Seasonal Relationships between Plasma and Fecal Testosterone in Response to GnRH in Domestic Ganders

Hirschenhauser, Katharina; Möstl, Erich; Péczely, P; Wallner, Bernard; Dittami, John; Kotrschal, Kurt

doi:10.1006/gcen.2000.7463

Cited by 59 publications

(50 citation statements)

References 39 publications

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“…These data suggest that the energetic state did not influence the sensitivity of the pituitary gland to GnRH. In other species, this sensitivity can fluctuate seasonally, increasing during the breeding season (Jawor et al, 2006;Hirschenhauser et al, 2000). Food restriction attenuated the LH response to GnRH in chickens (Bruggeman et al, 1998;Tanabe et al, 1981) and the testosterone response to GnRH in our study on Abert's towhees (Davies et al, 2015b).…”

Section: Pituitary Gland Responsiveness Under Energetic Deficitmentioning

confidence: 41%

Food restriction negatively affects multiple levels of the reproductive axis in male house finches, Haemorhous mexicanus

Valle

Carpentier

et al. 2015

Journal of Experimental Biology

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Nutrition influences reproductive functions across vertebrates, but the effects of food availability on the functioning of the hypothalamicpituitary-gonadal (HPG) axis in wild birds and the mechanisms mediating these effects remain unclear. We investigated the influence of chronic food restriction on the HPG axis of photostimulated house finches, Haemorhous mexicanus. Food-restricted birds had underdeveloped testes with smaller seminiferous tubules than ad libitum-fed birds. Baseline plasma testosterone increased in response to photostimulation in ad libitum-fed but not in food-restricted birds. Food availability did not, however, affect the plasma testosterone increase resulting from a gonadotropin-releasing hormone-I (GnRH) or a luteinizing hormone (LH) challenge. The number of hypothalamic GnRH immunoreactive (ir) but not proGnRH-ir perikarya was higher in food-restricted than in ad libitum-fed finches, suggesting inhibited secretion of GnRH. Hypothalamic gonadotropin-inhibitory hormone (GnIH)-ir and neuropeptide Y (NPY)-ir were not affected by food availability. Plasma corticosterone (CORT) was also not affected by food availability, indicating that the observed HPG axis inhibition did not result from increased activity of the hypothalamic-pituitaryadrenal (HPA) axis. This study is among the first to examine multilevel functional changes in the HPG axis in response to food restriction in a wild bird. The results indicate that food availability affects both hypothalamic and gonadal function, but further investigations are needed to clarify the mechanisms by which nutritional signals mediate these effects.

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Section: Pituitary Gland Responsiveness Under Energetic Deficitmentioning

confidence: 41%

Food restriction negatively affects multiple levels of the reproductive axis in male house finches, Haemorhous mexicanus

Valle

Carpentier

et al. 2015

Journal of Experimental Biology

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“…Hirschenhauser et al [2000] found that in domestic geese, measurements of fecal metabolites were much more variable than those of plasma hormones. One source of variability may be differences in fecal production [Bamberg et al, 1991].…”

Section: Discussionmentioning

confidence: 96%

Anuran gender identification by fecal steroid analysis

2005

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This study tested the hypothesis that steroid hormone metabolites can be measured in anuran feces and their concentrations used to identify the sex of adults. Fecal samples from American toads, Bufo americanus, and boreal toads, B. boreas boreas, were extracted using ethyl acetate, and the concentrations of estradiol, progesterone and testosterone metabolites were measured by enzyme immunoassays with antibodies commonly used to evaluate steroid hormone concentrations in mammalian species. In American toads, mean testosterone metabolite concentrations (Po0.05) between males (224.3715.5 ng/g feces) and females (80.7710.6 ng/g), but estradiol and progesterone metabolite concentrations did not. In contrast, estradiol immunoreactivity differed (Po0.05) between male (19.071.8 ng/g) and female (48.376.3 ng/g) boreal toads. Progesterone and testosterone metabolite concentrations did not differ. Fecal hormone metabolite analysis offers a promising noninvasive approach to gender identification in anuran amphibians. However, the group of metabolites differentiating gender may not be consistent among species.

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“…Intramuscular injections of GnRH temporarily stimulate the hypothalamo-pituitary-gonadal (HPG) axis, leading to release of luteinizing hormone (LH) from the pituitary, which stimulates steroid hormone secretion from the gonads (Johnson 2000). GnRH challenges are often used to assess the reproductive condition of individuals (Goymann and WingWeld 2004;Hirschenhauser et al 2000;Lacombe et al 1991;Moore et al 2002;Soma and WingWeld 2001), but recently GnRH challenges have been used to quantify seasonal and individual variation in capacity for steroid hormone synthesis (Jawor et al 2007). One consequence of a GnRH challenge is elevation of yolk steroid levels (e.g., testosterone), which has the potential to inXuence attributes of oVspring via the yolk.…”

Section: Introductionmentioning

confidence: 99%

Carotenoid supplementation and GnRH challenges influence female endocrine physiology, immune function, and egg-yolk characteristics in Japanese quail (Coturnix japonica)

et al. 2012

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Androgens and carotenoids circulating in plasma affect the physiology and behavior of vertebrates. Much is known about control mechanisms and functions of each of these substances, yet their interactive effects are not well understood. Here we examine possible additive, multiplicative, and interactive effects of testosterone and carotenoids on female endocrine physiology, immunocompetence, and investment in eggs by simultaneously manipulating levels of testosterone [via gonadotropin releasing hormone (GnRH) challenges] and carotenoids (via diet supplementation) in captive female Japanese quail (Coturnix japonica). Females were randomly assigned to one of four treatments: carotenoid supplementation, GnRH challenge, GnRH challenge + carotenoid supplementation, or control. Carotenoid supplementation significantly increased circulating plasma carotenoid levels and acquired immune system performance, but not innate immunity. GnRH challenges elevated circulating testosterone and carotenoid levels, and induced immunosuppression in females. However, females in the GnRH challenge + carotenoid supplementation treatment had higher cell-mediated immune responses than control females and similar responses to those of carotenoid-supplemented females. Hence, availability of carotenoids in female quail seemed to counteract immunosuppressive effects of GnRH challenges. Our results provide further evidence for synergistic effects of carotenoids and testosterone on endocrine physiology and immune function in female birds. Elevated plasma testosterone or carotenoids levels resulted in increased deposition of those compounds to eggs, respectively. Furthermore, because we found that concentrations of testosterone and carotenoids in yolks were correlated within each treatment group, differential deposition of hormones and carotenoids in eggs may not only respond to surrounding social and environmental conditions, but also to other components of the egg.

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Seasonal Relationships between Plasma and Fecal Testosterone in Response to GnRH in Domestic Ganders

Cited by 59 publications

References 39 publications

Food restriction negatively affects multiple levels of the reproductive axis in male house finches, Haemorhous mexicanus

Food restriction negatively affects multiple levels of the reproductive axis in male house finches, Haemorhous mexicanus

Anuran gender identification by fecal steroid analysis

Carotenoid supplementation and GnRH challenges influence female endocrine physiology, immune function, and egg-yolk characteristics in Japanese quail (Coturnix japonica)

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