Gimes G, Tóth M
2nd Department of Obstetrics and Gynecology, Semmelweis Medical University, Budapest, Hungary.
Acta Physiol Hung. 1993;81(1):101-8.
Agents causing accumulation of endogenous diacylglycerols (DAG) may be helpful in studies on the intracellular regulatory effects and on the mechanisms of attenuation of this putative second messenger. In a previous study (Tóth et al., BBA 921 (1987) 417-425) we have shown a marked stimulatory effect of low micellar concentration (0.05%, v/v) of Triton X-100 on the labelling of phosphatidic acid with (32P)phosphate in minced human primordial placenta. The present results demonstrate that 0.05% Triton X-100 inhibits nearly completely the conversion of (3H)diacylglycerols into (3H)triacylglycerols in placenta fragments incubated with (3H)glucose. However, this concentration of the detergent does not have any effect on the appearance of label in the sum of acylglycerols (comprising mono-, di- and triacylglycerols) and phosphatidylcholine, indicating a lack of effect on phosphatidate phosphohydrolase. The about 5-fold elevation of (3H)diacylglycerols was attended by an approximately 3-fold rise in (3H)phosphatidic acid and a 1.3-fold increase in the labelling of phosphatidylcholine. These findings provide supportive evidence that 1,2-DAG was formed due to inhibition of DAG-acyltransferase and suggest that some of the DAG was transformed into phosphatidic acid by diacylglycerol-kinase.
导致内源性二酰甘油（DAG）积累的试剂可能有助于研究细胞内调节作用以及这种假定的第二信使的衰减机制。在之前的一项研究中（托特等人，《生物化学与生物物理学学报》921（1987）417 - 425），我们已经表明，低胶束浓度（0.05%，v/v）的 Triton X - 100 对切碎的人原始胎盘用（32P）磷酸盐标记磷脂酸有显著的刺激作用。目前的结果表明，0.05% 的 Triton X - 100 几乎完全抑制了用（3H）葡萄糖孵育的胎盘碎片中（3H）二酰甘油向（3H）三酰甘油的转化。然而，这种洗涤剂浓度对酰基甘油（包括单酰、二酰和三酰甘油）和磷脂酰胆碱总和中的标记物出现没有任何影响，表明对磷脂酸磷酸水解酶没有作用。（3H）二酰甘油约 5 倍的升高伴随着（3H）磷脂酸约 3 倍的增加以及磷脂酰胆碱标记增加 1.3 倍。这些发现提供了支持性证据，即由于二酰甘油酰基转移酶的抑制形成了 1,2 - DAG，并表明一些 DAG 被二酰甘油激酶转化为磷脂酸。
