REDMAN C M, HOKIN L E
J Biophys Biochem Cytol. 1959 Oct;6(2):207-14. doi: 10.1083/jcb.6.2.207.
After incubation of pigeon pancreas slices with P(32) and isolation of various fractions by differential centrifugation the deoxycholate extract of the microsome fraction was found to account for over half of the phospholipide P and over half of the P(32) incorporated into the phospholipides. The remaining phospholipide P and P(32) were fairly evenly distributed in the nuclei, zymogen granules, mitochondria, microsomal ribonucleoprotein particles, and the soluble fraction. When enzyme secretion was stimulated with acetylcholine about two-thirds of the increment in radioactivity in the total phospholipides was found in deoxycholate soluble components of the microsome fraction. The remainder of the increment was distributed in the other fractions. This indicates that the cellular component in which the increase in phospholipide turnover occurs on stimulation of secretion is a membranous structure. Evidence is presented which indicates that the increment in radioactivity in the non-microsomal fractions on stimulation of secretion is due to contamination of these fractions with fragments of the stimulated membranous structure. The distribution of P(32) radioactivity in each of the chromatographically separated phospholipides in the various fractions from unstimulated tissue paralleled the distribution of radioactivity in the total phospholipide fraction, indicating that individual phospholipides are not concentrated in different fractions but are associated together in the membranous structures of the microsome fraction. The major proportion of the stimulation of the turnover of the individual phospholipides also occurred in the microsome fraction. The distribution of radioactivity from glycerol-1-C(14) in the total phospholipides and in the individual phospholipides in the various fractions was similar to the distribution of P(32). In the microsome fraction acetylcholine stimulated the incorporation of glycerol-1-C(14) in each phospholipide which showed a stimulation of P(32) incorporation. The significance of the turnover of phosphatides in microsomal membranes in relation to the mechanism of secretion is discussed.
用P(32)孵育鸽胰腺切片并通过差速离心分离出各种组分后，发现微粒体组分的脱氧胆酸盐提取物占磷脂P的一半以上，且占掺入磷脂中的P(32)的一半以上。其余的磷脂P和P(32)相当均匀地分布在细胞核、酶原颗粒、线粒体、微粒体核糖核蛋白颗粒和可溶性组分中。当用乙酰胆碱刺激酶分泌时，发现总磷脂中放射性增加的约三分之二存在于微粒体组分的脱氧胆酸盐可溶性成分中。增加的其余部分分布在其他组分中。这表明在分泌刺激时磷脂周转率增加的细胞成分是一种膜结构。有证据表明，分泌刺激时非微粒体组分中放射性的增加是由于这些组分被受刺激的膜结构碎片污染所致。来自未受刺激组织的各种组分中，经色谱分离的每种磷脂中P(32)放射性的分布与总磷脂组分中放射性的分布平行，这表明单个磷脂并非集中在不同组分中，而是在微粒体组分的膜结构中结合在一起。单个磷脂周转率的主要刺激部分也发生在微粒体组分中。甘油-1-C(14)在总磷脂和各种组分中单个磷脂中的放射性分布与P(32)的分布相似。在微粒体组分中，乙酰胆碱刺激了甘油-1-C(14)在每种显示P(32)掺入受刺激的磷脂中的掺入。本文讨论了微粒体膜中磷脂周转与分泌机制的关系。
