Hormonal daily variation co-varies with immunity in captive male bullfrogs (Lithobates catesbeianus)

Author(s)

Monteiro Titon, Stefanny Christie ^[1] ; Titon Junior, Braz ^[1] ; Assis, Vania Regina ^[1] ; Vasconcelos-Teixeira, Ronyelle ^[1] ; Garcia Neto, Patricio Getulio ^[1] ; Lima, Alan Siqueira ^[1] ; Ferreira, Leticia de Franca ^[1] ; Fernandes, Pedro A. ^[1] ; Gomes, Fernando Ribeiro ^[1] ; Markus, Regina P. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Biociencias, Dept Fisiol, Rua Matao, Trav 14, 101, BR-05508090 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: General and Comparative Endocrinology; v. 303, MAR 1 2021.
• Web of Science Citations: 3

Abstract

Almost all physiological processes within the organism, including immune parameters and hormones, follow a circadian rhythm. These daily fluctuations are often observed in free-living organisms; however, little is known regarding hormonal and immune daily variations in anurans, particularly under laboratory conditions. This study aimed to investigate the hormonal and immune daily variation in captive-bred Bullfrogs (Lithobates catesbeianus) under constant conditions (21 degrees C and 12:12 LD cycle). Our results showed a daily variation for plasma corticosterone (CORT), testosterone (T), and melatonin (MEL), as well as for blood leukocyte profile, phagocytic activity, and plasma bacterial killing ability (BKA). Hormonal profile and immune activity were higher at the dark when compared with the light phase; however, monocytes and lymphocytes followed the opposite pattern. Moreover, CORT was positively correlated with phagocytosis percentage of blood cells, BKA, and monocytes, while MEL and T showed a positive correlation with PP. Our results demonstrate the daily covariation of different immune variables and immunomodulatory hormones. These 24 h-day variations and covariation certainly have broad implications and need to be considered for better understanding anuran physiology both in the context of laboratory and field studies. (AU)

• FAPESP's process: 14/16320-7 - Impacts of climate/environmental change on the fauna: an integrative approach
• Grantee: Carlos Arturo Navas Iannini
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants
• FAPESP's process: 13/13691-1 - Immune-pineal axis: time-niology integrated to surveillance and defense
• Grantee: Regina Pekelmann Markus
• Support Opportunities: Research Projects - Thematic Grants