Negative endocrine control system for inflammation in rats
V.I. Stenberg 1,2, M.G. Bouley, B.M. Katz, K.J. Lee and S.S. Parmar
Department of Chemistry, University of North Dakota, Grand Forks, ND 58202, USA

Reference: Agents and Actions, 29, 189-195 (1990)

Abstract Inflammatory processes may be suppressed by endogenous mechanisms such as release of adrenocorticosteroid hormones through stimulation of the hypothalamus-pituitary-adrenal axis. In the present study, the relationship between the temporal development of carrageenan-induced edema in the hind limb of the rat and release in plasma of the principal endogenous adrenocorticosteroid of the rat corticosterone was investigated. Suplantar injection of carrageenan produced a biphasic increase in basal plasma corticosterone levels that was not attributed to diuranal variation. The plasma level of corticosterone increased rapidly after injection of carrageenan and peaked 12-fold at 20 min. This first phase increase was attributed to the stress of the injection since it was mimicked by subplantar injection of saline. The second phase of corticosterone release was gradual and peaked 12-fold 7 hr after injection of carrageenan. The second phase was not elicited by subplantar injection of saline. When the hypothalamus-pituitary-adrenal axis is impaired via hypophysectomy, carrageenan-induced edema is more intense and last longer than in control rats. The results demonstrate that adrenocorticosteroid hormones are released as a result of the stress of injection and by the inflammatory response. Release of adrenocorticosteroids acts as a feedback mechanism to suppress the inflammatory response.



1) Department of Chemistry, The University of North Dakota, Grand Forks
2) School of Medicine, The University of North Dakota, Grand Forks
3) Valley Medical Associates, Grand Forks
4) College of Pharmacy, North Dakota State University, Fargo, North Dakota, United States of America.
Reference: Int. J. Clin. Pharm. Res., 12(1), 11-18, 1992

Summary: A dysfunction in the endocrine control system for inflammation in rheumatoid arthritis serves as the theoretical basis for chronic inflammation in the study design described. Eighteen patients with rheumatoid arthritis, who acted as their own controls, were brought to a minimum symptom state through conventional means, trained, and allowed to control subsequent flares by a patient-initiated, flare-response prednisone regimen. The six-month trial was double-blind with a crossover at midpoint. While continuing stable non-steroidal anti-inflammatory and disease modifying antirheumatic drug therapies, the patients averaged additional 57% and 75% reductions from baseline in tender joint count and total pain score, respectively, on the prednisone therapy. The prednisone therapy was differentiated by improvement from that of a placebo by six of the nine parameters evaluated. The adverse events were no more frequent with prednisone than with placebo use. The efficacy of prednisone was increased threefold while reducing consumption by 40% when compared to the predecessor 5-mg prednisone/day clinical trial.