A ROLE OF SH-COMPOUNDS IN MATURATION OF MELANOSOMES IN CELLS CULTUREDFROM NEVUS OTA

A role of SH-compounds such as cysteine and glutathione in melanogenes is in dermal melanocytes cultured from Ota's nevus tissue was demonstr ated in relation to another substrate, dihydroxyphenylalanine (DOPA). Chemical analysis of eumelanin and pheomelanin was performed in additi on to the conventional electron microscopic observation. Supplements o f the culture medium with each of these compounds separately for two w eeks gave rise to the formation of pre-pheomelanosomes and secondary l ysosomes or myelinosome-like inclusions. When DOPA and glutathione wer e added to the medium together, the maturation of melanosomes was prom oted. This was proven by the increase in electron-density of pre-melan osomes observed as well as by the content of pheomelanin and eumelanin . However, mature melanosomes were not formed when each of these chemi cals was added to the medium individually for the same periods. The me lanosome maturation seemed to occur via a process involving secondary lysosomes or myelinosomes, in which more electron-dense particles accu mulated in the presence of both reagents. The pheomelanosomal process was also observed, but typical eumelanosome-related processes were not observed in this culture system.