Distribution of an enzyme which acetylates α-melanocyte stimulating hormone in rat brain and pituitary gland and effects of arcuate nucleus lesions
1982; Elsevier BV; Volume: 3; Issue: 1 Linguagem: Inglês
10.1016/0196-9781(82)90144-9
ISSN1873-5169
AutoresThomas L. O’Donohue, Mark C. Chappell,
Tópico(s)Regulation of Appetite and Obesity
ResumoThis study describes the distribution of an α-melanocyte stimulating hormone (α-MSH) acetyltransferase (MAT) in rat brain and pituitary gland. Highest activities of MAT were found in the neurointermediate lobe of the pituitary gland with the anterior lobe containing slightly less. Within the brain, lowest MAT activities were measured in the hypothalamus, the region which contained the highest concentrations of α-MSH. Relatively high enzyme activities of MAT were measured in the hippocampus, cortex and cerebellum—regions with very low α-MSH concentrations. The fact that MAT activity levels did not parallel α-MSH concentrations indicates that MAT was not solely localized to α-MSH synthesizing neurons or endocrine cells. Furthermore, arcuate nucleus lesions which depleted brain α-MSH failed to deplete MAT activity. Although MAT was not solely localized to α-MSH synthesizing cells, it may have functional significance for α-MSH acetylation due to compartmentalization with α-MSH in α-MSH synthesizing endocrine cells and neurons. Alternatively a second regionally specific MAT may exist.
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