Judd A M
Department of Zoology, Brigham Young University, Provo, Utah 84602, USA.
Life Sci. 1995;57(18):1641-6. doi: 10.1016/0024-3205(95)02143-7.
Several secretagogues increase prolactin (PRL) release from anterior pituitary cells through biochemical pathways that involve the liberation of arachidonate from cellular phospholipids. Vasoactive intestinal peptide (VIP) increases PRL release from anterior pituitary cells through a mechanism involving the generation of cAMP. In this study, we determined whether VIP increases the liberation of arachidonate from anterior pituitary cells. Primary cultures of anterior pituitary cells were prepared from the anterior pituitary gland of female Sprague-Dawley rats. After four to five days in culture, the incubation medium was replaced with [3H] arachidonate containing medium, and the cells incubated for 90 min. The cells were then extensively rinsed with incubation medium without [3H] arachidonate to remove the [3H] fatty acid not associated with cellular phospholipids. The pituitary cells were then incubated with medium containing various concentrations of VIP and the release of [3H] arachidonate and PRL into the incubation medium determined. VIP (500 nM) significantly increased [3H] arachidonate liberation from primary cultures of anterior pituitary cells at 30 min (p < 0.5) and 60 min (p < 0.01), but had no significant effect on the liberation of this fatty acid at 15 or 120 min. PRL release was significantly increased by VIP at 30, 60, and 120 min. VIP (60 min exposure) at concentrations of 100 and 500 nM significantly increased PRL release and arachidonate liberation in a concentration-dependent manner. Similarly, VIP increased [3H] arachidonate liberation from a preparation of anterior pituitary cells enriched in lactotropes. Since the increment in [3H] arachidonate liberation was greater in the lactotrope-enriched population than in the anterior pituitary cell preparation, it is highly probable that the lactotropes are the primary source of [3H] arachidonate liberated by VIP. These experiments provide evidence that [3H] arachidonate liberation may play a role in VIP-stimulated PRL release.
几种促分泌素通过涉及从细胞磷脂中释放花生四烯酸的生化途径增加垂体前叶细胞催乳素（PRL）的释放。血管活性肠肽（VIP）通过涉及生成环磷酸腺苷（cAMP）的机制增加垂体前叶细胞PRL的释放。在本研究中，我们确定VIP是否增加垂体前叶细胞花生四烯酸的释放。从雌性Sprague-Dawley大鼠的垂体前叶制备垂体前叶细胞原代培养物。培养四至五天后，将孵育培养基换成含[3H]花生四烯酸的培养基，细胞孵育90分钟。然后用不含[3H]花生四烯酸的孵育培养基大量冲洗细胞，以去除未与细胞磷脂结合的[3H]脂肪酸。然后将垂体细胞与含不同浓度VIP的培养基一起孵育，并测定[3H]花生四烯酸和PRL释放到孵育培养基中的量。VIP（500 nM）在30分钟（p < 0.5）和60分钟（p < 0.01）时显著增加垂体前叶细胞原代培养物中[3H]花生四烯酸的释放，但在15分钟或120分钟时对该脂肪酸的释放无显著影响。VIP在30、60和120分钟时显著增加PRL的释放。VIP（暴露60分钟）在100和500 nM浓度时以浓度依赖性方式显著增加PRL释放和花生四烯酸释放。同样，VIP增加了富含催乳素细胞的垂体前叶细胞制剂中[3H]花生四烯酸的释放。由于富含催乳素细胞群体中[3H]花生四烯酸释放的增加大于垂体前叶细胞制剂中的增加，催乳素细胞很可能是VIP释放[3H]花生四烯酸的主要来源。这些实验提供了证据表明[3H]花生四烯酸的释放可能在VIP刺激的PRL释放中起作用。
