Daily and LPS-induced variation of endocrine mediators in cururu toads (Rhinella icterica). (2nd January 2022)

• Record Type: Journal Article
• Authors: Bastos, Priscilla Rachel Oliveira; Titon, Stefanny Christie Monteiro; Titon Junior, Braz; Gomes, Fernando Ribeiro; Markus, Regina P.; Ferreira, Zulma S.
• Is Part Of: Chronobiology international. Volume 39:Number 1(2022)
• Page Start: 89
• Page End: 96
• Publication Date: 2022-01-02
• Subjects: Amphibian -- corticosterone -- daily variation -- inflammation -- melatonin; Chronobiology -- Periodicals; Biological rhythms -- Periodicals; Circadian rhythms -- Periodicals; 571.77
• DOI: 10.1080/07420528.2021.1974470
• Languages: English
• ISSNs: 0742-0528

Abstract

ABSTRACT: Increased plasma glucocorticoids (corticosterone – CORT, in amphibians) and melatonin (MEL) are associated with the daily activity phase and with environmental darkness, respectively. Besides, CORT and MEL also play pivotal immunomodulatory roles in several vertebrates. Herein we described the daily profile of plasma MEL and CORT for Rhinella icterica toads in captivity. Thereafter, we investigated the effects of lipopolysaccharide (LPS)-induced systemic inflammation on the production of CORT and MEL in the R. icterica . Captive toads showed CORT and MEL diurnal variation typical of nocturnal species, with increased values for CORT at ZT12 (18 h) and MEL peak at ZT18 (24 h). LPS-induced hormonal changes included increased plasma CORT and decreased ocular and plasma MEL when compared to those from toads treated with saline 2 h post-injection. Our results demonstrated the presence of a diurnal CORT and MEL variation in toads. We also showed the crosstalk between CORT and MEL during the toad's systemic inflammation in response to an immune challenge with LPS. Additionally, our results demonstrated that anuran eyes' MEL production might be regulated during the inflammatory processes.