199 medium. Analysis of the labelled proteins by SDS-PAGE and autoradiography revealed that isoproterenol enhanced the phosphorylation of four proteins with apparent molecular weights of 17, 20, 31 and 32 kDa and carbachol stimulated the phosphorylation of 31 and 32 K proteins. Isoproterenol-dependent ornithine decarboxylase induction and phosphorylation of the proteins were selectively suppressed by monensin but not by polymyxin B, whereas carbachol-dependent ornithine decarboxylase induction and protein phosphorylation were inhibited by polymyxin B but not by monensin. Neither monensin nor polymyxin B suppressed isoproterenol- or carbachol-stimulated amylase secretion. Time course experiments showed that sialagogue-stimulated protein phosphorylation preceded the increase of ornithine decarboxylase activity and had almost disappeared when it was maximal. Propranolol and atropine, antagonists of isoproterenol and carbachol, respectively, completely inhibited not only amylase secretion and ornithine decarboxylase induction but also protein phosphorylation stimulated by the corresponding agonists. These findings suggest that increased phosphorylation of specific proteins is associated with sialagogue-stimulated ornithine decarboxylase induction but not amylase secretion.
β-肾上腺素能（异丙肾上腺素）和胆碱能（卡巴胆碱）促唾液分泌剂在体内和体外均能增加小鼠腮腺中淀粉酶的分泌、鸟氨酸脱羧酶活性及DNA合成。这些激动剂增强了在无血清199培养基上漂浮的硅化镜片纸上培养的大鼠腮腺外植体中标记无机正磷酸盐掺入腮腺蛋白的过程。通过SDS-PAGE和放射自显影对标记蛋白进行分析显示，异丙肾上腺素增强了四种表观分子量分别为17、20、31和32 kDa的蛋白的磷酸化，而卡巴胆碱刺激了31和32 kDa蛋白的磷酸化。莫能菌素可选择性抑制异丙肾上腺素依赖性鸟氨酸脱羧酶的诱导及蛋白磷酸化，但多粘菌素B无此作用；而多粘菌素B可抑制卡巴胆碱依赖性鸟氨酸脱羧酶的诱导及蛋白磷酸化，但莫能菌素无此作用。莫能菌素和多粘菌素B均未抑制异丙肾上腺素或卡巴胆碱刺激的淀粉酶分泌。时间进程实验表明，促唾液分泌剂刺激的蛋白磷酸化先于鸟氨酸脱羧酶活性的增加，且在其达到最大值时几乎消失。分别作为异丙肾上腺素和卡巴胆碱拮抗剂的普萘洛尔和阿托品，不仅完全抑制了淀粉酶分泌和鸟氨酸脱羧酶的诱导，还抑制了相应激动剂刺激的蛋白磷酸化。这些发现提示，特定蛋白磷酸化增加与促唾液分泌剂刺激的鸟氨酸脱羧酶诱导有关，但与淀粉酶分泌无关。
