Abstract
Rat liver and brain slices were incubated in vitro with [3H]melatonin. Liver slices synthesized small amounts of [3H]5-methoxyindoleacetic acid [3H]5-MIAA) along with other melatonin metabolites including 6-hydroxymelatonin. Pretreatment of animals prior to killing with the irreversible monoamine oxidase inhibitor pargyline allowed [3H]5-methoxytryptamine ([3H]5-MT) to be recovered from the incubation. No [3H]5-MIAA or [3H]5-MT could be detected in incubations with hypothalamic slices or following intraventricular injection of [3H]melatonin. The possibility that the deacetylase aryl acylamidase was in part responsible for the deacetylation occurring in liver slices was examined. Liver aryl acylamidase was able to utilize [3H]melatonin as substrate to produce [3H]5-MT. Furthermore, the liver enzyme was inhibited by melatonin (K(i) 1 mM) when tested with the alternate substrate o-nitroacetanalide. Brain aryl acylamidase did not generate any detectable [3H]5-MT nor was it inhibited by melatonin. These results suggest that 5-MT is not formed in brain from melatonin although trace amounts of 5-MT in the periphery could be derived from this precursor.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1219-1226 |
| Number of pages | 8 |
| Journal | Journal of Neurochemistry |
| Volume | 32 |
| Issue number | 4 |
| State | Published - 1979 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
- Cellular and Molecular Neuroscience
Cite this
Melatonin : Deacetylation to 5-methoxytryptamine by liver but not brain aryl acylamidase. / Rogawski, Michael A; Roth, R. H.; Aghajanian, G. K.
In: Journal of Neurochemistry, Vol. 32, No. 4, 1979, p. 1219-1226.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Melatonin
T2 - Deacetylation to 5-methoxytryptamine by liver but not brain aryl acylamidase
AU - Rogawski, Michael A
AU - Roth, R. H.
AU - Aghajanian, G. K.
PY - 1979
Y1 - 1979
N2 - Rat liver and brain slices were incubated in vitro with [3H]melatonin. Liver slices synthesized small amounts of [3H]5-methoxyindoleacetic acid [3H]5-MIAA) along with other melatonin metabolites including 6-hydroxymelatonin. Pretreatment of animals prior to killing with the irreversible monoamine oxidase inhibitor pargyline allowed [3H]5-methoxytryptamine ([3H]5-MT) to be recovered from the incubation. No [3H]5-MIAA or [3H]5-MT could be detected in incubations with hypothalamic slices or following intraventricular injection of [3H]melatonin. The possibility that the deacetylase aryl acylamidase was in part responsible for the deacetylation occurring in liver slices was examined. Liver aryl acylamidase was able to utilize [3H]melatonin as substrate to produce [3H]5-MT. Furthermore, the liver enzyme was inhibited by melatonin (K(i) 1 mM) when tested with the alternate substrate o-nitroacetanalide. Brain aryl acylamidase did not generate any detectable [3H]5-MT nor was it inhibited by melatonin. These results suggest that 5-MT is not formed in brain from melatonin although trace amounts of 5-MT in the periphery could be derived from this precursor.
AB - Rat liver and brain slices were incubated in vitro with [3H]melatonin. Liver slices synthesized small amounts of [3H]5-methoxyindoleacetic acid [3H]5-MIAA) along with other melatonin metabolites including 6-hydroxymelatonin. Pretreatment of animals prior to killing with the irreversible monoamine oxidase inhibitor pargyline allowed [3H]5-methoxytryptamine ([3H]5-MT) to be recovered from the incubation. No [3H]5-MIAA or [3H]5-MT could be detected in incubations with hypothalamic slices or following intraventricular injection of [3H]melatonin. The possibility that the deacetylase aryl acylamidase was in part responsible for the deacetylation occurring in liver slices was examined. Liver aryl acylamidase was able to utilize [3H]melatonin as substrate to produce [3H]5-MT. Furthermore, the liver enzyme was inhibited by melatonin (K(i) 1 mM) when tested with the alternate substrate o-nitroacetanalide. Brain aryl acylamidase did not generate any detectable [3H]5-MT nor was it inhibited by melatonin. These results suggest that 5-MT is not formed in brain from melatonin although trace amounts of 5-MT in the periphery could be derived from this precursor.
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M3 - Article
C2 - 285213
AN - SCOPUS:0018763776
VL - 32
SP - 1219
EP - 1226
JO - Journal of Neurochemistry
JF - Journal of Neurochemistry
SN - 0022-3042
IS - 4
ER -