Dysregulation of the hypothalamo-pituitary axis in rheumatoid arthritis
Jorgensen, C.; Bressot, N.; Bologna, C.; Sany, J.
Journal of Rheumatology 22(10): 1829-1833
1995
ISSN/ISBN: 0315-162X PMID: 8991978 Document Number: 443478
Objective: To study the dynamic response of the hypothalamo-pituitary-adrenal axis and of prolactin (PRL) pituitary secretion in rheumatoid arthritis (RA). Methods: We performed a cortisol releasing hormone (CRH) provocation test followed by determination of adrenocorticotropin hormone (ACTH), beta-endorphin, and cortisol concentration, and then a thyrotropin releasing hormone (TRH) provocation test followed by assessment of PRL pituitary secretion in 10 patients with RA and 5 control subjects. All were women under 40 years of age. Hormone concentrations were assessed by radioimmunoassay. Results: Basal PRL cortisol, and ACTH concentrations were similar in patients with RA and controls. We observed a dissociation between the pituitary secretion of beta-endorphin and of ACTH in response to CRH in RA. The ACTH peak and total ACTH production (area under the curve, AUC) were similar in the 2 groups. In contrast, basal beta-endorphin was increased in RA (12.6 +- 1.41 vs 8.29 +- 0. 144 pg/ml), and the response upregulated (AUC: 83,080 +- 12, 100 vs 54,200 +- 2400) after CRH compared to controls (p lt 0.05). Cortisol adrenal response curve was blunted, but did not reach statistical significance. In contrast, the PRL response to TRH was increased at 120 and 150 min (3461 +- 303 vs 1897 +- 520 mu-IU/ml) (p lt 0.01) in patients with RA, independent of disease activity. Conclusion: We observed upregulated pituitary PRL secretion in RA, and a dissociation of ACTH and beta-endorphin secretion. These results suggest a dysregulation of the pituitary response to chronic stress. The implication concerning the neuroendocrine system in the chronic immune response in RA is discussed.