FOLLICLE-STIMULATING HORMONE-BETA SUBUNIT GENE IS EXPRESSED IN PARALLEL WITH A TRANSCRIPTION FACTOR AD4BP SF-1 IN HUMAN PITUITARY-ADENOMAS/

OBJECTIVES A transcription factor Ad4BP/SF-1 is implicated in the diff erentiation of gonadotrophs in the pituitary gland, but it is not know n whether human pituitary cells express this factor. The present study aimed to disclose (1) whether human pituitary adenomas express Ad4BP/ SF-1, and (2) if this is the case, what kinds of adenoma express the f actor. MATERIAL Total RNA was extracted from 23 pituitary adenomas obt ained by transsphenoidal surgery, and subjected to Northern blot analy ses using cDNAs of bovine Ad4BP/SF-1, porcine FSH-beta, LH-beta and gl ycoprotein hormone-alpha (GPH-alpha) subunits as radiolabelled probes. These adenomas included 13 clinically non-functioning adenomas, 1 GH/ PRL-producing adenoma, 6 GH-producing adenomas, 2 PRL-producing adenom as and 1 ACTH-producing adenoma. RESULTS The expression of Ad4BP/SF-1 exactly coincided with the expression of FSH-beta. Thus 5 out of 13 cl inically non-functioning adenomas expressed Ad4BP/SF-1 and only these 5 adenomas expressed FSH-beta. Interestingly, only one of the GH-produ cing adenomas also expressed Ad4BP/SF-1 as well as FSH-beta. GPH-alpha was expressed in 4 non-functioning adenomas and 2 hormonally function ing adenomas, but did not necessarily coincide with Ad4BP/SF-1 express ion. None of the 23 adenomas we tested expressed LH-beta, probably bec ause LH-beta-producing adenomas are rather rare. CONCLUSIONS The expre ssion of FSH-beta was parallel with Ad4BP/SF-1 expression, indicating that the expression of Ad4BP/SF-1 is restricted to cells derived from gonadotroph lineages in human pituitary adenomas.