Establishment in culture of a multihormone-secreting cell strain derived from the mtT/F4 rat pituitary tumor

Abstract

A clonal cell strain F₄C₁ has been established from the transplantable rat pituitary tumor MtT/F₄ and has been maintained in continuous culture for two years. The cells grow with a population doubling time of 48 hours; the karyotype with a modal number of 39 chromosomes includes a pair of large metacentric marker chromosomes. F₄C₁ cells in culture produce growth hormone and prolactin but not adrenocorticotropin in contrast to the MtT/F₄ tumor which secretes all three hormones in the host rat. The cloned cells lack specific receptors for thyrotropin-releasing hormone and do not respond to this agent with increased prolactin or decreased growth hormone production. Treatment with hydrocortisone results in a small increase in growth hormone and a small decrease in prolactin production. Tumors generated in rats from injected F₄C₁ cells secrete prolactin and growth hormone but not adrenocorticotropin. The results suggest that growth hormone and prolactin are produced by a single cell type in the MtT/F₄ tumor.