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Level of nutrition affects leptin concentrations in plasma and cerebrospinal fluid in sheep.
Data suggest that in sheep, as in other species, leptin production is correlated with the mass of adipose tissue and that the hormone passes from the circulation to the cerebrospinal fluid and then to hypothalamic sites, where it may affect appetite and perhaps GnRH secretion. Expand
Metabolic factors affecting the reproductive axis in male sheep.
These studies have focussed on the mature male sheep, a model in which high food intake stimulates GnRH-LH pulse frequency for only 10-20 days but continues to promote testicular growth over several months. Expand
Expression of orexin receptors in the brain and peripheral tissues of the male sheep
Orexins exert their effects through two specific receptors (OX1R and OX2R) that have been found mainly in the brain and also in peripheral tissues of rats and humans. Here, we demonstrate expressionExpand
Seasonality in male Australian cashmere goats: Long term effects of castration and testosterone or oestradiol treatment on changes in LH, FSH and prolactin concentrations, and body growth
The circannual cycle of gonadotrophin concentrations in goat bucks is dependent upon the presence of the testis, and it is suggested that circulating metabolites of testosterone, including oestradiol, are more important than testosterone itself in the maintenance of this cycle. Expand
Low maternal nutrition during pregnancy reduces the number of Sertoli cells in the newborn lamb.
It is concluded that undernutrition during pregnancy can reduce testicular development in the newborn, which may limit the ultimate number of Sertoli cells and, hence, the future capacity for sperm production and fertility. Expand
Effect of nutritional supplementation on quantities of glucose transporters 1 and 4 in sheep granulosa and theca cells.
The presence of GLUT1 and GLUT4 in the granulosa and theca of sheep follicles indicates that the transporters have a role within the ovary in the modulation of follicular function. Expand
The use of a 'first-wave' model to study the effect of nutrition on ovarian follicular dynamics and ovulation rate in the sheep.
High concentrations of metabolic hormones in fat ewes are associated with the development of more follicular waves and when a supplement is superimposed on this situation, changes in glucose and metabolic hormones allow more follicles to be selected to ovulate. Expand
Use of a new drug delivery formulation of the gonadotrophin-releasing hormone analogue Deslorelin for reversible long-term contraception in male dogs.
It is concluded that a single slow-release implant containing 6 mg Deslorelin has potential as a long-term, reversible antifertility agent for male dogs. Expand
Pituitary and testicular endocrine responses to exogenous gonadotrophin-releasing hormone (GnRH) and luteinising hormone in male dogs treated with GnRH agonist implants.
It was concluded that, in male dogs, implantation of a GnRH superagonist desensitised the pituitary gonadotrophs to GnRH and also led to adesensitisation of the Leydig cells to LH, which explains the profound reduction in the production of androgen and spermatozoa in deslorelin-treated male dogs. Expand
Dose-response studies for pituitary and testicular function in male dogs treated with the GnRH superagonist, deslorelin.
It is concluded that the dose-response relationship with deslorelin implants is not expressed with respect to the degree of suppression of reproduction, but on the maximum duration of suppression and thus to delay until recovery. Expand