Establishment of Clonal Strains of Rat Pituitary Tumor Cells That Secrete Growth Hormone¹^,²

TLDR

Three clonal epithelial cell strains were derived from a transplantable rat pituitary tumor and serially propagated for 14–25 months, subcultured every 2–3 weeks. The strains grew steadily (30–40 h generation time) for up to 25 months, all secreting growth hormone identical to normal rat pituitary hormone, with the most vigorous strain producing 20–40 fig μng cell N / 24 h and no decline in secretion. Endocrinology 82: 342 (1968).

Abstract

Three clonal strains of epithelial cells were established from a transplantable rat pituitary tumor. These strains have been serially propagated for 14–25 months. They were subcultured every 2–3 weeks. Cells of the original strain have increased by a factor of more than 1040. The generation times of the 3 lines were similar and ranged between 30 and 40 hr. Cells of all 3 strains synthesize growth hormone and secrete it into the culture medium. Growth hormone synthesized in vitro is indistinguishable from normal rat pituitary growth hormone as measured by micro-complement fixation and radioimmunoassay. The specific activity of growth hormone production was estimated to be 20–40 figμng cell nitrogen/24 hr for the most vigorous strain. There has been no decrease in the rate of cell division nor decline in growth hormone secretion since the cells were established in culture. (Endocrinology82: 342, 1968)