Covariates of corticotropin-releasing hormone (CRH) concentrations in cerebrospinal fluid (CSF) from healthy humans

Background: Define covariates of cerebrospinal corticotropin-releasing hormone (CRH) levels in normal humans. CRHCSF was measured in 9 normal subjects as part of an intensive study of physiological responses stressors in chronic pain and fatigue states. CRHCSF was first correlated with demographic, vital sign, HPA axis, validated questionnaire domains, baseline and maximal responses to pain, exercise and other stressors. Significant factors were used for linear regression modeling. Results: Highly significant correlations were found despite the small number of subjects. Three models were defined: (a) CRHCSF with blood glucose and sodium (explained variance = 0.979, adjusted R-2 = 0.958, p = 0.02 by 2-tailed testing); (b) CRHCSF with resting respiratory and heart rates (R-2 = 0.963, adjusted R-2 = 0.939, p = 0.007); and (c) CRHCSF with SF-36 Vitality and Multidimensional Fatigue Inventory Physical Fatigue domains (R-2 = 0.859, adjusted R-2 = 0.789, p = 0.02). Conclusions: Low CRHCSF was predicted by lower glucose, respiratory and heart rates, and higher sodium and psychometric constructs of well being. Responses at peak exercise and to other acute stressors were not correlated. CRHCSF may have reflected an overall, or chronic, set-point for physiological responses, but did not predict the reserves available to respond to immediate stressors.