Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
Gen Comp Endocrinol. 2021 Mar 1;303:113702. doi: 10.1016/j.ygcen.2020.113702. Epub 2020 Dec 20.
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 °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.
几乎生物体的所有生理过程，包括免疫参数和激素，都遵循昼夜节律。这些日常波动在自由生活的生物体中经常观察到；然而，对于蛙类（Lithobates catesbeianus）在实验室条件下的激素和免疫的日常变化，人们知之甚少。本研究旨在调查圈养牛蛙（Lithobates catesbeianus）在恒定条件（21°C 和 12:12 LD 循环）下的激素和免疫的日常变化。我们的结果表明，血浆皮质酮（CORT）、睾酮（T）和褪黑素（MEL）以及血液白细胞谱、吞噬活性和血浆杀菌能力（BKA）存在日常变化。与光照相比，激素和免疫活性在黑暗时更高；然而，单核细胞和淋巴细胞则相反。此外，CORT 与血细胞的吞噬百分比、BKA 和单核细胞呈正相关，而 MEL 和 T 与 PP 呈正相关。我们的结果表明，不同免疫变量和免疫调节激素存在日常变化。这些 24 小时的日间变化和变化必然具有广泛的影响，需要在实验室和野外研究中更好地理解蛙类生理学，需要考虑这些影响。
