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Re: Does MS-related plasma beta-endorphin vary in circadian manner?

Dear Editor

As it is well known, endorphin levels change in different circumstances, for example, in injury, illness, or as a result of circadian influences, among others.[1-7] It would be helpful to know which was the primary stimulus for endorphin level changes in MS patients. Perhaps a further experiment can show that it is or is not circadian.

References

(1) Covelli V, Massari F, Fallacara C, Munno I, Jirillo E, Savastano S, Tommaselli AP, Lombardi G. Interleukin-1 beta and beta-endorphin circadian rhythms are inversely related in normal and stress-altered sleep. Int J Neurosci. 1992 Apr;63(3-4):299-305.

(2) Iranmanesh A, Lizarralde G, Johnson ML, Veldhuis JD. Circadian, ultradian, and episodic release of beta-endorphin in men, and its temporal coupling with cortisol.J Clin Endocrinol Metab. 1989 Jun;68(6):1019-26.

(3) Sekiya K, Nawata H, Kato K, Motomatsu T, Ibayashi H. Diurnal rhythms of proopiomelanocortin-derived N-terminal peptide, beta-lipotropin, beta-endorphin and adrenocorticotropin in normal subjects and in patients with Addison's disease and Cushing's disease. Endocrinol Jpn. 1986 Oct;33(5):713-9.

(4) Melmed S. Series Introduction: The immuno-neuroendocrine interface. J Clin Invest, December 2001, Volume 108, Number 11, 1563-1566

(5) Barreca T, Siani C, Franceschini R, Francaviglia N, Messina V, Perria C, Rolandi E. Diurnal beta-endorphin changes in human cerebrospinal fluid. Life Sci. 1986 Jun 16;38(24):2263-7.

(6) Shanks MF, Clement-Jones V, Linsell CJ, Mullen PE, Rees LH, Besser GM. A study of 24-hour profiles of plasma met-enkephalin in man. Brain Res. 1981 May 18;212(2):403-9.

(7) Gil-Ad I, Dickerman Z, Amdursky S, Laron Z. Diurnal rhythm of plasma beta endorphin, cortisol and growth hormone in schizophrenics as compared to control subjects. Psychopharmacology (Berl). 1986;88(4):496-9.