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Summary. Kisspeptin is a hypothalamic neuropeptide that is critical for fertility. In virtually all species, kisspeptin neurons stimulate gonadotrophin-releasing hormone (GnRH) secretion and act as transmitters for sex-steroid feedback to GnRH neurons. In sheep, kisspeptin neurons are located in the preoptic area and the arcuate nucleus (ARC), with the latter involved in both oestradiol positive and negative feedback regulation of GnRH. In addition, sheep are ...

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bp0009rdr19 | Male Function and Spermatogenesis | REDR1986

Use of chimaeras to study development

Anderson G. B.

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bp0011cpr30 | VI Factors that Interact in the Control of Reproduction | CPR1982

Micronutrients and Reproduction

Hardy B. , Frape D. ,

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bp0014cpr6 | Culture and Manipulation of Pig Oocytes and Embryos | CPR1993

Manipulatingearly pig embryos

Niemann H. , Reichelt B. ,

On the basis of established surgical procedures for embryo recovery and transfer, the early pig embryo can be subjected to various manipulations aimed at a longterm preservation of genetic material, the generation of identical multiplets, the early determination of sex or the alteration of the genetic make-up. Most of these procedures are still at an experimental stage and despite recent considerable progress are far from practical application. Normal piglets have been ob...

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bp0015cpr20 | Aspects of OOcyfe and Embryonic Development in The Pig | CPR1997

Advances in in vitro production of pig embryos

Funahashi H. , Day B. N. ,

A series of integrated, effective techniques is required to produce pig embryos from follicular oocytes in vitro. The failure to form a male pronucleus and polyspermy have been serious problems in efforts to produce embryos efficiently in vitro from pig oocytes. The former problem is now considered to be due to oxidative stress and the latter has been partially solved by reducing the number of capacitated spermatozoa reaching the oocytes. By the use of n...

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bp0003rdr12 | Development of the Reproductive Axis | REDR1994

Ontogeny of GnRH systems

Caldani1 M , Antoine M , Batailler M , Duittoz A

In all vertebrate species studied, the main central population of GnRH neurones, which produces the final messages regulating reproduction, originates outside the brain. Early during fetal life, they appear in the olfactory placode epithelium and then migrate toward the base of the telencephalon in close association with the nervus terminalis, penetrate the brain within the nervus terminalis roots, reach their final locations and eventually grow axons toward their targets. Onl...

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bp0004rdr35 | Reproductive Technology | REDR1998

Aspects of follicular and oocyte maturation that affect the developmental potential of embryos

Mermillod P , Oussaid B , Cognié Y

The ability to mature, be fertilized and finally to develop into a viable embryo is acquired gradually by the oocyte during progressive differentiation throughout folliculogenesis. This process starts with oocyte growth during the first steps of follicular development. As the oocyte is close to its final size, other modifications occur, less spectacular but at least as important in determining the resulting ability of the oocyte to accomplish its reproductive purpose (developm...

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bp0009rdr18 | Male Function and Spermatogenesis | REDR1986

Transgenic livestock

Simons J. P. , Land R. B.

Summary. Single genes can now be added routinely to the genome of mice by molecular manipulation as simple Mendelian dominants; this complements the normal process of reproduction to give ‘transgenic’ animals. Success in ruminants is limited to a few examples in sheep and although gene expression has yet to be documented, there is every reason to expect that it will be achieved. The application of this technology to livestock improvement depends on...

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bp0011cpr1 | I The Male, Mating and Conception | CPR1982