bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxytocin delays oestradiol-induced luteolysis but does not affect oestradiol-induced luteinizing hormone secretion in the ewe
Authors: Sheldrick EL
Published: October 2005

Circulating concentrations of progesterone, the prostaglandin F2 alpha (PGF2 alpha), metabolite 13,14-dihydro-15-keto PGF2 alpha (DHKF2 alpha) and luteinizing hormone (LH) have been measured in cyclic ewes receiving a continuous infusion of oxytocin, in order to investigate the effect of maintained concentrations of circulating oxytocin on the luteolytic action of oestradiol-17 beta. Oxytocin (3 nmol h-1 intravenously) was given from Day 7 until Day 17 after oestrus with oestradiol-17 beta (2.76 mumol, intramuscularly in sesame oil, 0.5 mL-1) administered on Days 9 and 10. Control ewes, given a continuous infusion of saline (154 mmol L-1, 3 mL-1 h-1) and sesame oil on Days 9 and 10, underwent luteal regression at the expected time, with mean concentrations of plasma progesterone falling to below 1.5 nmol L-1 on Day 16 (0900 hours). Mean plasma progesterone concentrations fell to less than 1.5 nmol L-1 on Day 13 (0900 hours) in ewes receiving saline and oestradiol-17 beta. Oxytocin infusion delayed luteolysis in all treated ewes; those receiving oxytocin infusion and sesame oil failed to undergo luteal regression during the period studied and in animals receiving oxytocin and oestradiol-17 beta, luteolysis was significantly delayed when compared to ewes treated with saline and oestradiol with progesterone concentrations falling to < 1.5 nmol L-1 on Days 14 (n = 1 ewe), 15 (n = 1 ewe), 16 (n = 2 ewes) and > 17 (n = 2 ewes) (P < 0.05).
Clinical Oocyte Donation
Authors: Leeton J
Published: October 2005

General clinical aspects of oocyte donation in the human are briefly reviewed.
A Review of Endometrial Protein PP14 Secretion
during the Postovulatory Period and Pregnancy
Authors: Seppala M , Riittinen L , Kamarainen M , Julkunen M
Published: October 2005

A review of the authors' published work and of more recent and unpublished experiments includes
a summary of data on the site of synthesis of PP14 and its role as a local immunoregulator. Its
significance in reproductive performance is discussed.
Impaired Uterine Receptivity
in Infertile Women over Age 40
having Oocyte Donation and Correction
with Increased Progesterone Replacement
Authors: Meldrum DR , Marr B , Stubbs C , Wisot A , Yeo l , Hamilton F
Published: October 2005

Significantly fewer ongoing and delivered pregnancies occurred in infertile women aged >40 years
receiving oocyte donation from young normal women (8%, P<0.02) than in a similar group of younger
recipients receiving identical treatment (43%). A significant improvement (46Yo ongoing and delivered,
P<0.01) was achieved in another group of women over 40, treated with a doubled dose of progesterone.
The results are consistent with those observed in animal studies and suggest an effect of ageing
on uterine receptivity that is at least partly correctable by augmented progesterone stimulation of the
endometrium.
Viability of Human Follicular Oocytes
Collected from Unstimulated Ovaries
and Matured and Fertilized in vitro
Authors: Cha KY , Do BR , Chi HJ , Yoon TK , Choi DH , Koo JJ , Ko JJ
Published: October 2005

Immature human follicular oocytes were collected from unstimulated ovaries, matured and fertilized
in vitro and then transferred to patients with no ovarian dysfunction such as premature ovarian failure.
From 11 1 consenting donors, 422 immature oocytes were collected from 97 ovaries between January
1990 and October 1991. The number of oocytes collected from ovaries and their development were
recorded so that comparisons could be made among donors of different ages and ovarian condition,
such as menstrual cycle, cyclic and non-cyclic ovaries. The rate of fertilization in vitro showed a peak
in the 31-40-year age group; however, there was no statistical difference in the rate of oocyte maturation
and cleavage among the donors in the different age groups. Immature oocytes of the luted phase had
a significantly higher maturation rate than those of the follicular phase. There was no significant
difference in the number of recovered oocytes, or in the development of immature follicular oocytes,
between cyclic and non-cyclic ovaries. Mature follicular fluid and peritoneal fluid had a significant
effect on the development of immature follicular oocytes. Also, it was found that fertilized eggs
cleaved more frequently in the medium containing hypoxanthine compared with the medium without
hypoxanthine. Finally, from 21 transfer cycles, viable embryos were derived from immature follicular
oocytes, resulting in two pregnancies, both leading to the birth of normal babies. These findings
suggest that culture in vitro of immature follicular oocytes, from unstimulated ovaries, to a suitable
condition, could be used optimally for clinical applications such as human ovum donation
programmes.
Endocrinology of Early Pregnancy
in Women without Ovarian Function
Authors: Letur-Konirsch H , Cornel C , Taieb J , Fanchin R , Pietri V , Vialle MN , Frydman R
Published: October 2005

The purpose of this study is to determine the production of some factors in pregnant women (n = 18)
after oocyte donation and replacement therapy, in the three following situations: ongoing pregnancies,
abortions, and biochemical pregnancies.
In serum samples taken at least once a week during 16 weeks of theoretical amenorrhoea (w.a.)
and preserved at - 80C, the concentrations of 6 chorionic gonatrophin hormone (PhCG), oestradiol
(Ez), progesterone (P4), inhibin (I), growth hormone (OH), epidermal growth factor (EGF) and insulinlike
growth factor 1 (IGF1) were measured. In ongoing pregnancies, the hCG curve is similar in oocyte
donation and in pregnancies with a corpus luteum (CL). In early pregnancies, E2 and P4 reflect the
hormonal substitution. The trophoblast production of E2 is detectable between the 6th and 7th w.a.,
and that of P4 at the beginning of the 9th w.a. The inhibin is detectable 10 days after the transfer and
increases distinctly on the 6th w.a. The GH curve is lower in women suffering from premature ovarian
failure (POF) than in pregnant women possessing a CL; EGF and IGFl curves are uniform.
Maintenance of Pregnancy and Obstetric Outcome
in Donor Egg Pregnancies
Authors: Leeton J , Calderon I , Burden J , Azuma K , Renou P
Published: October 2005

Data are presented on the outcome of 43 pregnancies between 1983 and 1991. Maintenance of pregnancy
in agonadal women begins at the time of embryo implantation, and initial hormone replacement therapy
to prime the endometrium before embryo transfer is an important factor. Synchronization in agonadal
women is successful with the variable-length oestrogen replacement regime but can be difficult in
ovulating recipients.
The outcome of donor egg (DE) pregnancies in this study is comparable to that of IVF pregnancies,
with the possible exception of an increased rate of monozygous twins. Pre-eclampsia does not appear
to increase significantly in DE pregnancies. Vaginal delivery is possible for DE pregnancies in women
with ovarian failure.
The unique stability of the marsupial sperm acrosomal membranes examined by unprotected freeze-thawing and treatment with the detergent Triton X-100
Authors: Sistina Y , Lin M , Mate KE , Robinson ES , Rodger JC
Published: October 2005

In this study of the unique stability of the marsupial acrosome, experiments were carried out on the acrosomes of spermatozoa of the tammar wallaby (Macropus eugenii), common brushtail possum (Trichosurus vulpecula) and grey short-tailed opossum (Monodelphis domestica). Light microscopy showed that 4% of opossum and 15% of possum and wallaby spermatozoa lost their acrosomes after freeze-thawing. Electron microscopy revealed that freeze-thawing also induced changes in the acrosomal matrix of some acrosome intact spermatozoa. In both possum and wallaby, freeze-thawing increased the number of spermatozoa with vesiculation of the acrosomal matrix. Freeze-thawing disrupted the plasma membrane of spermatozoa but the acrosomal membranes remained intact. Immediately on addition of high concentrations of TX-100 (0.02% and 0.04%) there was significant loss of acrosomes and motility in possum and wallaby spermatozoa. Lower concentrations of TX-100 (< or = 0.01%) did not affect motility for up to 30 min in all three species, and there was no significant loss of acrosomes. Although loss of acrosomes did not occur under mild detergent treatment, 56% of wallaby and 70% of possum spermatozoa had altered acrosomes after 30 min in 0.01% TX-100. Electron microscopy revealed that acrosomes were undergoing a vesiculation process similar to that seen after freeze-thawing. Often the plasma membrane of detergent-treated spermatozoa was disrupted and had formed plasma membrane vesicles. However, the acrosomal membranes remained intact despite major changes to the acrosomal matrix. The study confirmed the remarkable stability of the marsupial acrosome and suggested that this is probably based in the acrosomal membranes.
Ovarian function and its manipulation in the tammar wallaby, Macropus eugenii
Authors: Rodger JC , Cousins SJ , Mate KE , Hinds LA
Published: October 2005

This study aimed to develop a superovulation protocol for the monovulatory tammar wallaby (Macropus eugenii), and examined the regulation of ovarian activity which leads to alternate ovulation in this marsupial. The most effective stimulatory treatment was 20 I.U. pregnant mare serum gonadotrophin (PMSG) given intramuscularly (i.m.) 20 days after the activation of an oestrous cycle by the removal of a sucking pouch young (RPY). Bromocriptine treatment was given at the time of RPY if the animal was in early seasonal quiescence. Mating had generally occurred when animals were examined 2 days after PMSG treatment on the morning of Day 22 RPY. Ovulation occurred only if the animal was treated on Day 22 or 23 (i.e. 2 or 3 days after PMSG) with gonadotrophin releasing hormone (GnRH) to induce a luteinizing hormone (LH) surge. Three 30-micrograms injections of GnRH (in 0.2 mL olive oil) were delivered as i.m. injections at 3-h intervals. Radioimmunoassay confirmed that the PMSG dose used did not elevate circulating steroid hormone concentrations beyond those found in normal cycles and that the GnRH protocol led to an LH surge of at least 6 h. Although multiple ovulation was achieved, the number of ovulations was low (2 or 3 per female). A major factor influencing the low ovulation rate was that generally only one ovary responded. Fertilized eggs and cleaving embryos were obtained. However, the fertility of induced ovulations has not yet been examined systematically. Laparoscopic examination through successive natural cycles confirmed that follicle growth and ovulation in the tammar wallaby alternates between the right and left ovary. Inhibition of follicle development in the corpus luteum (CL)-bearing ovary was also seen in females treated with the exogenous gonadotrophin (PMSG/GnRH) superovulation protocol. Follicle development was inhibited during the first half of the cycle in the non-CL-bearing ovary and during the entire cycle in the CL-bearing ovary. This inhibition seemed to occur at the follicular level because exogenous gonadotrophin was unable to initiate a response during periods of inhibition and the response to gonadotrophin differed in the two ovaries. The number of follicles growing in the non-CL-bearing ovary in response to an exogenous gonadotrophin stimulus was inversely related to the weight of the growing CL for the first 19 days after RPY.(ABSTRACT TRUNCATED AT 400 WORDS)
Use of single or multiple injections of FSH in embryo collection programmes in goats
Authors: Batt PA , Killeen ID , Cameron AW
Published: October 2005

The yield of embryos from goats treated with single injections of FSH combined with low doses of PMSG was compared with that from goats treated with conventional superovulatory regimens based on multiple doses of FSH. In one experiment, 101 female goats were assigned to 10 groups. One group received six injections of FSH-P (FSH-P control); a second group received eight injections of Ovagen (Ovagen control). The remaining eight groups conformed to a 2x2x2 factorial design in which goats received a single injection of a low or high dose of either FSH-P or Ovagen in combination with a low or high dose of PMSG. All goats were run with harnessed, entire bucks. Ovaries were examined by laparoscopy and embryos were recovered from goats that had ovulated and been mated. The mean number of normal embryos collected per goat was significantly greater in the FSH-P control group in all except those groups treated with either low or high doses of PMSG combined with a low dose of Ovagen or a low dose of PMSG combined with a high dose of Ovagen. Most goats ovulated and ovulation rates were not significantly different from the mean of the FSH-P control, except for those treated with a low dose of FSH-P combined with either low or high doses of PMSG. Embryo recovery rates were significantly lower in groups treated with a high dose of PMSG combined with a high dose of either Ovagen or FSH-P, or with low doses of PMSG and FSH-P, than in the FSH-P control.(ABSTRACT TRUNCATED AT 250 WORDS)
Tissue and endocrine responses to gestrinone and danazol in the treatment of endometriosis
Authors: Forbes KL , Thomas FJ
Published: October 2005

An open comparative study of gestrinone and danazol in the treatment of endometriosis demonstrated a similar decrease in the extent of active endometriotic deposits, assessed visually following therapy. Biochemical endocrinological changes during therapy with gestrinone showed that basal concentrations of gonadotrophin remained unchanged, oestradiol concentrations varied and the free fraction of testosterone increased. A similar range of side effects was reported in both treatment groups, consisting predominantly of 'androgenic' effects in 10 of 15 women treated with gestrinone and 5 of 12 treated with danazol. The results suggest that gestrinone is an effective alternative agent for the treatment of endometriosis.
Expression and regulation of the tumour necrosis factor-alpha gene in the female reproductive tract
Authors: Hunt JS
Published: October 2005

Tumour necrosis factor-alpha (TNF), a potent cytokine originally identified as a product of activated macrophages, is now known to be produced by many types of cells, and has been implicated in regulation of normal tissue homeostasis as well as in cellular differentiation. In humans and some murids, the TNF gene is expressed in ovaries, oviducts, uteri, placentas and embryos. Specific transcripts and proteins have been identified in oocytes, granulosa and theca cells, luminal and glandular epithelial cells, myometrial cells, decidual cells, placental trophoblast, macrophage-like cells and embryonic skin. Both prior and subsequent to implantation, uterine TNF mRNA and protein appear in specific cell lineages in an ordered temporal sequence. This and other findings indicate that transcription of the TNF gene in the uterus is regulated either directly or indirectly by ovarian and/or placental hormones. By contrast, there is as yet no evidence for regulation of this gene by other uterine cytokines such as colony stimulating factor-1 (CSF-1). Although the functions of this pleiotrophic, multifunctional molecule are largely unknown, the findings to date are consistent with the postulate that TNF is involved in gamete development, cyclic changes in the uterus, cancers of the female reproductive tract, placental maturation and embryonic development.
Conceptus development in vivo, endometrial and conceptus protein release in vitro following blastocyst transfer to ewes induced to ovulate at 28 days post-partum
Authors: Wallace JM , Aitken RP , Cheyne MA
Published: October 2005

The use of laparoscopic insemination to deposit semen into the tip of the uterine horn ensures fertilization in ewes induced to ovulate at 3-5 weeks post-partum. Acceptable pregnancy rates are achieved if embryos from post-partum donors are transferred to a normal uterine environment yet embryos rarely survive when transferred or returned to a post-partum uterus. Blastocyst transfer procedures were developed to test whether the post-partum uterus can support conceptus development during the period of rapid growth coincident with the maternal recognition of pregnancy. In Experiment 1, the efficiency of the blastocyst transfer procedure was determined using control ewes > 150 days post-partum. Eight of nine recipient ewes established pregnancies and 75% of blastocysts survived to term. In Experiment 2, blastocysts were transferred to control (n = 12) or post-partum (n = 10) recipients that had been induced to ovulate 28 days after lambing during the breeding season. Conceptus development was assessed 96 h after blastocyst transfer on Day 15 of the cycle. At this time, conceptus mass in the seven post-partum ewes which remained pregnant was generally lower than in the 11 corresponding control ewes. Conceptus and endometrial tissues were cultured separately for a further 24 h in vitro in the presence of [3H]leucine to determine production of oTP-1 and the pregnancy-specific endometrial protein p70 respectively. Oxytocin binding sites were measured in endometrial tissue. Following 96 h culture in a post-partum uterus the conceptus retained its competence to synthesize and secrete ovine trophoblast protein 1 (oTP-1) in vitro. However, despite normal oTP-1 production the conceptus tissue failed to completely suppress endometrial oxytocin receptor binding. The negative correlation between p70 production and oxytocin receptor density implies a possible role for this protein in the suppression of oxytocin receptor synthesis required to prevent luteolysis in pregnant ewes.
Incorporation of substrate carbon from
Authors: Waugh EE , Wales RG
Published: October 2005

Of the substrate carbon incorporated from 1.12 mM [U-14C]acetate as sole energy substrate during a 2.5-h incubation, a large proportion was isolated in the acid-soluble fraction. Although there was no significant change over time in the rate of entry into this pool for embryos, the rate of accumulation by the trophoblast and yolk sac increased as development progressed. At Days 13 and 15 of pregnancy, incorporation of acetate into the acid-insoluble fraction of embryos accounted for almost half the total label accumulated. The rate of this incorporation fell rapidly over time and by Day 19 less than 30% of carbon accumulated was in this fraction. By contrast, the rate of incorporation into this fraction by trophoblastic tissue was low at Day 13 but rose dramatically as development progressed. Incorporation by the yolk sac into acid-insoluble components also rose with time. At the early stages of pregnancy studied, lipid synthesis accounted for the majority of acetate carbon accumulated by the conceptus in the acid-insoluble pool. At later stages of development, incorporation into lipids constituted a minor pool of acetate carbon. Some acetate carbon was found in the glycogen fraction of the conceptus. The rate of incorporation into the acid-soluble glycogen fraction by embryos was constant throughout the period studied. By contrast, trophoblast increased its rate of incorporation markedly into both acid-soluble and acid-insoluble glycogen pools as did the yolk sac from Day 17.(ABSTRACT TRUNCATED AT 250 WORDS)
No alpha-lactalbumin-like activity detected in a low molecular mass protein fraction of rat epididymal extract
Authors: Tang Y
Published: October 2005

The same low M(r) protein fraction of epididymal luminal fluid as that studied previously by Hamilton in 1981 was assayed for alpha-lactalbumin (alpha-lac) activity with bovine milk galactosyltransferase (GalTase) as the enzyme source and bovine serum albumin (BSA) to make the total protein concentrations of all the samples in each assay constant. No alpha-lac activity could be detected in this fraction. When glucose was used as an acceptor, radioactivity passing through the ion exchange column used to retain the remaining UDP-galactose did increase with the amount of the proteins of the low M(r) fraction, but this increase was observed not only for samples with an acceptor but also for samples without. The increased radioactive product co-migrated in high-voltage electrophoresis with galactose, not lactose. When GlcNAc was used as an acceptor, the situation was the same, and the increased radioactive product co-migrated with galactose, not LacNAc. No inhibition of bovine milk GalTase activity by the low M(r) proteins was observed. Addition of protein, either BSA or the low M(r) fraction of epididymal luminal fluid, to assay medium that contained no proteins other than GalTase enhanced the GalTase activity both in forming lactose in the presence of glucose and also LacNAc in the presence of GlcNAc. It appears that the earlier reports of alpha-lac-like activity in epididymal fluids and extracts may have been due to the presence of enzymes liberating free galactose from UDP-galactose and/or a stimulatory non-specific effect of the protein in the solutions on the lactose synthesis activity of the GalTase.
Capacity of goat epididymal spermatozoa to undergo the acrosome reaction and subsequent fusion with the egg plasma membrane
Authors: Harayama H , Kusunoki H , Kato S
Published: October 2005

The capacity to undergo the acrosome reaction and subsequent fusion with the egg plasma membrane was examined in goat epididymal spermatozoa. Spermatozoa from the proximal and distal caput and distal cauda were preincubated in a sealed glass tube for induction of the acrosome reaction, and their viability, acrosome morphology and penetrability into zona-free hamster eggs were determined. A simplified triple-stain technique revealed that most of the preincubated live spermatozoa in the samples from the distal caput and distal cauda epididymides underwent morphological changes that indicated the occurrence of the acrosome reaction. Electron microscopic examination revealed that the outer acrosomal membrane of many spermatozoa in these samples showed fusion at multiple sites to the plasma membrane. However, the rates of acrosome-reacted cells in the proximal caput spermatozoa were still lower. The sperm penetration assay demonstrated that the penetration rates of distal caput and distal cauda spermatozoa preincubated for 2 h were 93% and 74% respectively, whereas proximal caput spermatozoa scarcely penetrated into eggs. These results indicate that increasing numbers of goat spermatozoa improve in the functions related to the acrosome reaction and subsequent fusion with the egg plasma membrane during their transit through the caput epididymidis.
Changes in oestrogen receptor protein, mRNA expression and localization in the endometrium of cyclic and pregnant gilts
Authors: Geisert RD , Brenner RM , Moffatt RJ , Harney JP , Yellin T , Bazer FW
Published: October 2005

Conceptus secretion of oestrogen on Day 11 of gestation is involved with establishment of pregnancy in the pig. Changes in oestrogen receptor (ER) protein, mRNA and cellular localization in the endometrium were evaluated during the oestrous cycle and early pregnancy of the gilt. In nonpregnant gilts, concentration of nuclear ER in the endometrium increased from Days 0 to 12 followed by a decline on Day 15 of the oestrous cycle. In pregnant gilts, changes in endometrial nuclear ER during Days 10, 12, 15 and 18 were similar to that in cyclic pigs. Analysis of endometrial ER mRNA expression did not detect any difference between cyclic and pregnant pigs between Days 10 and 15 postoestrus. Expression of ER mRNA in endometrium of cyclic and pregnant gilts was greatest on Day 10 followed by a decline on Day 15. Endometrial ER mRNA increased on Day 18 of the oestrous cycle, but remained low during pregnancy. Immunocytochemical localization of ER in the endometria of cyclic and pregnant gilts indicated that there was intense staining for ER in stromal cells and moderate to strong staining in surface and glandular epithelial cells during oestrus (Day 0) and Day 18 of the oestrous cycle. However, stromal ER staining was absent from Days 5 to 15 of the oestrous cycle and continued to be suppressed on Day 18 of pregnancy. Immunocytochemical staining of ER in the surface and glandular epithelium was readily detectable from Days 0 to 12 of the oestrous cycle and during pregnancy. Intensity of staining for ER declined in surface epithelial cells on Day 15 in both cyclic and pregnant pigs whereas positive staining for ER in glandular epithelium was absent. Staining for ER on uterine surface epithelial cells increased during pro-estrus (Day 18) of cyclic gilts but remained similar to Day 15 in pregnant gilts. Changes in endometrial ER protein, mRNA and localization in surface epithelium are consistent with a physiological role for conceptus oestrogen secretion in uterine function and maternal recognition of pregnancy in the pig.
Successful fertility experiments with cryopreserved spermatozoa of barramundi, Lates calcarifer (Bloch), using dimethylsulfoxide and glycerol as cryoprotectants
Authors: Palmer PJ , Blackshaw AW , Garrett RN
Published: October 2005

The fertility of cryopreserved Lates calcarifer sperm was studied to increase the availability of semen for routine fertilization of stripped eggs and to provide a tool for selective breeding. Semen diluted (1:4 v/v) and frozen (-196 degrees C) with 5% dimethylsulfoxide (DMSO) or 10% glycerol (final concentration) as cryoprotectants was used to inseminate freshly stripped ova. Frozen-thawed sperm were motile for about 4 min after being mixed with seawater. In the DMSO medium, post-thaw sperm activation was immediate after dilution with seawater, but in the glycerol medium maximum motility intensity was delayed for up to 1 min. When eggs and sperm were mixed before the addition of seawater, semen frozen with DMSO as cryoprotectant gave a mean hatch rate (84.1%) no different (P > 0.05) from that of unfrozen semen diluted with Ringer's solution (80.7%) or with DMSO (83.7%), but higher (P < 0.05) than that of semen frozen with glycerol (60.9%). Adding sperm to seawater 30 s before mixing with eggs did not improve the fertility of sperm cryopreserved with glycerol. Eggs inseminated with glycerol-cryoprotected sperm showed higher mortality during incubation than those inseminated with DMSO-cryoprotected sperm. Sperm held in liquid nitrogen for 90 days with DMSO as cryoprotectant yielded acceptable fertilization and hatching rates with semen-to-ova ratios of up to 1:100 (v/v) , and produced fish with no apparent abnormalities over a 29-day period after hatch. These results show that cryopreservation of L. calcarifer sperm is feasible and well suited to a variety of hatchery purposes.
Gene expression of potential morphogens during hair follicle and tooth formation: a review
Authors: Panaretto BA
Published: October 2005

Early work on the morphogenesis of hairs and teeth was largely descriptive histology and established the times and order of visible initiation of anlagen and their patterns of development. However, in the last 30 years, many growth factors have been discovered; more recently, their expression during morphogenesis has been determined and immunohistochemistry has enabled the visualization of structural elements of organs. This review is concerned primarily with aspects of these recent phases of research with respect to the formation of hairs and, to a lesser degree, teeth. The expression of several growth factors including bone morphogenetic proteins 2 and 4, the glycoprotein tenascin, the proteoglycan syndecan, and the expression of the mammalian homologue of Notch, cadherins and epimorphin is examined here during the early stages of organogenesis, primarily to review the type of research that should be extended to the organogenesis of wool fibres in Merino sheep. Signal transduction, the third and increasingly complex phase of research that is now rapidly developing, follows the establishment of ligand-receptor complexes during morphogenesis and is included here in a preliminary way.
Some effects of genotype and composition of the culture medium on the development of mouse zygotes in vitro
Authors: Du ZF , Wales RG
Published: October 2005

The effects of EDTA and the presence of glucose and glutamine in CZB medium on the development of mouse zygotes of different genotype were investigated. Although 30-80% of zygotes (depending on the cross) passed the 2-cell stage in EDTA-free medium, the addition of a low concentration of EDTA was necessary in these experiments to obtain blastocysts in culture. In reciprocal crosses between outbred (Qs), inbred (DBA/2) and hybrid (B10D2F1) stock, there was evidence of a strong influence of the maternal genome on zygote development, with those from B10D2F1 females performing best irrespective of sire. A paternal influence on development was also evident but the most successful sire varied with the genotype of female used and reciprocal crosses differed greatly in the ability of the resultant zygote to develop in culture. For zygotes recovered from Qs females, CZB medium containing glucose and glutamine supported development to the blastocyst stage better than did medium devoid of these substrates. Tests with embryos from B10D2F1 females indicated that the presence of glucose for the whole or for part of the incubation period stimulated blastocyst development. However, the addition of glutamine to the medium in these tests had no significant effect on the development of blastocysts.
Embryonic development in culture of the marsupials Antechinus stuartii (Macleay) and Sminthopsis macroura (Spencer) during preimplantation stages
Authors: Yousef A , Selwood L
Published: October 2005

Forty-nine blastocysts from 11 brown antechinus, Antechinus stuartii, and 96 blastocysts from 17 stripe-faced dunnarts, Sminthopsis macroura, were used to develop a culture system for embryos during preimplantation stages. Blastocysts of brown antechinus were collected on Days 6-9 for unilaminar stages, Days 16-21 for bilaminar stages and Days 20 and 21 for trilaminar stages. Blastocysts of stripe-faced dunnarts were collected on Day 6 for unilaminar stages, Days 6-8 for bilaminar stages and Day 8 for trilaminar stages. Culture media were Dulbecco's modified Eagle's medium (DMEM) with 4.5% glucose and Whittingham's T6 medium both of which were supplemented with 5, 10, 12.5 and 20% fetal calf serum (FCS). Antechinus serum (5%) and bovine serum albumin (0.1%, 0.2%) were also added to some media. Human amniotic fluid (HAF) and Monomed media were also tested. Blastocysts were cultured at 35 degrees C in 5% CO2 in air. DMEM + 10% FCS and HAF supported normal development for the longest periods and over the greatest range of stages. Developmental failure of blastocysts in vitro during expansion of the unilaminar blastocyst and formation of the bilaminar blastocyst suggests that these stages may be dependent on uterine signals. When cultured in DMEM + 10% FCS, the rate of development of bilaminar and trilaminar blastocysts into organogenesis was 4 h slower than in vivo in the stripe-faced dunnart and about 6 h slower than in vivo in the brown antechinus. Embryos of stripe-faced dunnarts were cultured to within 18 h of birth.
A model for follicle selection and the determination of ovulation rate in the ewe
Authors: Scaramuzzi RJ , Adams NR , Baird DT , Campbell BK , Downing JA , Findlay JK , Henderson KM , Martin GB , McNatty KP , McNeilly AS , Tsonis CG
Published: October 2005

A model for folliculogenesis is proposed that is based as far as possible on a knowledge of physiological, rather than anatomical, changes taking place during follicle development. The model is therefore functional, rather than descriptive, and consists of five classes of follicles that have been defined by their dependency and sensitivity to gonadotrophins. These classes are: primordial, committed, gonadotrophin-responsive, gonadotrophin-dependent and ovulatory. The model is an attempt to encourage discussion and to promote the integration of morphological models of folliculogenesis with recent advances in the molecular endocrinology of the ovarian follicle. Two hypotheses for the mechanisms that determine ovulation rate are developed in light of the model. In the first, multiple ovulation results when the viability of gonadotropin-dependent follicles is enhanced. In the second, multiple ovulation is caused by increasing the number of gonadotrophin-responsive follicles available for further development; this results from the increasing rate of folliculogenesis and the throughput of follicles. The final section of this paper examines how these two hypothetical mechanisms, which are not mutually exclusive, appear to account for most of the known genetical and environmental effects on ovulation rate of sheep. In particular, the effects of nutrition, genotype, exogenous gonadotrophins, immunity to both oestrogens and androgens, and immunity to inhibin are discussed.
Seasonal reproduction in flying foxes, reviewed in the context of other tropical mammals
Authors: O'Brien GM
Published: October 2005

Megachiroptera inhabit the Old World tropics and most are seasonal breeders having defined times of testis growth, mating and parturition. In Pteropus scapulatus, the little red flying fox, the robust rhythm of testis cycles is resistant to modification by photoperiod. P. poliocephalus, the greyheaded flying fox, can be manipulated by photoperiod but responds slowly and incompletely. Most mammals live in the tropics, many in seasonally harsh climates, and many breed seasonally. However, few long-lived tropical mammals have been investigated for photoperiodic entrainment of annual reproductive cycles, and only animals from the edge of the tropics have responded. Thus, in long-lived tropical mammals, factors that regulate seasonal breeding have not yet been identified. Endogenous oscillators may generate circannual rhythms centrally. Downstream pathways (reproduction, metabolism, antlers, etc.) may derive their rhythm directly from the oscillator or may be modified by environmental cues. Plasticity of the circannual oscillator resolves confusion from previous contrasts between circannual rhythms and environmentally cued patterns. Plasticity may continue throughout life (species responsive to zeitgebers), but the oscillator may be 'set' in utero in some tropical species. Feedback effects from temperature, nutrition, hormones, etc. can be readily tested in this model of an oscillator generating an endogenous circannual rhythm.
Pro-opiomelanocortin (POMC) gene expression, as identified by in situ hybridization, in purified populations of interstitial macrophages and Leydig cells of the adult rat testis
Authors: Li H , Risbridger GP , Clements JA
Published: October 2005

The presence of testicular pro-opiomelanocortin (POMC) mRNA and POMC-derived peptides has recently been demonstrated in purified preparations of interstitial macrophages and in Leydig cells of the adult rat testis by Northern blot analysis and immunocytochemistry. In the present study, in situ hybridization provided further evidence that the POMC gene is expressed by both purified interstitial macrophages and Leydig cells. The cellular localization of the POMC transcripts was similar for both cell types, silver grains being predominantly located in the cytoplasm. The specificity of the labelling was demonstrated by the lack of silver grains in the preparations pretreated with RNAase or hybridized with an insulin cDNA probe, a gene known not to be expressed in these cell types. An additional control was provided by hybridization with a sense POMC RNA probe, which gave a less intense signal when compared with the antisense RNA probe under the same experimental conditions. The results confirm POMC gene expression in both macrophages and Leydig cells in the adult rat testis.
Effect of culture from the zygote stage on the metabolism of glucose and glutamine by 2-cell embryos and blastocysts recovered from outbred or F1 hybrid female mice
Authors: Du ZF , Wales RG
Published: October 2005

The oxidation and incorporation of glucose and glutamine by embryos derived from cultured zygotes was compared with the utilization of these substrates by embryos recovered directly from the reproductive tract of pregnant females. The oxidation of glutamine was greater at the blastocyst stage than at the 2-cell stage. Embryos derived from outbred females (Qs) were less active in the oxidation of glutamine than those from hybrid (B10D2F1) females and development in culture was detrimental to this oxidation, especially in blastocysts from the outbred stock. The oxidation of glutamine was stimulated by the presence of glucose at the 2-cell stage but reduced by its presence at the blastocyst stage. Maternal genotype had no effect on the oxidation of glucose at either the 2-cell or blastocyst stage, and only at the blastocyst stage was there evidence of a detrimental effect of culture. The oxidation of glucose was stimulated by the presence of glutamine at the 2-cell stage but depressed by its addition at the blastocyst stage. Incorporation of glutamine increased with development, but this was reduced at the blastocyst stage by development in culture, especially if the blastocysts were derived from outbred females. Incorporation of glucose also increased with development. At the 2-cell stage, culture reduced incorporation of this substrate, especially into the acid-soluble fraction of embryos from outbred females. In blastocysts, incorporation of glucose into the acid-insoluble fraction was depressed by culture and in embryos from outbred females. In contrast to glucose oxidation, incorporation of glucose into the acid-soluble fraction was reduced by the addition of glutamine at the 2-cell stage but increased by its addition at the blastocyst stage.
Gestation periods in the Pere David's deer (Elaphurus davidianus): evidence for embryonic diapause or delayed development
Authors: Brinklow BR , Loudon AS
Published: October 2005

It has been suggested that the gestation length of the Pere David's deer is around 280 days, which is significantly longer than any other deer species except the roe deer (approximately 300 days) which exhibits embryonic diapause. The present study was designed to determine whether embryonic diapause exists in the Pere David's deer by accurately monitoring gestation length. There was no difference in gestation length (283-284 days) between animals mated early and later in the breeding season. Hence, although Pere David's deer exhibit a longer gestation period than that predicted from maternal body weight, there is no evidence for seasonal control of implantation. Actual birth weight is as predicted from an interspecific comparison of ungulates. The data imply either that there is an obligate period of embryonic diapause, irrespective of season, or that postimplantation fetal growth rate is slow compared with that in other deer species.
Changes in androgen concentrations during puberty and their relation to behaviour in male Saccostomus campestris (Gray 1844), an African rodent
Authors: Westlin LM , Dott HM
Published: October 2005

Sexual development in male Saccostomus campestris, the pouched mouse, was studied in terms of morphological development and changes in concentrations of plasma testosterone and androstenedione. The interaction of adult females and males following the introduction of a male was observed at all stages of the oestrous cycle. The histology of the reproductive organs is similar to that of other rodents. Measurements of the diameter of the seminiferous tubules and the width of the seminiferous epithelium suggest asymptotic growth but, although the diameter had not reached the asymptote at 70 days of age the epithelial width was close to the calculated asymptote at 55 days of age. Intraindividual variation was no greater than variation between individuals of the same age from 55-70 days. Spermatids were not seen in any animals younger than 45 days, but all animals over 55 days of age had spermatozoa in the epididymis. By 70 days of age, fertile matings were observed. At this stage, the seminiferous tubule diameter was still increasing slowly but plasma concentrations of testosterone and androstenedione had reached adult levels; at no time was the concentration of testosterone greater than androstenedione. The males were never aggressive towards females; however, they were severely attacked by females at all stages of the oestrous cycle except pro-oestrus. Only rarely did males show aggression to other males.
Epididymal constituents and related substances in the storage of spermatozoa: a review
Authors: Setchell BP , Sanchez-Partida LG , Chairussyuhur A
Published: October 2005

In vertebrate animals, the duration of storage of viable spermatozoa in the epididymis varies from a few hours in birds to many months in reptiles and bats. The available information on the unusual composition of the epididymal luminal fluid is summarized, and the effect of the various constituents on sperm motility is described. Spermatozoa would probably be best stored in an immotile state and some constituents of epididymal luminal fluid may be able to inhibit the motility of mammalian spermatozoa during storage in vitro. If this effect can then be removed at the time of insemination, by changing the spermatozoa to a different medium, such a procedure may allow storage of spermatozoa at room or even body temperature for extended periods.
Sperm recovery techniques to maximize fertilizing capacity
Authors: Mortimer D
Published: October 2005

Because seminal plasma contains factors that inhibit the fertilizing ability of spermatozoa, it is essential that spermatozoa be separated from it quickly and efficiently. Although the success of a sperm preparation method is often assessed by the yield of motile spermatozoa, the choice of a method also depends on its technical complexity, the materials and apparatus required and time costs. Any exposure of spermatozoa during preparation to factors that may cause iatrogenic sperm dysfunction must obviously be avoided. Consequently, methods involving centrifugal washing prior to the selection of motile spermatozoa should be avoided. Direct swim-up from semen is the simplest way to obtain highly motile sperm populations and can be a very rapid procedure with normal semen samples. Two-layer discontinuous Percoll gradients give excellent yields when the lower layer contains 81% (v/v) Percoll. However, for severely asthenozoospermic cases the results can be disappointing and a Nycodenz gradient may be better, although the 'mini-Percoll' technique might be useful if special care is taken to protect the spermatozoa from damage induced by free radicals. In such cases the migration-sedimentation approach can also be successful. Abnormal samples, especially those with increased viscosity, may benefit from prior dilution with culture medium, or even chymotrypsin-induced liquefaction, before density gradient centrifugation. Finally, pharmacological stimulation of sperm motility may increase yields but, for in vitro fertilization (IVF), such spermatozoa must be used to inseminate oocytes as soon as possible after exposure to the stimulant, although after its removal.
The choice of the most appropriate microfertilization technique for human male factor infertility
Authors: Trounson AO
Published: October 2005

Comparisons were made among techniques used to treat male factor infertility. Patients with semen quality below that recognized by World Health Organization criteria as normal had a better success rate when treated by gamete intrafallopian transfer than by in vitro fertilization (25% v. 7% pregnancy rate per patient). When < 2 x 10(6) motile sperm were recovered, the fertilization rate and embryo cleavage rate were higher for microdrop insemination than for conventional insemination. When 7000-370,000 motile sperm were recovered, microdrop insemination resulted in a higher fertilization rate (46%) and a higher incidence of pregnancies (23% of patients treated) than subzonal sperm microinjection (SUSM). However, for patients with 5000-50,000 motile sperm, the immediate transfer of SUSM oocytes to the Fallopian tube increased pregnancy rates for this technique to 24% of patients treated. Direct microinjection of epididymal sperm from azoospermic men into the cytoplasm of oocytes resulted in pronuclear formation in 27% of oocytes; in comparison, pronuclear formation occurred in 5% of SUSM oocytes. These data led to formulation of a logical treatment programme for male factor infertility.
A modern view of male infertility
Authors: Silber SJ
Published: October 2005

It is archaic to view male factor infertility today separately from in vitro fertilization (IVF) and treatment of the female partner. Oligoasthenozoospermia may be an inherited condition (most likely on the Y chromosome), and is refractory to any treatment of the male including hormones and varicocelectomy. IVF technology is the only justifiable approach for achieving a pregnancy in these couples. The reasons for this view and the suggested modern approach to couples with oligoasthenozoospermia are outlined in this review. However, obstructive azoospermia is different as it can be successfully corrected with microsurgery in over 90% of men. When it cannot be corrected, as in congenital absence of vas, microsurgical sperm retrieval combined with IVF can still be highly effective in producing pregnancy with sperm from the husband. The most important arena for research into male infertility in the next decade will be to map out the deletions on the Y chromosome that might result in defective spermatogenesis, and which probably cause most cases of non-obstructive male factor infertility.
Embryo development capacity of oocytes fertilized by immature sperm and sperm treated with motility stimulants
Authors: Lacham-Kaplan O , Trounson AO
Published: October 2005

The fertilizing ability of mouse spermatozoa develops during maturation and coincides with the acquisition of motility. The lack of progressive motility of spermatozoa from the testis and precaudal segments of the epididymis interferes with their ability to fertilize oocytes after insemination in vitro. The removal of cumulus cells for insemination in vitro and the use of subzonal injection of a single spermatozoon resulted in a higher number of oocytes fertilized by immature caput and corpus spermatozoa. High rates of embryonic arrest and retarded development were observed in oocytes fertilized by caput and corpus spermatozoa when compared with oocytes fertilized by cauda spermatozoa. However, when the oocytes were enclosed in their cumulus cells or microinjected with a single spermatozoon, these effects were reduced. A block in embryonic development was also observed after human and mouse oocytes were exposed to the sperm motility stimulants pentoxifylline (PTF) and 2-deoxyadenosine (DOA). These observations suggest that exposure of oocytes to PTF and DOA should be avoided.
Peripheral and local regulators of folliculogenesis
Authors: Findlay JK
Published: October 2005

The role of the gonadotrophins follicle-stimulating hormone (FSH) and luteinizing hormone and the putative local regulators, activin and follistatin, in the control of folliculogenesis is reviewed. An account of early work on the development and application of assays for FSH and inhibin is given, together with a summary of the data on the ovarian responsiveness to gonadotrophin and follicular atresia. Models for studying local regulation of granulosa cells in vitro are described and the data from these experiments reviewed. It is concluded that activin has a role in the development and maintenance of healthy oestrogenic follicles, preventing premature luteinization, whereas follistatin opposes these effects of activin and promotes luteinization or atresia.