Author
BURDICK, NICOLE - Texas Agrilife Research | |
AGADO, BRIAN - Texas Agrilife Research | |
RANDEL, RON - Texas Agrilife Research | |
NEUENDORFF, DON - Texas Agrilife Research | |
Carroll, Jeffery - Jeff Carroll | |
VANN, RHONDA - Mississippi State University | |
Chitko-Mckown, Carol | |
LAWHON, SARA - Texas A&M University | |
WELSH JR, TOM - Texas Agrilife Research |
Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 1/7/2010 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Cortisol suppresses many aspects of immune function. However, recent publications suggest acute cortisol exposure may actually enhance immune function (Dhabhar. 2009. Neuroimmunomod. 16:300). The objective of this study was to determine the influence of acute increases in endogenous cortisol on expression of cytokines and the glucocorticoid receptor (GR) in isolated peripheral blood mononuclear cells (PBMCs). Blood samples were collected from Brahman heifers via jugular catheters at -3, 0, 1, 2, and 4 hours relative to a challenge with 0.1 IU/kg BW ACTH. Plasma cortisol was determined by RIA. The PBMCs were isolated and frozen until RNA isolation. Extracted RNA was amplified by RT-qPCR to determine expression of GR, tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin-4 (IL-4), and IL-10. Cortisol concentrations tended to decrease between cannulation (-3 hr) and initiation of the ACTH challenge (time 0 hr; P=0.07). Expression of IFN-gamma increased 16-fold relative to expression at cannulation. In response to ACTH, cortisol concentrations peaked at 1 hour (P less than or equal to 0.001) before decreasing to pre-challenge values. Expression of all cytokines and GR increased in response to ACTH, yet showed different expression patterns (P=0.01-0.06). This suggests that stimuli that increase endogenous cortisol concentrations may influence the expression of cytokines, and therefore modulate the immune system. |