Ethanol-induced changes in gastric mucosal content of cyclic AMP and ATP in the rat

Biochemical interactions of ethanol with the arachidonic acid cascade

A rapidly increasing scientific literature now supports the possibility of an alcohol-prostaglandin interaction. This chapter reviews evidence for both direct and indirect biochemical interactions between ethanol and the metabolism of arachidonic acid and several related compounds. Much of the present data is based on pharmacological manipulation of prostaglandin (PG) levels by potent nonsteroid anti-inflammatory agents such as indomethacin. Indomethacin markedly alters the behavioral response to ethanol, particularly in the mouse model. These data suggest that PGs are involved in the behavioral response to acute ethanol exposure in the mouse. In other animal models, alcohol has been reported to alter blood platelet metabolism of arachidonic acid, to suppress the enzymatic degradation of PGs, and to alter the response of the adenyl cyclase system to several hormones including PGs of the "E" series. In humans, both the stimulation and inhibition of PG synthesis is reported to aid the treatment of various aspects of alcoholism. Further, PGs are reported to protect against alcohol-induced fatty liver, and both PGs and arachidonic acid protect the gastric mucosa against ethanol-induced lesions. Certainly the residual consequences of acute, excessive ethanol consumption are commonly treated with a prostaglandin synthesis inhibitor. The material in this chapter is an attempt to review the data and to discuss the molecular mechanism underlying these observations.

Alterations in maternal and fetal prostaglandin dehydrogenase as a result of maternal ethanol consumption

Various lines of research have suggested that ethanol consumption may alter prostaglandin-related physiology. Our laboratory has reported that chronic exposure to high doses of ethanol lowers the ability of kidney and lung homogenates from rats to catabolize prostaglandin E2 and F2 alpha via 15-prostagladin dehydrogenase (PGDH). Because of the apparently unique role played by prostaglandins in conception, growth and development of the fetus and parturition, we have attempted to determine if the alterations observed in male rats also occur in females and if any alterations in fetal metabolism result from maternal ethanol exposure. Further, we have measured the influence of ethanol administration on renal clearance of the 15-keto metabolite of PGF2 alpha in an attempt to determine the in vivo significance of the enzyme inhibition observed in vitro. Initial results indicate the following. 1) Female Holtzman rats doses at 2.0, 5.0 and 7.0 mg ethanol/kg during the first, second, and third trimesters of pregnancy, respectively, showed losses in renal PGDH activity similar to those found in males (1.52 versus 1.05 picomole/min/mg, p < 0.001 by matched t-test). 2) Placental tissue (amnion) isolated from these same animals on day 21 of the pregnancies also showed a significant decrease in PGDH activity (14.79 versus 11.77 picomoles/min/mg, p < 0.01). 3) Kidney homogenates from fetuses delivered on day 21 of the pregnancies showed a significant increase in PGDH relative to pair-dosed controls (16.77 versus 12.65 picomoles/min/mg, p < 0.01). 4) In a separate experiment, urinary clearance of PGF2 alpha metabolite was inhibited in a dose related manner up to a level of 6 gm/kg.