Effects of bromocriptine and cyproheptadine on basal and corticotropin-releasing factor (CRF)-induced ACTH release in a patient with Nelson's syndrome.
The effects of bromocriptine, a dopamine agonist, and cyproheptadine, a serotonin antagonist, on basal and corticotropin-releasing factor (CRF)-stimulated ACTH release were investigated in a 40-year-old female patient with Nelson's syndrome. Oral administration of either bromocriptine (2.5 mg) or cyproheptadine (8 mg) caused a marked drop in plasma ACTH levels. Intravenous administration of synthetic ovine (o) CRF (50 micrograms) produced an exaggerated response of plasma ACTH. Short-term (3-week) treatment with either bromocriptine (7.5 mg/day) or cyproheptadine (12 mg/day) resulted in a marked suppression of basal ACTH release. Furthermore, a blunted response of plasma ACTH to oCRF was observed after short-treatment with either drug. However, after a longer period of treatment with cyproheptadine (18-week), plasma ACTH levels rose again and hyperresponsiveness to oCRF was restored to the pretreatment levels. These data indicate that synthetic oCRF is a potent secretagogue for ACTH release in a patient with Nelson's syndrome. It is suggested that bromocriptine and cyproheptadine are effective drugs in reducing basal and CRF-stimulated ACTH release, possibly acting at the pituitary level in this case. However, the apparent refractoriness after chronic treatment with cyproheptadine may limit its therapeutic use in the present case.
D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000378:metabolism*; D000328:Adult; D001481:Basal Metabolism; D001971:Bromocriptine / Q000627:therapeutic use*; D003346:Corticotropin-Releasing Hormone / Q000627:therapeutic use*; D003533:Cyproheptadine / Q000627:therapeutic use*; D004723:Endorphins / Q000097:blood; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D006801:Humans; D008236:Lypressin / Q000494:pharmacology; D009347:Nelson Syndrome / Q000097:blood / Q000188:drug therapy / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000378:metabolism*; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology; D001615:beta-Endorphin
D004723:Endorphins; D003533:Cyproheptadine; D007987:Gonadotropin-Releasing Hormone; D001971:Bromocriptine; D008236:Lypressin; D013973:Thyrotropin-Releasing Hormone; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone