RELEASE AND REGULATION OF ENDOGENOUS ADENOSINE DURING HEMORRHAGE

Pretreatment of animals with dilazep, a blocker of adenosine uptake, p otentiated the increased concentrations of adenosine in venous blood b y 6-fold and raised arterial adenosine concentrations by 3-fold. Pretr eatment of animals with erythro-9-)2-hydroxy-3-nonyl)adenine (EHNA), a n inhibitor of adenosine deaminase, also potentiated the increased con centrations of adenosine in venous blood by 6-fold and raised arterial adenosine concentrations by 3-fold. Pretreatment with combination of dilazep and EHNA furthermore increased venous adenosine levels by 11 t imes and arterial adenosine levels by 6 times. These data clearly sugg est that hemorrhage induced extensive adenosine release and the releas ed endogenous adenosine was eliminated quickly from plasma by the upta ke mechanism and adenosine deaminase.