Seasonal Plasticity in the Peptide Neuronal Systems: Potential Roles of Gonadotrophin-Releasing Hormone, Gonadotrophin-Inhibiting Hormone, Neuropeptide Y and Vasoactive Intestinal Peptide in the Regulation of the Reproductive Axis in Subtropical Indian We

2015 ◽  
Vol 27 (5) ◽  
pp. 357-369 ◽  
Author(s):  
Surbhi ◽  
A. Rastogi ◽  
S. Rani ◽  
V. Kumar
Keyword(s):  
Neuropeptide Y ◽  
Vasoactive Intestinal Peptide ◽  
Releasing Hormone ◽  
Seasonal Plasticity ◽  
Reproductive Axis ◽  
Gonadotrophin Releasing Hormone ◽  
Neuronal Systems

Variable duration of reproductive suppression in male coyotes (Canis latrans) treated with a high dose of the gonadotrophin-releasing hormone agonist deslorelin

2017 ◽  
Vol 29 (7) ◽  
pp. 1271 ◽  
Author(s):  
Marjorie J. MacGregor ◽  
Cheryl S. Asa ◽  
Donal C. Skinner
Keyword(s):  
Canis Latrans ◽  
Animal Health ◽  
Management Strategies ◽  
High Dose ◽  
Sperm Production ◽  
Releasing Hormone ◽  
Reproductive Axis ◽  
Gonadotrophin Releasing Hormone ◽  
Breeding Seasons

Effective and humane management strategies for coyotes (Canis latrans) remain elusive. We hypothesised that exposure to a high dose of a gonadotrophin-releasing hormone (GnRH) agonist would cause prolonged suppression of the reproductive axis. Two groups of male coyotes were administered 47 mg deslorelin in the form of either five 9.4-mg controlled-release Suprelorin (Peptech Animal Health, Macquarie Park NSW, Australia) implants (n = 3) or 10 4.7-mg implants (n = 5). In the first group, deslorelin suppressed plasma LH, testosterone and testes volume in two of three coyotes for three breeding seasons. In the second group, two of five deslorelin-treated coyotes had no sperm production after 1 year and plasma LH, FSH, testosterone and testes volume were suppressed. Although plasma gonadotropins and testosterone were suppressed in three treated coyotes in group two, testes volume and sperm production were evident. Because the duration of suppression differed among individual coyotes, we further hypothesised that a variation in deslorelin release underlay the variability. To test this, we analysed in vivo plasma profiles of deslorelin concentrations. These profiles suggested that deslorelin concentrations >100 pg mL–1 are required to maintain suppression in male coyotes. For field implementation, the development of an implant capable of releasing deslorelin for the life of the coyote is necessary.

scholarly journals Severity of the Catabolic Condition Differentially Modulates Hypothalamic Expression of Growth Hormone-Releasing Hormone in the Fasted Mouse: Potential Role of Neuropeptide Y and Corticotropin-Releasing Hormone

Endocrinology ◽  
2007 ◽  
Vol 148 (1) ◽  
pp. 300-309 ◽  
Author(s):  
Raul M. Luque ◽  
Seungjoon Park ◽  
Rhonda D. Kineman
Keyword(s):  
Neuropeptide Y ◽  
Mrna Levels ◽  
Releasing Hormone ◽  
Ghrelin Receptor ◽  
Ghrh Receptor ◽  
Transient Rise ◽  
Biphasic Effect ◽  
Neuronal Systems ◽  
Induced Changes

To determine whether the severity of the catabolic condition differentially regulates the GH axis, male mice were either fed ad libitum or fasted for 12, 24, and 48 h. Hypothalami, pituitaries, and stomachs were collected for assessment of mRNA levels by quantitative real-time RT-PCR, and blood collected for measurement of plasma hormone and metabolite levels by commercial assay kits. Overnight (12 h) fasting resulted in a significant suppression of circulating glucose, insulin, IGF-I, and leptin levels and an increase in corticosterone, free fatty acids, and n-octanoyl ghrelin levels, and these directional changes were maintained at the 24- and 48-h time points. Fasting (24 h) also increased circulating GH levels, which was associated with an increase in pituitary mRNA levels for GHRH receptor and ghrelin receptor and a decrease in mRNA levels for somatostatin (SST) receptor (SSTR) subtypes, SSTR2, SSTR3, and SSTR5, where the changes in ghrelin receptor and SSTR expression persisted after 48 h fasting. Hypothalamic SST mRNA levels were not altered by fasting, whereas there was a transient rise in stomach SST mRNA levels 24 h after food withdrawal. In contrast, there was a biphasic effect of fasting on GHRH expression. GHRH mRNA levels were significantly elevated at 12 and 24 h but fell to ∼50% of fed controls 48 h after food withdrawal. A sequential rise in hypothalamic neuropeptide Y (NPY) and CRH mRNA levels preceded the fall in GHRH expression, where fasting-induced changes in CRH and GHRH mRNA levels were not observed in 48-h-fasted NPY knockout mice. These observations, in light of previous reports showing both NPY and CRH can inhibit GHRH expression and GH release, suggest that these neuronal systems may work in concert to control the ultimate impact of fasting on GH axis function.

scholarly journals Analysis of gonadotrophin-releasing hormone-1 and kisspeptin neuronal systems in the nonphotoregulated seasonally breeding eastern rock elephant-shrew (Elephantulus myurus )

2018 ◽  
Vol 526 (15) ◽  
pp. 2388-2405
Author(s):  
Katarina Medger ◽  
Nigel C. Bennett ◽  
Christian T. Chimimba ◽  
Maria K. Oosthuizen ◽  
Jens D. Mikkelsen ◽  
...  
Keyword(s):  
Releasing Hormone ◽  
Elephant Shrew ◽  
Gonadotrophin Releasing Hormone ◽  
Neuronal Systems ◽  
Seasonally Breeding
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