Bioscientifica Proceedings

Oocyte maturation, a simple and visible phenomenon, is about to be transformed into a complex and not so visible molecular cascade leading to the marking of the following generation. The study of oocyte maturation in mammals is progressively changing towards a more molecular approach. This review addresses the main challenges in the study of RNA extraction and quantification in oocytes and embryos as well as the importance of the mRNA maturation. The identification of specific...

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Enhanced secretion of PGF2α from endometrial explants in vitro in response to oxytocin is associated with augmented activities of phospholipase A2, phospholipase C and prostaglandin endoperoxide H synthase (PGS). In early pregnancy, maintenance of the corpus luteum is associated with an absence of pulsatile PGF2α secretion; an increase in endometrial inhibitors of phospholipase A2 and PGS contribute to the antilute...

Inhibin, activin and follistatin are protein hormones with diverse physiological roles. The involvement of inhibin in the regulation of pituitary FSH production and secretion in adult males and non-pregnant females is well established. However, it is unlikely that inhibin plays a similar role in pregnancy in ruminants. Inhibin and activin molecules show a high degree of structural similarity to potent growth and differentiation factors of the transforming growth factor β ...

The ancestral wild pig is a short day length seasonal breeder. The domestic pig appears to have retained some of this seasonality as evidenced by a reduction in fertility during the summer—autumn period. The most important aspect of this seasonality is a reduction in the number of mated sows that farrow. Many of these sows conceive and embryos develop normally for 20 - 25 days before pregnancy is terminated and the sow returns to oestrus (25 - 35 days after mating). In ot...

Research in France and in the UK confirms the prolificacy of the Chinese Meishan breed to be about three to four piglets greater than that of control Large White females. Crossbreeding studies clearly indicate that this breed difference is due to genes acting in the dam and not in the litter itself. There is high heterosis for litter size in F1 Meishan x Large White crossbred females, such that their litter size is similar to or greater than that of purebred Me...

The immune system discriminates 'self' from 'non-self', and eliminates that which it determines to be non-self. Mammalian pregnancy appears to represent a failure of self-non-self discrimination, yet it is a highly successful reproductive strategy. We present evidence that the immune system of the female pig responds to the challenges of both mating and the presence of conceptuses. Mating induces an influx of inflammatory leukocytes into the endometrial stroma and uterine...

Among livestock species, swine exhibit the most severe naturally-occurring intra-uterine growth restriction (IUGR) primarily due to a reduction in net protein synthesis. Thus, new knowledge about fetal metabolism of amino acids (AA), which are building blocks for proteins and regulators of intracellular protein turnover, can provide a solution to this problem. Among all AA, requirements of glutamate and glutamine by fetal pigs are quantitatively the highest, but cannot b...

Summary. Studies of isolated cell types from sheep follicles revealed several functional changes which occur during follicular maturation. Cyclic AMP production by granulosa cells from the smallest follicles studied (1–3 mm diameter) was stimulated by FSH but not by hCG, suggesting functional FSH receptors at this early stage of differentiation. Medium-sized follicles (4–6 mm) responded to both FSH and hCG. Granulosa cells were unable to synthesize a...

Abstract unavailableKeywords: inhibin; oestradiol; cow; pig; FSH© 1991 Journals of Reproduction & Fertility Ltd...