INVITRO REGULATION OF RAT PROLACTIN MESSENGER-RIBONUCLEIC-ACID POLY(A) TAIL LENGTH - MODULATION BY BROMOCRIPTINE

Recent analysis of endocrine gene transcripts has revealed that severa l hormone mRNAs exhibit regulated size changes (due to alterations in length of the 3' poly(A) tail) which may function as an additional lev el of control in the determination of gene expression. We have now sho wn, through the novel application of an organ culture technique, that prolactin mRNA exhibits a similar regulated change in poly(A) tail len gth when rat anterior pituitary glands are explanted. The effect is ob served in glands of either male or female rats and is specific with re spect to growth hormone and alpha-tubulin mRNAs. Furthermore, we have also found that the size change in prolactin mRNA is attenuated in the presence of bromocriptine, indicating regulation through a dopaminerg ic pathway.