title: Desensitization to somatostatin analogue (Octreotide) observed in a patient with acromegaly.
abstract: We encountered a 33-year-old female patient with a pituitary growth hormone (GH)-secreting macroadenoma. The patient was treated with somatostatin analogue (Octreotide) in combination with bromocriptine for 2 months before a transsphenoidal adenomectomy was carried out. Octreotide (300-800 micrograms/day) in combination with bromocriptine was effective in reducing the size of the adenoma by 36%, but produced only a marginal decrease in serum GH. After the operation, bromocriptine alone (15 mg/day) did not lower the level of GH which was produced by residual adenoma tissue. When octreotide (200 micrograms/day) was resumed along with the bromocriptine one year after the operation, it effectively lowered serum GH for 6 months. Thereafter, octreotide therapy became ineffective with a concomitant rise in serum GH and somatomedin C, which was not accompanied by an increase in tumor size. This was a rare case of acromegaly that showed desensitization to octreotide after long-term treatment.
authors.affiliation: Third Department of Internal Medicine, University of Yamanashi Medical School, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Haraguchi
authors.forename: M
authors.initials: M
authors.lastname: Ohtaka
authors.forename: K
authors.initials: K
authors.lastname: Takazawa
authors.forename: T
authors.initials: T
authors.lastname: Endo
authors.forename: T
authors.initials: T
authors.lastname: Onaya
mesh_terms: D000172:Acromegaly / Q000188:drug therapy* / Q000209:etiology; D000236:Adenoma / Q000188:drug therapy / Q000378:metabolism* / Q000601:surgery; D000328:Adult; D000568:Amenorrhea; D001971:Bromocriptine / Q000008:administration & dosage / Q000627:therapeutic use*; D004351:Drug Resistance; D005260:Female; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D015282:Octreotide / Q000008:administration & dosage / Q000627:therapeutic use*; D010911:Pituitary Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000601:surgery
chemical_list: D001971:Bromocriptine; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D015282:Octreotide