The aim of this study was to investigate effects of reduced stress hormone by adrenalectomy on rat plasma levels of lysophosphatidic acid (LPA) and other lysophospholipids. We measured activities of lysophospholipase D (lysoPLD) in plasma and lipid phosphate phosphatase (LPP) in blood by determining choline and inorganic phosphate, respectively. LPA, lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE), lysophosphatidylinositol (LPI), lysophosphatidylserine (LPS) and lysophosphatodylglycerol were quantified by LC–MS/MS. In adrenalectomized rats, plasma levels of LPA, LPE, LPS and LPI, but not LPC, were increased. The increased level of LPA were due to decreased LPC level, increases plasma activity of lysoPLD toward LPC and decreased LPP activity toward LPA. Daily injections of deoxycoricosterone into rats selectively reversed increased level of LPS. Our results suggest enzymatic mechanism for increased plasma level of LPA, and indicate that the circulating levels of lysophospholipids including LPA in rats are differently affected by artificial suppression of release of adrenergic hormones.

本研究的目的是探讨肾上腺切除术减少应激激素对大鼠血浆溶血磷脂酸 (LPA) 和其他溶血磷脂水平的影响。我们分别通过测定胆碱和无机磷酸盐来测量血浆中溶血磷脂酶 D (lysoPLD) 和血液中脂质磷酸磷酸酶 (LPP) 的活性。通过 LC-MS/MS 对 LPA、溶血磷脂酰胆碱 (LPC)、溶血磷脂酰乙醇胺 (LPE)、溶血磷脂酰肌醇 (LPI)、溶血磷脂酰丝氨酸 (LPS) 和溶血磷脂酰甘油进行定量。在肾上腺切除的大鼠中，LPA、LPE、LPS 和 LPI 的血浆水平升高，但 LPC 没有升高。 LPA 水平升高是由于 LPC 水平降低、lysoPLD 对 LPC 的血浆活性增加以及 LPP 对 LPA 的活性降低。每天向大鼠注射脱氧皮质酮选择性地逆转 LPS 水平的升高。我们的结果提示了 LPA 血浆水平增加的酶促机制，并表明大鼠中包括 LPA 在内的溶血磷脂的循环水平受到人工抑制肾上腺素能激素释放的不同影响。