title: Short-term Preoperative Octreotide for Thyrotropin-secreting Pituitary Adenoma.
abstract: BACKGROUND
  Thyrotropin-secreting pituitary adenomas (TSHomas) are a rare cause of hyperthyroidism. Somatostatin (SST) analogs work by interacting with somatostatin receptors (SSTRs). This study aimed to evaluate short-term preoperative octreotide (OCT) use in TSHoma patients and to investigate SSTR2 and SSTR5 expression and observe structural changes in tumor tissue.
  
  
  METHODS
  We reviewed records and samples from eight TSHoma patients treated between July 2012 and July 2015. We tested immunohistochemically for SSTR2/5 expression and examined TSHoma cells for morphological changes. Signed rank sum test was used to compare the efficacy of short-term preoperative OCT treatment.
  
  
  RESULTS
  OCT treatment (median time: 7.9 days, range: 3-16 days; median total dose: 1.8 mg, range: 0.9-4.2 mg) led to significant decrease in all patients' thyroid hormone levels (FT3 [nmol/L]: 8.33 [7.02, 12.29] to 4.67 [3.52, 5.37] [P = 0.008]; FT4 [pmol/L]: 25.36 [21.34, 28.99] to 16.66 [14.88, 21.49] [P = 0.016]; and TSH [μU/ml]: 5.80 [4.37, 6.78] to 0.57 [0.19, 1.24] [P = 0.008]). All the eight tumor specimens expressed high SSTR2 protein levels; 5/8 expressed high SSTR5, but 3/8 that expressed low SSTR5 presented a significantly higher TSH suppression rate (P = 0.036). Electron microscopy showed subcellular level impairments, including clumped nuclear chromatin and reduced cytoplasmic volume. Golgi complexes were observed in the OCT-treated TSHoma specimens.
  
  
  CONCLUSIONS
  OCT can control hormone levels and damage the ultrastructure of tumor cells and organelles. Short-term response to OCT may be related to SSTR5 expression. Preoperative SST analog treatment for TSHoma could be considered as a combination therapy.
authors.affiliation: Department of Endocrinology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China.
authors.forename: Hong-Juan
authors.initials: HJ
authors.lastname: Fang
authors.affiliation: Department of Endocrinology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Fu
authors.affiliation: Department of Pathology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China.
authors.forename: Huan-Wen
authors.initials: HW
authors.lastname: Wu
authors.affiliation: Department of Ultropathology, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100050, China.
authors.forename: Yi-Lin
authors.initials: YL
authors.lastname: Sun
authors.affiliation: Beijing Neurosurgical Institute, Beijing Institute for Brain Disorders, Brain Tumor Center, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China.
authors.forename: Yang-Fang
authors.initials: YF
authors.lastname: Li
authors.affiliation: Beijing Neurosurgical Institute, Beijing Institute for Brain Disorders, Brain Tumor Center, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China.
authors.forename: Ya-Zhuo
authors.initials: YZ
authors.lastname: Zhang
authors.affiliation: Department of Endocrinology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China.
authors.forename: Li-Yong
authors.initials: LY
authors.lastname: Zhong
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D015282:Octreotide / Q000627:therapeutic use*; D010911:Pituitary Neoplasms / Q000188:drug therapy* / Q000378:metabolism*; D017481:Receptors, Somatostatin / Q000378:metabolism*; D013972:Thyrotropin / Q000378:metabolism*
chemical_list: D017481:Receptors, Somatostatin; C574734:SSTR2 protein, human; C094573:somatostatin receptor 5; D013972:Thyrotropin; D015282:Octreotide