bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxygen concentration and protein source affect the development of preimplantation goat embryos in vitro
Authors: Batt PA , Gardner DK , Cameron AW
Published: October 2005

The effect of oxygen concentration and the source of protein in culture medium on the development of 2- to 4-cell goat embryos in vitro was investigated. Embryos were collected from superovulated Angora-Cashmere-cross goats 48 h after ovulation and cultured for 6 days in synthetic oviduct fluid (SOF) medium under one of two oxygen concentrations (20% or 7%) and in the presence of one of five protein sources; Miles bovine serum albumin (Miles BSA), Commonwealth Serum Laboratory bovine serum albumin (CSL BSA), goat serum (GS), fetal calf serum (FCS) and human serum (HS). In the presence of 20% oxygen the percentage of embryos reaching the expanded and/or hatched blastocyst stage in SOF medium containing Miles BSA was 29%, with a mean cell number per embryo of 28.1 +/- 6.0 (+/- s.e.m.). Use of an oxygen concentration of 7% significantly increased the percentage of embryos reaching this stage (80%, P less than 0.01) and the mean number of cells per embryo (65.3 +/- 8.2, P less than 0.01). The mean number of cells of the early-cleavage-stage embryos was significantly lower when the medium contained CSL BSA, GS or FCS (42.7 +/- 5.6, 29.0 +/- 6.1 and 21.3 +/- 3.2, respectively) than with Miles BSA (92.8 +/- 6.4) or HS (104.8 +/- 17.2) (P less than 0.01). Under 7% oxygen and with Miles BSA or HS, embryos were morphologically comparable to those developed in vivo, but the mean cell numbers in vitro were only approximately half those obtained in vivo.
Metabolism of fructose-1,6-bisphosphate by mature boar spermatozoa
Authors: Jones AR , Montague MD
Published: October 2005

Mature epididymal boar spermatozoa converted glucose and fructose to carbon dioxide and lactate and maintained high concentrations of ATP. In the presence of (S)-alpha-chlorohydrin these processes were inhibited and there was an accumulation of fructose-1,6-bisphosphate and dihydroxyacetone phosphate. With fructose-1,6-bisphosphate as the substrate, the concentration of ATP was maintained, carbon dioxide was evolved and dihydroxyacetone phosphate accumulated. Cells pre-incubated with (S)-alpha-chlorohydrin did not maintain ATP levels, evolved less carbon dioxide and produced dihydroxyacetone phosphate. Assays of incubates in which fructose-1,6-bisphosphate was used as the substrate showed the presence of equilibrium quantities of fructose-6-phosphate and glucose-6-phosphate which were not detected when either fructose or glucose were used as substrates. [14C]Fructose and [14C]glucose were not produced from [14C]fructose-1,6-bisphosphate in spermatozoal incubates which had or had not been pre-incubated with (S)-alpha-chlorohydrin. Evidence is presented that a high concentration of fructose-1,6-bisphosphate leads to the formation of fructose-6-phosphate and glucose-6-phosphate but not of fructose and/or glucose.
Ovariectomized does do not require progesterone priming for oestrous behaviour
Authors: Sutherland SR , Lindsay DR
Published: October 2005

Ewes need to be primed with progesterone in order to achieve sensitivity to oestrogen. This relationship was examined in goats. In experiment 1 the median effective dose of oestradiol benzoate (ODB) required to induce oestrus during the breeding season (July) in progesterone-primed ovariectomized does was 15 micrograms, a dose similar to that reported to be required in ewes. In experiment 2 (initiated in March) the requirement for progesterone priming before injection of ODB to induce oestrus after a period without any exogenous hormone treatment, was compared in goats and sheep. Without progesterone priming, ovariectomized does were sensitive to doses of ODB between 20 and 80 micrograms, whereas ewes were not. This indicates that, unlike sheep, goats may not require progesterone priming in order to exhibit oestrus at the beginning of the breeding season. After being primed with progesterone, ewes were more sensitive to ODB than were does. In primed ewes the median effective dose of ODB was 12 micrograms whereas in does it was 27 micrograms. These differences may be due to a seasonal effect on oestrous behaviour or differences in sensitivity to oestrogen between the species.
Postcopulatory myometrial activity in the rat as seen by video-laparoscopy
Authors: Crane LH , Martin L
Published: October 2005

Myometrial activity was analysed by video-laparoscopy in unmated and mated oestrous female rats. In the former, most contractions propagated caudally and were predominantly longitudinal, with circular contractions limited to weak peristalsis. Mating had dramatic effects on activity, inducing a high frequency of strong peristaltic and non-peristaltic circular contractions propagating both cranially and caudally. Activity remained elevated for up to 10 h, decreasing to control levels as uterine contents were lost when the vaginal plug disintegrated. Mechanical stimulation of the cervix, sufficient to induce pseudopregnancy, increased the frequency of weak peristalsis but did not induce myometrial activity comparable to that seen after mating. Treatment of mated females with indomethacin returned myometrial activity towards control levels, suggesting that myometrial stimulation involved prostanoid production. After mating to intact males the uterus took on a characteristic blue colour suggestive of hypoxia. This too was abolished by indomethacin treatment. Removal of accessory reproductive glands from males showed that induction of myometrial activity and the colour change both required constituents from the vas deferens, seminal vesicles and coagulating glands. Males lacking seminal vesicles or coagulating glands were infertile. The prolonged myometrial activity and putative hypoxia induced by seminal constituents may be important in survival and selection of sperm.
Opioid involvement in LH release during the negative feedback effects of oestradiol and progesterone in dairy cows
Authors: Nanda AS , Ward WR , Dobson H
Published: October 2005

To create a clearly defined and uniform feedback phase of oestradiol, 1 mg oestradiol benzoate (OE2) was injected i.m. either 15-43 days post partum in 7 cows (Expt 1), or 12 h after prostaglandin oestrus synchronization of 4 cyclic cows (Expt 2 and 3). An endogenous opioid peptide (EOP) antagonist (250 mg naloxone), an EOP agonist (300 mg morphine), or a combination of the two was given in Expt 1, 2 and 3 respectively as a single i.v. injection in cows 16-18 h after OE2, i.e. in the negative feedback phase and before the expected onset of an induced luteinizing hormone (LH) surge. Blood samples were collected every 15 min for 1 h before and 2 h after each treatment. In Expt 1, naloxone failed to increase LH release when given during the negative feedback phase, but caused excessive release in one cow in which the LH surge had just begun. In all cows in Expt 2, morphine suppressed LH release (P less than 0.05). In Expt 3, naloxone prevented the suppressive effects of morphine for the first hour after treatment; a transient rise in LH occurred in one cow in which treatment was given 1 h before the start of the LH surge. In Expt 4, 250 mg naloxone was injected i.v. into 4 cows that had a plasma progesterone concentration of 1.5-3.1 ng mL-1 in the luteal phase of the oestrous cycle: naloxone failed to increase LH concentrations. It is concluded that LH can be further suppressed by opiates given to cows during the negative feedback phase of oestradiol.(ABSTRACT TRUNCATED AT 250 WORDS)
Beta adrenoceptors mediate the catecholamine-induced stimulation of oxytocin secretion from cultured bovine granulosa cells
Authors: Luck MR , Munker M
Published: October 2005

Bovine granulosa cells were treated in culture with alpha- and beta-adrenoceptor ligands to determine the receptor subtype mediating their response to catecholamines. The secretion of oxytocin by granulosa cells in serum-free medium was measured on the fourth day of culture (during the period of acquisition of a luteal phenotype). Cultures were performed in the presence of 0.5 mM ascorbic acid, which increased hormone output and potentiated the response to catecholamines. The effects of adrenaline and noradrenaline on oxytocin secretion were concentration-dependent; maximum stimulation was over 700% with adrenalin (EC50 92 nM) and 500% with noradrenaline (EC50 87 nM). The response to noradrenaline (10(-6) M) and adrenaline (10(-6) M) could be blocked by propranolol but not by phentolamine, suggesting that beta- rather than alpha-adrenoceptors were involved. Blockade by metoprolol and practolol (beta 1-adrenoceptor antagonists) was poor and dobutamine (beta 1-agonist) was weakly stimulatory. A concentration-dependent stimulatory response (EC50 200 nM) was obtained with salbutamol (beta 2-adrenoceptor agonist) and stimulation by adrenaline or salbutamol could be blocked by a selective beta 2-adrenoceptor antagonist (ICI 118,551). It is concluded that, during luteinization, the long-term response of bovine granulosa cells to stimulation induced by catecholamines is mediated through beta- rather than alpha-adrenoceptors. Although the beta 2-subtype is probably involved, the similar potencies of adrenaline and noradrenaline are uncharacteristic of beta 2-adrenoceptors and may be peculiar to the long-term response shown by these cells.
Studies on the role of liver cytochrome P-450 and oestradiol metabolism in the effects of nutrition and phenobarbital on ovulation rate in the ewe
Authors: Payne E , Smith JF , Cope BC , McGowan LT
Published: October 2005

Coopworth ewes were differentially fed to produce 60 heavy (62 kg) and 80 light (45 kg) ewes. They were then fed a low protein (100 g protein kg-1 dry matter) pelleted ration. On Day 7 of the oestrous cycle after synchronization the following treatments were commenced in groups of 10 ewes: 4 low liveweight groups received low protein (LP), high protein (HP; 230 g protein kg-1 dry matter), LP + phenobarbital (PB; 1 g per os per day in gelatin capsules for 10 days) and LP + triacetyloleandomycin (TAO, 0.5 g day-1 in capsule for 10 days); while 3 high liveweight groups received LP, HP and HP + carbon tetrachloride (CCl4, 0.1 mL kg-1 bodyweight as a single dose). The experiment was repeated using another 7 groups of 10 ewes at an interval of 3 weeks. PB, TAO, high liveweight, and protein diet increased the ovulation rate whereas treatment with CCl4 reduced the ovulation rate. Because of the small number of ewes in some treatment protocols, only changes due to liveweight and protein diet were statistically significant. Liver weight and microsomal protein were increased by all treatments except CCl4 which caused a decrease. PB and TAO increased cytochrome P-450 and associated enzyme activities, in particular those related to cytochrome P-450p or P-450NF (including oestradiol 2-hydroxylation) in the human liver. In vitro, TAO binding indicated that the specific cytochrome was induced by PB and TAO but there were no direct effects of protein diet and liveweight. Most of the data support the theory that nutritionally induced increases in ovulation rate in ewes could result from changes in oestradiol metabolism, but the lack of induction of the specific cytochrome by protein diet and high liveweight suggests that increased ovulation caused by these factors may be the physiological response to several metabolic changes.
Effects of medroxyprogesterone acetate (MPA) on myometrial activity in unmated rats: a study in vivo using video-laparoscopy
Authors: Crane LH , Martin L
Published: October 2005

Unmated female rats received medroxyprogesterone acetate (MPA) on the day of oestrus. Myometrial activity in vivo was quantified by video-laparoscopy 24-96 h later. Changes induced by MPA resembled those in early pregnancy/pseudopregnancy, but were not as extreme. There was a significant increase in circular contractions, followed by a decline, as in mated rats. Increases in circular contractions propagating caudally were as large as in mated rats, but increases in those propagating cranially were much smaller and qualitatively different. MPA induced only small increases in the frequency of longitudinal contractions propagating cranially, whereas large increases occurred in pregnancy/pseudopregnancy. We conclude that in early pregnancy/pseudopregnancy, increased circular activity is induced by rising progesterone levels. However, progesterone alone does not account for the increased contractions propagating cranially in mated rats. We suggest that these are induced by increased pacemaker activity in the region of the cervix, possibly activated by stimuli received during copulation.
Effects of photoperiod on the reproductive physiology of male flying foxes, Pteropus poliocephalus
Authors: McGuckin MA , Blackshaw AW
Published: October 2005

Melatonion concentrations were determined in plasma pools obtained from adult male Pteropus poliocephalus (autumn mating season) at four times of the year. Melatonin levels increased within 3 h of sunset and remained elevated for the duration of the scotophase at all times of the year. Two photoperiod manipulation experiments were performed to examine the role of daylength in the regulation of the timing of the breeding season of this species. In Experiment 1, three adult males were transferred from natural short days to 16L:8D for 137 days and then photoperiod was progressively decreased over 120 days to 9L:15D; this photoperiod was then maintained for 350 days. Testicular volume (TV) peaked during decreasing photoperiod well before the time of maximal size in natural conditions. During the period in extended short photoperiod these bats showed several cycles of TV change with a progressively decreasing interval between cycles. In Experiment 2, nine adult males were exposed to the same shift to 16L:8D as in Experiment 1, but were subsequently split into three groups: 8L:16D, progressive decrease to 8L:16D and maintenance in 16L:8D. The 8L:16D and decreasing photoperiod groups showed coincident premature increases in TV, as in Experiment 1, whereas in the 16L:8D group TV increased at about the same time as in animals in natural photoperiod. Melatonin determination in the different experimental groups showed that duration of secretion was related to the length of the scotophase in all cases. These experiments demonstrate that regulation of the timing of reproduction in males of this species is influenced by changes in daylength.
Effects of the progesterone antagonist RU486 on myometrial activity in vivo in early pregnant and pseudopregnant rats
Authors: Crane LH , Martin L
Published: October 2005

Myometrial activity in vivo was quantified by video-laparoscopy in early pregnant rats given doses of RU486 which caused embryo abortion and blocked the action of progesterone on the vagina. All treatments diminished the frequency of circular contractions and abolished the curling movements of the uterus which are characteristic of pregnant, pseudopregnant and progestin-treated rats. The effects of RU486 on circular contractions were similar in pseudopregnant rats, i.e. they were not a consequence of embryo abortion. These results support the thesis that increased myometrial circular contractions in early pregnancy and pseudopregnancy are induced by increasing levels of progesterone. Effects of RU486 on longitudinal contractions were more complex: the highest dose inhibited longitudinal contractions on Day 5 of pregnancy and pseudopregnancy, but increased their frequency on Day 6. The acute inhibition of longitudinal contractions by RU486 was unexpected and the mechanism remains to be elucidated. The later increase in the frequency of longitudinal contractions appears to be due to antagonism of progesterone by RU486. The frequency of caudal longitudinal contractions on Day 6 in mated rats given RU486 was similar to that in unmated oestrous rats, but the frequency of cranial longitudinal contractions was significantly higher. These results support the hypothesis that stimuli received during copulation may have long-term effects on myometrial activity, by increasing pacemaker activity at the cervix.
Addition of superoxide dismutase and catalase does not necessarily overcome developmental retardation of one-cell mouse embryos during in-vitro culture
Authors: Payne SR , Munday R , Thompson JG
Published: October 2005

There is evidence that developmental blocks observed in mouse embryos during culture in vitro may be the result of free radical-induced cellular dysfunction. We have further investigated this possibility by examining the effects of 5% O2 and the antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), on mouse 1-cell embryo development. The results demonstrate that development of CF-1 strain embryos is enhanced by incubating in 5% CO2, 5% O2, 90% N2 (5/5/90) compared with 5% CO2 in air (5/air) (P < 0.01) and by culturing in the presence of other embryos. Superoxide dismutase significantly improved embryonic development (35 +/- 5% v. 17 +/- 4% morulae/blastocysts, P < 0.001) at a concentration of 100 units mL-1 when embryos were gassed under 5/5/90. At a concentration of 1000 units mL-1, SOD was detrimental to development (P < 0.001). Injection of SOD and/or CAT into embryos had not effect on development. Development has also been examined in four strains of mice (CF-1, Quackenbush (random-bred strains), Balb-C (inbred) and the F1 hybrid of CBA x C57B1) in the presence or absence of 100 units SOD mL-1 and 1000 units CAT mL-1. Embryonic development was markedly different among the four strains examined, with F1 hybrid > Balb-C (P < 0.001), Balb-C > CF-1 (P < 0.05) and Quackenbush embryos performing very poorly compared with the embryos of the other three strains (P < 0.001).
Characterization and autoradiographic localization of the epidermal growth factor receptor in the jejunum of neonatal and weaned pigs
Authors: Kelly D , McFadyen M , King TP , Morgan PJ
Published: October 2005

Receptors for epidermal growth factor (EGF) were characterized on the intestinal membranes of newborn, sucking and weaned pigs. 125I-labelled EGF (125I-EGF) binding to membrane homogenates was time-dependent, saturable, linearly correlated to membrane protein and reversible. Analysis of saturation curve data revealed a single class of 125I-EGF binding sites in both newborn and weaned pigs. Receptor levels tended to be higher in weaned than in newborn pigs; the converse was true for the receptor affinity. In contrast, virtually no binding sites were found on the intestinal membranes of sucking pigs. Autoradiography in vitro of jejunal sections of newborn and weaned pigs demonstrated 125I-EGF receptors on both microvillar and basolateral surfaces of enterocytes, suggesting that luminal EGF could influence developmental processes in the intestine either directly or indirectly following transcytosis of the ligand.
Monoclonal anti-idiotypic antibody to progesterone with internal image properties
Authors: Khole V , Hegde U
Published: October 2005

An auto-anti-idiotypic approach was used to generate mouse monoclonal anti-idiotypic antibody E9F11F6 (Ab2) to progesterone. A conjugate of 4-pregnane 3,20 dione and bovine serum albumin was used as the immunogen. E9F11F6 bound to a rabbit anti-progesterone antibody in a linear concentration-dependent manner. It inhibited the binding of [3H]progesterone to a monoclonal anti-progesterone antibody, E9D5 (Ab1); this inhibition was concentration dependent. Results from chase experiments showed that this inhibitory activity of Ab2 was not due to steric hindrance but was a result of direct binding to the ligand combining site. Indirect immunofluorescence studies also showed that Ab2 and progesterone bound to similar binding sites on Ab1. Overall, the results suggest that E9F11F6 contains an internal image of at least part of the progesterone molecule, and that it can be classified as an Ab2 beta antibody. This anti-idiotypic antibody may be of value in further studies of endocrine and reproductive physiology.
Early endometrial microvascular response during implantation in the rat
Authors: Rogers PA
Published: October 2005

The endometrial microvasculature becomes intimately involved in the events of early implantation. This paper reviews aspects of this microvascular involvement during implantation in the rat. There is a major increase in vascular permeability surrounding the implanting embryo, leading to significant local changes in microvascular architecture. This is followed by a shutdown of the capillaries closest to the embryo as the primary decidual zone develops. At this time, endometrial capillaries adjacent to the primary decidual zone become dilated, with over twice the average diameter of intersite capillaries. Endometrial neutrophils are reduced around the implanting blastocyst, mitigating against a role for these inflammatory mediators in vascular aspects of the implantation process. Angiogenesis does not appear to increase at the implantation site, although there is an increase in production of endometrial endothelial cell migratory signal a few hours prior to the commencement of implantation.
Glycoconjugates as positive and negative modulators of embryo implantation
Authors: Carson DD , Jacobs AL , Julian J , Rohde LH , Valdizan MC
Published: October 2005

A variety of studies indicate that complex glycoproteins participate in or modulate adhesive interactions occurring during embryo implantation. In particular, proteoglycans and proteins that bind proteoglycans are involved at multiple stages of this process. Identification of these binding proteins and the molecular controls over glycoconjugate expression are required to develop a comprehensive understanding of the implantation process.
Studies in vitro of effects of steroid hormones and the blastocyst on endometrial function in the sheep
Authors: Salamonsen LA , Cherny RA , Findlay JK
Published: October 2005

Normal endometrial function is a result of regulation by the combination of ovarian steroids and local agents arising from within the embryo-maternal unit. We have used in vitro techniques to examine the role of steroid hormones and ovine trophoblast interferon on endometrial function in the ewe. Immunolocalization of oestrogen receptors in endometrial tissue demonstrated marked changes throughout the cycle and in early pregnancy with maximal concentrations during the follicular and very early luteal phases. Protein secretion from highly purified cultured ovine stromal and epithelial endometrial cells, and the direction of secretion from polarized epithelial cells, has been examined by incorporation of [35S]methionine and by one- and two-dimensional gel electrophoresis. Protein synthesis is greater in stromal than in epithelial cells and more protein is secreted apically than basally from epithelial cells. A number of common and some different proteins are secreted by the two cell types. One secreted protein is matrix metalloproteinase-3 (stromelysin) which degrades components of basement membranes. Ovine trophoblast interferon attenuates the production of prostaglandins from ovine endometrial cells but its action is not by an effect on localization or concentration of the enzyme prostaglandin synthase or on expression of the gene for prostaglandin synthase. Such studies in vitro contribute to our understanding of how the endometrium is prepared for implantation.
Uterine secretion of prostaglandin F2 alpha in the ewe: regulation at the cellular level by ovarian hormones and the conceptus
Authors: Silvia WJ
Published: October 2005

Changes in the ability of the uterus to secrete prostaglandin F2 alpha (PGF2 alpha) in response to oxytocin may play a critical role in determining when endogenous secretion of PGF2 alpha begins. The cellular mechanisms that regulate uterine secretion of PGF2 alpha in response to oxytocin have not been completely defined. Several intracellular components that may contribute to this regulation have been studied, including phospholipase C (PLC), prostaglandin H endoperoxide synthase (PGS) and receptors for oxytocin. All of these components change during the oestrous cycle and are associated with the development of uterine secretory responsiveness to oxytocin. Progesterone appears to play the principal role in regulating oxytocin receptors, PLC and PGS. The conceptus appears to suppress the increase in receptors for oxytocin and PLC activity that typically occurs around the time of luteal regression.
Hormonal control of concentrations of endometrial oxytocin receptors in the ewe
Authors: Fairclough RJ , Lau TM
Published: October 2005

Uterine oxytocin receptors have been shown to play a major role in the regulation of uterine prostaglandin F2 alpha release during the oestrous cycle and early pregnancy in sheep. The concentration of endometrial oxytocin receptors increases sharply from around Day 13 of the oestrous cycle to reach a maximum between Days 15 and 16. The high concentration of endometrial oxytocin receptors at this time coincides with the release of endogenous uterine prostaglandin F2 alpha during luteal regression and the maximum uterine prostaglandin F2 alpha response to an oxytocin stimulus. The concentration of uterine oxytocin receptors appears to be regulated by both progesterone and oestradiol. Studies in ovariectomized ewes have shown that initially progesterone lowers the concentration of endometrial oxytocin receptors, but after prolonged treatment with progesterone the concentration of oxytocin receptors increases; this suggests that the uterine-PGF2 alpha response to oxytocin has become refractory to the inhibitory effects of progesterone. The concentration of endometrial oxytocin receptors is also lowered by short-term oestradiol treatment. However, oestrogen treatment of ewes after long-term treatment with progesterone does not result in an increase in the concentration of oxytocin receptors following the cessation of progesterone treatment. On the basis of these and other data it is proposed that in the normal oestrous cycle the concentration of endometrial oxytocin receptors is initially depressed by both oestradiol and progesterone but that the marked increase in the concentration of oxytocin receptors over Days 13-16 of the cycle is due primarily to the withdrawal of the inhibitory influence of progesterone alone. During early pregnancy the release of uterine prostaglandin F is suppressed.(ABSTRACT TRUNCATED AT 250 WORDS)
Genes for the trophoblast interferons and their distribution among mammals
Authors: Leaman DW , Cross JC , Roberts RM
Published: October 2005

The trophoblast interferons (IFN), ovine and bovine trophoblast protein-1 (oTP-1 and bTP-1 respectively), possess many properties in common with other Type I IFN, including antiviral and antiproliferative activities. However, they differ from other IFN subtypes in terms of their specific pattern of expression and poor responsiveness to viral stimulation. We describe here data that suggest that the trophoblast IFN genes are also distinct from other Type I IFN genes with respect to species distribution, promoter organization and transcriptional regulation. These results have important implications in terms of trophoblast IFN gene evolution and add credence to the concept that the trophoblast IFN genes are a distinct IFN gene subtype well suited for their role in early pregnancy.
Metabolic and developmental responses of preimplantation embryos to platelet activating factor (PAF)
Authors: Ryan JP , O'Neill C , Ammit AJ , Roberts CG
Published: October 2005

Platelet activating factor (PAF) is an ether phospholipid produced by preimplantation embryos of a number of species. Production of PAF by embryos has been measured by detecting thrombocytopenia in a splenectomized mouse bioassay, platelet aggregation bioassays in vitro and a specific radioimmunoassay. Production is highly variable and is adversely affected by culture in vitro. It has, however, been correlated with morphology, development rates in vitro and the pregnancy potential of embryos following transfer. Investigations using PAF-antagonists have established an essential role for PAF in early pregnancy. Together with studies that have shown PAF to have direct effects on embryonic metabolism during culture in vitro, these observations suggest that PAF acts as an embryonic autocoid. Hence, a major site of action for embryo-derived PAF in vivo is the embryo itself. Supplementation of embryo culture media with PAF had no effect on the rate of development in vitro of 2-cell mouse embryos through to the blastocyst stage. However, PAF increased cell numbers of blastocysts cultured from the 2-cell stage and the mitotic index of embryos at both the 8-cell and blastocyst stages. Supplementation of culture media with PAF has also been shown to increase the implantation potential of both mouse and human embryos cultured in vitro. In the mouse, the effect of PAF in enhancing implantation rates was most evident when the developmental potential of untreated embryos was suboptimal. These observations suggest that the production of embryo-derived PAF is one limiting factor in maintaining the viability of embryos cultured in vitro.
The effect of leukaemia inhibitory factor (LIF) on embryogenesis
Authors: Fry RC
Published: October 2005

Leukaemia inhibitory factor (LIF) was originally identified as a haemopoetic factor that induced the differentiation of certain myeloid leukaemia cell lines. In contrast to this action, LIF was subsequently shown to inhibit the spontaneous differentiation of murine embryonic stem cells in culture, thus maintaining their pluripotency and ability to contribute to the germline of chimaeric mice. In the mouse, mRNA for LIF is expressed by the endometrial glands of the uterus coincident with the time of blastocyst implantation and receptors have been found on the preimplantation blastocyst. The signal for LIF expression appears to be of maternal origin, perhaps regulated by oestradiol. Recombinant LIF improves the development of murine and ovine blastocysts in culture although there is some species specificity with respect to the type of LIF that is bioactive. It is proposed here that LIF acts on the trophectoderm of the rapidly expanding blastocyst and improves the implantation rate of otherwise compromised embryos. Further studies in livestock should elicit therapeutic uses for LIF in embryo culture, embryo transfer and embryo survival in vivo.
Antibodies, implantation and embryo survival
Authors: Heap RB , Taussig MJ , Wang MW , Whyte A
Published: October 2005

The diverse strategies adopted among species for the maintenance of luteal function converge to meet the indispensable requirement for this hormone particularly at the time of onset of implantation. What has emerged from immunization studies is the difference that exists between various species in the effects of progesterone depletion. The findings affirm the uterus as a primary site of progesterone action in the preimplantation period of gestation in the mouse, whereas in the hamster the positive feedback by progesterone on pituitary luteotrophin secretion is important in maintaining luteal function and hormone secretion at a level necessary for uterine preparation. The impact of progesterone in the rat seems to be established within 48 h after fertilization, whereas in the ferret the hormone's action ensures a suitable uterine environment in which the early embryo can flourish. Its effects in early pregnancy in the marmoset are ambiguous from the present studies unless it emerges that target organ responses are tuned to low concentrations of active steroid. However, the discoveries in mice of a conserved family of immunoglobulin genes used exclusively by immunogenic forms of progesterone conjugated to proteins to stimulate antibody production, and of antibody binding to the uterine epithelium, reveal systems potentially inimical for embryo survival. The endometrial expression of the proto-oncogene erb-A at a time when the embryo has not yet arrived in the uterus, and of antibody-binding to the uterine epithelium, are early maternal responses whose significance require closer examination. The present findings support the hypothesis that the primary site of action of progesterone during the preimplantation period differs between species, and that it is not only the mother that recognizes, but the embryo that initiates early changes before the onset of implantation 'in the bed of soil that nourishes it', a symbiosis that may yet prove to be a common feature of the adoption of viviparity as a preferred mode of reproduction.
Effect of continuous infusion of oxytocin on ovarian function and uterine oxytocin receptor concentration in the cyclic ewe
Authors: Sheldrick EL
Published: October 2005

Intact cyclic ewes have been used in experiments designed to examine the mechanism by which uterine oxytocin receptor synthesis is controlled during the oestrous cyclic. Previous experiments have shown that the prostaglandin F2 alpha analogue cloprostenol is luteolytic in ewes receiving oxytocin by continuous intra-venous infusion. When ewes receiving oxytocin are given cloprostenol uterine oxytocin receptor concentrations are raised, whereas in animals receiving oxytocin alone, they remain low. To investigate whether inhibition of oxytocin receptor binding activity by oxytocin is either dependent on elevated plasma progesterone concentrations or over-ridden by oestrogens secreted by ovarian follicles maturing as a result of cloprostenol treatment, ewes were given oxytocin by continuous intravenous infusion (3 nmol h-1) between Days 12 and 17 after oestrus and one of the following: no further treatment; cloprostenol [125 micrograms intramuscularly (i.m.)] on Day 15; progesterone, by subcutaneous implant, from Day 14 with cloprostenol on Day 15; medroxyprogesterone acetate (MPA; 6 mg depot i.m.) on Day 14 followed by cloprostenol on Day 15; or oestradiol-17 beta (2.75 mumol i.m.) on Days 14 and 15. Concentrations of oxytocin receptor were measured at autopsy on Day 17 in caruncular endometrium, intercaruncular endometrium and myometrium. Ovarian follicles and corpora lutea were examined to determine the effect of treatment on these tissues. Treatment with oxytocin alone resulted in the maintenance of corpora lutea, reduced follicular development and a low concentration of uterine oxytocin receptor. Cloprostenol initiated luteolysis in oxytocin-treated ewes. This was associated with a high level of oxytocin receptor binding activity in all ewes except those receiving exogenous progesterone.(ABSTRACT TRUNCATED AT 250 WORDS)
FSH and LH receptor concentrations in large ovarian follicles of beef cows in high and low levels of body condition at nine weeks post partum
Authors: Rhind SM , Bramley TA , Wright IA , McMillen SR
Published: October 2005

An experiment was conducted to determine whether or not the effect of body condition at parturition, and thereafter, on the duration of the post-partum anoestrous period was mediated through differences in gonadotrophin receptor concentrations in the ovarian follicles. Two groups of cows were fed to achieve body condition scores of > or = 2.75 (H; n = 14) or < or = 2.00 (L; n = 15) at parturition (this had led to differences in the duration of post-partum anoestrus in previous experiments) and then fed to maintain liveweight and condition until ovariectomy at nine weeks post partum. There was no effect of body condition on the mean (+/- s.e.) number of large (> or = 8 mm diameter) follicles per cow (3.0 +/- 0.27) but a greater proportion of the follicles of H cows, compared with L cows, was oestrogenic (secreting > 250 pg oestradiol h-1 in culture) (0.75 v. 0.5; chi 2 = 3.40; P = 0.06). Mean concentrations (pg hormone bound per mg protein) of follicle stimulating hormone (FSH) receptors in both granulosa (H, 157.3; L, 136.6; standard error of difference (s.e.d.) = 27.2) and thecal tissue (H, 4.14; L, 4.35; s.e.d. = 1.66) were similar for H and L cows. There was no difference associated with treatment in luteinizing hormone (LH) receptor concentrations in either granulosa (H, 40.3; L, 37.2; s.e.d. = 6.67) or thecal tissue (H, 48.9; L, 48.0; s.e.d. = 6.03). The concentration of FSH receptors in granulosa tissue was lower in non-oestrogenic follicles than in oestrogenic follicles (80.0 v. 188.1; s.e.d. = 40.4; P < 0.01).
Oocyte Donation: Ethical Perspectives
Authors: Charlesworth M
Published: October 2005

Oocyte donation is a means by which an infertile woman, who cannot produce her own ova, can have
a child with the help of IVF and embryo transfer. Since it is a serious matter to donate one's gametes
to another, both donor and recipient should be given sufficient information and counselling to enable
them to make an informed choice and, as far as possible, to control the process.
Forming a family by means of oocyte donation should also be seen within the broad context of the
other various modes of family formation, namely by donor insemination, adoption, surrogacy, etc.
The concept of 'the family' is a pluralistic one, as different forms of the family can coexist in our
society.
Family formation by oocyte donation should therefore not be considered to be deviant, or subversive
of the traditional concept of the family.
Role and Expression of Colony Stimulating Factor-1
and Steel Factor Receptors and their Ligands
during Pregnancy in the Mouse
Authors: Arceci RJ , Pampfer S , Pollard JW
Published: October 2005

It is becoming apparent that the effects of female sex steroid hormones can be mediated by locally
synthesized polypeptide growth factors in the uterus. In this paper we describe the patterns of expression
of two such growth factors, steel factor and colony stimulating factor-1 (CSF-I), and their transmembrane
tyrosine kinase receptors, the products of the c-kit and c-fms proto-oncogenes respectively.
Both these uterine synthesized cytokines are directed to uterine hematopoietic cells, the preimplantation
embryo and to the extra-embryonic tissues during the postimplantation period. Studies with the
CSF-1-deficient osteopetrotic (op/op) mouse show that CSF-1 has important roles during embryonic
development and in the regulation of uterine macrophages. These studies establish that CSF-1, whose
sex steroid hormone-induced synthesis is restricted to the uterine epithelium, has a paracrine action on
embryos as well as being a mediator of epithelial-mesenchymal interactions.
Structure of the Plasma Membrane
of Uterine Epithelial Cells in Blastocyst Attachment:
a Review
Authors: Murphy CR
Published: October 2005

Changes in the molecular organization of the plasma membrane of uterine epithelial cells during early
pregnancy and, in particular, at the attachment period are reviewed. The review focuses on attachment
in rodents but other species are also considered. Alterations in protein content and type, as determined
with electrophoretic and freeze-fracture techniques, and an increase in tight junction complexity occur
in several species. Ultrastructural histochemistry shows that glycocalyx carbohydrates of different species
both increase and decrease depending on the type of carbohydrate. Changes in membrane cholesterol
content also occur and recent studies showing major reorganization of the actin-containing membrane
skeleton are reviewed to show the dynamism of this plasma membrane during the period of uterine
receptivity for attachment of the blastocyst.
Uterine Receptivity
Authors: Rogers PAW
Published: October 2005

Reduced uterine receptivity can play a major role in human infertility, particularly following ovarian
stimulation as occurs during ovulation induction and IVF. Many of the conventional histological and
morphological markers used to identify normal progestational changes in the human uterus are
inadequate as markers of uterine receptivity for implantation, and new techniques including ultrasound
and morphometric measurement will be required. At the same time, a'better understanding of the
cellular processes involved in human implantation is required if we are to identify markers of uterine
receptivity. Recent observations suggest that the uterus is normally a barrier to embryo implantation
and that uterine receptivity is in fact the loss of this barrier function, rather than the acquisition of new
structural or functional capabilities.
Models for Human Implantation
Derived from Implantation in vitro
Authors: Lindenberg S , Pedersen B , Hamberger L , Kimber SJ
Published: October 2005

This paper is a review of previously published laboratory results as well as data not published before.
The developmental phases that separate the events of implantation are discussed and comparative studies
are made of implantation in vitro in different species.
Oocyte Donation: Review of Results
Authors: King CM , Kovacs GT
Published: October 2005

This paper reviews the results of oocyte donation programmes around the world. Data on 1608 cycles
of ovum donation were received from 11 clinics and medical centres. Significance among and between
groups of donors and recipients was also assessed.
The Role of Accreditation Committees in Oocyte Donation
Authors: Cox LW
Published: October 2005

The formation of the Reproductive Technology Accreditation Committee of the Fertility Society of
Australia is recorded. In the three Australian States that have legislated in respect of reproductive
technology, the role of the Committee has been recognized and, in two States, representatives of the
State Authority join the Committee for the official visits to the clinics. Accreditation by the Committee
is required before a licence to operate is issued. The Committee's modus operandi is described.
Aspects of the Committee's discussions on oocyte donation are described. These include oocyte
collection, categories of donors, payment or coercion of donors, matching and exclusion of donors,
information and counselling of donors, prevention of infection in recipients and the technical aspects.
Guidelines have been developed which, if not complied with, would lead to loss of accreditation.
The advantages and disadvantages of voluntary regulation and of regulating practice by legislation
are discussed briefly. The joint inspection arrangements already in place appear to be a practical
solution.
Production and secretion of progesterone in vitro and presence of platelet activating factor (PAF) in early pregnancy of the marsupial, Macropus eugenii
Authors: Kojima T , Hinds LA , Muller WJ , O'Neill C , Tyndale-Biscoe CH
Published: October 2005

The corpus luteum (CL) of the tammar is suppressed by lactation. Removal of the sucking pouch young induces reactivation of the CL which produces a peak in plasma progesterone concentration on Day 5, 6 or 7; reactivation of the embryo after diapause precedes by one day this transient peak of progesterone. This study examines progesterone production and secretion in vitro by the CL and the production of platelet activating factor (PAF) by the endometrium during this stage of pregnancy (Days 0 and 3-8). Blood samples were collected twice daily to determine for each animal (n = 28) at autopsy the relationship of PAF production to the day of the progesterone peak. Significant changes in basal plasma progesterone concentrations were used to define four groups according to the time the animals were killed: Group A, Day 0; Group B, other animals showing no significant change; Group C, peripheral progesterone concentration increasing; Group D, peripheral progesterone concentration decreasing after the peak. At autopsy on successive days, blood samples were taken from the heart, caudal vein and uterine branch of the ovarian vein, and CL and endometria were prepared for explant culture. Progesterone contents of pre- and post-incubation luteal tissues and of medium were determined at 4, 12 and 24 h to estimate production and secretion rates. The values for all progesterone parameters from animals in Group C were significantly higher than in the other groups. It is concluded that the progesterone peak results from a change in rate of production and secretion of progesterone by the CL, one day before the peak in peripheral plasma, and that this change could provide the first signal to the uterus. Endometrium was incubated for 24 h and the medium assayed for PAF. High concentrations of PAF were detected in half the animals in Groups B and C, that is, before or at the time progesterone was increasing. This is the first measurement of PAF in any marsupial and the first demonstration of the release of PAF by the endometrium. The detection of PAF provides a candidate for an endometrial signal that is responsive to the rising progesterone concentration in the utero-ovarian vein draining the CL-bearing ovary and that may stimulate reactivation of the blastocyst.
Relationship between clustering of post-ovulatory and hierarchical follicles and their order of ovulation in the mature domestic hen (Gallus gallus domesticus)
Authors: Waddington D , Walker MA
Published: October 2005

Hierarchical (> 8 mm) and post-ovulatory follicles from the ovaries of laying hens at 45 and 86 weeks of age were assigned to clusters defined by the coalescence of their follicular stalks. They were also classified by size to give the succession in which ovulation had occurred, or would occur for the hierarchical follicles. The association between the order of ovulation and the observed clusters was compared with randomness and with dependence on the cluster in which the immediately preceding ovulation occurred. The order of ovulation was associated randomly with clusters, and was independent of the cluster containing the preceding ovulation. Many perceived clusters of successive follicles and post-ovulatory follicles may be compatible with a random order of ovulation. These findings do not support theories of stimulation or inhibition of adjacent follicles, leading to eventual ovulation, by a dominant follicle.
Active immunization of Merino ewe lambs with recombinant bovine alpha inhibin advances puberty and increases ovulation rate
Authors: O'Shea T , Bindon BM , Forage RG , Findlay JK , Tsonis CG
Published: October 2005

Ewe lambs (n = 24-25) were immunized at 3, 7 and 15 weeks of age with recombinant bovine alpha-inhibin (rec inhibin) or with bovine monoclonal antibody purified inhibin (bMPI) obtained by immunochromatography from bovine follicular fluid or with adjuvant alone (control). Antibodies in the plasma of the lambs immunized with the inhibin preparations bound to iodinated 31 kDa bovine inhibin. Binding was minimal after the primary immunization, increased after each booster immunization and remained elevated until at least 45 weeks of age (29% for rec inhibin and 11% for bMPI). Of the group treated with rec inhibin, 10 ovulated as lambs (control 0/22; bMPI 3/21) and onset of overt oestrous activity (as hoggets) was advanced (P < 0.05) by 17 days in lambs immunized with rec inhibin. As hoggets, the ovulation rate was greater (P < 0.01) in the rec inhibin immunized lambs (4.41 +/- 0.67) than in the control animals (1.27 +/- 0.15) but not in the bMPI-treated lambs (1.40 +/- 0.16). After a further immunization at 17 months of age, however, ovulation rate increased (P < 0.01) in the bMPI-immunized group (3.40 +/- 0.47) but was unchanged in the lambs immunized with rec inhibin (2.80 +/- 0.52) and those in the control group (1.15 +/- 0.08). There were no effects of immunization on plasma concentrations of either follicle stimulating hormone (FSH) or luteinizing hormone (LH). The initial smaller response seen with the bMPI may be due to either the presence of compounds other than inhibin in such preparations or the small absolute amount of inhibin injected.(ABSTRACT TRUNCATED AT 250 WORDS)