Previous studies from this laboratory showed that adenosine amplifies the action of luteinizing hormone (LH) severalfold in rat and human luteal cells by an intracellular, adenosine 5'-triphosphate (ATP)-linked process. The objective of this study was to evaluate the contribution of phosphocreatine (PCr) and creatine kinase (CK) to the dynamics of luteal ATP metabolism. Levels of PCr in luteinized rat ovaries were similar to those seen in liver but were ~1 and 7% of levels found in skeletal and heart muscle, respectively. In isolated rat luteal cells, little detectable PCr was seen after incubation in the presence or absence of adenosine, although cell ATP levels were increased twofold by adenosine treatment. The presence or absence of LH had no effect on either PCr or ATP levels in incubations of isolated luteal cells. Analysis of CK activity in tissue and cell homogenates showed that the specific activity of CK in luteal cells was in the same range as that seen in liver but <1/30 of that seen in skeletal muscle. From these studies we conclude that rat luteal cells contain little, if any, PCr and low levels of CK. Thus the rapid changes in ATP levels that are seen in rat luteal tissue and cells may occur because these cells have little capacity to buffer ATP levels with a reservoir of high-energy phosphate groups in the form of PCr.
|Original language||English (US)|
|Journal||American Journal of Physiology - Endocrinology and Metabolism|
|State||Published - 1987|
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Physiology (medical)