We studied the pigmentary activity of the peptides gamma1, gamma2 and gamma3 melanocyte stimulating hormone (MSH), which differ in the structure of their Ctermini, using hamster and mouse melanoma cell lines responsive to betaMSH by increasing tyrosinase activity. Gamma1MSH alone or in combination with betaMSH had no effect on either cell line. Gamma2MSH alone was biologically inactive but potentiated betaMSH stimulation of tyrosinase activity. Gamma3MSH at high concentration (10 μM) induced tyrosinase activity and dendrite formation in the hamster melanoma line. When added together with betaMSH, gamma3MSH partially inhibited the tyrosinase activity response to betaMSH. Thus, gammaMSH peptides have low intrisic melanotropic activity in mammalian melanoma cells; the specific pigmentary responses appear to be affected by the structure of the Cterminal portion.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Pharmacology, Toxicology and Pharmaceutics(all)