Effects of Starvation and Refeeding on Gonadotropin and Thyrotropin Subunit mRNAs in Male Japanese Quail

Kobayashi, Masaki; Cockrem, John F.; Ishii, Susumu

doi:10.2108/zsj.19.449

Cited by 14 publications

(8 citation statements)

References 51 publications

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“…We found that plasma LH did not change over the study in either the ad libitum-fed birds or the birds subjected to 2 weeks of food restriction; by contrast, food restriction for 4 weeks caused plasma LH to decrease. This finding is in line with other food availability manipulation studies of wild and domesticated avian and mammalian species, which generally show that food restriction decreases plasma LH and FSH (Tanabe, Ogawa & Nakamura 1981;Hoshino et al 1988;Lal et al 1990;Hahn 1995;Kobayashi, Cockrem & Ishii 2002;Hill, Elmquist & Elias 2008; but see Perfito et al 2008). Declines in plasma gonadotropins in response to negative energetic status appear to be due to decreases in the anterior pituitary gland content of their corresponding subunit mRNAs (Kobayashi, Cockrem & Ishii 2002;Ciccone, Dunn & Sharp 2007), but it remains unclear whether energetic status directly modulates levels of these mRNA subunits.…”

Section: H Y P O T H a L A M I C A N D A N T E R I O R P I T U I T A supporting

confidence: 86%

“…; Lal et al . ; Hahn ; Kobayashi, Cockrem & Ishii ; Hill, Elmquist & Elias ; but see Perfito et al . ).…”

Section: Discussionmentioning

confidence: 99%

“…). Declines in plasma gonadotropins in response to negative energetic status appear to be due to decreases in the anterior pituitary gland content of their corresponding subunit mRNAs (Kobayashi, Cockrem & Ishii ; Kobayashi & Ishii ; Ciccone, Dunn & Sharp ), but it remains unclear whether energetic status directly modulates levels of these mRNA subunits. Indeed, food restriction also reduces the sensitivity of the pituitary gland gonadotrope to GnRH (Tanabe, Ogawa & Nakamura ).…”

Section: Discussionmentioning

confidence: 99%

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Food availability, energetic constraints and reproductive development in a wild seasonally breeding songbird

et al. 2015

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Summary In many organisms, food availability is a proximate cue that synchronizes seasonal development of the reproductive system with optimal environmental conditions. Growth of the gonads and secondary sexual characteristics is orchestrated by the hypothalamic–pituitary–gonadal (HPG) axis. However, our understanding of the physiological mechanisms by which food availability modulates activity of the HPG axis is limited.It is thought that many factors, including energetic status, modulate seasonal reproductive activation. We tested the hypothesis that food availability modulates the activity of the HPG axis in a songbird. Specifically, we food‐restricted captive adult male Abert's Towhees Melozone aberti for 2 or 4 weeks during photoinduced reproductive development. A third group (control) received ad libitum food throughout. We measured multiple aspects of the reproductive system including endocrine activity of all three levels of the HPG axis [i.e. hypothalamic gonadotropin‐releasing hormone‐I (GnRH‐I), plasma luteinizing hormone (LH) and testosterone (T)], and gonad morphology. Furthermore, because gonadotropin‐inhibitory hormone (GnIH) and neuropeptide Y (NPY; a potent orexigenic peptide) potentially integrate information on food availability into seasonal reproductive development, we also measured the brain levels of these peptides.At the hypothalamic level, we detected no effect of food restriction on immunoreactive (ir) GnRH‐I, but the duration of food restriction was inversely related to the size of ir‐GnIH perikarya. Furthermore, the number of ir‐NPY cells was higher in food‐restricted than control birds. Food restriction did not influence photoinduced testicular growth, but decreased plasma LH and T, and width of the cloacal protuberance, an androgen‐sensitive secondary sexual characteristic. Returning birds to ad libitum food availability had no effect on plasma LH or T, but caused the cloacal protuberance to rapidly increase in size to that of ad libitum‐fed birds.Our results support the tenet that food availability modulates photoinduced reproductive activation. However, they also suggest that this modulation is complex and depends upon the level of the HPG axis considered. At the hypothalamic level, our results are consistent with a role for the GnIH and NPY systems in integrating information on energetic status. There also appears to be a role for endocrine function at the anterior pituitary gland and testicular levels in modulating reproductive development in the light of energetic status and independently of testicular growth.

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Section: H Y P O T H a L A M I C A N D A N T E R I O R P I T U I T A supporting

confidence: 86%

“…; Lal et al . ; Hahn ; Kobayashi, Cockrem & Ishii ; Hill, Elmquist & Elias ; but see Perfito et al . ).…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Food availability, energetic constraints and reproductive development in a wild seasonally breeding songbird

et al. 2015

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“…Supporting this hypothesis, other avian studies found that food restriction can decrease plasma LH (Hahn, 1995;Kobayashi et al, 2002). Alternatively or additionally, food restriction may decrease the sensitivity of Leydig cells to LH.…”

Section: Testicular Response To Energetic Deficitmentioning

confidence: 74%

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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“…2–) and this does not take into account the concentration of TSHβ subunit mRNA, for which no information is available. The view that the common α rather than the LHβ mRNA levels is predictive of LH secretion in birds is supported by observations in Japanese quail where changes in plasma LH induced by feed restriction and refeeding were correlated with common α, but not LHβ subunit mRNAs (33, 34). This is in contrast to mammals where neither the common α or LHβ subunit mRNAs are predictive of plasma LH concentrations (35).…”

Section: Discussionmentioning

confidence: 91%

Gonadotrophin Inhibitory Hormone Depresses Gonadotrophin α and Follicle‐Stimulating Hormone β Subunit Expression in the Pituitary of the Domestic Chicken

Ciccone

Dunn

Boswell

et al. 2004

J Neuroendocrinology

175

106

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Studies performed in vitro suggest that a novel 12 amino acid RF amide peptide, isolated from the quail hypothalamus, is a gonadotrophin inhibitory hormone (GnIH). The aim of the present study was to investigate this hypothesis in the domestic chicken. Injections of GnIH into nest-deprived incubating hens failed to depress the concentration of plasma luteinizing hormone (LH). Addition of GnIH to short-term (120 min) cultures of diced pituitary glands from adult cockerels depressed follicle-stimulating hormone (FSH) and LH release and depressed common alpha and FSHbeta gonadotrophin subunit mRNAs, with no effect on LHbeta subunit mRNA. Hypothalamic GnIH mRNA was higher in incubating (out-of-lay) than in laying hens, but there was no significant difference in the amount of hypothalamic GnIH mRNA in out-of-lay and laying broiler breeder hens at the end of a laying year. It is concluded that avian GnIH may play a role in controlling gonadotrophin synthesis and associated constitutive release in the domestic chicken.

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Effects of Starvation and Refeeding on Gonadotropin and Thyrotropin Subunit mRNAs in Male Japanese Quail

Cited by 14 publications

References 51 publications

Food availability, energetic constraints and reproductive development in a wild seasonally breeding songbird

Food availability, energetic constraints and reproductive development in a wild seasonally breeding songbird

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

Gonadotrophin Inhibitory Hormone Depresses Gonadotrophin α and Follicle‐Stimulating Hormone β Subunit Expression in the Pituitary of the Domestic Chicken

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