Abstract # 99:

Scheduled for Friday, June 18, 2010 07:00 PM-09:00 PM: Session 18 (Medallion Ballroom C/D/E/F) Poster Presentation


A. F. Hamel, E. Henchey, J. Meyer and M. A. Novak
University of Massachusetts Amherst, Amherst, MA 01003, USA

Measurement of cortisol in hair is an emerging biomarker for chronic stress in both human and nonhuman primates. Yet due to the external nature of this matrix, hair is potentially vulnerable to a partial loss of cortisol from within the interior of the shaft due to repeated exposure to water (e.g., rainfall in the case of primates living outdoors) and shampoo (in the case of human studies). To test the effect of water treatment with or without shampoo on levels of hair cortisol, hair samples collected from 20 rhesus monkeys (Macaca mulatta) were divided into four separate pools.  Each pool was subdivided into the following five treatment conditions: 10, 20, or 30 shampoo washes, 20 washes with water only, or a no-wash control.  For each washing, experimental samples were treated for 45 seconds with either a 10% aqueous solution of a commercially available shampoo or water in a disposable tube. The solution was then drained from the tube and four 30-second rinses with water were performed. Samples were blow-dried after each wash-rinse cycle and later processed for cortisol content (Davenport et al., 2006). Results show that exposure of hair to 20 water washes caused a significant reduction in cortisol levels compared to control samples [Paired t-test: P<0.05].  In addition, washing with shampoo also caused significant cortisol loss for each of the three shampoo conditions [Paired t-tests: P<0.05].  Samples subjected to 20 shampoo washes were not significantly different from samples subjected to 20 water washes [P>0.05].  Thus, repeated exposure to water with or without shampoo removes significant amounts of cortisol from the interior of the hair shaft.