EFFECTS OF ADENOSINE CYCLIC-NUCLEOTIDES ON THE SYNTHESIS OF HUMAN CHORIONIC-GONADOTROPIN IN TRANSFORMED HUMAN PLACENTAL CELLS

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  • 1 January 1980
    • journal article
    • research article
    • Vol. 40  (11) , 4025-4030
Abstract
The synthesis of human chorionic gonadotropin (HCG) and its subunits was studied in SV40 tsA mutant-transformed human 1st-trimester and term placental cells at 33.degree. C (the temperature at which the cells have the transformed phenotype) and at 40.degree. C (the temperature at which the tsA transformants regain their nontransformed phenotype). 8-Bromo cAMP (8BrcAMP) and dibutyryl cAMP (Bt2cAMP) greatly induced the synthesis of HCG.alpha. with little or no stimulation of the synthesis of HCG in transformed placental cells grown at 33 or 40.degree. C. The ratio of HCG.alpha. to HCG in these cells, therefore, increased in the presence of either nucleotide. 8BrcAMP and Bt2cAMP also greatly induced the synthesis of HCG.alpha. in nontransformed secondary placental cells (at 6th-20th passage), although the synthesis of HCG was not detectable in these cells under the experimental conditions used. The synthesis of HCG as well as HCG.alpha. was stimulated in choriocarcinoma cells by 8BrcAMP and Bt2cAMP. The ratio of HCG.alpha. to HCG in uninduced choriocarcinoma cells increased during growth in culture. 8BrcAMP stimulated the synthesis of HCG preferentially in these cells, thus decreasing the ratio of HCG.alpha. to HCG. Adenosine cyclic nucleotides have different effects on the production of HCG but not on HCG.alpha. in SV40 tsA-transformed placental cells and choriocarcinoma cells.