[Characterization of gonadotropic cells in a new pituitary tumor cell line]

The pituitary tumor cell line RC-4B/C was established in The Jackson Laboratory from an aged rat pituitary adenoma. Immunocytochemical studies of this cell line showed that all pituitary cell types were present. Approximately 20% reacted with antisera (AS) to ovine (o) LH beta, 8.6% with AS to oFSH beta, 15% with AS to rat PRL, 12% with AS to equine GH, 9% with AS to porcine TSH beta and 8.6% with AS to ACTH1-24. Using NIDDK rat kits, RIA showed about 0.38, 0.08 and 607.50 ng per 10(6) cells of LH, FSH and PRL, respectively, vs 33.9, 75.6 and 573 ng in freshly dispersed rat pituitary cells. The GnRH receptor content of the cell line was about a half that of normal rat pituitary cells but the receptor affinity was the same. A chronic treatment of the cells for about 5 months with a "sub-physiological" concentration (3.7 pM) of a GnRH agonist had 3 major effects: 1) as compared to the controls, a 3-fold increase in the cell number in the log phase; 2) an increase of the percentage of FSH beta cells from 8.6 to 21.9% whereas LH beta cells and the cell content of LH and FSH remained stationary; 3) a decrease of the percentage of PRL cells from 15 to 6.5% and an almost 250-fold decrease of PRL cell content. Incorporation studies with [35S] Met demonstrated that the alpha subunit in the cell line was only partly glycosylated. Pretreatment of the cells with 5 nM estradiol restored, at least partly, glycosylation of alpha.(ABSTRACT TRUNCATED AT 250 WORDS)