[Melanotropic hormone in the green frog (Rana esculenta): biochemical and radioimmunological study].

The alpha-MSH levels in the frog hypophysis were measured by use of a sensitive ans specific radioimmunoassay. Sephadex G-50 gel chromatography of frog pars distalis and pars intermedia extracts showed that frog hypophyseal MSH was chemically related to synthetic alpha-MSH. Rat tissue homogenates were capable of degrading frog pars intermedia MSH as well as synthetic alpha-MSH. These results provide evidence that the frog hypophysis--pars intermedia and pars distalis--contains an alpha-MSH-like peptide.