Establishment of four functional, clonal strains of animal cells in culture.

The single-cell plating technique was used to develop four clonal cell lines that perform organ-specific functions after being serially cultured for prolonged periods. These strains include steroid-secreting Leydig cells, melanomacells that form pigment, and two strains from a hormone-secreting rat pituitary tumor. One of the cell lines from the pituitary tumor secretes growt hormone, while another line derived from the same tumor secretes a substance similar to adrenocorticotropic hormone.