Ovarian inflammation mediated by Toll-like receptor 4 increased transcripts of maternal effect genes and decreased embryo development†

Obese women are subfertile and have reduced assisted reproduction success, which may be due to reduced oocyte competence. We hypothesize that consumption of a high-fat/high-sugar diet induces ovarian inflammation, which is a primary contributor to decreased oocyte quality and pre-implantation embryo development. To test this hypothesis, C57BL/6 (B6) mice with a normal inflammatory response and C3H/HeJ (C3H) mice with a dampened inflammatory response due to dysfunctional Toll-like receptor 4 were fed either normal chow or high-fat/high-sugar diet. In both B6 and C3H females, high-fat/high-sugar diet induced excessive adiposity and hyperglycemia compared to normal chow-fed counterparts. Conversely, ovarian CD68 levels and oocyte expression of oxidative stress markers were increased when collected from B6 high-fat/high-sugar but not C3H high-fat/high-sugar mice. Following in vitro fertilization of in vivo matured oocytes, blastocyst development was decreased in B6-high-fat/high-sugar but not C3H high-fat/high-sugar mice. Expression of cumulus cell markers of oocyte quality were altered in both B6 high-fat/high-sugar and C3H high-fat/high-sugar. However, there were no diet-dependent differences in spindle abnormalities in either B6 or C3H mice, suggesting potential defects in cytoplasmic maturation. Indeed, there were significant increases in the abundance of maternal effect gene mRNAs in oocytes from only B6 high-fat/high-sugar mice. These differentially expressed genes encode proteins of the subcortical maternal complex and associated with mRNA metabolism and epigenetic modifications. These genes regulate maternal mRNA degradation at oocyte maturation, mRNA clearance at the zygotic genome activation, and methylation of imprinted genes suggesting a mechanism by which inflammation induced oxidative stress impairs embryo development.

Naturally occurring androgen excess cows are present in dairy and beef herds and have similar characteristics to women with PCOS

Beef cows with excess androstenedione (A4; High A4) in follicular fluid (FF) and secreted by the ovarian cortex have been reported from the University of Nebraska-Lincoln physiology herd displaying characteristics reminiscent of polycystic ovary syndrome (PCOS). Thus, we hypothesized that naturally occurring High A4 cows were present in other dairy and beef herds. Fourteen Jordan (Amman, Jordon) dairy heifers and 16 U.S. Meat Animal Research Center beef heifers were classified by FF (High A4: A4 > 40 ng/mL and Control: A4 < 20 ng/mL) and/or cortex culture media (High A4 > 1 ng/mL/d or Control < 1 ng/mL/d). High A4 dairy heifers (n = 6) had greater A4 concentrations (7.6-fold) in FF and (98-fold) greater in ovarian cortex culture media with greater numbers of primordial and fewer later-stage follicles than Controls (n = 8) even after 7 d of culture. Also, the ovarian cortex had greater staining for Picro Sirius red in High A4 dairy heifers compared with Controls indicating increased fibrosis. Thecal cells from High A4 dairy heifers had greater STAR, LHCGR, CYP17A, CD68, and PECAM mRNA expression with increased mRNA abundance of CYP17A1 and CD68 in the ovarian cortex cultures compared with Control dairy heifers. Similarly, cortex culture media from High A4 beef heifers (n = 10) had increased A4 (290-fold; P ≤ 0.001), testosterone (1,427-fold; P ≤ 0.001), and progesterone (9-fold; P ≤ 0.01) compared with Control heifers with increased primordial follicles and decreased later-stage follicles even after 7 d of culture, indicating abnormal follicular development. High A4 ovarian cortex cultures from beef heifers also had increased fibrosis markers and greater expression of PECAM (P = 0.01) with a tendency for increased vascular endothelial cadherin compared with Controls (n = 6). These two trials support our hypothesis that naturally occurring androgen excess cows are present in other dairy and beef herds. The ability to identify these females that have excess A4 ovarian microenvironments may allow for their use in understanding factors causing abnormal follicle development linked to androgen excess and inflammation.

VEGFA165 can rescue excess steroid secretion, inflammatory markers, and follicle arrest in the ovarian cortex of High A4 cows†

A population of cows with excess androstenedione (A4; High A4) in follicular fluid, with follicular arrest, granulosa cell dysfunction, and a 17% reduction in calving rate was previously identified. We hypothesized that excess A4 in the ovarian microenvironment caused the follicular arrest in High A4 cows and that vascular endothelial growth factor A would rescue the High A4 phenotype. In trial 1, prior to culture, High A4 ovarian cortex (n = 9) had greater numbers of early stage follicles (primordial) and fewer later-stage follicles compared to controls (n = 11). Culture for 7 days did not relieve this follicular arrest; instead, High A4 ovarian cortex had increased indicators of inflammation, anti-Mullerian hormone, and A4 secretion compared to controls. In trial 2, we tested if vascular endothelial growth factor A isoforms could rescue the High A4 phenotype. High A4 (n = 5) and control (n = 5) ovarian cortex was cultured with (1) PBS, (2) VEGFA165 (50 ng/mL), (3) VEGFA165B (50 ng/mL), or (4) VEGFA165 + VEGFA165B (50 ng/mL each) for 7 days. Follicular progression increased with VEGFA165 in High A4 cows with greater early primary, primary, and secondary follicles than controls. Similar to trial 1, High A4 ovarian cortex secreted greater concentrations of A4 and other steroids and had greater indicators of inflammation compared to controls. However, VEGFA165 rescued steroidogenesis, oxidative stress, and fibrosis. The VEGFA165 and VEGFA165b both reduced IL-13, INFα, and INFβ secretion in High A4 cows to control levels. Thus, VEGFA165 may be a potential therapeutic to restore the ovarian steroidogenic microenvironment and may promote folliculogenesis.

Transcriptomic data of bovine ovarian granulosa cells of control and High A4 cows

Microarray analysis using Affymetrix Bovine GeneChip 1.0 ST Array to determine RNA expression analysis was performed on somatic granulosa cells from two different groups of cows classified based on androstenedione concentration within the follicular fluid (Control vs High A4) of estrogen-active dominant follicles. The normalized linear microarray data was deposited to the NCBI GEO repository (GSE97017 - RNA Expression Data from Bovine Ovarian Granulosa Cells from High or Low Androgen-Content Follicles). Subsequent ANOVA determined genes that were enriched (≥ 1.5 fold more) or decreased (≤ 1.5 fold less) in the High A4 granulosa cells compared to Control granulosa cells and analyzed filtered datasets of these differentially expressed genes are presented as tables. MicroRNAs that are differentially expressed in Control and High A4 granulosa cells are also reported in tables. The standard deviation of the analyzed array data in relation to the log of the expression values are shown as a figure. Ingenuity Pathway Analysis determined upstream regulators of differently expressed genes as presented in a table. These data have been further analyzed and interpreted in the companion article "A High-Androgen Microenvironment Inhibits Granulosa Cell Proliferation and Alters Cell Identity" (McFee et. al., 2021 [1].

A high-androgen microenvironment inhibits granulosa cell proliferation and alters cell identity

A naturally occurring bovine model with excess follicular fluid androstenedione (High A4), reduced fertility, and polycystic ovary syndrome (PCOS)-like characteristics has been identified. We hypothesized High A4 granulosa cells (GCs) would exhibit altered cell proliferation and/or steroidogenesis. Microarrays of Control and High A4 GCs combined with Ingenuity Pathway Analysis indicated that High A4 GCs had cell cycle inhibition and increased expression of microRNAs that inhibit cell cycle genes. Granulosa cell culture confirmed that A4 treatment decreased GC proliferation, increased anti-Müllerian hormone, and increased mRNA for CTNNBIP1. Increased CTNNBIP1 prevents CTNNB1 from interacting with members of the WNT signaling pathway thereby inhibiting the cell cycle. Expression of CYP17A1 was upregulated in High A4 GCs presumably due to reduced FOS mRNA expression compared to Control granulosa cells. Furthermore, comparisons of High A4 GC with thecal and luteal cell transcriptomes indicated an altered cellular identity and function contributing to a PCOS-like phenotype.

Attainment and maintenance of pubertal cyclicity may predict reproductive longevity in beef heifers†

We hypothesized the manner that heifers achieve puberty may indicate their future reproductive longevity. Heifers with discontinued or delayed cyclicity during puberty attainment may have irregular reproductive cycles, anovulation, and infertility in their first breeding season contributing to a shorter reproductive lifespan. Therefore, plasma progesterone (P4) was measured from weaning to breeding on 611 heifers born 2012-2017 and four pubertal classifications were identified: (1) Early; P4 ≥ 1 ng/ml < March 12 with continued cyclicity, (2) Typical; P4 ≥ 1 ng/ml ≥ March 12 with continued cyclicity, (3) Start-Stop; P4 ≥ 1 ng/ml but discontinued cyclicity, and (4) Non-Cycling; no P4 ≥ 1 ng/ml. Historical herd records indicated that 25% of heifers achieved puberty prior to March 12th in the 10 years prior to the study. Start-Stop and Non-Cycling yearling heifers were lighter indicating reduced growth and reproductive maturity traits compared with Early/Typical heifers. In addition, Non-Cycling/Start-Stop heifers were less responsive to prostaglandin F2 alpha (PGF2α) to initiate estrous behavior and ovulation to be artificially inseminated. Non-Cycling heifers had fewer reproductive tract score-5 and reduced numbers of calves born in the first 21-days-of-calving during their first breeding season. Within the Start-Stop classification, 50% of heifers reinitiated cyclicity with growth traits and reproductive parameters that were similar to heifers in the Early/Typical classification while those that remained non-cyclic were more similar to heifers in the Non-Cycling group. Thus, heifers with discontinued cyclicity or no cyclicity during puberty attainment had delayed reproductive maturity resulting in subfertility and potentially a shorter reproductive lifespan.

Vascular endothelial growth factor A isoforms modulate follicle development in peripubertal heifers independent of diet through diverse signal transduction pathways

Follicular progression during peripuberty is affected by diet. Vascular endothelial growth factor A (VEGFA) induces follicle progression in many species; however, there are limited studies to determine if diet may alter the effects of angiogenic VEGFA165-stimulated follicle progression or antiangiogenic VEGFA165b follicle arrest. We hypothesized that diet affects the magnitude of angiogenic and antiangiogenic VEGFA isoform actions on follicular development through diverse signal transduction pathways. To test this hypothesis, beef heifers in our first trial received Stair-Step (restricted and refeeding) or control diets from 8 to 13 months of age. Ovaries were collected to determine follicle stages, measure vascular gene expression and conduct ovarian cortical cultures. Ovarian cortical cultures were treated with phosphate-buffered saline (control), 50 ng/ml VEGFA165, VEGFA165b, or VEGFA165 + VEGFA165b. The Stair-Step heifers had more primordial follicles (P &lt; 0.0001), greater messenger RNA abundance of vascular markers VE-cadherin (P &lt; 0.0001) and NRP-1 (P &lt; 0.0051) than controls at 13 months of age prior to culture. After culture, VEGFA isoforms had similar effects, independent of diet, where VEGFA165 stimulated and VEGFA165b inhibited VEGFA165-stimulated follicle progression from early primary to antral follicle stages. In vitro cultures were treated with VEGFA isoforms and signal transduction array plates were evaluated. VEGFA165 stimulated expression of genes related to cell cycle, cell proliferation, and growth while VEGFA165b inhibited expression of those genes. Thus, VEGFA isoforms can act independently of diet to alter follicle progression or arrest. Furthermore, follicle progression can be stimulated by VEGFA165 and inhibited by VEGFA165b through diverse signal transduction pathways.

Obesity-Dependent Increases in Oocyte mRNAs Are Associated With Increases in Proinflammatory Signaling and Gut Microbial Abundance of Lachnospiraceae in Female Mice

RNAs stored in the metaphase II-arrested oocyte play important roles in successful embryonic development. Their abundance is defined by transcriptional activity during oocyte growth and selective degradation of transcripts during LH-induced oocyte maturation. Our previous studies demonstrated that mRNA abundance is increased in mature ovulated oocytes collected from obese humans and mice and therefore may contribute to reduced oocyte developmental competence associated with metabolic dysfunction. In the current study mouse models of diet-induced obesity were used to determine whether obesity-dependent increases in proinflammatory signaling regulate ovarian abundance of oocyte-specific mRNAs. The abundance of oocyte-specific Bnc1, Dppa3, and Pou5f1 mRNAs as well as markers of proinflammatory signaling were significantly increased in ovaries of obese compared with lean mice which were depleted of fully grown preovulatory follicles. Chromatin-immunoprecipitation analyses also demonstrated increased association of phosphorylated signal transducer and activator of transcription 3 with the Pou5f1 promoter in ovaries of obese mice suggesting that proinflammatory signaling regulates transcription of this gene in the oocyte. The cecum microbial content of lean and obese female mice was subsequently examined to identify potential relationships between microbial composition and proinflammatory signaling in the ovary. Multivariate Association with Linear Models identified significant positive correlations between cecum abundance of the bacterial family Lachnospiraceae and ovarian abundance of Tnfa as well as Dppa3, Bnc1, and Pou5f1 mRNAs. Together, these data suggest that diet-induced changes in gut microbial composition may be contributing to ovarian inflammation which in turn alters ovarian gene expression and ultimately contributes to obesity-dependent reduction in oocyte quality and development of infertility in obese patients.

Altered theca and cumulus oocyte complex gene expression, follicular arrest and reduced fertility in cows with dominant follicle follicular fluid androgen excess

Aspiration of bovine follicles 12-36 hours after induced corpus luteum lysis serendipitously identified two populations of cows, one with High androstenedione (A4; >40 ng/ml; mean = 102) and another with Low A4 (<20 ng/ml; mean = 9) in follicular fluid. We hypothesized that the steroid excess in follicular fluid of dominant follicles in High A4 cows would result in reduced fertility through altered follicle development and oocyte maternal RNA abundance. To test this hypothesis, estrous cycles of cows were synchronized and ovariectomy was performed 36 hours later. HPLC MS/MS analysis of follicular fluid showed increased dehydroepiandrosterone (6-fold), A4 (158-fold) and testosterone (31-fold) in the dominant follicle of High A4 cows. However, estrone (3-fold) and estradiol (2-fold) concentrations were only slightly elevated, suggesting a possible inefficiency in androgen to estrogen conversion in High A4 cows. Theca cell mRNA expression of LHCGR, GATA6, CYP11A1, and CYP17A1 was greater in High A4 cows. Furthermore, abundance of ZAR1 was decreased 10-fold in cumulus oocyte complexes from High A4 cows, whereas NLRP5 abundance tended to be 19.8-fold greater (P = 0.07). There was a tendency for reduction in stage 4 follicles in ovarian cortex samples from High A4 cows suggesting that progression to antral stages were impaired. High A4 cows tended (P<0.07) to have a 17% reduction in calving rate compared with Low A4 cows suggesting reduced fertility in the High A4 population. These data suggest that the dominant follicle environment of High A4 cows including reduced estrogen conversion and androgen excess contributes to infertility in part through altered follicular and oocyte development.

Progressive obesity alters the steroidogenic response to ovulatory stimulation and increases the abundance of mRNAs stored in the ovulated oocyte

Obese women who are able to attain pregnancy are at increased risk for early-pregnancy loss due, in part, to reduced oocyte quality. We and others have demonstrated that female Lethal Yellow (LY) mice and female C57BL/6 mice fed a high fat diet (B6-HFD) exhibit phenotypes consistent with human obesity. These studies also showed that zygotes collected from LY and B6-HFD females have reduced developmental competence. The current hypothesis is that LY and B6-HFD females exhibit an abnormal response to gonadotropin stimulation compared to C57BL/6 controls fed normal rodent chow (B6-ND), resulting in the ovulation of oocytes with an altered molecular phenotype which may contribute to its reduced developmental competence. To test this hypothesis, age-matched B6-ND, B6-HFD, and LY females were stimulated with exogenous gonadotropins, then circulating hormone levels and the phenotypes of ovulated oocytes were analyzed. There was no difference in ovulation rate or in the percentage of morphologically abnormal oocytes collected from the oviduct of any females. Progesterone and progesterone/estradiol ratios, however, were increased in B6-HFD and LY compared to B6-ND females 16 hr post-human chorionic gonadotropin treatment. The transcript abundance of several candidate oocyte genes was also increased in B6-HFD- and LY-derived oocytes compared to B6-ND-derived oocytes. These data suggest that increased insulin and leptin levels of obese females elevated circulating progesterone concentrations, altered transcriptional activity during oocyte growth, and/or impaired mechanisms of RNA translation and degradation during oocyte maturation. These changes in mRNA abundance likely contribute to reduced oocyte quality and the subsequent poor embryogenesis associated with obesity.

Ept7 influences estrogen action in the pituitary gland and body weight of rats

Estrogens control many aspects of pituitary gland biology, including regulation of lactotroph homeostasis and synthesis and secretion of prolactin. In rat models, these actions are strain specific and heritable, and multiple quantitative trait loci (QTL) have been mapped that impact the responsiveness of the lactotroph to estrogens. One such QTL, Ept7, was mapped to RNO7 in female progeny generated in an intercross between BN rats, in which the lactotroph population is insensitive to estrogens, and ACI rats, which develop lactotroph hyperplasia/adenoma and associated hyperprolactinemia in response to estrogen treatment. The primary objective of this study was to confirm the existence of Ept7 and to quantify the impact of this QTL on responsiveness of the pituitary gland of female and male rats to 17β-estradiol (E2) and diethylstilbestrol (DES), respectively. Secondary objectives were to determine if Ept7 influences the responsiveness of the male reproductive tract to DES and to identify other discernible phenotypes influenced by Ept7. To achieve these objectives, a congenic rat strain that harbors BN alleles across the Ept7 interval on the genetic background of the ACI strain was generated and characterized to define the effect of administered estrogens on the anterior pituitary gland and male reproductive tissues. Data presented herein indicate Ept7 exerts a marked effect on development of lactotroph hyperplasia in response to estrogen treatment, but does not affect atrophy of the male reproductive tissues in response to hormone treatment. Ept7 was also observed to exert gender specific effects on body weight in young adult rats.

Mapping of three genetic determinants of susceptibility to estrogen-induced mammary cancer within the Emca8 locus on rat chromosome 5

The ACI rat model of 17β-estradiol (E2)-induced mammary cancer has gained wide use in the study of breast cancer etiology, prevention, and genetics. Emca8, a QTL that determines susceptibility to E2-induced mammary cancer, was previously mapped to rat chromosome 5 (RNO5) in an intercross between resistant Brown Norway (BN) and susceptible ACI rats. In this study, a panel of congenic rat strains, each of which carries BN alleles across a defined segment of RNO5 on the ACI genetic background, was generated and used to map more precisely the Emca8 determinants of mammary cancer susceptibility. Three distinct genetic determinants were localized within Emca8, and two of these were mapped to intervals of less than 15 megabases. Emca8.1 harbors Cdkn2a, Cdkn2b, and other genes and is orthologous to the 9p21 breast cancer locus identified in genome-wide and candidate gene association studies. Emca8.2 harbors Cdkn2c and other genes and is orthologous to the 1p32 locus in humans that is frequently deleted in breast cancers. Both Emca8.1 and Emca8.2 harbor copy number variants that are orthologous to copy number variant regions in humans. Gene expression profiles were defined for mammary tissues from E2-treated ACI and ACI.BN-Emca8 rats to define the impact of Emca8 on gene expression and identify differentially expressed genes residing within Emca8.1 and Emca8.2. This study further illustrates the relevance of the ACI rat model of E2-induced mammary cancer for identifying novel genetic determinants of breast cancer susceptibility and defining the mechanisms through which estrogens contribute to breast cancer development. Cancer Prev Res; 6(1); 59-69. ©2012 AACR.

cAMP-dependent regulation of ovulatory response genes is amplified by IGF1 due to synergistic effects on Akt phosphorylation and NF-κB transcription factors

Granulosa cells play a crucial role as mediator of the LH-dependent ovulatory response. The intraovarian factor IGF1 is produced by ovarian somatic cells of healthy follicles during the ovulatory response. The objective of this study was to identify mechanisms by which IGF1, alone or in combination with LH, regulates the expression of genes in granulosa cells, which are crucial for ovulation. To achieve this objective, short-term, primary murine granulosa cell cultures were treated for 2-8  h with 1 mM 8-bromoadenosine 3',5'-cAMP to mimic the LH surge and/or 100  ng/ml IGF1. While cAMP induced significant increases in the expression of important ovulatory response genes including amphiregulin (Areg), epiregulin (Ereg), betacellulin (Btc), or interleukin 6 (Il6), IGF1 alone had no effect. However, co-treatment of cells with IGF1 and cAMP had a synergistic effect on Areg, Ereg, Btc, and Il6 mRNA abundance. Pretreatment of granulosa cells with the MEK1/2 inhibitor U0126 demonstrated that cAMP-dependent increases in Areg, Ereg, Btc, and Il6 were mediated by extracellular regulated kinase 1/2 phosphorylation. However, western blot analyses coupled with pretreatment of cells with the PI3K inhibitor LY294002 indicated that the synergistic effect of cAMP and IGF1 on transcript levels was due in part to cooperative increases in Akt phosphorylation. Western blot analyses also demonstrated that IGF1 and the combined treatment of cAMP and IGF1 decreased NF-κB p65 phosphorylation and increased NF-κB p52 levels. Together, these data indicate that IGF1 may amplify cAMP-dependent regulation of ovulatory response gene expression above an important threshold level and therefore represents a novel role for IGF1 during ovulation.

Tissue-specific actions of the Ept1, Ept2, Ept6, and Ept9 genetic determinants of responsiveness to estrogens in the female rat

Ept1, Ept2, Ept6, and Ept9 are quantitative trait loci mapped in crosses between the ACI and Copenhagen (COP) rat strains as genetic determinants of responsiveness of the pituitary gland to estrogens. We have developed four congenic rat strains, each of which carries, on the genetic background of the ACI rat strain, alleles from the COP rat strain that span one of these quantitative trait loci. Relative to the female ACI rats, female ACI.COP-Ept1 rats exhibited reduced responsiveness to 17beta-estradiol (E2) in the pituitary gland, as evidenced by quantification of pituitary mass and circulating prolactin, and in the mammary gland, as evidenced by reduced susceptibility to E2-induced mammary cancer. The ACI.COP-Ept2 rat strain exhibited reduced responsiveness to E2 in the pituitary gland but did not differ from the ACI strain in regard to susceptibility to E2-induced mammary cancer. Interestingly, female Ept2 congenic rats exhibited increased responsiveness to E2 in the thymus, as evidenced by enhanced thymic atrophy. The ACI.COP-Ept6 rat strain exhibited increased responsiveness to E2 in the pituitary gland, which was associated with a qualitative phenotype suggestive of enhanced pituitary vascularization. The ACI.COP-Ept9 rat strain exhibited reduced responsiveness to E2 in the anterior pituitary gland, relative to the ACI rat strain. Neither Ept6 nor Ept9 impacted responsiveness to E2 in the mammary gland or thymus. These data indicate that each of these Ept genetic determinants of estrogen action is unique in regard to the tissues in which it exerts its effects and/or the direction of its effect on estrogen responsiveness.

Spleen but not tumor infiltration by dendritic and T cells is increased by intravenous adenovirus-Flt3 ligand injection

Dendritic cell (DC) expansion is regulated by the hematopoietic growth factor fms-like tyrosine kinase 3 ligand (Flt3L). DCs are critical to the control of tumor growth and metastasis, and there is a positive correlation between intratumoral DC infiltration and clinical outcome. In this report, we first demonstrate that single intravenous (i.v.) injections of adenovirus (Adv)-Flt3L significantly increased splenic dendritic, B, T and natural killer (NK) cell numbers in both normal and mammary tumor-bearing mice. In contrast, the numbers of DCs and T cells infiltrating the tumors were not increased. Consistent with the minimal effect on immune cell infiltration, i.v. Adv-Flt3L injections had no therapeutic activity against orthotopic mammary tumors. In addition, we noted tumor and Adv-Flt3L expansion of Gr1(+)CD11b(+) immature myeloid suppressor cells (IMSCs), which may inhibit the therapeutic efficacy of Adv-Flt3L-expanded DCs.

Pharmacokinetics and biodistribution of RGD-targeted doxorubicin-loaded nanoparticles in tumor-bearing mice

We report the biodistribution and pharmacokinetics (PK) of a cyclic RGD-doxorubicin-nanoparticle (NP) formulation in tumor-bearing mice. The NP core was composed of inulin multi-methacrylate with a targeting peptide, cyclic RGD, covalently attached to the NPs via PEG-400. Seventy-two percent of the doxorubicin was attached to the NP matrix via an amide bond; 28% of doxorubicin was entrapped as unconjugated drug. The PK of total, unconjugated and metabolized doxorubicin was examined for 5 days following intravenous (i.v.) administration of the NP formulation (250 microg doxorubicin equiv.), revealing a bi-exponential fix with a terminal half-life of 5.99 h. In addition, the biodistribution studies revealed decreasing drug concentrations over time in the heart, lung, kidney and plasma and accumulating drug concentrations in the liver, spleen and tumor. The drug concentration in these latter tissues peaked between 24 and 48 h with the liver, spleen and tumor containing 56, 3.5 and 1.8% of the administered dose at t=48 h, respectively. In contrast to all of the organs studied, the tumors contained high levels of a doxorubicin metabolite.

Transforming growth factor beta receptor expression in hyperstimulated human granulosa cells and cleavage potential of the zygotes

A possible relationship between transforming growth factor beta receptor type I (TbetaRI) and type II (TbetaRII) protein expression in human granulosa cells and the quality of preimplantation embryo development in vitro was studied using immunoblot analysis of TbetaRI and TbetaRII in hyperstimulated granulosa cells and morphological assessment of the cleavage potential of the zygotes in vitro. Washed granulosa cells were collected from </= 35-yr-old women with either tubal defects or mild endometriosis who were undergoing controlled ovarian hyperstimulation prior to oocyte retrieval for in vitro fertilization. TbetaRI and TbetaRII were immunoprecipitated from 100 000 g soluble and crude membrane fractions using receptor-specific antibodies and analyzed by Western immunoblotting, and the relative expression was quantitated from the luminographs. The gross morphology (embryo grade) of the preimplantation embryos developed in vitro was determined using a stereomicroscope. Both TbetaRI and TbetaRII are expressed in the soluble and membrane fractions of granulosa cells. Most notably, the zygote always developed into a grade 1 quality preimplantation embryo when the oocyte originated from a follicle that expressed a low amount of TbetaR protein in the granulosa cell membrane. Reduced expression of TbetaR in the granulosa cell membrane may form a mechanism critically regulating TGFbeta action on granulosa cells, and the latter in turn precisely control oocyte development, hence, the subsequent cleavage potential.

Hydrogen peroxide suppresses low-density lipoprotein (LDL) uptake and LDL-supported steroidogenesis by porcine luteal cells

The present study tested the hypothesis that hydrogen peroxide (H2O2) inhibits low-density lipoprotein (LDL) uptake and LDL-supported steroidogenesis by luteal cells. LDL uptake: dispersed porcine luteal cells from mid-cycle (days 6-11, estrus = day 0) were incubated for 0-120 min at 37 degrees C in F-10 medium + 0.1% BSA containing various concentrations of H2O2 (0-1000 microM). Cells were washed with catalase (2800 U/ml), and then with fresh medium. Cell viability based on trypan blue exclusion was unaltered by H2O2 exposure through 60 min. H2O2-exposed cells were incubated with fluorescent-tagged-LDL (Dil-LDL; 1 microgram/ml) for 10 min at 37 degrees C. Fluorescence of small (SLC) and large (LLC) luteal cells was analyzed by flow cytometry (n = 6 experiments). H2O2 (> or = 10 microM) caused a progressive reduction (P < 0.01) in mean fluorescence intensity (MFI) of SLC and LLC indicative of up to a 30-35% decline in LDL uptake. Progesterone (P) production: dispersed luteal cells (4 x 10(4)/0.2 ml) were pre-cultured in DMEM/F-12 medium overnight (approximately 18 h) in 96-well culture plates. Wells were rinsed and fresh media (0.2 ml) containing H2O2 (0-500 microM) was added. After 30 min, the following treatments were added: human(h)LDL (0 or 50 micrograms/ml), human chorionic gonadotropin (hCG; 0 or 100 ng/ml), hCG + LDL, or 22R-hydroxycholesterol (22[OH]-C; 0 or 25 micrograms/ml). Cells were incubated for an additional 4 h, and P concentrations in final media samples were measured by RIA.(ABSTRACT TRUNCATED AT 250 WORDS)

Loss of low-density lipoprotein utilization by regressing porcine luteal cells: effects of protein kinase C activation

We recently reported a decline in low-density lipoprotein (LDL) uptake by regressing porcine luteal cells that correlated with diminished LDL stimulation of progesterone (P) production. The objectives of the present study were to determine 1) whether loss of LDL utilization is a specific lesion in the steroidogenic pathway in regressing luteal cells and 2) whether in vitro activation of protein kinase C (PKC) in mid-cycle luteal cells acutely suppresses LDL utilization. Dispersed cells (4 x 10(4)/0.2 ml) from mid-(Days 6-10, estrus = Day 0; n = 5) or late-(Days 15-18; n = 7) cycle porcine CL were cultured in Dulbecco's Modified Eagle/F-12 medium supplemented with insulin, transferrin, sodium selenite, and aprotinin for 24 h with human (h) LDL (0-100 micrograms/ml), 22(R)-hydroxycholesterol (22[OH]-C;-0-25 micrograms/ml), or pregnenolone (0-1000 nM). P production by mid-cycle luteal cells was dose-dependently increased (p < 0.05) by LDL (up to 2.8-fold), 22(OH)-C (up to 3.2-fold), and pregnenolone (> 3-fold). In contrast, LDL (10-100 micrograms/ml) failed to stimulate P production by late-cycle luteal cells. But 22(OH)-C (up to 4-fold) and pregnenolone (> 10-fold) were as effective in promoting (p < 0.05) steroidogenesis relative to basal levels in late luteal cells as in mid-cycle cultures. The PKC activator, TPA (12-O-tetradecanoyl-phorbol-13-acetate; 10 ng/ml), inhibited (approximately 20%; p < 0.01) basal and LDL-supported steroidogenesis, but did not suppress 22(OH)-C-stimulated P secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Decline in fluorescent low density lipoprotein (LDL) uptake by small and large porcine luteal cells with advancing age of the corpus luteum

The present study was designed to test the hypothesis that the ability of small luteal cells (SLC) and/or large luteal cells (LLC) to take up low density lipoprotein (LDL) declines with advancing age of the CL. Ovaries from 100-110-kg gilts were classified as early (Days 4-6; n = 5), mid (Days 8-12; n = 6)-, or late (Days 15-18; n = 5) cycle on the basis of gross morphology. Multiple CL from each ovary were pooled and enzymatically dissociated. An aliquot of dispersed luteal cells was reserved for cell culture. Remaining cells were incubated (approximately 4 x 10(5) cells/0.25 ml Dulbecco's Modified Eagle's Medium [DMEM] + 0.1% BSA) for 20 min at 37 degrees C with human LDL (10 micrograms/ml) tagged with the fluorescent probe, Dil (Dil-LDL). Washed and fixed cells were then isolated by flow cytometry into SLC and LLC subpopulations on the basis of forward and 90 degrees light scatter. Cellular fluorescence was analyzed within each subpopulation. The percentage of fluorescent, i.e., Dil-LDL-positive (+), SLC did not differ between early (29.8 +/- 5.9%) and mid (40.5 +/- 6.8%)-cycle, but declined (p < 0.01) in late CL (7.0 +/- 1.6%). Similarly, the percentage of Dil-LDL-(+) LLC was unchanged between early (80.5 +/- 2.0%) and mid (78.6 +/- 4.2%)-cycle, but diminished (p < 0.01) in late (40.2 +/- 1.9%) CL. Moreover, the percentage of total cells isolated in the LLC subpopulation declined dramatically (p < 0.01) between mid (8.0 +/- 0.9%)- and late (1.6 +/- 0.2%) cycle, but the percentage of SLC did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of catecholestradiol on short-lived corpora lutea in beef cows

The influence of intrauterine administration of catecholestradiol (4-hydroxylated estradiol) on lifespan of the initial postpartum corpus luteum was evaluated in suckled beef cows. In experiment 1, postpartum cows (n = 23) were untreated (CONTROL) or received intrauterine infusions (0700 and 1700 hr) of either vehicle (SAL) or catecholestradiol (CATE; 4 micrograms) from day 15 to 22 (day 0 = parturition). Blood samples were collected three times weekly (day 15 to 100) and analyzed for progesterone. In experiment 2, cows received twice daily intrauterine infusions of either vehicle (n = 18), or catecholestradiol (n = 19), from day 25 +/- .5 to day 30 +/- .5. Following the final infusion, calves were temporarily weaned from all cows for 48 hr. At the end of the 48 hr weaning period, cows in each infusion group received either an i.m. injection of 1,000 IU hCG (SAL+hCG, n = 9; CATE+hCG, n = 9) or no further treatment (SAL, n = 9; CATE, n = 10). Blood samples were collected daily for 21 d following calf removal and 3 times weekly through 100 d postpartum. In both experiments, the initial postpartum elevation in peripheral progesterone concentrations was characterized as either a short (< 5 d) or extended (> 8 d) luteal phase. In experiment 1, postpartum anestrous interval (60 +/- 3.4 d) and incidence of short luteal phases (77%) were similar among CONTROL, SAL and CATE treatments. In experiment 2, luteal phases were induced within 10 d of onset of weaning in 90, 100, 56 and 60% of cows in SAL+hCG, CATE+hCG, SAL and CATE treatments, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of luteinizing hormone secretion in prepubertal heifers fed an energy-deficient diet

The effects of feeding a diet restricted in energy on the endocrine mechanisms regulating LH secretion in prepubertal heifers were examined. On Day 0, thirty heifers were assigned to be either ovariectomized (OVX; n = 10), ovariectomized and administered an estradiol implant (OVXE; n = 10), or to remain ovary-intact (INT, n = 10). Five heifers each were then assigned to be fed either a control (C) or a two-phase, low-to-high energy (L), dietary treatment. The C diet was formulated to support weight gains of 1.1 kg/day throughout the experiment (Day 0-197). Heifers receiving the L treatment were provided a diet restricted in energy (33% of C diet) from Day 0-127 followed by a diet similar to that fed to heifers receiving the C treatment from Day 128-197. Secretion of LH increased rapidly following ovariectomy in C-OVX and L-OVX heifers. During the period of energy restriction, LH pulse frequency was reduced, and mean LH concentration, pulse amplitude, and pituitary response to LHRH were greater in L-OVX than in C-OVX heifers. In L-OVXE and L-INT heifers, secretion of LH was low and unchanged during the period of dietary energy restriction. In contemporaneous treatment groups fed the C diet (C-OVXE and C-INT), frequency of LH pulses increased gradually during this period and C-INT heifers attained puberty on Day 121 +/- 18. Upon switching heifers in the L-OVX, L-OVXE, and L-INT treatments to the C diet, all characteristics of LH secretion changed markedly within 14 days to levels similar to those detected in the C treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro prostaglandin production by bovine corpora lutea destined to be normal or short-lived

Basal and calcium ionophore (CaI)-influenced production of prostaglandins (PGs) by corpora lutea (CL) destined to be normal or short-lived were compared. Ovulation was induced in 24 lactating beef cows with human chorionic gonadotropin (hCG, 1000 IU) administered between 35 and 40 days postpartum. Ten cows received norgestomet implants for 9 days prior to induced ovulation (Normal CL) and 14 served as untreated controls (Subnormal CL). Five cows in each treatment were unilaterally ovariectomized on Day 6 (Day 0 = day of hCG administration) and CL were collected. Blood samples were collected daily through-out the experimental period from cows not ovariectomized. Plasma progesterone (P4) in ovary-intact animals indicated that short-lived CL were induced in 8/8 cows not pretreated with norgestomet, and normal luteal lifespan was observed in 4/5 implanted cows. Dispersed luteal cells were incubated for 8 h with 0, 0.05, 0.5, or 5 microM CaI (A23187). Incubation media were analyzed for P4, PGF2 alpha, 6-keto-PGF1 alpha (PGI), and PGE2. The weight, cell number, and basal or CaI-influenced production of P4 did not differ between Normal CL and Subnormal CL. Basal production of PGF2 alpha, PGI, and PGE2 was higher in Subnormal CL than in Normal CL (p less than 0.05). In response to 0.05 microM CaI, PGF2 alpha was stimulated in Subnormal CL (p less than 0.01), while PGI (p less than 0.05) and PGE2 (p less than 0.1) were increased in Normal CL. Production of PGs was reduced by 5 microM CaI in Subnormal CL (p less than 0.01), but not in Normal CL.(ABSTRACT TRUNCATED AT 250 WORDS)