ON A NEW AEROBIC METABOLITE WHOSE PRODUCTION BY BRAIN IS INHIBITED BY APOMORPHINE, EMETINE, ERGOTAMINE, EPINEPHRINE, AND MENADIONE

¹ From the Department of Physiology and Pharmacology, Duke University School of Medicine, Durham, N. C.

1. Suspensions of tissue incubated aerobically produce a substance arbitrarily called B, which can be measured quantitatively by two empirical tests. Evidence is presented suggesting that B contains an aminopyrimidine, an amino, and an aldehyde group.

2. The best producers of B are brain and liver, followed by kidney, spleen, heart, testis, and skeletal muscle. Small intestine, pancreas and blood produce none. One astrocytoma was active, whereas a glioblastoma and fibroblastoma were not.

3. A detailed study was made of the production of B by suspensions of brain, the chief results of which follow:

4. The addition of tissue extracts (blood, liver, kidney, etc.) to brain enhances the rate and amount of B production, suggesting the activity of coenzymes and precursors.

5. Apomorphine, ergotamine, emetine, ergotoxin, epinephrine, menadione, and ergonovine (arranged in descending order of potency) are the most powerful inhibitors of B production. KCN and methylene blue also inhibit.

6. The rate of B production is increased by incubation in oxygen instead of air, even though the rate of respiration remains unchanged. It is thus possible for oxygen tension to affect the metabolism of brain without changing the rate of respiration.

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