Somatotroph-specific Aip-deficient mice display pretumorigenic alterations in cell-cycle signaling

Mary P. Gillam, Cheol Ryong Ku, Yang Jong Lee, Jean Kim, Se Hoon Kim, Sue Ji Lee, Byungjin Hwang, Jae Hyung Koo, Rhonda D. Kineman, Hiroaki Kiyokawa, Eun Jig Lee*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Patients with familial isolated pituitary adenoma are predisposed to pituitary adenomas, which in a subset of cases is due to germline inactivating mutations of the aryl hydrocarbon receptor-interacting protein (AIP) gene. Using Cre/lox and Flp/Frt technology, a conditional mouse model was generated to examine the loss of the mouse homolog, Aip, in pituitary somatotrophs. By 40 weeks of age, > 80% of somatotroph specific Aip knockout mice develop growth hormone (GH) secreting adenomas. The formation of adenomas results in physiologic effects recapitulating the human syndrome of acromegaly, including increased body size, elevated serum GH and insulin-like growth factor 1 levels, and glucose intolerance. The pretumorigenic Aip-deficient somatotrophs secrete excess GH and exhibit pathologic hyperplasia associated with cytosolic compartmentalization of the cyclin-dependent kinase (CDK) inhibitor p27kip1 and perinuclear accentuation of CDK-4. Following tumor formation, the Aip-deficient somatotrophs display reduced expression of somatostatin receptor subtype 5 with impaired response to octreotide. The delayed tumor emergence, even with loss of both copies of Aip, implies that additional somatic events are required for adenoma formation. These findings suggest that pituitary hyperplasia precedes adenomatous transformation in somatotroph-specific Aip-deficient mice and reveal potential mechanisms involved in the pretumorigenic state that ultimately contribute to transformation.

Original languageEnglish (US)
Pages (from-to)78-95
Number of pages18
JournalJournal of the Endocrine Society
Issue number2
StatePublished - Jan 1 2017


  • Aryl hydrocarbon receptor-interacting protein
  • Knockout mice
  • Pituitary adenoma predisposition
  • Pituitary hyperplasia
  • Pituitary tumor

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism


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