Rice G E, Thorburn G D
Can J Physiol Pharmacol. 1985 Apr;63(4):309-14. doi: 10.1139/y85-056.
The subcellular localization of oxytocin within the corpus luteum of sheep was investigated using differential and density gradient centrifugation. Oxytocin was associated with a particulate fraction which sedimented to a density of 1.054-1.061 g/mL. The exclusion of [3H]oxytocin from this particulate fraction is indicative that particulate oxytocin represents endogenous compartmentalization. Particulate oxytocin, incubated in buffered medium at 37 degrees C, was stable for up to 1 h and the release of oxytocin was not affected by the pH of the incubation medium, over the range 5.5-8.5. Oxytocin release, however, was stimulated by incubating particle-bound oxytocin in buffered medium of low osmolality (less than 200 mosmol). These data are similar to the physicochemical properties reported for peptide-containing neurohypophysial secretory granules. Ultrastructural analysis of oxytocin-containing fractions revealed the presence of electron-dense granules (diameter, 200-250 nm). These data are suggestive that oxytocin, in the corpus luteum of sheep, is contained within a population of secretory granules which occur in high numbers during the midluteal phase of the oestrous cycle.
利用差速离心和密度梯度离心法研究了催产素在绵羊黄体中的亚细胞定位。催产素与一种沉降到密度为1.054 - 1.061 g/mL的颗粒部分相关。从该颗粒部分中排除[3H]催产素表明颗粒性催产素代表内源性区室化。在37℃的缓冲介质中孵育的颗粒性催产素在长达1小时内保持稳定，并且在5.5 - 8.5的范围内，催产素的释放不受孵育介质pH值的影响。然而，通过在低渗透压（小于200 mosmol）的缓冲介质中孵育颗粒结合的催产素可刺激催产素的释放。这些数据与报道的含肽神经垂体分泌颗粒的物理化学性质相似。对含催产素部分的超微结构分析显示存在电子致密颗粒（直径200 - 250 nm）。这些数据表明，在绵羊黄体中，催产素存在于一群分泌颗粒中，这些颗粒在发情周期的黄体中期大量出现。
