Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
Gen Comp Endocrinol 2022 Sep 15;326:114072. doi: 10.1016/j.ygcen.2022.114072.
Show Gene links Show Anatomy links

Impaired negative feedback and death following acute stress in glucocorticoid receptor knockout Xenopus tropicalis tadpoles.

Paul B , Sterner ZR , Bhawal R , Anderson ET , Zhang S , Buchholz DR .

Blood glucocorticoid levels are regulated by the hypothalamo-pituitary-adrenal/interrenal axis (HPA axis in mammals, HPI axis in amphibians), and negative feedback by glucocorticoid signaling is a key player in that regulation. Glucocorticoid and mineralocorticoid receptors (GR and MR) mediate negative feedback in mammals, but little is known about nuclear receptor-mediated feedback in amphibians. Because amphibians have only one corticosteroidogenic cell type responsible for glucocorticoid and mineralocorticoid production, we hypothesized that GR knockout (GRKO) tadpoles have elevated levels of glucocorticoids and mineralocorticoids as well as axis components regulating their production. We also examined the response to stress and potential for increased aldosterone signaling in GRKO tadpoles. We found that GRKO tadpoles have severe hyperactivity of the HPI axis, namely high mRNA expression levels of pomc, cyp17a1, cyp21a2, cyp11b2, and star, and high tissue content of corticosterone, aldosterone, 17-hydroxyprogesterone, 21-deoxycortisol, and progesterone. Such aberrant HPI activity was accompanied by reduced survival after acute temperature shock and shaking stress. Like mammalian models of HPA hyperactivity, GRKO tadpoles have high MR mRNA expression levels in brain, kidney, heart, and skin and high levels of the inflammatory cytokine tnf-α and the profibrotic factor tgf-β in kidneys. This study showed GR is critical for negative feedback to the amphibian HPI axis and for survival from acute stressors. This study also showed GRKO tadpoles exhibit altered expression/overproduction of regulators of salt-water homeostasis and associated biomarkers of kidney disease.

PubMed ID: 35697317
Article link: Gen Comp Endocrinol

Species referenced: Xenopus tropicalis
Genes referenced: avp ctgfl cyp11b2 cyp17a1 cyp21a2.1 edn1 fn1 nr3c1 nr3c2 pomc rpl8 star tgfb1 tnf
GO keywords: corticosteroid receptor signaling pathway [+]

Article Images: [+] show captions