Regulation of central and peripheral carbohydrate reserves after selective inhibition of enzyme monoamine oxidase: comparison between fed and starved rats.

1. Maintenance of brain, liver and heart glycogen after selective inhibition of enzyme monoamine oxidase with clorgyline and deprinil was studied in normally fed or starved rats. 2. The administration of clorgyline to fed rats produces an important decrease in glycogen of the brain after 3 h of injection whereas the same treatment to starved rats resulted in complete exhaustion of brain glycogen stores. 3. Deprinil administration provoked a complete disappearance of glycogen in brain in fed rats after one and three hours of the injection but the same dose given to starved rats had a similar effect only after one hour since three hours after brain glycogen reserves of starved rats were close to the control values. 4. Clorgyline did not modify hepatic glycogen in fed rats but in starved rats in increase after three hours of administration took place. 5. Deprinil decreased liver glycogen in fed rats but the starved rats showed increases after one and three hours. 6. Heart glycogen increased in fed rats after clorgyline injection but starved rats showed slight decreases. Deprinil decreased cardiac glycogen slightly in fed as well as starved rats. 7. After one hour of deprinil injection glycemia was at the lowest value in fed rats but the decrease in starved rats was less marked. Three hours after deprinil or clorgyline administration both groups showed increases in glycemia. 8. Marked differences in the degree of MAO inhibition between fed and starved rats were observed after clorgyline and deprinil administration. The brain of starved rats showed only 49% inhibition whereas fed rats had 91% enzyme inhibition after three hours of deprinil treatment.