Corticotropin releasing factor stimulates cAMP formation in pituitary corticotropic tumor cells.
Addition of corticotropin-releasing factor (CRF) to membranes from two ACTH-secreting pituitary tumors strikingly increased in a dose-dependent fashion adenylate cyclase (AC) activity. Significant stimulation was already apparent at 10(-9)M CRF. Stimulation of AC activity by CRF in membranes from non-tumoral tissue adjacent to tumoral corticotrophs was considerably lower, and was lacking in membranes from a growth hormone secreting tumor. These data correlated well with in vivo pre-surgery and post-surgery ACTH responsiveness to CRF of the tumor bearing patients. Basal AC activity was higher in pituitary adenomas than in non-tumoral adjacent tissue. It is concluded that 1) a CRF-sensitive AC exists in ACTH-secreting tumor cells and, 2) increased sensitivity to CRF, as evidenced by greater stimulation of AC activity, may be responsible for the increased ACTH output of tumoral corticotrophs.
D000172:Acromegaly / Q000378:metabolism; D000236:Adenoma / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000328:Adult; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D003480:Cushing Syndrome / Q000378:metabolism; D000242:Cyclic AMP / Q000096:biosynthesis*; D005260:Female; D013006:Growth Hormone / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000378:metabolism*
D000324:Adrenocorticotropic Hormone; D013006:Growth Hormone; D003346:Corticotropin-Releasing Hormone; D000242:Cyclic AMP