EXPRESSION OF ACTIVIN INHIBIN SUBUNIT MESSENGER RIBONUCLEIC-ACIDS BY GONADOTROPH ADENOMAS/

As an initial step in determining whether activin could play a role in the development of gonadotroph adenomas, we attempted to determine if activin/inhibin subunit messenger ribonucleic acids (mRNAs) are expre ssed by these pituitary tumors. We selected 19 pituitary adenomas that had been excised by transsphenoidal surgery and determined by immunoc ytochemical criteria to be gonadotroph adenomas. Total RNA was extract ed from these adenomas and reverse transcribed. The resulting pit-1 co mplementary DNA, expected to be present only in somatotroph, lactotrop h, and thyrotroph cells, was amplified by the polymerase chain reactio n to test the possibility that the adenoma tissue was contaminated by normal pituitary tissue. Only the 10 adenomas that did not express pit -1 mRNA were subjected to further analysis by polymerase chain reactio n amplification of the adenoma reverse transcriptase products for the activin/inhibin beta(B)-, beta(A)- and alpha-subunits. All 10 adenomas expressed beta(B)-subunit, none of the 10 expressed the beta(A)-subun it, and 6 of the 10 expressed the alpha-subunit. We conclude that gona dotroph adenomas express mRNAs for activin/inhibin beta(B)- and alpha- subunits. The relationship of beta(B) expression to the pathogenesis o f gonadotroph adenomas remains to be determined.