Open AccessOzone-Induced Dysregulation of Neuroendocrine Axes Requires Adrenal-Derived Stress Hormones
Author(s) -
Andres R. Henriquez,
John S. House,
Samantha J. Snow,
Colette N. Miller,
Mette C. Schladweiler,
Anna Fisher,
Hongzu Ren,
Matthew C. Valdez,
Prasada Rao S. Kodavanti,
Urmila P. Kodavanti
Publication year - 2019
Publication title -
toxicological sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.352
H-Index - 183
eISSN - 1096-6080
pISSN - 1096-0929
DOI - 10.1093/toxsci/kfz182
Subject(s) - endocrinology , medicine , hypothalamus , hormone , prolactin , adrenocorticotropic hormone , brainstem , melatonin , glucocorticoid , luteinizing hormone , corticotropin releasing hormone , inhalation , biology , chemistry , anatomy
Acute ozone inhalation increases circulating stress hormones through activation of the sympathetic-adrenal-medullary and hypothalamic-pituitary-adrenal axes. Rats with adrenalectomy (AD) have attenuated ozone-induced lung responses. We hypothesized that ozone exposure will induce changes in circulating pituitary-derived hormones and global gene expression in the brainstem and hypothalamus, and that AD will ameliorate these effects. Male Wistar-Kyoto rats (13 weeks) that underwent sham surgery (SHAM) or AD were exposed to ozone (0.8 ppm) or filtered-air for 4 h. In SHAM rats, ozone exposure decreased circulating thyroid-stimulating hormone (TSH), prolactin (PRL), and luteinizing hormone (LH). AD prevented reductions in TSH and PRL, but not LH. AD increased adrenocorticotropic hormone approximately 5-fold in both air- and ozone-exposed rats. AD in air-exposed rats resulted in few significant transcriptional differences in the brainstem and hypothalamus (approximately 20 genes per tissue). In contrast, ozone-exposure in SHAM rats resulted in either increases or decreases in expression of hundreds of genes in the brainstem and hypothalamus relative to air-exposed SHAM rats (303 and 568 genes, respectively). Differentially expressed genes from ozone exposure were enriched for pathways involving hedgehog signaling, responses to alpha-interferon, hypoxia, and mTORC1, among others. Gene changes in both brain areas were analogous to those altered by corticosteroids and L-3,4-dihydroxyphenylalanine, suggesting a role for endogenous glucocorticoids and catecholamines. AD completely prevented this ozone-induced transcriptional response. These findings show that short-term ozone inhalation promotes a shift in brainstem and hypothalamic gene expression that is dependent upon the presence of circulating adrenal-derived stress hormones. This is likely to have profound downstream influence on systemic effects of ozone.