The possible meaning of tissue remodeling in the adrenal gland of the Eurasian beaver (Castor fiber L.) – in vivo and in vitro chloroquine studies

Considering the superior physiological role of the adrenal glands in stress reaction and the lack of suitable experimental models or systems, we undertook studies in the largest European rodent, the Eurasian beaver. Emphasis was also put on aquatic pollution (e.g., with chloroquine, CQ). Adrenals were obtained from beaver females, and an adrenocarcinoma cell line (H295R) was exposed to CQ. Immunohistochemistry/immunofluorescence, Western blotting, and immunoenzymatic assay were used for analysis of: (i) steroidogenic enzymes: 3β-hydroxysteroid dehydrogenase (3β-HSD) and P450 aromatase, (ii) androgen and estrogen receptors (AR and ER), (iii) metalloproteinases (MMP2 and MMP9), (iv) cancer signaling proteins (N-cadherin, and Adenosine Monophosphate-activated Protein Kinase and the Mechanistic Target of Rapamycin AMPK/mTOR) presence/abundance, and (v) androgen and estrogen concentrations. In the adrenal cortex, the localization and similar abundance level of the steroidogenic and receptor proteins, together with comparable concentrations of sex hormones, were revealed. The MMP2 and MMP9 were active and widely distributed. In adrenal cells after CQ, an aromatase decrease ( p < 0.001), an AR decrease ( p < 0.001), and an ER increase ( p < 0.001) in abundance, together with a decrease ( p < 0.001) in the level of estrogens, were found. Additionally, CQ increased ( p < 0.001) MMP2, decreased ( p < 0.001) MMP9, and decreased ( p < 0.001) N-cadherin abundance simultaneously with the decreased AMPK/mTOR abundance and phosphorylation ( p < 0.001) with an increased ( p < 0.05) ratio of pAMPK T172/AMPK. The beaver adrenal cortex may serve as a supplementary, noncanonical model for adrenal physiopathological studies involving environmental contamination, stress response, and tissue remodeling. Possible anticancer estrogen and MMP-driven CQ properties (based on sex hormone signaling/production, N-cadherin, AMPK/mTOR mechanism) need in-depth studies. • The female beaver adrenal cortex exhibits AR, ER, 3β-HSD, and aromatase presence and abundance. • In the adrenal cortex, comparable concentrations of androgens and estrogens are present. • In the adrenal cortex, the MMP2 and MMP9 are widely distributed and active. • After CQ, adrenal cells exhibit changes in the abundance of aromatase, AR, and ER. • CQ decreases the estrogen level. • CQ affects MMP2, MMP9, N-cadherin abundance, and phosphorylation of the mTOR and AMPK.