Human retinoblastoma Y79 cells contain both insulin-specific mRNA and insulin-binding sites

We previously reported the presence of insulin-like immunoreactivity in cells from the human retinoblastoma Y79 cell line. In the present study, in situ DNA hybridization techniques were applied, using a human insulin cDNA probe to investigate whether the insulin-like activity is due to local synthesis of insulin. Our results suggest that Y79 cells contain mRNA for the synthesis of insulin or a homologous peptide. In addition, 125I-insulin binding autoradiographic studies show that these cells also contain specific insulin-binding sites. It is suggested that insulin may play an autocrine and/or paracrine role in the maintenance and metabolism of the Y79 retinoblastoma cells.