Maternal stress and fish reproduction: The role of cortisol revisited

Abstract

Stressor‐induced elevation of circulating cortisol levels is generally considered to have an inhibitory effect on reproduction in teleosts. However, mature female fish have higher levels of circulating cortisol levels, and this is particularly telling in salmonids during their spawning migration. This raises the possibility that a cortisol buffering capacity is active at the level of the gonad. This is particularly important given the recent findings in zebrafish (Danio rerio, Cyprinidae) that zygotic cortisol content, either high or low, can alter developmental programming. Therefore, a tight regulation of corticosteroid during oogenesis may be essential for proper ovarian development. Here, we focus on the temporal dynamics of cortisol in the ovary and its role in regulating the different processes related to oogenesis. Maternally deposited cortisol along with the local production of this steroid by the ovary may be involved in the regulation of oogenesis. We propose two critical stages when cortisol may exert a modulatory effect on oogenesis. The first stage occurs during vitellogenesis when maternal cortisol is incorporated into the yolk, and the second is during maturation and ovulation when cortisol may have a regulatory role on the action of maturation‐inducing hormones. A key protective mechanism to prevent excess cortisol deposition appears to be the upregulation of 11β‐hydroxysteroid dehydrogenase 2 in the theca and/or granulosa cells of the developing oocyte in response to excess maternal cortisol stimulation. Taken together, cortisol dynamics during oogenesis is complex, but maintaining a “Goldilocks” concentration of this steroid may be a critical process governing successful spawning and progeny development.

Measuring cortisol, the major stress hormone in fishes

“…Second, the sex of fishes can affect basal cortisol levels, in a species-specific manner (Barcellos et al, 2001;Haddy & Pankhurst, 1999;Kubokawa et al, 1999). Third, cortisol production can vary with life stage and reproductive state (Faught & Vijayan, 2018;Tsalafouta et al, 2014). In addition, food intake can affect cortisol synthesis, with fasted animals producing generally more cortisol than fed conspecifics (Barcellos et al, 2010;Barton et al, 1988).…”

Physiological consequences of an altered flow regime on Alabama bass (Micropterus henshalli)

“…Changes in leukocyte distribution (increasing neutrophils and decreasing lymphocytes, herein referred to as N:L ratios) are considered to be induced by the release of glucocorticoids into the bloodstream (Dhabhar et al, 1996). We sampled fish by angling in the fall 2011 to reduce any confound effects associated with sampling fish close to spawning (Faught & Vijayan, 2018). We also sampled at a time where temperatures were similar amongst the two sites and was not considered as a covariate (Suski, Killen, Kieffer, & Tufts, 2006).…”

Cortisol Directly Stimulates Spermatogonial Differentiation, Meiosis, and Spermiogenesis in Zebrafish (Danio rerio) Testicular Explants

“…Cortisol is the primary glucocorticoid hormone in teleost fish released in response to a stressor exposure upon the activation of the hypothalamic-pituitary-interrenal (HPI) axis (for a review see Schreck and Tort [1]; Milla et al [2]; Faught and Vijayan [3]). The activation of the HPI axis first involves the release of corticotropin-releasing factor (CRF) from the hypothalamic preoptic area, which in turn stimulates the anterior pituitary to secrete the adrenocorticotropic hormone (ACTH) [4][5][6][7].…”

“…The activation of the HPI axis first involves the release of corticotropin-releasing factor (CRF) from the hypothalamic preoptic area, which in turn stimulates the anterior pituitary to secrete the adrenocorticotropic hormone (ACTH) [4][5][6][7]. The circulating ACTH acts on the interrenal gland (analogous to the adrenal gland in mammals) and stimulates the synthesis and secretion of cortisol [3,5,8,9]. An important action of cortisol is to increase glucose bioavailability and improve an organism's ability to cope with stress condition.…”

“…An important action of cortisol is to increase glucose bioavailability and improve an organism's ability to cope with stress condition. In addition, glucocorticoids can also impact other physiological functions, including reproduction [1,3,5,8]. In this regard, it is widely accepted that stress and cortisol may have inhibitory effects on reproduction in vertebrates including teleost fish [3,[10][11][12].…”