Regulation of gene expression by hypoxia

D. E. Millhorn, M. Czyzyk-Krzeska, D. A. Bayliss, Edward Lawson

Research output: Contribution to journalArticle


The present study was undertaken to determine if gene expression for tyrosine hydroxylase (TH), the rate limiting enzyme in the biosynthesis of catecholamines, is regulated in the carotid body, sympathetic ganglia and adrenal medulla by hypoxia. We found that a reduction in oxygen tension from 21% to 10% caused a substantial increase (200% at 1 hour and 500% at 6 hours exposure) in the concentration of TH mRNA in carotid body type I cells but not in either the sympathetic ganglia or adrenal gland. In addition, we found that hypercapnia, another natural stimulus of carotid body activity, failed to enhance TH mRNA in type I cells. Removal of the sensory and sympathetic innervation of the carotid body failed to prevent the induction of TH mRNA by hypoxia in type I cells. Our results show that TH gene expression is regulated by hypoxia in the carotid body but not in other peripheral catecholamine synthesizing tissue and that the regulatory mechanism is intrinsic to type I cells.

Original languageEnglish (US)
Issue number8 SUPPL.
Publication statusPublished - 1993
Externally publishedYes



  • Carotid body
  • In situ hybridization
  • Messenger RNA
  • Oxygen
  • Tyrosine hydroxylase

ASJC Scopus subject areas

  • Physiology

Cite this

Millhorn, D. E., Czyzyk-Krzeska, M., Bayliss, D. A., & Lawson, E. (1993). Regulation of gene expression by hypoxia. Sleep, 16(8 SUPPL.).