Stages Of Reproductive Cycle Research Articles

Depressed mood through women's reproductive cycle: correlation to mood at menopause

Objectives Depressive symptoms are frequent through the different stages of a woman's reproductive cycle. The aim of this study was to evaluate a possible correlation of depressive mood before menstruation, during pregnancy, after delivery and around the menopause.Methods The sample consisted of 110 women (mean age 52 years, standard deviation 4 years) who rated their mood at present and retrospectively at different stages of the reproductive cycle. Mood was rated using a visual analogue scale.Results A significant statistical association was found between the present mood and mood at the premenstrual period, but not with mood at pregnancy or after delivery. These findings were independent of age, menopausal status or use of hormone replacement therapy.Conclusions The statistical association between depressed mood around menopause and before menstruation supports the assumption that there is a common etiology, which could be attributed to hormonal or psychological factors, or both.

192 AMINO ACID TRANSPORTER EXPRESSION IN BOVINE OVIDUCT EPITHELIAL CELLS

Oviduct fluid provides the environment for the gametes and early embryo but little is known about the mechanisms underlying its formation. Components of oviduct fluid have been shown to be present at concentrations different from that in blood, indicative of selective transport by the epithelial cells lining the lumen. For example, amino acid concentrations in oviduct fluid differ from those in extracellular fluid and have also been shown to be important to preimplantation embryos in vitro, enhancing development, especially when added at physiological concentrations. However, little is known about amino acid transport systems in the oviduct, and the aim of this work was to search for mRNA transcripts for amino acid transporters in bovine oviduct epithelial cells. Contra- and ipsi-lateral oviducts were removed from abattoir-derived reproductive tracts at specific stages of the reproductive cycle. Oviducts were trimmed of surrounding tissue and fat and slit longitudinally to expose the luminal surface. Bovine oviduct epithelial cells (bOEC) were scraped from the surface using a sterile glass coverslip and washed by centrifugation. mRNA was isolated using Trizol-chloroform extraction and lithium chloride precipitation methods. PCR was used to detect cDNA encoding the amino acid transporters CAT-1, CAT-4, and LAT1. A negative control (water) and a positive control (human placental cDNA) were included in each experiment and β-actin expression was used as a positive control for cDNA library generation. Products were separated by agarose gel electrophoresis. PCR for β-actin resulted in the presence of a positive band in all samples, showing successful extraction of mRNA and generation of cDNA libraries. mRNA for CAT-1 and LAT1 was detected in bOEC from contra- and ipsi-lateral oviducts and from each cycle stage tested. There was, however, no detectable mRNA for CAT-4 in any of the samples. To our knowledge, this is the first report of amino acid transporter expression in the mammalian oviduct. CAT-1 is a ubiquitous sodium-independent uniporter of cationic amino acids that has been localized to the basolateral membrane of epithelial cells. The presence of mRNA for this amino acid transporter in all samples tested is therefore to be expected. LAT1 is a obligatory exchanger which exports glutamine and cystine and imports large uncharged branched-chain amino acids. This transporter may be partly responsible for the high concentration of glutamate in the basal compartment of in vitro cell cultures reported in our previous work (Whitear and Leese 2007 Biennial Meet. Joint Fertil. Soc., York, UK). CAT-4 shares only 40% sequence homology with CAT-1 and its function is unknown. Its expression appears to be restricted to brain, testis, and placenta, and the absence of mRNA for the oviduct was, perhaps, not surprising. Further experiments will investigate expression levels of other amino acid transporters in bOEC and transporter localization using immunohistochemistry. This work was funded by the BBSRC and ANGLE Technology Ltd.

Nutrient digestibility of rabbit does in different stages of reproductive cycle under tropical conditions

Effect of stages of reproductive cycle on body weight, feed intake and apparent nutrient digestibility of rabbits was investigated. Pregnant/lactating (PL) does increased their feed intake above pregnant lactating does. Dry matter (DM) digestibility was higher in pregnant does than in lactating, PL or open does. Digestibility of crude fibre, crude protein (CP) and nitrogen-free extractives (NFE) were significantly higher for open and pregnant does than lactating and PL does. Ether extract (EE) digestibility was similar for pregnant, lactating and PL does. Digestible CP requirement of does increased with physiological state from open to PL states. Open and pregnant does were meeting their protein requirement while lactating and PL does were not meeting their requirement. Feed intake was higher for first week pregnant, fourth week pregnant, first week lactating, first week pregnant/fourth week lactating and second week pregnant/fourth week lactating does than open does. DM digestibility was higher for first and fourth week pregnant does than the other physiological stages. EE digestibility was similar for all physiological stages. CP digestibility was higher in fourth week pregnant does than the other physiological stages. Fourth week pregnant does had higher NFE digestibility than first and fourth week lactating and the various stages of concurrent pregnant and lactating does. Open does, first and fourth week pregnant does were meeting their protein requirement while does in the first and fourth week of lactating and stages of concurrent PL were not meeting their requirement.

Effect of temperature changes on the reproductive cycle of roach in Lake Geneva from 1983 to 2001

In Lake Geneva, the surface water temperature has increased by 1° C over 20 years probably as a result of climate change. The effects of changes in temperature on the reproductive cycle of the roach Rutilus rutilus were assessed in a 19 year survey. Over time, spawning tended to begin earlier. The consequences of temperature changes were assessed on two different stages of the female reproductive cycle: the development of the ovaries from the beginning of autumn to ovulation, and the onset of the spawning period. The development of the ovaries was studied for 7 consecutive years from October to June. From 1 October to the onset of spawning, it was possible to assess the gonado‐somatic index (IG) of females in terms of time expressed as a sum of degree‐days. The correlation between IG and the sum of degree‐days was +0·97. The onset of the roach spawning period in Lake Geneva was triggered by a thermal threshold (median and range 190 ± 10 degree‐days for the 15 previous days). From October to April, climate warming accelerated the development of gonads, then in May, a thermal threshold that triggered the onset of roach spawning occurred earlier.

Alterations in enzyme activities in vital organs of triploid female catfish Heteropneustes fossilis (Bloch)

Triploid Heteropneustes fossilis (Bloch) showed sterility and higher growth potential than the normal diploid fish. Activities of some metabolic enzymes such as cytosolic NADP-malate dehydrogenase (NADP-MDH), mitochondrial NAD-malate dehydrogenase (NAD-MDH) and glutamate pyruvate transaminase (GPT) were evaluated in liver, brain and kidney along with glucose-6-phosphate dehydrogenase (G-6-P D) in ovary of female triploid catfish. Activities of these enzymes showed distinct seasonal periodicity, mostly with highest activities in prespawning and spawning periods, in both diploid and triploid catfish but differed in magnitude. In triploid liver, GPT showed higher activity than the diploid counterpart in prespawning and spawning periods. On the contrary, mitochondrial NAD-MDH and cytosolic NADP-MDH in this organ showed a consistent lower activity than the diploid in all stages or in some stages of reproductive cycle respectively. Interestingly, none of the enzymes in brain and kidney of triploid female catfish showed significant changes in comparison to the diploid counterpart. The triploid ovary maintained a significantly lower level of G-6-P D activity throughout the resting, preparatory and pre-spawning periods compared to the diploid ovary. Lower level of malic enzymes (NAD-MDH and NADP-MDH) in liver and G-6-P D in ovary are in close synchrony with lower level of estradiol-17beta in plasma of female triploids as found in earlier study.

Asexual transmission, non-suppressiveness and meiotic extinction of small plasmid-like derivatives of the mitochondrial DNA in Neurospora crassa

For reasons that are not obvious, sets of related plasmid-like elements that consist of short segments of DNA that overlap the 5′ terminal region of the mitochondrial large-subunit rRNA gene sometimes appear spontaneously and become amplified in the mitochondria of some cytochrome-deficient and/or UV-sensitive mutants of Neurospora crassa. These elements are transmitted efficiently through hyphal anastomoses and appear to invade the mitochondria of recipient strains, but they do not cause senescence and at best cause only slight deficiencies in cytochromes a and b even though they are transcribed copiously. Hence, the small elements are not suppressive and, unlike large deletion derivatives of the mitochondrial chromosome, do not displace normal mtDNA molecules in vegetatively propagated mycelia. Unlike the mitochondrial chromosome, large plasmid-like mtDNA derivatives and true mitochondrial plasmids, the small plasmid-like mtDNA derivatives are rarely transmitted sexually even though they persist without selection in very high copy numbers in vegetative cells. The high copy numbers and high stability of these elements in vegetatively propagated cultures suggests that their monomers contain all the features required for their replication and transmission in the hyphae and conidia of Neurospora. However, the mt- rnl-derived molecules appear to lack a sequence or attribute required for the maintenance or transmission of mitochondrial genetic elements at some stage of the sexual reproductive cycle, including ascospore maturation and germination.

Taste responses to dilute sucrose solutions are modulated by stage of the estrous cycle and fenfluramine treatment in female rats

Meal size is decreased during the estrous stage of the rat's ovarian reproductive cycle. This is mediated, in part, by estradiol's ability to increase the strength by which negative-feedback signals function to inhibit meal size. For example, we recently reported that the anorectic effect of fenfluramine, a serotonin agonist, is enhanced during estrus. Here, we investigated whether a decrease in the strength of positive-feedback signals, like those related to the taste of food, contributes to the decrease in meal size observed either in estrous rats or following fenfluramine treatment. Rats were given brief access to six sucrose solutions (0.0, 0.025, 0.05, 0.1, 0.2, and 0.4 M) and the mean number of licks to these solutions was monitored in diestrous and estrous rats treated with 1 mg/kg fenfluramine or saline vehicle. Following saline treatment, estrous rats displayed fewer licks than diestrous rats to the 0.025 M sucrose solution. Following fenfluramine treatment, a decrease in the number of licks to 3 of the 5 sucrose solutions was observed in diestrous rats only. This decrease in sucrose palatability was limited to brief access tests, as overnight preference for the 0.025 M sucrose solution was not decreased by fenfluramine in either diestrous or estrous rats. Our findings suggest that estrous rats experience a decrease in the strength of positive-feedback signals elicited by a dilute sucrose solution and that the anorectic effect of fenfluramine is associated with a decline in positive-feedback signaling in the diestrous rat.

Maturation and reproductive cycle of female armorhead Pseudopentaceros wheeleri from the southern Emperor-northern Hawaiian Ridge Seamounts

The stage of ovarian development and annual reproductive cycle of female armorhead Pseudopentaceros wheeleri collected from seamounts of the southern Emperor—northern Hawaiian Ridge in 1993 and 1995–1996 was investigated through use of the gonadal somatic index (GSI) and ovarian histology. The stages of oocyte development were classified into eight developmental stages (perinucleolus, cortical alveolus, oil droplet, early yolk globule, late yolk globule, migratory nucleolus, prematuration, and maturation) based on histological characteristics. Oocytes of different size and developmental stage were present within ovaries during the spawning season. Oocyte development appears to be asynchronous and armorhead apparently spawn several times during the spawning season. The stage of the most developed oocyte was used to classify the stage of ovarian maturation. The GSI increased gradually with ovarian development. Oocytes in the perinucleolus, cortical alveolus, and oil droplet stages were present in ovaries throughout the year. Early and late yolk globule stages appeared during August–September indicating that yolk formation begins during late summer. The migratory nucleolus through maturation stages were detected during November–January. Post ovulatory follices were present during November–March, and GSI values rapidly decreased in February. Results indicate that spawning occurs during November–February and peaks during December–January.

HoxA10-like proteins in the reproductive tract of the viviparous lizard Eulamprus tympanum and the oviparous lizard Lampropholis guichenoti

The gene HoxA10 and its protein product are essential for the formation of the extensions of the plasma membrane called uterodomes or pinopods in mammalian uterine epithelia. In mice, the presence of the HoxA10 protein and uterodomes is needed for uterine receptivity to blastocyst implantation. The viviparous lizard Eulamprus tympanum displays uterodomes whereas the oviparous lizard Lampropholis guichenoti does not. To explore the theory that HoxA10 is involved in the formation of uterodomes we investigated whether HoxA10 immunoreactive proteins were present in both species during their reproductive cycles. Oviduct proteins from vitellogenic, gravid or non-reproductive L. guichenoti ( n = 19) and E. tympanum ( n = 28) were separated by electrophoresis and analysed by Western blot and specific antibodies to HoxA10. E. tympanum displayed HoxA10 immunoreactive bands at 59 and 63 kDa in 20 out of the 28 samples. All of the L. guichenoti samples displayed HoxA10 immunoreactive bands, 18 had bands at 59 and 64 kDa and 1 animal had a single band at 59 kDa. There were no significant differences in the level of HoxA10 immunoreactivity between the different stages of reproductive cycle in either species. The different molecular mass of the larger band in L. guichenoti (64 kDa) compared to E. tympanum (63 kDa) indicates that the two lizards express different isoforms of the HoxA10-like proteins and it will be interesting in future studies to determine whether there are differences in the biological activity of the proteins that regulate different physiological functions in the uterus of viviparous and oviparous lizards.

The anorectic effect of fenfluramine is influenced by sex and stage of the estrous cycle in rats

The controls of food intake differ in male and female rats. Daily food intake is typically greater in male rats, relative to female rats, and a decrease in food intake, coincident with the estrous stage of the ovarian reproductive cycle, is well documented in female rats. This estrous-related decrease in food intake has been attributed to a transient increase in the female rat's sensitivity to satiety signals generated during feeding bouts. Here, we investigated whether sex or stage of the estrous cycle modulate the satiety signal generated by fenfluramine, a potent serotonin (5-HT) releasing agent. To examine this hypothesis, food intake was monitored in male, diestrous female, and estrous female rats after intraperitoneal injections of 0, 0.25, and 1.0 mg/kg D-fenfluramine. The lower dose of fenfluramine decreased food intake only in diestrous and estrous females, suggesting that the minimally effective anorectic dose of fenfluramine is lower in female rats, relative to male rats. Although the larger dose of fenfluramine decreased food intake in both sexes, the duration of anorexia was greater in diestrous and estrous female rats, relative to male rats. Moreover, the magnitude of the anorectic effect of the larger dose of fenfluramine was greatest in estrous rats, intermediate in diestrous rats, and least in male rats. Thus our findings indicate that the anorectic effect of fenfluramine is modulated by gonadal hormone status.

Size of the donor follicle, but not stage of reproductive cycle or seasonality, influences meiotic competency of selected domestic dog oocytes

Ability of ovarian oocytes from the domestic dog to complete nuclear maturation in vitro (IVM) varies markedly among donors and generally is 20% or less of all oocytes cultured. To identify the cause(s) underlying these significant variations in meiotic maturation (to metaphase II; MII), we retrospectively analyzed data from 1,643 oocytes recovered from 90 bitches for which stage of reproduction and season of year were known. Neither stage of reproduction (proestrus/estrus, diestrus, anestrus, or prepuberty) nor season (P > 0.05) influenced the ability of oocytes to achieve nuclear maturation in vitro. A second study was conducted to examine the impact of follicular size on meiotic maturation. Populations of large oocytes were recovered from four categories of follicles (ranging from <0.5 to > 2 mm in diameter) and cultured in TCM 199 for 48 hr. Follicular size influenced (P < 0.05) meiotic competence. Mean percentages of MII oocytes were 16.9 +/- 9.2, 26.1 +/- 7.6, 38.4 +/- 9.2, and 79.5 +/- 10.9 for oocytes recovered from < 0.5 mm, > or = 0.5-< 1 mm, 1-2 mm, and > 2 mm diameter follicles, respectively. In summary, stage of reproduction and season have no impact on the ability of dog oocytes to achieve nuclear maturation in vitro. However, we demonstrated for the first time that dog oocytes acquire meiotic competency during follicular development. IVM success of selected oocytes from large size follicles (almost 80%) is about 60% higher than measured in most previous studies involving randomly collected oocytes.

269 EFFECTS OF REPRODUCTIVE STATUS AND OOCYTE QUALITY ON THE DEVELOPMENTAL COMPETENCE OF OOCYTES FOLLOWING IN VITRO PRODUCTION IN DOMESTIC CAT

A recent study showed that the developmental competence of cat oocytes after IVM and IVF was affected by the estrous cycle stage of the donor (Freistedt et al. 2001 Biol. Reprod. 65, 9-13). This study was conducted to examine the effect of the cat reproductive cycle stage and the oocyte quality on the developmental competence of the oocyte following IVF production. Cat ovaries were collected at veterinary clinics and stored at 4�C for 24 h. Based on the presence or absence of follicles and corpora lutea, the ovaries were classified into the luteal, follicular, or inactive stage. Cumulus oocyte complexes (COCs) from the different stage ovaries were separated at recovery into three ranks (A, B, and C) according to pigmentation, uniformity and smoothness of ooplasm, and amount of surrounding cumulus cell mass and were cultured separately in 100 �L drops of maturation medium (TCM-199), supplemented with 0.4% bovine serum albumin, 0.1 IU/mL (human menopausal gonadotropin (HMG), 10 IU/mL HCG, 1 �g/mL 17�-estradiol, and 100 �g/mL gentamicin) for 24-h at 38�C, 5% CO2 in air. After 24-h in vitro culture, the oocytes were transferred into 100 �L sperm microdrops of Brackett-Oliphant medium (2 � 106 sperm/mL) for fertilization and were co-incubated for 12 h. Subsequently, presumptive zygotes were transferred into a modified Earle's balanced salt solution (MK-1) supplemented with 4 mg/mL BSA and 50 �g/mL gentamicin. Three days after insemination, all embryos were transferred into culture medium of MK-1 supplemented with 5% (v/v) fetal bovine serum and 50 �g/mL gentamicin. The cleaved embryos were further cultured for 5 days to evaluate their ability to develop to the blastocyst stage. Data were analyzed by ANOVA. The percentages of COCs of A (35.5%, 31.8%, 27.7%), B (41.5%, 39.9%, 42.9%), and C (23.0%, 28.3%, 29.4%) ranks did not show significant differences (P &gt; 0.05) among the reproductive stages of ovaries (luteal, follicular, and inactive, respectively). There were significant differences in the percentages of cleavage (P &lt; 0.05) among the A, B, and C ranks of oocytes from ovaries classified as luteal and follicular stages (50%, 35%, 1.8%; 52%, 35%, 3.9%, respectively, P &lt; 0.05). However, there were no significant differences between the A and B ranks of oocytes obtained from inactive stages of ovaries (47% vs. 44%, respectively; P &gt; 0.05) but there was a significant difference for C rank (1.9%). The percentages of blastocyst formation were significantly different (P &lt; 0.05) among the ranks of oocytes obtained from luteal, follicular, and inactive stages (27%, 14.6%, and 0% for A; 24%, 11.7%, and 0.6% for B; 35%, 21.6%, and 2.9% for C). However, there were no significant differences (P &gt; 0.05) among the reproductive cycle stages of ovaries in the three oocyte ranks with respect to the percentages of cleavage and blastocyst formation.These results indicate that the reproductive stage of donor cat ovaries stored at 4�C for 24 h has no apparent effect on the developmental competence of the oocyte following IVF, but development is affected by oocyte quality.

126 EFFECTS OF THE REPRODUCTIVE STATUS ON DEVELOPMENTAL COMPETENCE OF RECIPIENT OOCYTES AFTER SOMATIC CELL NUCLEAR TRANSFER IN CAT

The reproductive status of donor cat has been suggested to influence developmental competence of the oocytes after IVM/IVF (Karja et al. 2002 Theriogenology 57, 2289–2298). This study was conducted to examine the effect of the reproductive cycle stage of cat ovaries supplying recipient oocytes for nuclear transfer (NT) on the developmental competence of the oocytes after somatic cell nuclear transfer. Cat ovaries were collected at local veterinary clinics and stored at 35°C for a short period (1–6 h). Based on the presence or absence of follicles and corpora lutea, the ovarian pairs collected were classified into the inactive, follicular or luteal stages. Cumulus-oocyte complexes (COCs) were obtained from ovaries at each stage of the reproductive cycle by mincing/dissection and matured in vitro for 24 h, as previously described (Karja et al. 2002 Theriogenology 57, 2289–2298). In vitro matured oocytes from ovaries at the inactive (n = 114), follicular (n = 124), and luteal (n = 126) stages were mechanically enucleated in PBS supplemented with 5 μL mL−1 of cytochalasin B and 3 mg mL−1 BSA, and reconstructed with fibroblast cells derived from uterus tissue. The couplets were fused in Zimmerman medium with a single DC pulse of 1.5 kV cm−1 for 50 μs. The successfully fused couplets were activated by a 5-min exposure to 10 μg mL−1 calcium ionophore A23187 in MK1 medium (Kanda et al. 1998 J. Vet. Med. Sci. 60, 423–431) followed by 5 h of incubation in MK1 medium supplemented with 10 μg mL−1 cycloheximide. The NT embryos were cultured in MK1 medium supplemented with 4 mg mL−1 BSA at 38.0°C in a humidified atmosphere of 5% CO2 in air. At 72 h of culture, all cleaved NT embryos were transferred to fresh MK1 medium supplemented with 5% fetal calf serum for an additional 4 days to evaluate their ability of development to the blastocyst stage. Data were analyzed by ANOVA. There were no significant differences (P &gt; 0.05) among the fused oocytes derived from ovaries at the inactive, follicular, and luteal stages with respect to the percentages of cleavage (64.4%, 69.4%, and 74.5%, respectively) and blastocyst formation (17.4%, 21.0%, and 12.0%, respectively). These results indicate that the reproductive cycle stage of cat ovaries has no apparent effect on the development at competence of recipient oocytes after somatic cell nuclear transfer.

Reproductive biology of Moenkhausia intermedia (Eigenmann) (Pisces, Characiformes) in Itumbiara Reservoir, Goiás, Brazil

To study the reproductive biology of Moenkhausia intermedia (Eigenmann, 1908) in Itumbiara reservoir, Paranaíba river, Goiás, Brazil, a total of 301 specimens (237 females and 64 males) were captured quaterly from January to December 1993. The gonadosomatic index of females and males were related to morphologic variations of the gonads in different reproductive cycle stages (RCS). Analysis of RCS frequency and variations in the gonadosomatic index showed that M. intermedia reproduces during the whole year with fractional spawning. The smallest standard length at advanced maturity stage was estimated as 6.6 cm for females and 6.0 cm for males. The stomach repletion and coelomic fat indexes of both sexes reached peak values in the rest stage, suggesting that this species probably store energy in this phase and consume its fat reserve during reproduction. In the Itumbiara reservoir there was female predominance (4:1). Males were smaller than females, indicating sexual dimorphism in M. intermedia.

The Antiproliferative Agents trans-Bis(resorcylaldoximato) copper(II) and trans-Bis(2,3,4- trihydroxybenzaldoximato)copper(II) and Cytopathic Effects of HIV

trans-Bis(resorcylaldoximato)copper(II) and trans-bis-(2,3,4-trihydroxybenzaldoximato)copper(II) (CuRES2 and CuTRI2, respectively) have been tested for antiviral properties against HIV, using an in vitro assay that measures the ability of the test compounds to prevent the killing of susceptible human cells by HIV. In the case of CuTRI2, T4 lymphocytes (CEM-V and CEM-Z cell lines) were exposed to HIV at a virus to cell ratio approx. 0.05 in microtiter plates. In the case of CuRES2, a human leukemia cell line (MT-2) was used instead. The tetrazolium salt XTT was added to all wells, and the cultures were incubated and analyzed spectrophotometrically to quantitate formazan production and viewed microscopically for detection of viable cells. In spite of their antiproliferative properties, neither agent had any detectable ability to prevent the cytopathic effects of HIV in cultures of the target cells used. Because the test system employed was constructed in such a way as to detect antiviral agents acting at any stage of the virus reproductive cycle, the results obtained strongly suggest that neither studied agent has any value as the direct prevention of the cell destruction caused by HIV is concerned.

Effects of prolactin on the luteinizing hormone response to gonadotropin- releasing hormone in primary pituitary cell cultures during the ovine annual reproductive cycle.

In the sheep pituitary, the localization of prolactin (PRL) receptors in gonadotrophs and the existence of gonadotroph-lactotroph associations have provided morphological evidence for possible direct effects of PRL on gonadotropin secretion. Here, we investigated whether PRL can readily modify the LH response to GnRH throughout the ovine annual reproductive cycle. Cell populations were obtained from sheep pituitaries during the breeding season (BS) and the nonbreeding season (NBS), plated to monolayer cultures for 7 days, and assigned to receive one of the following treatments: 1) nil (control), 2) acute (90- min) bromocriptine (ABr), 3) chronic (7-day) bromocriptine (CBr), 4) ABr and PRL, 5) CBr and PRL, 6) PRL alone, or 7) thyrotropin-releasing hormone. Cells were treated as described above, with the aim of decreasing or increasing the concentrations of PRL in the culture, and simultaneously treated with GnRH for 90 min. The LH concentrations in the medium were then determined by RIA. GnRH stimulated LH in a dose-dependent manner during both stages of the annual reproductive cycle. During the NBS, single treatments did not significantly affect the LH response to GnRH. However, when PRL was combined with bromocriptine, either acutely or chronically, GnRH failed to stimulate LH release at all doses tested (P < 0.01). In contrast, during the BS, the LH response to GnRH was not affected by any of the experimental treatments. These results reveal no apparent effects of PRL alone, but an interaction between PRL and dopamine in the regulation of LH secretion within the pituitary gland, and a seasonal modulation of this mechanism.

Morphometry and morphology of nucleus of the Sertoli and interstitial cells of the tambaqui Colossoma macropomum (Cuvier, 1881) (Pisces: Characidae) during the reproductive cycle.

This study allowed the characterization of the tambaqui Colossoma macropomum testes structural organization, emphasizing Sertoli and interstitial cells and analyzing morphometrically the Sertoli cell nucleus diameter and the interstitial tissue area during the reproductive cycle. Fragments of tambaqui testes were collected in the following reproductive cycle stages: immature, resting, maturation I and II, mature, and regression, and were histologically processed. The Sertoli cells were found at the periphery of the cysts of germinative lineage cells and the nuclei were shown to be smaller as these cells developed. The interstitial cells were better observed between the seminiferous lobules next to vessels in the interstitial tissue of maturing testes.

Purification of two types of gonadotropin receptors from carp ovarian follicles: overlapping recognition by two different ligands

Teleostean gonadotropin receptors were solubilized from the plasma membrane preparation of carp ovarian follicles by lithium diiodosalicylate and Triton X-100. Solubilization resulted fourfold increase in GTH binding activity as compared to the crude plasma membrane preparation. An addition of 25% glycerol and protease inhibitors to the solubilized receptor retained more than 90% original activity at −20 °C for 30 days. Gel filtration through Sephadex G 100 significantly increased the specific binding capacity from 70 fmol/mg protein (soluble receptor) to 250 fmol/mg protein. Peak I of gel filtration showing the receptor activity was further purified by affinity chromatography on purified salmon GTH II — Sepharose with a remarkable increase in specific binding capacity from 250 fmol/mg protein (gel filtration peak) to 2300 pmol/mg protein for salmon GTH I ligand and 2800 pmol/mg protein for GTH II ligand. In SDS–PAGE affinity eluate the active peak showed two distinct bands corresponding to 66 and 62 kDa molecular masses. These two proteins were clearly separated in FPLC Mono S chromatography, 62 kDa as GTHR I and 66 kDa as GTHR II. The former preferably binds to GTH I ligand, while the latter to GTH II, although both demonstrated overlapping recognition to both the ligands. GTH receptor protein I (GTHR I) and II (GTHR II) were purified 42,000- and 54,000-fold, respectively. Competitive binding inhibition studies indicate GTH I and ovine FSH a better ligand for GTHR I, while GTH II and ovine LH were preferable ligands for GTHR II. Biological relevance of these two receptor proteins was ascertained by monitoring the specific binding capacity of GTHR I and II at different stages of the annual reproductive cycle. GTHR I–GTH I was a prevailing complex during preparatory and pre-spawning stages, while GTHR II–GTH II was the dominant one at the maturational and final maturational stages. It may be concluded there are two GTH receptor proteins, each having a preferred ligand. The overlapping ligand-binding activity and profile of each receptor ligand complex suggest their link to seasonal development and maturation of carp ovarian follicle.

Reproductive Signals of Female Lizards: Pattern of Trait Expression and Male Response

AbstractRelative to the volume of studies concerning the function and evolution of male‐biased sexually dimorphic traits, instances of female‐biased sexual dimorphisms remain largely unstudied, especially in species with conventional sex roles. I investigated the signal function of a female‐specific ornamental trait using the striped plateau lizard (Sceloporus virgatus, Phrynosomatidae) as a model system. During the reproductive season, female S. virgatus develop orange color on their throats that is absent in conspecific males. I established the relationship between color expression and female reproductive state, and determined male response to female color. I show that dynamic changes occurring within the color patch can potentially identify each stage of the female reproductive cycle, largely because of a lag in patch growth relative to color intensification. Sexual receptivity is associated with intense patches rapidly growing in size; ovulation occurs near peak color expression; and the unreceptive period is associated with large patches fading in intensity. Because females express orange color during both the receptive and unreceptive periods, the pattern of color expression is consistent with the courtship‐stimulation and courtship‐rejection hypotheses of signal function. Males may preferentially associate with females that have more highly developed color patches during the courtship season, and/or ignore such females when they are unreceptive. An examination of male behavior towards unfamiliar females indicates that female color has a role in courtship stimulation but has little, if any, role in courtship rejection. During the pre‐mating season, males maintained significantly closer affiliation with, and tended to perform more social behavior towards females with more intense color. During the post‐mating season, female color had no apparent effect on male behavior. The evolution and current function of female ornaments may vary among taxonomically‐related species as a result of differences in ecology, social system, and life‐history.

In vitro maturation, fertilization and development of domestic cat oocytes recovered from ovaries collected at three stages of the reproductive cycle

This study was conducted to examine the effect of the donor cat’s reproductive cycle stage on in vitro maturation (IVM), in vitro fertilization (IVF), and in vitro development of oocytes recovered from ovaries that were collected and stored at 35 °C for a short period (1–6 h). Based on the presence or absence of follicles and corpora lutea, the ovarian pairs collected were classified into inactive, follicular, or luteal stages. Nuclear status of 161 cumulus–oocyte complexes (COCs) were examined immediately after recovery; 91.3% of the oocytes were found to be at the immature germinal vesicle (GV) stage, and 3.7% of the oocytes were at metaphase II (MII) stage. The percentage of the oocytes at the GV stage was significantly lower in the follicular stage than in the inactive stage ( P<0.01). Of the oocytes from the follicular stage, 9.1% were at MII stage. After culture for 24 h, however, the proportions of oocytes that reached metaphase I and MII were not different among the reproductive cycle stages of the ovaries collected ( P>0.05). After co-incubation with sperm, 63.1% of oocytes were fertilized, but there were no significant differences among the reproductive cycle stages of the ovaries with respect to the proportions of normal and polyspermic fertilization. However, the number of oocytes reaching cleavage stage and development to the morula and blastocyst stages from follicular stage ovaries were significantly lower ( P<0.05) than those obtained from inactive and luteal stage ovaries. These results indicate that the reproductive cycle stage of donor cat ovaries, stored at 35 °C, has no apparent effects on the frequencies of maturation and fertilization of oocytes, but influences developmental competence of the oocytes following IVM or IVF.