Glucocorticoid receptor antagonism by mifepristone alters phosphocreatine breakdown during sepsis.
OBJECTIVE
To determine the role of glucocorticoids in the regulation of myocellular energetics induced by sepsis by means of the glucocorticoid receptor antagonist mifepristone (RU 38486).


METHODS
Randomized controlled study.


METHODS
University laboratories.


METHODS
Thirty-two adult male Wistar rats.


METHODS
Animals were randomly assigned to 1 of 4 groups. In 2 groups, mifepristone (10 mg/kg) was administered by gavage feeding 2 hours before cecal ligation and single 18-gauge needle puncture or sham operation. The other 2 groups of animals received placebo gavage feedings 2 hours before their surgical procedures. Twenty-four hours after operation, high-energy phosphate ratios, intracellular pH, the forward rate constant for the creatine kinase reaction, and phosphocreatine breakdown rates were measured in the gastrocnemius muscle by in vivo phosphorus 31 magnetic resonance spectroscopy. Tissue and blood samples were collected to measure creatine and adenosine 5'-triphosphate concentrations, Na(+)-K+ adenosine triphosphatase activity, and circulating corticosterone levels.


RESULTS
Circulating corticosterone levels were twice as high in septic animals as in sham-operation control rats (P < .01). Phosphocreatine breakdown rates and Na(+)-K+ adenosine triphosphatase activity were significantly higher (40% and 75%, respectively; P < .01) in placebo-treated septic rats than in sham-operation control rats. However, phosphocreatine breakdown rates and Na(+)-K+ adenosine triphosphatase activity in mifepristone-treated septic animals were not significantly elevated above control levels.


CONCLUSIONS
Pretreatment with mifepristone reduces the demand for adenosine triphosphate production from phosphocreatine breakdown and downregulates Na(+)-K+ adenosine triphosphatase activity during sepsis.
Mitsuo
T
T
Laboratory for Surgical Metabolism and Nutrition, Brigham and Women's Hospital, Boston, Mass., USA.
Rounds
J
J
Prechek
D
D
Wilmore
D W
DW
Jacobs
D O
DO
D000255:Adenosine Triphosphate / Q000032:analysis / Q000097:blood / Q000378:metabolism; D000818:Animals; D003345:Corticosterone / Q000097:blood; D003401:Creatine / Q000032:analysis / Q000097:blood; D003402:Creatine Kinase / Q000378:metabolism; D015536:Down-Regulation; D004734:Energy Metabolism; D006727:Hormone Antagonists / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D015735:Mifepristone / Q000494:pharmacology*; D018482:Muscle, Skeletal / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism*; D010759:Phosphorus Isotopes; D010919:Placebos; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D011965:Receptors, Glucocorticoid / Q000037:antagonists & inhibitors*; D018805:Sepsis / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D006727:Hormone Antagonists; D010710:Phosphates; D010759:Phosphorus Isotopes; D010919:Placebos; D011965:Receptors, Glucocorticoid; D010725:Phosphocreatine; D015735:Mifepristone; D000255:Adenosine Triphosphate; D003402:Creatine Kinase; D000254:Sodium-Potassium-Exchanging ATPase; D003401:Creatine; D003345:Corticosterone