Influence of stress-induced intermediates on gonadotropin gene expression in gonadotrope cells

Abstract

Despite extensive investigation, a comprehensive understanding of the mechanisms whereby stress impacts fertility remains elusive. Since the 1930s, when Hans Selye popularized studying adaptations to stress (Selye, 1937), we have learned that compensatory mechanisms involve a complex interplay of neural and hormonal processes that allow various body functions to adjust to stress, in a coordinated manner. In terms of reproduction, the adjustment to a stressor interferes with integrated functioning at multiple levels of regulation – the hypothalamus, anterior pituitary gland, gonads, and neural centers coordinating behavior. Various mediators are postulated to participate in reproductive suppression. These include catecholamines, cytokines, prostaglandins, endogenous opioid peptides, and hormones of the hypothalamic-pituitary-adrenal axis. This review focuses on one class of mediators, the glucocorticoids, and provides our views on the relevance and mode of action of this inhibitory intermediate within the anterior pituitary gonadotrope, as a potential cellular site whereby glucocorticoids contribute to stress-induced reproductive suppression.

Management Strategies Aiming to Improve Horse Welfare Reduce Embryonic Death Rates in Mares

“…The disruption of the social order, such as dominance rank and variations in population density, predisposes to reduced well-being (Fraser 1992). The stress response depends on the intensity and duration of the stressor (Dobson and Smith 2000), resulting in suppressed gonadotrophin secretion and inhibition of reproduction (Tilbrook et al 2000;Breen and Mellon 2014) due to an increase in plasma concentrations of the glucocorticoids, cortisol and corticosterone. These results may explain (a, b) in columns indicate significant difference (p = 0.02).…”

“…The stress response depends on the intensity and duration of the stressor (Dobson and Smith 2000). Prolonged or chronic stress results in suppressed gonadotrophin secretion and inhibition of reproduction (Tilbrook et al 2000;Breen and Mellon 2014) due to an increase in plasma concentrations of the glucocorticoids, cortisol and corticosterone. The effect of endogenously or exogenously raised cortisol levels on the minute-tominute gonadotrophin secretion patterns has not been studied in horses (Alexander and Irvine 2011).…”

Glucocorticoid-Mediated Regulation of Circadian Rhythms: Interface with Energy Homeostasis and Reproduction

“…Glucocorticoids are also among the central mechanisms controlling HPG axis function. It is quite clear that exposure to increased glucocorticoid levels, either induced by stress condition or by exogenous administration, may significantly interfere with reproductive function, with massive impacts on fertility [88][89][90].…”

Anti-Müllerian Hormone Levels and Urinary Cortisol in Women With Chronic Abdominal Pain

“…HPA dysregulation due to repeated or prolonged stressors, such as chronic pain, stimulates cortisol secretion, reducing pulsatile luteinizing hormone (LH) secretion and interrupting the follicular phase of the menstrual cycle (Breen & Mellon, 2014). At homeostatic levels, cortisol contributes to steroid biosynthesis and maintenance of gonadotropin release; elevated cortisol levels suppress gonadotropin releasing hormone (GnRH) secretion at the level of the pituitary and increases rates of follicle atresia (Whirledge & Cidlowski, 2010; Whirledge & Cidlowski, 2013).…”