Recent evidence suggests that progesterone is required for ovulation, luteinization, and the maintenance of luteal structure and function in primates. Progesterone action is mediated by intracellular progesterone receptors (PRs), and PRs are detectable by immunocytochemistry in the monkey corpus luteum. However, changes in total luteal PR and PR isoform expression ...

Changes in the autonomic control of the circulation may contribute to the maternal hemodynamic adaptation to early pregnancy. To evaluate this, we studied mean arterial pressure (MAP) and heart rate (HR) in chronically instrumented, conscious rats in early (days 4, 6, 8, and 10) and late (day 18) pregnancy (n ...

Ovarian follicular waves were characterized before and after breeding in 52 lactating beef cows and 16 heifers. Effects of two (2 W) or three (3 W) waves of follicular development and associated patterns of concentrations of steroids in jugular serum on pregnancy rate were examined. Animals were observed for oestrus ...

Significant modifications of the uterine circulation are observed during pregnancy, with uterine circulation accounting for up to 11% of cardiac output at the end of pregnancy. We studied the reactivity of the uterine microcirculation to determine the time course of uterine mechanical and pharmacological alterations during pregnancy and postpartum. Arcuate ...

This study examined changes in ovine endometrial phospholipids and fatty acid concentrations associated with luteolysis and the establishment of pregnancy in the ewe on days 3, 12 and 15, respectively. Results from this study indicate that endometrial lipids increased as the oestrous cycle progressed from days 3 to 12 and ...

Human granulosa cells collected from in vitro fertilization have previously been cultured to provide a system to simulate the granulosa lutein cells of the corpus luteum. In most of these systems, the cultures have been relatively short term, and attempts to simulate the normal pattern of hormone production observed during ...

Pituitary hormones are essential for the maintenance of the corpus luteum in the pregnant mouse during the first half of gestation. Thereafter, hormones from the placenta take over the luteotropic role of the pituitary hormones. Mouse placental lactogen-I (mPL-I) and mPL-II, two PRL-like hormones produced in the placenta, are probably ...

This study aimed to investigate if pregnancy-induced hypoalgesia occurs in the sow, and to examine the role of endogenous opioids which are known to be released in response to nociception. Sixteen Large White x Landrace multiparous sows were tested in straw bedded pens (2.5 x 2.5 m) during weeks 4, ...

It has been suggested that tissue inhibitor of metalloproteinases (TIMP)-1 has a role in reproductive tissues, regulating tissue remodeling or enhancing embryonic development. Oviductal TIMP-1 mRNA levels and protein expression were examined in gilts during the estrous cycle and early pregnancy and in steroid-treated ovariectomized (OVX) gilts by explant culture, ...

In an attempt to sort out the respective contributions of sprouting and intussusceptive microvascular growth (IMG) during chicken chorioallantoic membrane (CAM) development, we analyzed the morphology and the quantitative growth of the capillary bed of the CAM by light microscopy. By perfusing the CAM microvasculature with highly concentrated colloidal gold ...

The effects of norepinephrine (NE) uptake inhibitors on the porcine uterine artery's contractile response to NE and their potential alteration during early pregnancy (Day 13 postcoitus; day of coitus = Day 0) in comparison with the end of the luteal phase (Days 11-14; first day of behavioral estrus = Day ...

To examine the contributions of endogenous inhibin and estradiol to the regulation of FSH and LH secretion in the pregnant rat, some rats were passively immunized against inhibin and/or estradiol, and others were ovariectomized, on Days 5, 10, 15, and 20 of pregnancy. Ovarian and uterine venous blood was collected ...

The altered myometrial contractile activity near term of pregnancy is partly due to changes in the responsiveness to catecholamines. Previous experiments have basically been concerned with uterine adrenoceptor binding characteristics. In the present study we have evaluated total myometrial DNA, beta 2-adrenoceptor mRNA and isoproterenol-induced relaxation of rat isolated uterine ...

Female gray short-tailed opossums (Monodelphis domestica) with known breeding dates were anesthetized with isoflurane for ultrasonographic pregnancy detection. Beginning on gestational day 9, gravid females could be identified using a 9-MHz mechanical sector-scanning transducer equipped with a standoff pad. Fluid-filled vesicles 3 to 4 mm in diameter were seen within ...

Immunohistochemical techniques were used to localize acidic and basic fibroblast growth factor (FGF) polypeptides in porcine uterine and conceptus tissues collected on Days 10 through 14 of gestation, which is the peri-implantation period, and in uterine tissues collected on the same days of the estrous cycle. Our results demonstrate differential ...

This study examines reproductive efficiency in the common marmoset monkey, Callithrix jacchus, using sequential ultrasound examinations to establish ovulation number, implantation rate, and incidence of prenatal loss. Ultrasound was carried out with a 10 or 7.5 mHz probe in nonsedated animals, daily during the late follicular phase, approximately twice a ...

Skewing of the sex ratio at birth occurs in red deer in response to dominance status, with dominant hinds giving birth to a higher proportion of male calves than subordinates. To investigate the physiological basis for this phenomenon, reproductive tracts were collected from red deer during a cull for management ...

It is hypothesized that the two-cell model for estrogen production by the ovarian follicle is preserved in the primate corpus luteum, but there is little direct evidence to support this theory. To determine the sites of androgen and estrogen synthesis within the primate corpus luteum and to ascertain whether changes ...

Secretion of progesterone in vitro by mature day 8 ovine corpora lutea (CL) of the estrous cycle was increased linearly by ovine LH (1, 10 and 100 ng/ml) or prostaglandin E2 (PGE2) 1, 10 and 100 ng/ml) in a dose dependent manner (P < or = 0.05). Progesterone secretion in ...

In this study we investigated the expression of the two cyclooxygenases, cox-1 and -2, in sheep uterine tissues during the estrous cycle and early pregnancy. We identified the cox-2 isoform in the ovine uterus by Western blot and demonstrated that the two cyclooxygenases exhibited different patterns of expression. Cox-1 was ...

The protein hormone relaxin is secreted by the ovaries throughtout the second half of the 23 day pregnancy in the rat. We recently reported that neutralization of endogenous relaxin with monoclonal antibodies for rat relaxin decreases water consumption during the daily light period during the second half of pregnancy in ...

In pregnancy, complex hormonal and hemodynamic changes develop. In this study, we tested the hypothesis that these pregnancy-associated changes are accompanied by an alteration of the compliance of central conduit vessels. To this end, we determined in awake, restrained pregnant rats the distensibility (DC) and compliance (CC) coefficients of the ...

As estrogen and progesterone are proposed regulators of luteal function, this study was undertaken to correlate the presence of receptors for these steroids with luteal function during early pregnancy. Corpora lutea (CL) were obtained from nonpregnant baboons during the midluteal [ML; days 7-8 postovulation (PO)] and late luteal (LL: days ...

Bitches were examined to see whether canine deciduoma could be induced at some reproductive stages with the different conditions of corpora lutea by inserting a silk suture into the uterine lumen. The bitches stimulated in the early and middle stages of diestrus or in unilateral pregnancy corresponding to these diestrous ...

The objective of this study was to characterize the adverse effects of triphenyltin chloride (TPTCl) during early pregnancy. Following successful mating, female rats were given TPTCl by gastric intubation at 3.1, 4.7, or 6.3 mg/kg on days 0 to 3 of pregnancy or at 6.3, 12.5, or 25.0 mg/kg on ...

Leukaemia inhibitory factor (LIF), a pleiotropic cytokine, is essential for blastocyst implantation in mice and maintains the development of ovine embryos in culture. The expression of LIF was examined by northern blot analysis in endometrial tissue from cyclic (days 4-16) and pregnant (days 4-20) ewes, and the corresponding protein was ...

Glycodelin is a glycoprotein named for its unique carbohydrate structure. Glycodelin is produced by the secretory endometrium during the late luteal phase and returns to baseline during menses of the ensuing cycle, whereas in conceptive cycles it rapidly increases. Although progesterone and possibly estradiol are required for glycodelin production, they ...

In an attempt to characterize proteins secreted by the corpus luteum, explant cultures of luteal slices from cows taken on Days 3, 7, 11, 14, 17, and 19 of the estrous cycle, and Days 17, 88, 180, and > 240 of pregnancy were incubated with H-leucine for 24 h. Proteins ...

Recently, it was demonstrated that endogenous relaxin promotes growth of the vagina during the second half of pregnancy in rats and that administration of porcine relaxin promotes growth of the uterus in nonpregnant or early pregnant gilts. This study examined the effects of circulating relaxin on growth of both the ...

Twenty Polish Landrace gilts were grouped immediately after mating as follows: Experiment I-- Group 1 (5 gilts), control animals and Group 2 (5 gilts), injected i.m. with dexamethasone (30 mg/kg) at 12-h intervals from day 13 to day 22 of pregnancy; Experiment II--Group 3 (5 gilts), injected i.m. with corn ...

The objective of the study was to clarify the potency and action of cabergoline, a dopamine agonist, in preventing and terminating pregnancy in rats. Cabergoline administered s.c. to female rats on days 1, 2 and 3 of pregnancy prevented implantation of the fertilized ova and development of the embryos. The ...

To determine the relationship between cellular proliferation and the presence of FGF-1 and FGF-2 in the ovine corpus luteum (CL) during early pregnancy, ewes received an intravenous injection of bromodeoxyuridine (BrdU) 1 h before slaughter (n = 3/day) on day 12 after estrus (nonpregnant) or on days 12, 18, 24 ...

The etiology of inborn hip dysplasia is unknown. In general, a multifactorial genesis is assumed. The influence of hormones on the development of the fetal hip joint and its stability is discussed as well as mechanical influences. This study was carried out with the intention to examine the correlation between ...

Cathepsin L has been proposed to be involved with the endothelial-chorial type of placentation in the cat. Little information concerning the presence and secretion of cathepsin L is available for a species with noninvasive epitheliochorial placentation such as the pig. Cathepsin L activity in uterine flushings and endometrium from gilts ...

PURPOSE: Our aim was to examine the changes in spatiotemporal tenascin (TN) expression in mouse uterus during early pregnancy, when the uterine tissue undergoes a tremendous restructuring. METHODS: Using immunohistochemistry and in situ hybridization, the changes in distribution of TN protein in mouse uterine tissues in pregnancy Day 0 through ...

Although luteinizing hormone (LH) of the anterior pituitary is considered primarily responsible for the initiation of luteinization in most species, the mechanisms governing the subsequent life and death of the corpus luteum vary among species. In women and in nonhuman primate, the corpus luteum derives its support from LH that ...

The propagation of individual action potentials during spontaneous bursts of activity in isolated pregnant rat myometrium in the final stage of pregnancy was analyzed. Simultaneous recordings from 240 extracellular recording sites (inter-electrode distance 1 mm) made it possible to reconstruct, in spatial and temporal details, the conduction of the electrical ...

The blood coagulation status was studied in 31 bitches of different breeds during 33 oestrous cycles and during nine pregnancies. Two other bitches were ovariohysterectomized and received subcutaneous injections of oestradiol benzoate for 7 consecutive days. Blood samples were taken in early and late follicular phases, at ovulation, at day ...

A field investigation was undertaken in mated bitches to assess the efficacy and safety of a low dose of oestradiol benzoate (0.01 mg kg-1), given by subcutaneous or intramuscular injection, on days 3, 5 and sometimes day 7 after mating. Twenty-five veterinary practices in the UK collected data from 358 ...

Dexamethasone was administered orally for 7.5 or 9.5 days to 80 pregnant bitches to terminate unwanted pregnancy at an outpatient clinic. Treatment was initiated at day 30-35 (n = 74) or day 45-50 (n = 6) of confirmed pregnancy using one of two dosages. In 62 bitches, dexamethasone was administered ...

Over a period of approx. 15 months, post-mortem (PM) examinations were made on genital organs (34 gilts and 81 sows) from a sow-pool with reproductive disturbances. Anamnestic data on the animals included information about parity number, date of farrowing, dates of weaning, oestrus and service, and cause of culling. At ...

Mesotocin (MT), the oxytocin-like peptide of the tammar wallaby (Macropus eugenii) is important for delivery of live young. The tammar mesotocin receptor (MTR) was first characterized using the iodinated oxytocin receptor antagonist [125I]d(CH2)5 [Tyr(Me)2, Tyr4, Orn8, Tyr-NH(2)9]-vasotocin. MTR concentrations were then measured in matched samples of gravid and nongravid myometrium ...

The effect of tributyltin chloride (TBTCl) administered during early pregnancy on pregnancy maintenance was evaluated in rats. Inseminated females were orally administered TBTCl at a dose of 0, 8.1, 12.2 or 16.3 mg/kg on day 0 through day 7 of pregnancy. Females were sacrificed on day 20 of pregnancy and ...

Pregnancy-dependent mammary tumors (PDMT) of GR/A mice and transplantable PDMT (TPDMT-4 line) in DDD mice, are exceptionally stable in hormone dependence, continue to grow until parturition and regress soon after delivery. In order to study the regression mechanism of PDMT and TPDMT-4, morphological and biochemical changes were examined in the ...

Myometrial function in pregnancy is regulated by a range of hormonal stimuli, including glucocorticoids, particularly in the period leading up to parturition. Glucocorticoid hormone action is dependent not only on expression of glucocorticoid receptor (GR) within target cells, but also on local expression of the enzyme 11beta-hydroxysteroid dehydrogenase (11betaHSD). Therefore, ...

Pregnancy and parturition are accompanied by unique behavioral changes. Only some of the neural mechanisms behind the dramatic changes in behavior are understood. Estrogen's action within the medial preoptic nucleus (MPN) is necessary for the induction of maternal behavior around the time of parturition, and estrogen acts within the ventromedial ...

Changes and local distribution of oviductal progesterone (P(4)) concentration during the estrous cycle and early pregnancy in cows were investigated. Intact reproductive tracts were collected from 16 Holstein cows at an abattoir. Samples were classified in to 4 stages (follicular, postovulatory, luteal and early pregnant,< 20 d) based on visual ...

OBJECTIVE: Our purpose was to compare the effects of peptidyl and nonpeptidyl oxytocin antagonists on the pregnant rat uterus in relation to the progress of gestation. STUDY DESIGN: Pregnant rats with gestational ages of 17 and 21 days were used. A saturation binding of tritiated oxytocin to myometrial membrane preparation ...

Follicles were monitored daily by ultrasound and blood samples for FSH assay were collected daily from eight heifers from day 90 of pregnancy to the emergence of the first postpartum follicular wave. Follicles > or = 6 mm in diameter emerged in groups or waves in each heifer (P < ...

It has been hypothesized that conceptus estrogens influence endometrial protein secretion during pregnancy in swine. To test this hypothesis, the effect of estrone and estradiol treatment from d 30 to 60 of pregnancy or pseudopregnancy on endometrial protein secretion was investigated. Pregnant (P; n = 16) and pseudopregnant (PP) gilts ...