Prolactin and growth hormone synthesis and thymidine incorporation in dissociated rat pituitary tumor cells.
The effect of in vivo diethylstilbestrol (DES) treatment on the MtT/W15 transplantable pituitary tumor was examined in dissociated pituitary cells by measuring the rate of incorporation of [3H]thymidine into DNA and the synthesis of prolactin (PRL) and growth hormone (GH) as assessed by the rate of incorporation of [3H]leucine. MtT/W15 transplantable pituitary tumors from rats treated for 3 weeks with DES showed significant reduction in the extent of [3H]thymidine incorporation compared with tumor cells from untreated rats (2231 +/- 182 vs 172 +/- 17 dpm/10(5) cells; n = 3). In addition, tumor cells from DES-treated rats showed a significant increase in GH synthesis compared with tumor cells from untreated rats. In contrast to these findings, dissociated pituitary cells from non-tumor-bearing rats given 10 mg DES in Silastic tubing for 3 weeks showed a three-fold increase in PRL synthesis compared to cells from untreated control rats (29.3 +/- 1.5 vs 10.0 +/- 0.9% of total radioactivity in gel; n = 3. There was also a four-fold increase in the rate of [3H]thymidine incorporation after DES-treatment in non-tumor-bearing rats (695 +/- 114 vs 178 +/- 13.9 dpm/10(5) cells; n = 3). These results indicate that DES inhibits MtT/W15 pituitary tumor cell proliferation, while stimulating synthesis of GH.
D000818:Animals; D004054:Diethylstilbestrol / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D013006:Growth Hormone / Q000096:biosynthesis*; D066298:In Vitro Techniques; D010902:Pituitary Gland / Q000187:drug effects; D010911:Pituitary Neoplasms / Q000378:metabolism* / Q000473:pathology; D011388:Prolactin / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D013936:Thymidine / Q000378:metabolism*; D014316:Tritium
D004967:Estrogens; D014316:Tritium; D004054:Diethylstilbestrol; D011388:Prolactin; D013006:Growth Hormone; D013936:Thymidine