Study summary · research use only
alpha-Melanocyte-stimulating hormone, MSH 11-13 KPV and adrenocorticotropic hormone signalling in human keratinocyte cells
Plain-language summary
Paraphrased from the published abstract below — not a verdict on whether anything works.
This in vitro study examined signalling by alpha-melanocyte-stimulating hormone (alpha-MSH), its C-terminal tripeptides (KPV, KP-D-V), and ACTH peptides in human keratinocytes. The authors report that no rise in cyclic AMP was detected in HaCaT or normal keratinocytes in response to these peptides, but rapid intracellular calcium responses occurred to alpha-MSH, KPV, KP-D-V, and ACTH (10(-15) to 10(-7) M) in HaCaT cells only in the presence of the adenosine agonist PIA. Normal keratinocytes also responded to ACTH 1-17. Chinese hamster ovary cells stably transfected with the MC-1 receptor showed elevated intracellular calcium with alpha-MSH and KPV peptides.
Abstract
alpha-MSH signals by binding to the melanocortin-1 receptor (MC-1R) and elevating cyclic AMP in several different cells. The anti-inflammatory properties of this peptide are also believed to be cyclic AMP dependent. The carboxyl terminal tripeptides of alpha-MSH (KPV / KP-D-V) are the smallest minimal sequences reported to prevent inflammation but it is not known if they operate via MC-1R or cyclic AMP. The aim of this study was to examine the intracellular signalling of key MSH and ACTH peptides in human keratinotocytes. No elevation in cyclic AMP was detected in either HaCaT or normal human keratinocytes in response to alpha-MSH, KPV or ACTH peptides. Rapid and acute intracellular calcium, however, were observed in HaCaT keratinocytes in response to alpha-MSH (10(-15)-10(-7) M), KPV (10(-15)-10(-7) M), KP-D-V (10(-15)-10(-7) M) and ACTH (10(-15)-10(-7) M), but only in the presence of PIA, an adenosine agonist that inhibits the cyclic AMP pathway. Normal keratinocytes responded to all the above peptides but in addition responded to ACTH 1-17 (10(-13)-10(-7) M) in contrast to the HaCaT keratinocytes. Stable transfection of Chinese hamster ovary cells with the MC-1 receptor showed that alpha-MSH and the KPV peptides elevated intracellular calcium.
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