Can flaxseed, chia or puncture vine affect mare ovarian cell functions and prevent the toxic effect of the environmental contaminant toluene?

The aim of this in vitro study was to examine the potential effect of functional food plant extracts, namely, extracts of flaxseed (Linum usitatissimum L.), chia (Salvia hispanica) and puncture vine (Tribulus terrestris L.), on basic mare ovarian cell functions and their response to the environmental contaminant toluene. Mare granulosa cells were incubated with and without toluene (0, 0.02, 0.2 or 2.0 µg/mL) in the presence or absence of flaxseed, chia and puncture vine extracts (10 µg/mL). Markers of cell proliferation (accumulation of proliferating cell nuclear antigen, PCNA) and apoptosis (accumulation of bax), viability (Trypan blue extrusion) and the release of progesterone (P), oxytocin (OT) and prostaglandin F 2 alpha (PGF) were measured. Toluene reduced all other measured parameters except OT release. All the tested plants were able to reduce cell viability and the release of P and PGF, but they did not influence other indexes. Moreover, flaxseed mitigated toluene action on ovarian cell proliferation, apoptosis, OT and PGF, whilst puncture vine prevented and inverted toluene action on P and PGF ourput. Chia extract did not modify toluene action on any parameter. On the other hand, toluene was able to promote the inhibitory action of flaxseed on cell viability and P release and to prevent the inhibitory action of all the plant extracts on PGF release. The present study (1) is the first demonstration, that flaxseed, chia and puncture vine can directly suppress mare ovarian cell functions, (2) shows that toluene can suppress basic ovarian cell functions and modify the reproductive effect of food plants and (3) demonstrates the ability of flaxseed and puncture vine, but not of chia, to prevent some toxic effect of toluene on mare ovarian cell functions.

Ginkgo, fennel, and flaxseed can affect hormone release by porcine ovarian cells and modulate the effect of toluene.

Experimental studies have documented the toxic effects of toluene on the mammalian female reproductive processes. The aim of this in vitro study was to examine the potential of functional food plant extracts, namely, of ginkgo, fennel, and flaxseed, in modifying the toluene-induced effects on ovarian hormone release. Porcine granulosa cells were incubated with ginkgo, fennel, or flaxseed extracts (0, 1, 10, or 100 µg/mL) and/or toluene (10 µg/mL). Enzyme immunoassays were used in order to measure the release of progesterone (P), oxytocin (OT), and prostaglandin F (PGF) in the culture media. Toluene suppressed the release of P and enhanced the release of OT and PGF. All tested plant extracts reduced P and increased OT release, while the PGF output was found inhibited by ginkgo and stimulated by fennel and flaxseed. When the cells were incubated with toluene and each one of the plant extracts, toluene was able to prevent their action on P release, as well as those of fennel and flaxseed on OT and PGF release. Moreover, ginkgo enhanced but fennel or flaxseed prevented the toluene-induced effects on OT and PGF release. These observations (i) document novel aspects of the toluene-induced toxicity; (ii) demonstrate the direct influence of ginkgo, fennel, and flaxseed extracts on the ovarian secretory activity; (iii) inform our understanding of the interrelationship between toluene and the tested plant extracts with regard to their effects on ovarian hormone release; (iiii) demonstrate the ability of fennel and flaxseed to prevent adverse effect of toluene on ovarian hormones.

Corrigendum to: Direct action of leptin, obestatin and ginkgo on hormone release by luteinised human ovarian granulosa cells.

CONTEXT: The role of metabolic hormones, medicinal plants and their interrelationships in the control of human reproductive processes are poorly understood. AIMS: To examine how leptin, obestatin and ginkgo (Ginkgo biloba L.) affect human ovarian hormone release. METHODS: We analysed the influence of leptin and obestatin alone and in combination with ginkgo extract on cultured human ovarian granulosa cells. The release of progesterone (P), insulin-like growth factor I (IGF-I), oxytocin (OT) and prostaglandin F (PGF) were analysed by enzyme immunoassay and enzyme-linked immunosorbent assay. KEY RESULTS: Leptin addition promoted the release of all the measured hormones. Obestatin stimulated the release of P, IGF-I and OT and inhibited PGF output. Ginkgo suppressed P, IGF-I and OT and promoted PGF release. Furthermore, ginkgo changed the stimulatory action of leptin on PGF to an inhibitory one. CONCLUSIONS: Leptin and obestatin are involved in the control of human ovarian hormone release and ginkgo influences their function. IMPLICATIONS: Leptin and obestatin could be useful as stimulators of human ovarian cell functions. The suppressive influence of ginkgo on ovarian function should lead to the development of ginkgo-containing drugs.

Direct action of leptin, obestatin and ginkgo on hormone release by luteinised human ovarian granulosa cells.

CONTEXT: The role of metabolic hormones, medicinal plants and their interrelationships in the control of human reproductive processes are poorly understood. AIMS: To examine how leptin, obestatin and ginkgo (Ginkgo biloba L.) affect human ovarian hormone release. METHODS: We analysed the influence of leptin and obestatin alone and in combination with ginkgo extract on cultured human ovarian granulosa cells. The release of progesterone (P), insulin-like growth factor I (IGF-I), oxytocin (OT) and prostaglandin F (PGF) were analysed by enzyme immunoassay and enzyme-linked immunosorbent assay. KEY RESULTS: Leptin addition promoted the release of all the measured hormones. Obestatin stimulated the release of P, IGF-I and OT and inhibited PGF output. Ginkgo suppressed P, IGF-I and OT and promoted PGF release. Furthermore, ginkgo changed the stimulatory action of leptin on PGF to an inhibitory one. CONCLUSIONS: Leptin and obestatin are involved in the control of human ovarian hormone release and ginkgo influences their function. IMPLICATIONS: Leptin and obestatin could be useful as stimulators of human ovarian cell functions. The suppressive influence of ginkgo on ovarian function should lead to the development of ginkgo-containing drugs.

Tribulus terrestris can suppress the adverse effect of toluene on bovine and equine ovarian granulosa cells.

Influence of oil-related product toluene and herbal remedy puncturevine Tribulus terrestris L. (TT) on female reproduction is known. Yet, mechanisms of their action on ovaries in different species and potential protective effect of TT against adverse toluene action remain to be established. We studied the effect of toluene, TT, and their combination on ovarian granulosa cells from two mammalian species (cows and horses). Viability, markers of proliferation (PCNA) and apoptosis (bax), steroid hormones, IGF-I, oxytocin, and prostaglandin F (PGF) release were analyzed by trypan blue exclusion test, quantitative immunocytochemistry, and EIA/ELISA. Toluene suppressed all analyzed parameters. In both species, TT stimulated proliferation and reduced progesterone, oxytocin, and PGF. In horses, TT inhibited testosterone and IGF-I. In both species, TT supported toluene effect on viability, steroids, IGF-I, and PGF, and inverted its action on apoptosis. In cows, TT promoted toluene effect on proliferation. In horses, TT supported toluene effect on oxytocin but suppressed its influence on proliferation. In both species, toluene induced inhibitory action of TT on viability, steroids, IGF-I, and PGF, and prevented its stimulatory action on proliferation. In cows, toluene supported inhibitory action of TT on oxytocin and prevented its stimulatory action on apoptosis. In horses, toluene induced stimulatory effect of TT on apoptosis. Our results indicate potential toxic toluene effect on farm animal ovaries, applicability of TT as a biostimulator of farm animal reproduction and as a protector against the adverse influence of toluene on female reproduction.

Progesterone Receptor Coregulators as Factors Supporting the Function of the Corpus Luteum in Cows.

Progesterone receptor (PGR) for its action required connection of the coregulatory proteins, including coactivators and corepressors. The former group exhibits a histone acetyltransferase (HAT) activity, while the latter cooperates with histone deacetylase (HDAC). Regulations of the coregulators mRNA and protein and HAT and HDAC activity can have an indirect effect on the PGR function and thus progesterone (P4) action on target cells. The highest mRNA expression levels for the coactivators-histone acetyltransferase p300 (P300), cAMP response element-binding protein (CREB), and steroid receptor coactivator-1 (SRC-1)-and nuclear receptor corepressor-2 (NCOR-2) were found in the corpus luteum (CL) on days 6 to 16 of the estrous cycle. The CREB protein level was higher on days 2-10, whereas SRC-1 and NCOR-2 were higher on days 2-5. The activity of HAT and HDAC was higher on days 6-10 of the estrous cycle. All of the coregulators were localized in the nuclei of small and large luteal cells. The mRNA and protein expression levels of the examined coactivators and corepressor changed with the P4 level. Thus, P4 may regulate CL function via the expression of coregulators, which probably affects the activity of the PGR.

Interrelationships between metabolic hormones, leptin and ghrelin, and oil-related contaminants in control of oxytocin and prostaglandin F release by feline ovaries.

We examined the effects of metabolic hormones leptin and ghrelin, and the oil-related environmental contaminants toluene and xylene on the release of ovarian hormones by gravid and non-gravid cats, as well as the functional interrelationships between metabolic hormones and contaminants. Ovarian fragments of non-gravid cats were cultured with and without leptin and toluene. Next, ovarian fragments of either non-gravid or gravid animals were cultured with and without ghrelin and xylene. Oxytocin (OT) and prostaglandin F (PGF) release was measured using ELISA. We confirm ovarian OT and PGF production by feline ovary, demonstrate the involvement of leptin and ghrelin in controlling OT and PGF release, show the direct influence of toluene and xylene on feline ovarian secretory activity, indicate the ability of leptin and ghrelin to mimic and promote the main contaminant effects, demonstrate that oil-related contaminants can prevent and even invert the effects of leptin and ghrelin on the ovary, and suggest the gravidity-associated changes in ability of ghrelin to promote xylene action on PGF (but not to OT), but not in basic ovarian OT and PGF release and their response to ghrelin or xylene.

Mechanisms of the direct effects of oil-related contaminants on ovarian cells.

We studied the influence of oil-related environmental contaminants (OREC) on the viability, hormone secretion, and protein expression using cultured porcine ovarian granulosa cells. Addition of benzene and xylene promoted proliferation and apoptosis and reduced ovarian cell viability whereas toluene induced apoptosis only. The release of progesterone (P4) and oxytocin (OT) was promoted by benzene and xylene, and suppressed by toluene while prostaglandin F (PGF) output was stimulated by benzene and toluene, but not xylene. The addition of FSH to the culture medium increased ovarian cell proliferation and hormone release, but did not affect apoptosis. However, this FSH's proliferative effect has been prevented in presence of benzene. On the other hand and in the presence of FSH, toluene prevented P4 release and decreased PGF release, while xylene prevented PGF release. We concluded that OREC can affect reproductive processes by directly influencing ovarian cell proliferation, apoptosis, viability, hormone release, and response to gonadotropins.

Effects of benzene, quercetin, and their combination on porcine ovarian cell proliferation, apoptosis, and hormone release.

We hypothesized that the environmental contaminant benzene and the plant antioxidant quercetin may affect ovarian cell functions and that quercetin could offer protection against the adverse effects of benzene. This study aimed to examine the action of benzene, quercetin, and their combination on porcine ovarian granulosa cell functions. We elucidated the effects of benzene (20  µ g mL - 1 ), quercetin (at the doses 0, 1, 10, 100  µ g mL - 1 ), and their combination on ovarian granulosa cell functions (proliferation, apoptosis, and hormone release) in vitro using immunocytochemistry and enzyme immunoassay respectively. Benzene alone stimulated proliferation, apoptosis, and oxytocin release and inhibited progesterone and prostaglandin F release. Quercetin alone inhibited proliferation, apoptosis, and stimulated oxytocin release but did not affect progesterone and prostaglandin F release. When used in combination with benzene, quercetin promoted the inhibitory effect of benzene on progesterone release. Overall, these data suggest that benzene and quercetin have direct stimulatory and inhibitory effects, respectively, on basic ovarian functions. Moreover, no protective action of quercetin against the effects of benzene was found. Rather, it was found to enhance the effect of benzene on progesterone release. Therefore, quercetin cannot be considered for preventing or mitigating the effects of benzene on reproductive processes.

Transcription factor p53 regulates healthy human ovarian cells function.

The aim of our study was to understand the role of transcription factor p53 in the control of healthy human ovarian cell functions. Ovarian granulosa cells were transfected with a cDNA construct encoding p53. The intracellular accumulation of p53, of the apoptosis marker bax, and of the proliferation marker PCNA, as well as the release of progesterone (P4), insulin-like growth factor I (IGF-I), oxytocin (OT), and prostaglandin F (PGF) and E2 (PGE) were evaluated by quantitative immunocytochemistry and RIA/IRMA. Transfection with the p53 cDNA construct resulted in the accumulation of p53 and bax, in a reduced level of released PCNA and PGF, and in an increased PGE output. No changes in P4, IGF-I, and OT secretion were found. These observations are the first demonstration of the involvement of p53 in the control of healthy human ovarian cell functions, namely, in the downregulation of proliferation, in the upregulation of apoptosis, and in the alteration of PGF and PGE release, but not of P4, IGF-I, or OT.

Expression of membrane progestin receptors (mPRs) α, ß and γ in the bovine uterus during the oestrous cycle and pregnancy.

Progesterone (P4) affects cell function through the nuclear progesterone receptor and membrane-bound progesterone binding proteins, including the membrane progestin receptors (mPRs) alpha (mPRα), beta (mPRß) and gamma (mPRγ), which belong to the progestin and adipoQ receptor family (PAQR7, 8 and 5, respectively). The aim of this study was to determine the mRNA and protein expression levels of mPRα, mPRß and mPRγ through real-time PCR and Western blot analyses, respectively, and to determine the cellular localization of these proteins in the bovine endometrium and myometrium on days 2-5, 6-10, 11-16 and 17-20 of the oestrous cycle and weeks 3-5, 6-8 and 9-12 of pregnancy (n = 5/each time period). The resulting data showed the highest (P < 0.05) mPRα and mPRß mRNA expression in the endometrium on days 11-16 of the oestrous cycle compared to the other stages. In the myometrium, the level of mPRα mRNA was the lowest (P < 0.05) on days 6-16 of the oestrous cycle, while mPRß was the lowest on days 11-16. There were no changes (P > 0.05) in mPRγ mRNA expression in the endometrium and myometrium during the oestrous cycle. During pregnancy, in the endometrium and myometrium, the levels of mPRα and mPRß mRNA were comparable with those observed during the oestrous cycle. However, mPRγ mRNA expression was the highest (P < 0.001) during all stages of pregnancy compared with that observed during the oestrous cycle in both uterine tissues. The mPRα protein level only changed in the myometrium and was the highest (P < 0.05) during weeks 9-12 of pregnancy. However, in the endometrium, the expression of mPRß protein was higher (P < 0.05) on days 6-10 of the oestrous cycle than during weeks 6-8 of pregnancy. Strong positive immunoreactions for all mPR proteins were observed in the luminal and glandular epithelium but were less evident in the stromal cells and myocytes. In addition, all proteins were also localized in the endothelial cells of blood vessels in the uterus, suggesting that P4 may affect blood flow in this organ through mPRs. The presence of mPR receptors in the uterus indicates their participation in the regulation of uterine functions.

Apoptosis signal-regulating kinase (ASK-1) controls ovarian cell functions.

The involvement of the apoptosis signal-regulating kinase 1 (ASK1)-related signalling pathway in the control of reproduction is unknown. This study aimed to investigate the role of ASK-1 in the control of basic ovarian functions (proliferation, apoptosis and hormone release) and its response to ovarian hormonal regulators (leptin and FSH). We compared the accumulation of ASK-1, proliferation marker proliferating cell nuclear antigen (PCNA), apoptosis marker Bax and apoptosis and proliferation regulating transcription factor p53 and the release of progesterone (P4), oxytocin (OT), insulin-like growth factor I (IGF-I) and prostaglandins F (PGF) and E (PGE) using cultured porcine ovarian granulosa cells transfected with ASK-1 cDNA and cultured with leptin or FSH. This study is the first to demonstrate that ASK-1 does not affect cell apoptosis and viability in ovarian cells, but promotes cell proliferation, suppresses p53, alters the release of ovarian hormones (P4, OT, IGF-I, PGF and PGE) and defines their response to the upstream hormonal regulators leptin and FSH. Therefore, ASK-1 can be considered a new and important regulator of multiple ovarian functions.

The involvement of the phosphorylatable and nonphosphorylatable transcription factor CREB-1 in the control of human ovarian cell functions.

The objective of our study was to elucidate the role of the transcription factor CREB-1 in controlling ovarian cell proliferation, apoptosis, and hormone release and the significance of CREB-1 phosphorylation in these processes. Human ovarian granulosa cells were transfected with a gene construct encoding wild-type CREB-1 (CREB-1 WT) or CREB-1 nonphosphorylatable mutant (CREB-1 M1). The expression of total and phosphorylated CREB-1, markers of proliferation (PCNA) and apoptosis (bax), as well as the release of progesterone, oxytocin, prostaglandin F2 alpha (PGF2), prostaglandin E2 (PGE2), and insulin-like growth factor I (IGF-I) were compared by immunocytochemistry, enzyme immunoassay (EIA), and immunoradiometric assay (IRMA). Transfection with CREB-1 WT or CREB-1 M1 increased total CREB-1 expression and proliferation and decreased the release of oxytocin, PGE2, and IGF-I by ovarian cells. CREB-1 M1, not CREB-1 WT, promoted apoptosis and inhibited progesterone output. PGF2 release was inhibited by CREB-1 WT but stimulated by CREB-1 M1 construct. Phosphorylated CREB-1 was undetected in any cell group. These observations confirm the involvement of CREB-1 in the control of ovarian cell proliferation, apoptosis, and steroid hormone release. This is the first demonstration of the involvement of CREB-1 in the regulation of the ovarian non-steroidal hormones such as oxytocin, PGF2, PGE2, and IGF-I. The absence of CREB-1 phosphorylation, similar effects exerted by CREB-1 WT and CREB-1 M1 on cell proliferation and release of oxytocin, PGE2, and IGF-I, and the influence of CREB-1 M1 on apoptosis and progesterone suggest that phosphorylation plays no role in the action of CREB-1 on the majority of analyzed functions of human ovarian cells.

Methylation of progesterone receptor isoform A and B promoters in the reproductive system of cows.

The aim of this study was to investigate whether the promoters of progesterone receptor isoform A (PGRA) and B (PGRB) are methylated and to determine the percentage of methylation occurring for each isoform. Genomic DNA was isolated from the corpora lutea (CL) and endometrial slices from cows on Days 2-5, 6-10, 11-16 and 17-20 of the oestrous cycle. DNA was bisulphite-converted and amplified using methyl-specific polymerase chain reaction (PCR) with primers that detect both methylated and unmethylated sequences. The determination of the percentage of the methylation was performed using HpaII and MspI restriction enzymes. Methyl-specific PCR showed partial methylation of PGRA and PGRB promoters in the CL and endometrium during the oestrous cycle. Methylation for PGRA was between 15 and 17% and for PGRB was in the range of 6 to 7.7% during the oestrous cycle in the CL. In the endometrium, the methylation for PGRA was between 6 and 7.3% and for PGRB was between 3 and 4.8% during the oestrous cycle. The data obtained indicate that the higher promoter methylation of the PGRA isoform could be a mechanism for regulation of PGRA inhibitory activity against PGRB and, in this way, methylation may influence the regulation of progesterone action in the CL and endometrium.

Yucca schidigera can promote rabbit growth, fecundity, affect the release of hormones in vivo and in vitro, induce pathological changes in liver, and reduce ovarian resistance to benzene.

This study evaluated the effect of Yucca schidigera (YS) extract on the physiological, reproductive, and endocrine indexes of New Zealand White rabbit does. Six-week-old rabbit does were fed a standard diet (control group) or a diet enriched with 5 or 20g of Y powder extract per 100-kg feed mixture for 350days. The does were artificially inseminated after induction of superovulation. Weight gain; conception and kindling rate; viability of pups and mothers; histopathological state of liver and muscle; plasma levels of progesterone (P4), oxytocin (OT), and prostaglandin F (PGF); and the release of P4, insulin-like growth factor I (IGF-I), OT, and PGF by isolated ovarian fragments and their response to the addition of benzene were analyzed. YS extract supplementation promoted weight gain and induced histopathological changes in the liver (creased vacuolization and occurrence of fuchsinophile inclusions in hepatocytes, liver fibrosis, hyperemia, occurrence of Kupffer cells, signs of necrosis and inflammation). YS consumption was not associated with changes in muscle (occurrence of fuchsinophile inclusions and signs of atrophy, interstitial edema, and inflammation), although Y2 increased muscle vascularization. YS supplementation increased conception and kindling rates but did not affect viability of pups or adult animals. Moreover, it enhanced plasma OT and PGF levels; plasma P4 concentration was increased by low-dose YS, but decreased by high-dose YS. Cultured ovarian fragments isolated from YS-fed does released more P4 and PGF and less IGF-I than ovarian fragments of control animals. However, YS supplementation did not affect ovarian OT release. Benzene alone did not influence the release of hormones by ovaries of control does. YS supplementation induced the inhibitory effect of benzene on the release of PGF, but not on other ovarian hormones. Collectively, these results suggest that dietary supplementation of YS extract can stimulate rabbit performance (growth and fecundity), which may be due to the promotion of P4, OT, and PGF release. It could, however, induce some pathological changes in the liver and reduce resistance of ovaries to the environmental contaminant benzene.

Mink aging is associated with a reduction in ovarian hormone release and the response to FSH and ghrelin.

The endocrine mechanisms of mink ovarian hormones release and reproductive aging are poorly investigated. The aims of our study were to: (1) identify hormones produced by mink ovaries (the steroids progesterone [P] and estradiol [E], the peptide hormone oxytocin [OT], and the prostaglandin F [PGF] and prostaglandin E [PGE]); (2) examine the effect of FSH and ghrelin on the release of the hormones listed previously; and (3) understand whether these hormones can be involved in the control of mink reproductive aging, i.e., whether aging can be associated with changes (a) in the basal release of P, E, OT, PGF, or PGE and (b) their response to FSH and ghrelin. Fragments of ovaries of young (yearlings) and old (3-5 years of age) minks were cultured with and without FSH and ghrelin (0, 1, 10, or 100 ng/mL), and the release of hormones was analyzed by EIA/RIA. We found that isolated ovaries were able to release P, E, OT, PGF, and PGE, and the levels of P produced in the ovaries of old animals were lower than those produced in the ovaries of young animals, whereas the levels of other hormones did not differ. FSH was able to stimulate P and E and suppress OT and PGF and did not affect PGE release. Aging was associated with the inhibition of the effect of FSH on ovarian P and E, the appearance of the inhibitory action of FSH on OT, and the disappearance of this action on ovarian PGF. PGE was not affected by FSH, irrespective of animal age. Ghrelin was able to promote E (but not P) and suppress OT, PGF, and PGE output. Aging was associated with the appearance of an inhibitory influence of ghrelin on ovarian OT and PGE and with the disappearance of this influence on PGF output. Aging did not affect the action of ghrelin on ovarian P and E. Our observations (1) confirm the production of P and E and show that OT, PGF, and PGE are released from mink ovaries, (2) confirm the involvement of FSH and demonstrate the involvement of ghrelin in the control of mink ovarian hormone release, and (3) suggest that reproductive aging in minks is due to a reduction in basal P release and alterations in the response of E, OT, PGF (but not of PGE) to FSH and ghrelin.

Aging influences steroid hormone release by mink ovaries and their response to leptin and IGF-I.

The aim of our study was to understand whether ovarian steroid hormones, and their response to the metabolic hormones leptin and IGF-I leptin, could be involved in the control of mink reproductive aging via changes in basal release of ovarian progesterone and estradiol. For this purpose, we compared the release of progesterone and estradiol by ovarian fragments isolated from young (yearlings) and old (3-5 years of age) minks cultured with and without leptin and IGF-I (0, 1, 10 or 100 ng/ml). We observed that isolated ovaries of older animals produced less progesterone but not less estradiol than the ovaries of young animals. Leptin addition stimulated estradiol release by the ovarian tissue of young animals but inhibited it in older females. Leptin did not influence progesterone output by the ovaries of either young or older animals. IGF-I inhibited estradiol output in young but not old animals, whereas progesterone release was inhibited by IGF-I irrespective of the animal age. Our observations demonstrate the involvement of both leptin and IGF-I in the control of mink ovarian steroid hormones release. Furthermore, our findings suggest that reproductive aging in minks can be due to (a) reduction in basal progesterone release and (b) alterations in the response of estradiol but not of progesterone to leptin and IGF-I.

Luteotropic and luteolytic factors regulate mRNA and protein expression of progesterone receptor isoforms A and B in the bovine endometrium.

The aim of the present study was to examine the effects of luteotropic and luteolytic factors on the mRNA and protein levels of progesterone receptor isoforms A (PGRA) and B (PGRB) in the bovine endometrium. Endometrial slices from Days 6-10 and 17-20 of the oestrous cycle were treated with LH (100ngmL-1), oestradiol (E2; 1×10-8M), prostaglandin (PG) E2 (1×10-6M) and PGF2α (1×10-6M) and the nitric oxide donor NONOate (1×10-4M); these treatments lasted for 6h for mRNA expression analysis and 24h for protein expression analysis. On Days 6-10 of the oestrous cycle PGRAB (PGRAB; the entire PGRA mRNA sequence is common to the PGRB mRNA sequence) mRNA expression in endometrial slices was enhanced by E2 treatment (P<0.001), whereas PGRB mRNA expression was increased by LH (P<0.001), E2 (P<0.05) and NONOate (P<0.05) treatment. On Days 17-20, PGRAB mRNA expression increased after E2 (P<0.001) and PGE2 (P<0.05) treatment; PGRB mRNA expression was increased by PGE2 (P<0.05) and PGF2α (P<0.01) treatment, but decreased by LH (P<0.05). On Days 6-10 protein levels of PGRA were stimulated by E2 (P<0.01), whereas PGRB protein levels were increased by LH (P<0.05) and E2 (P<0.05). On Days 17-20 of the oestrous cycle, PGRA protein levels were enhanced by E2 (P<0.05) and PGF2α (P<0.05), whereas PGRB protein levels were stimulated by PGE2 (P<0.05) and PGF2α (P<0.001). These data suggest that luteotropic and luteolytic factors affect PGRA and PGRB mRNA and protein levels, and this may regulate the effects of progesterone on endometrial cells.

Short-term incubation of bovine placentome sections as a tool to study xenobiotic mechanism of action.

Studies on the effects of various factors, including xenobiotics, on the maternal-fetal connections in the placenta are restricted by the lack of a simple and inexpensive research model. We used placentomes collected at a slaughterhouse to in vitro study the bovine sections contained integral maternal-fetal connections. The placentomes from cows (n=4/experiment, 120-150 days post coitum) were cut using a razor blade into 60-80 mg sections and incubated in either DMEM/Ham's F-12 or M-199 supplemented with FCS (2%, 5% or 10%), amniotic fluid (AF or inactive AF, 10% or 20%) or both. The sections (n=4/supplement) were incubated for 24 or 48 h in a water bath at 37.5°C in an atmosphere of 5% CO2 and 95% O2. The structure and secretory activity of placentome sections were maintained when incubated in DMEM/Ham's F-12 with 2% FCS and 10% AF. M-199 was less acidified than DMEM/Ham's F-12 during incubation, and thus, this medium was better able to maintain the integrity of the placenta and the secretion of estradiol, progesterone and oxytocin for 48 h. Moreover, we detected a decrease in the expression of placenta-specific 1 (PLAC1) mRNA (an indicator of trophoblast proliferation) and an increase in the levels of keratin 8 (KRT8; a marker of normal placental barrier function) and hypoxia induced factor 1α (HIF1α; a marker of hypoxia) mRNA. These results indicate the presence of adaptation and repair mechanisms and confirm the biological activity of the placentome sections. We propose the use of placentome sections as an in vitro model to study maternal-fetal connections in cows.

Onapristone (ZK299) and mifepristone (RU486) regulate the messenger RNA and protein expression levels of the progesterone receptor isoforms A and B in the bovine endometrium.

The aim of this study was to examine whether progesterone (P(4)) and its antagonists, onapristone (ZK299) and mifepristone (RU486), affect the levels of PGRA and PGRB messenger RNA (mRNA) and protein in the cow uterus which may be important in understanding whether the final physiological effect evoked by an antagonist depends on PGR isoform bound to the antagonist. Endometrial slices on Days 6 to 10 and 17 to 20 of the estrous cycle were treated for 6 or 24 hours for mRNA and protein expression analysis, respectively, with P4, ZK299, or RU486 at a dose of 10(-4), 10(-5), or 10(-6) M. In the samples on Days 6 to 10 of the estrous cycle, PGRAB mRNA was stimulated by P(4) (10(-4) M; P < 0.01) and RU486 (10(-6); P < 0.001) and was decreased by ZK299 (10(-5); P < 0.05). In contrast, PGRB mRNA was decreased by the all P(4) (P < 0.01) and ZK299 (P < 0.001) doses and by two of the RU486 doses (10(-4) M; P < 0.01 and 10(-5) M; P < 0.01). In samples on Days 17 to 20 of the estrous cycle, PGRAB mRNA was stimulated by RU486 (10(-5) M; P < 0.001). PGRB mRNA was decreased by P(4) (10(-4) and 10(-5) M; P < 0.001), ZK299 (10(-4) and 10(-5) M; P < 0.001), and RU486 (10(-4) M; P < 0.01 and 10(-6) M; P < 0.001) and was increased by ZK299 (10(-6) M; P < 0.001) and RU486 (10(-5) M; P < 0.001). In samples on Days 6 to 10 of the estrous cycle, PGRB protein levels were decreased (P < 0.05) by all three ZK299 doses and by two of the RU486 doses (10(-4) M; P < 0.05 and 10(-5) M; P < 0.01). In contrast, in samples on Days 17 to 20, both PGRA and PGRB protein levels were decreased by ZK299 stimulation (10(-5) M; P < 0.05 and 10(-5) M; P < 0.01, respectively), whereas only PGRA protein levels were increased by RU486 (10(-5) M; P < 0.01). Both ZK299 and RU486 may exhibit both agonist and antagonist properties depending on which receptor isoform they affect. As a result, an increase or decrease in the expression of a particular PGR isoform will be observed.