Hypogonadism predisposes males to the development of behavioural and neuroplastic depressive phenotypes

Mice with ablated adult brain neurogenesis are not impaired in antidepressant response to chronic fluoxetine

“…Finally, the prevailing perception in the literature, suggests FST to be a proper test to show neurogenesis-dependence of antidepressant efficacy. Several groups described X-irradiation to block antidepressant effects using FST (e.g., Zhu et al, 2010;Garza et al, 2012) while correlative observations linking antidepressant treatment effects in FST and adult hippocampal neurogenesis have been reported numerous times (Liu et al, 2008;Silva et al, 2008;Schmidt and Duman, 2010;Wainwright et al, 2011;Wang et al, 2011;Jiang et al, 2012;Lin and Wang, 2014;Lu et al, 2014).…”

Assessing gonadal hormone contributions to affective psychopathologies across humans and animal models

“…However, when castrated as adults, mice displayed more anxiety-like behaviours on the elevated plus maze when compared to sham-castrated controls (McDermott et al, 2012). Further investigation of affective behaviours in castrated adult male rats indicates elevations in anxiety-like and depressive-like behaviours following chronic stressors, compared to sham males that experienced the same chronic stress paradigm (Wainwright et al, 2011). These findings suggest that androgen deficiencies in adult male rodents increase their vulnerability to chronic stressors and resulting anxiety and/or depression.…”

“…In terms of hypogonadism, reduction or removal of estrogen and androgen, or the withdrawal of progesterone all resulted in increases in anxiety-like behaviours when compared to control subjects (de Chaves et al, 2009;Diz-Chaves et al, 2012;Gulinello et al, 2003;Isles et al, 2004;Lagunas et al, 2010;Lewejohann et al, 2009;Li et al, 2012;McDermott et al, 2012;Schneider and Popik, 2007;Slack et al, 2009;Wainwright et al, 2011;Walf et al, 2009). Measures of depressive-like behaviours were less consistent, for example, aged female rodents did not display increases in depressive-like symptoms when estradiol was absent (Diz-Chaves et al, 2012) though this effect differed depending on the age at ovariectomy and the duration of estradiol replacement (Lagunas et al, 2010).…”

“…In both humans and rodents, there is evidence for an interaction of the hippocampus and amygdala in anxiety and depression , specifically, both brain areas that are responsive to fluctuations in gonadal hormones (McEwen, 2010). Furthermore, reports from the rodent literature highlight that stressors can exacerbate psychopathologies resulting from gonadal hormone dysregulation, regardless of whether this dysregulation results in hormonal deficiencies or excesses (Goel and Bale, 2008;Lagunas et al, 2010;Seney et al, 2012;Wainwright et al, 2011). Additionally, recent evidence confirms that the rodent brain expresses all the molecular mechanisms necessary to synthesize gonadal hormones de novo (Konkle and McCarthy, 2011).…”

Effects of testosterone on the spatial ecology, coloration, and brain regions in western fence lizards, Sceloporus occidentalis

“…It is well established that in songbirds, T increases the size of the song control regions and neurogenesis in the HVC, a song related region in the brain (Barker et al, 2014;, Balthazart et al, 2010;Dittrich et al, 2014;Rasika et al, 1994). Moreover, T affects brain regions not directly related to reproduction, such as the hippocampus, again generally increasing size or neurogenesis; for example, in mammals, T and estradiol increase hippocampal neurogenesis and gonadectomy decreased cell proliferation in the dentate gyrus (Spritzer et al, 2011;Wainwright et al, 2011). Castrated males with T replacement displayed higher cell proliferation in one region of the subventricular zone than castrated males, but had equal cell proliferation compared to sham operated males (Farinetti et al, 2015).…”