Melanin-Dispersing Effect of Adenosine 3″,5″-Monophosphate on Amphibian Melanophores

Abstract

Because of conflicting prior reports of the effect of 3″,5″-AMP (adenosine 3″,5″- monophosphate) on frog melanophores, the effect of this substance has been studied on amphibian melanophores. Although lower concentrations produce some darkening, 10 HIm is required to markedly darken isolated frog skin or expand tissue cultured salamander embryonic melanophores. The darkening of frog skin by 3″,5″-AMP was not sodium dependent. The darkening produced by combinations of 3″,5″-AMP with melanocyte-stimulating hormone (MSH) or caffeine was equal to the sum of the darkening produced by these agents alone. The results were discussed in terms of the possibility that 3″,5″- AMP may be the “second messenger” for MSH and caffeine action on melanophores. (Endocrinology81: 283, 1967)