Effect of Glucocorticoid and Melatonin on Immune Function of an Indian Tropical Bird, Perdicula Asiatica: An in Vivo and in Vitro Study

Abstract

Inverse relationship between circulatory levels of glucocorticoids and melatonin has been reported for most of the vertebrates including human beings. We report the importance of glucocorticoid along with melatonin in avian immune regulation in an Indian tropical bird, Perdicula asiatica with in vivo and in vitro approach. Dexamethasone (30llg/bird/day) treatment of the male birds suppressed the immune activity as judged by the spleen activity (mass, anatomy), circulating total leukocyte, and lymphocyte count, blastogenic response, increased % apoptosis and cytokine (IL-2) production by splenocytes. Melatonin (25Ilg/100g B.wt.lday) treatment increased the above-mentioned immune parameters whereas melatonin together with dexamethasone restored the suppressed immune parameters by dexamethasone to control level. In vitro melatonin (2.5 pM) supplementation to splenocyte cultures restored the dexamethasone (211M) suppressed splenocyte proliferation, % apoptosis and IL-2 production. Therefore, melatonin antagonized the suppressive effect of synthetic glucocorticoid on all immune parameters studied in vivo as well as in vitro. Furthermore, exogenous administration of dexamethasone and melatonin treatment altered the circulatory level of corticosterone and melatonin in an inverse manner. It is therefore, suggested that a hormonal trade-off between glucocorticoid and melatonin exists under in vivo and in vitro conditions, being involved in maintenance of the immune function of P. asiatica probably by involving cytokines i,e. IL-2 mediated pathway.

The effects of low levels of light at night upon the endocrine physiology of western scrub‐jays (Aphelocoma californica)

“…The relationship between glucocorticoid secretion and MEL can be complex. Studies indicating that CORT can sometimes lead to increased MEL, and that exogenous MEL can ameliorate the effects of CORT, have led to the hypothesis that MEL functions as a protector against negative effects of stress (Barriga et al, ; Saito et al, ; Cuoto‐Moraes et al, ; Detanico et al, ; Singh et al, ; Baxi et al, ). Perhaps more relevant to the current study is evidence that CORT and MEL can be inversely related (i.e., stress and elevated CORT resulted in depressed MEL levels; Jessop et al, ; Nikaido et al, ).…”

Cholesterol, Cytokines and Diseases

“…NKT cells recognize (glyco)lipid antigens presented by CDld expressed on macrophages and dendritic cells (98)(99)(100)(101)(102)(103). Upon recognition of a glycolipid antigen, invariant NKT cells rapidly produce a unique mixture of cytokines, including Th I (lFN-g, IL-12 and TNF-a) and Th2 (lL-4, IL-5, IL-IO and IL-13) cytokines (104)(105)(106). NKT cells can be activated by the in-vivo administration of u-galactosylceramide, and mature NKT cells respond with an early burst of IL-4 followed by IFN-y, which are both pro-atherogenic cytokines (107)(108)(109).…”

Psychological Stress and Cancer

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