Bioscientifica Proceedings

Experiments were conducted to further our understanding of the cellular and molecular mechanisms that regulate luteal function in ewes. Inhibition of protein kinase A (PKA) reduced (P < 0.05) secretion of progesterone from both small and large steroidogenic luteal cells. In addition, the relative phosphorylation state of steriodogenic acute regulatory protein (StAR) was more than twice as high (P&hairsp;<&hairsp;0.05) in large vs small luteal cells. Large steroidogenic...

Currently, there is no method to diagnose pregnancy non-invasively in most wildlife species that experience delayed implantation and pseudopregnancy, either during embryonic diapause or placental pregnancy. The aim of this study was to utilize farm-raised mink (Neovison vison) as a model species to evaluate changes in the fecal proteome associated with pregnancy. Specific objectives were to: 1) determine if fecal peptides were differentially abundant in parturient ver...

Summary. Studies have consistently demonstrated that 4-cell pig embryos can be cultured to the blastocyst stage in a simple salt solution containing bovine serum albumin (BSA). Pig embryos appear to be detrimentally affected by lower levels of lactate and pyruvate than are mouse embryos, but in general their in-vitro requirements are similar. Results from embryos cultured between the 4-cell and blastocyst stages are consistent enough to allow the use of c...

Summary. Maternal recognition of pregnancy in sheep, cattle and goats involves physiological mechanisms that result in protection of corpora lutea from luteolysis by modification or inhibition of uterine production of luteolytic pulses of prostaglandin (PG) F-2α. Ovine, bovine and caprine luteal cells release oxytocin in a pulsatile manner during late dioestrus. Oxytocin then binds to its endometrial receptors and initiates luteolytic pulses of PGF-2&#945...

Abstract unavailable© 1995 Journals of Reproduction and Fertility Ltd...

Uterine differentiation in cattle and sheep begins prenatally, but is completed postnatally. Mechanisms regulating this process are not well defined. However, studies of urogenital tract development in murine systems, particularly those involving tissue recombination and targeted gene mutation, indicate that the ideal uterine organizational programme evolves epigenetically through dynamic cell–cell and cell–matrix interactions that define the microenvironmental conte...

The uterus plays a central role in the reproductive biology of mammals. Adaptation of the uterus from an oviparous to a viviparous nature required changes that involved production of a uterine environment that could support the development of the embryo and fetus. Production of a suitable environment includes the synthesis and secretion of products by the uterine endometrium. However, the uterine endometrium is not a single homogeneous unit, but rather consists of several...

Abstract unavailable© 2009 Society for Reproduction and Fertility...

The physiological mechanisms controlling ovulation rate in mammals involve a complex exchange of endocrine signals between the pituitary gland and the ovary, and a localized exchange of intraovarian hormones between the oocyte and its adjacent somatic cells. The discoveries in sheep of mutations in bone morphogenetic protein 15 (BMP15) and bone morphogenetic protein receptor type IB (BMPR-IB) together with recent findings on the physiological effects of growth differentiation ...