Cooper C L, Holz R W
Division of Science, Northeast Missouri State University, Kirksville 63501.
Biochem Biophys Res Commun. 1993 Aug 16;194(3):1135-42. doi: 10.1006/bbrc.1993.1940.
To evaluate the requirement of bovine adrenal chromaffin cells for inositol phospholipids in secretion, the effects of neomycin and spermine on secretion and phosphoinositide metabolism were compared. Spermine and neomycin had virtually identical effects on secretion and phosphoinositide levels. Both polyamines 1) partially maintained secretion when added to permeabilized cells in the absence of ATP, 2) had no effect when added to cells in the presence of ATP and 3) inhibited secretion when present with the Ca2+ stimulus. In the absence of ATP the enhancements to secretion due to incubation with either polyamine were associated with sustained levels of the polyphosphoinositides. The ability of spermine and neomycin to maintain secretion and the polyphosphoinositides in the absence of ATP supports the hypothesis that the maintenance of the polyphosphoinositides is necessary for secretion. Neomycin was found to inhibit Ca2+ stimulated production of both inositol bis- and tris-phosphates while spermine was found to selectively inhibit inositol bis-phosphate production and had no effect on Ca(2+)-stimulated inositol tris-phosphate production in permeabilized cells.
为了评估牛肾上腺嗜铬细胞分泌过程中对肌醇磷脂的需求，比较了新霉素和精胺对分泌及磷酸肌醇代谢的影响。精胺和新霉素对分泌及磷酸肌醇水平具有几乎相同的作用。两种多胺：1）在无ATP时添加到透化细胞中可部分维持分泌；2）在有ATP时添加到细胞中无作用；3）在存在Ca2+刺激时抑制分泌。在无ATP时，与任一多胺孵育引起的分泌增强与多磷酸肌醇的持续水平相关。精胺和新霉素在无ATP时维持分泌及多磷酸肌醇的能力支持了多磷酸肌醇的维持对分泌是必需的这一假说。发现新霉素抑制Ca2+刺激的肌醇二磷酸和三磷酸的产生，而精胺选择性抑制肌醇二磷酸的产生，对透化细胞中Ca(2+)刺激的肌醇三磷酸的产生无影响。
