DETECTION OF GROWTH-HORMONE, PROLACTIN AND HUMAN BETA-CHORIONIC GONADOTROPIN MESSENGER-RNA IN GROWTH HORMONE-SECRETING PITUITARY-ADENOMAS AND IN PROLACTIN-SECRETING PITUITARY-ADENOMAS BY INSITU HYBRIDIZATION USING A NONISOTOPIC DETECTION METHOD

A non-isotopic in situ hybridization method with digoxigenin-labelled probes was used to examine growth hormone (GH), prolactin (PRL) and hu man beta-chorionic gonadotropin (beta-hCG(LH)) gene expression in 63 p ituitary tumours in acromegaly and 20 adenomas in hyperprolactinaemia. hCG and LH were detected simultaneously because of the extensive homo logy (more than 90%) of their mRNA sequences (1). A comparison with fo rmer results obtained with S-35-labelled probes shows the value of the easier and faster non-isotopic method. Additionally, immunohistochemi cal data are included to give even more evidence for the synthesis of the respective hormones by the tumour cells. In all 63 adenomas in acr omegaly, GH mRNA was revealed in 59 PRL mRNA and in 36 beta-hCG(LH) mR NA. A positive immunostaining for GH was found in all, for PRL in 40, and for beta-hCG(LH) in 34 adenomas. The comparison of the two in situ hybridization methods revealed no differences concerning GH mRNA dete ction, but not all tumours positive after non-isotopic PRL and beta-hC G(LH) mRNA detection showed signals with the radioactive method. Refer ring to the 20 PRL-secreting adenomas, PRL gene expression was demonst rable in all, GH mRNA in 12, and beta-hCG(LH) mRNA in 2 cases. Compari ng the positive results of immunohistochemistry with those of in situ hybridization, correspondence was found in 19 cases for PRL, in 5 case s for GH and in no case for beta-hCG(LH).