In vitro effects of two environmental toxicants, beauvericin and glyphosate in Roundup, on cell numbers and steroidogenesis of bovine ovarian cells

Beauvericin is an emerging Fusariotoxin naturally occurring in cereal grains throughout the world whereas glyphosate (N-phosphonomethyl-glycine) is a non-selective systemic herbicide used worldwide. The purpose of this study is to evaluate a newly developed ovarian cell culture system (that includes both granulosa and theca cells) as an in vitro model for toxicological studies. Specifically, the effects of beauvericin and glyphosate in formulation with Roundup on ovarian cell numbers and steroid production were evaluated. Ovaries collected from cattle without luteal structures were sliced into 30-70 pieces each, and granulosa and theca cells were collected. Harvested cells were cultured for 48 h in 10% fetal bovine serum-containing medium followed by 48 h in serum-free medium containing testosterone (500 ng/mL; as an estrogen precursor) with the following eight treatments: (1) controls, (2) FSH (30 ng/mL) alone, (3) FSH plus insulin-like growth factor-1 (IGF1; 30 ng/mL), (4) FSH plus IGF1 plus beauvericin (3 µM), (5) FSH plus IGF1 plus glyphosate in Roundup (10 µg/mL), (6) FSH plus IGF1 plus fibroblast growth factor 9 (FGF9, 30 ng/mL), (7) a negative control without added testosterone, and (8) IGF1 plus LH (30 ng/mL) with basal medium without added testosterone. In the presence of FSH, IGF1 significantly increased cell numbers, estradiol and progesterone production by severalfold. Glyphosate in Roundup formulation significantly inhibited IGF1-induced cell numbers and estradiol and progesterone production by 89-94%. Beauvericin inhibited IGF1-induced cell numbers and estradiol and progesterone by 50-97% production. LH plus IGF1 significantly increased androstenedione secretion compared with controls without added testosterone indicating the presence of theca cells. In conclusion, the present study demonstrates that toxicological effects of beauvericin and glyphosate in Roundup formulation are observed in a newly developed ovarian cell model system and further confirms that both glyphosate and beauvericin may have the potential to impair reproductive function in cattle.

Zootoxins and Domestic Animals: A European View

Zootoxins are produced by venomous and poisonous species and are an important cause of poisoning in companion animals and livestock in Europe. Little information about the incidence of zootoxin poisoning is available in Europe, with only a few case reports and review papers being published. This review presents the most important zootoxins produced by European venomous and poisonous animal species responsible for poisoning episodes in companion animals and livestock. The main zootoxin-producing animal species, components of the toxins/venoms and their clinical effects are presented. The most common zootoxicoses involve terrestrial zootoxins excreted by the common toad, the fire salamander, the pine processionary caterpillar, and vipers. The lack of a centralized reporting/poison control system in Europe makes the evaluation of the epidemiology of zootoxin-induced poisonings extremely difficult. Even if there are many anecdotal reports in the veterinary community about the exposure of domestic animals to terrestrial and marine zootoxins, the number of published papers regarding these toxicoses is low. Climate change and its consequences regarding species distribution and human-mediated transportation are responsible for the emerging nature of some intoxications in which zootoxins are involved. Although new venomous or poisonous animal species have emerged in regions where they were previously unreported, zootoxins produced by native species remain the main concern in Europe. The diversity of poisonous and venomous animal species and the emerging nature of certain poisonings warrant the continuous update to such knowledge by veterinary professionals and animal owners. This review offers an overview about zootoxin-related poisonings in domestic animals in Europe and also provides important information from a health perspective.

Developmental and hormonal regulation of FBN1 and OR4M1 mRNA in bovine granulosa cells

Recent studies have reported hormonal regulation of expression of fibrillin 1 (FBN1), the gene that encodes asprosin, in bovine theca cells, however, hormonal regulation of gene expression of FBN1 and the asprosin receptor, olfactory receptor 4M1 (OR4M1), has not been evaluated in granulosa cells (GC). This study was designed to characterize FBN1 and OR4M1 gene expression in GC during development of bovine dominant ovarian follicles, and to determine the hormonal regulation of FBN1 and OR4M1 mRNA expression in GC. GC FBN1 mRNA abundance was greater (P < 0.05) in medium (5.1-8 mm) estrogen inactive (EI) follicles than in large (>8.1 mm) or small (1-5 mm) EI follicles. In comparison, GC OR4M1 mRNA abundance was greater (P < 0.05) in small EI follicles than in large or medium EI follicles. Abundance of OR4M1 mRNA in GC of follicles collected on days 3 to 4 (early growth phase) and on days 5 to 6 (late growth phase) was similar, whereas FBN1 mRNA abundance was greater (P < 0.05) on days 5 to 6 vs days 3 to 4. Hormonal regulators for FBN1 mRNA abundance in cultured small-follicle GC were identified: TGFβ1 causing a 2.45-fold increase, WNT3A causing a 1.45-fold increase, and IGF1 causing a 65% decrease. Steroids, leptin, insulin, growth hormone, follicle stimulating hormone, fibroblast growth factor 9 and epidermal growth factor had no effect on FBN1 mRNA abundance. Abundance of OR4M1 mRNA in GC was regulated by progesterone with 3.55-fold increase, but other hormones did not affect GC OR4M1 mRNA abundance. Findings indicate that both FBN1 and OR4M1 gene expression are hormonally and developmentally regulated in bovine follicles, and thus may affect asprosin production and its subsequent role in ovarian follicular function in cattle.

Enniatin B1: Emerging Mycotoxin and Emerging Issues

Although over the last 10 years several studies have focused on the emerging mycotoxins known as enniatins (ENNs), there is still a lack of knowledge regarding their toxicological effects and the development of a correct risk assessment. This is especially true for enniatin B1 (ENN B1), considered the younger sister of the widely studied enniatin B (ENN B). ENN B1 has been found in several food commodities and, as with other mycotoxins, presents antibacterial and antifungal properties. On the other hand, ENN B1 has shown cytotoxic activity, impairment of the cell cycle, the induction of oxidative stress, and changes in mitochondrial membrane permeabilization, as well as negative genotoxic and estrogenic effects. Overall, considering the paucity of information available regarding ENN B1, further studies are necessary to perform a risk assessment. This review summarizes information on the biological characteristics and toxicological effects of ENN B1 as well as the future challenges that this mycotoxin could present.

Effects of asprosin on estradiol and progesterone secretion and proliferation of bovine granulosa cells

Asprosin is an adipokine synthesized by the white adipose tissue that regulates glucose homeostasis and that has been reported to affect bovine theca cell function and follicular growth, but its role on granulosa cell functions remains to be unveiled. Hence, the objective of this study was to investigate asprosin impacts on granulosa cell steroidogenesis. Bovine granulosa cells from small ovarian follicles were cultured in vitro to investigate the effects of asprosin on cell proliferation, production of steroids, mRNA abundance of genes that encode steroidogenic enzymes and cell cycle regulators, and protein relative abundance of steroidogenic signaling pathways. Asprosin was shown to affect granulosa cell functions in a dose-dependent manner. In the presence of FSH, asprosin enhanced estradiol production and stimulated an increase in mRNA expression of FSHR and CYP19A1 in a dose-dependent manner. In the presence of IGF1, asprosin decreased estradiol production, increased progesterone production, altered PKA relative protein expression, and tended to alter the ratio of p-ERK1/2/total ERK1/2 protein expression in a dose-dependent manner. Furthermore, asprosin increased p-53 gene expression in basal culture conditions and with or without FSH and IGF1. Taken together, findings of this study show that asprosin is a regulator of granulosa cell functions and the effects of asprosin depend on dose and cell culture conditions.

Insulin-like growth factor 1 and the hormonal mediation of sibling rivalry

In altricial animals, young are completely dependent on parents for provisioning. The ability to outcompete siblings to receive parental provisioning has clear fitness benefits, and may be mediated by hormones that influence growth. We analyzed the effects of insulin-like growth factor 1 (IGF-1) on body size, growth, and sibling rivalry in eastern bluebirds (Sialia sialis). To determine whether IGF-1 is upregulated in response to the competitive environment, we manipulated brood sizes and examined the effect on IGF-1 levels, nestling body size, growth rate, and behavior. In a separate experiment, we injected nestlings with exogenous IGF-1 to study its impacts on body size, growth rate, and sibling competition. Brood size manipulation did not influence endogenous IGF-1 levels, but male nestlings with higher IGF-1 levels early in the nestling period tended to have greater mass gain than males with lower IGF-1 levels. Nestlings with higher IGF-1 levels also tended to be fed more frequently by parents. In the injection experiment, IGF-1 injected individuals tended to be heavier than vehicle injected young by the end of the nestling period, which suggests that IGF-1 can influence mass gain in bluebirds. IGF-1 has been proposed to be a mediator of life-history strategies and post-hatching behavior. Our results suggest that although bluebird nestlings do not adaptively elevate IGF-1 in response to the presence or number of siblings, IGF-1 may influence growth during the nestling period. These findings shed light on sibling competition, life history strategies, and the hormones that underlie them.

In Vitro Effects of Enniatin A on Steroidogenesis and Proliferation of Bovine Granulosa Cells

The emerging Fusarium mycotoxins enniatins (ENNs) have been the focus of new research because of their well-documented existence in various cereal and grain products. Research findings indicate that reproductive disorders may be caused by exposure to Fusarium mycotoxins, but little work has evaluated ENNs on reproductive function. Therefore, to determine the effects of ENNA on the proliferation and steroidogenesis of granulosa cells (GC), experiments were conducted using bovine GC cultures. In vitro, ENNA (1−5 μM) inhibited (p < 0.05) hormone-induced GC progesterone and estradiol production. The inhibitory effect of ENNA on estradiol production was more pronounced in small- than large-follicle GC. In large-follicle GC, 0.3 μM ENNA had no effect (p > 0.10) whereas 1 and 3 μM ENNA inhibited GC proliferation. In small-follicle GC, ENNA (1−5 μM) dramatically decreased (p < 0.05) GC proliferation. Using cell number data, the IC50 of ENNA was estimated at 2 μM for both follicle sizes. We conclude that ENNA can directly inhibit ovarian function in cattle, decreasing the proliferation and steroid production of GC.

Hormone regulation of thrombospondin-1 mRNA in porcine granulosa cells in vitro

Thrombospondin-1 (THBS1) is involved in the process of angiogenesis and is down-regulated by insulin-like growth factor 1 (IGF1) in porcine granulosa cells (GC), but what other hormones regulate GC THBS1 and its role in follicular growth is unclear. Thus, six experiments were conducted to determine the influence of other hormones on THBS1 gene expression in porcine GC, and to determine if THBS1 mRNA changes during follicular development. For Exp. 1-5, small (1-5 mm) follicles from ovaries of abattoir gilts were aspirated, GC collected and treated with FSH, IGF1, fibroblast growth factor 9 (FGF9), Sonic hedgehog (SHH), estradiol, cortisol, and/or prostaglandin E2 (PGE2). FSH, IGF1 and FGF9 each decreased (P < 0.05) THBS1 mRNA abundance. Alone, PGE2 increased (P < 0.05) THBS1 mRNA abundance. PGE2 significantly attenuated the FSH-induced inhibition of THBS1 mRNA expression. Estradiol, cortisol, and SHH had no effect on THBS1 mRNA abundance. In Exp. 6, small (1-3 mm), medium (4-6 mm) and large (7-14 mm) follicles were aspirated to measure abundance of THBS1 mRNA in GC which did not differ (P > 0.10) between small and medium-sized follicles but was threefold greater (P < 0.05) in large compared to small or medium follicles. We hypothesize that the inhibitory effects of FSH, IGF1 and FGF9 on the antiangiogenic gene THBS1 could contribute to promoting angiogenesis in the developing follicle, while stimulation of THBS1 mRNA by PGE2 may help reduce angiogenesis during the preovulatory period when PGE2 and THBS1 mRNA are at their greatest levels.

Effects of grape phenolics, myricetin and piceatannol, on bovine granulosa and theca cell proliferation and steroid production in vitro

Myricetin (a flavonol) and piceatannol (a stilbenoid) are naturally occurring phenolic compounds in red wine with cardio-protective and anti-carcinogenic effects, but their potential reproductive effects have not been investigated. Thus, the present study was designed to determine if myricetin and piceatannol can directly affect ovarian function using bovine granulosa cells (GC) and theca cells (TC) as in vitro model systems to evaluate effects on cell proliferation and steroid production. In Experiment 1 and 2, myricetin and piceatannol at 30 μM blocked insulin-like growth factor 1 (IGF1)-induced progesterone production by GC without affecting GC numbers. In contrast, myricetin stimulated IGF1-induced estradiol production, whereas piceatannol at 30 μM inhibited IGF1-induced estradiol production by 90% in GC. In Experiment 3 and 4, TC androstenedione and progesterone production and TC proliferation was inhibited by myricetin and piceatannol at 30 μM. In Experiment 5, piceatannol (30 μM) reduced the Fusarium mycotoxin, beauvericin (6 μM)-induced inhibition on progesterone production and cell proliferation. Myricetin (30 μM) reduced the inhibitory effect of beauvericin on estradiol but not progesterone production or cell proliferation. In conclusion, the red wine phenols, myricetin and piceatannol, directly affected GC and TC steroidogenesis, and were able to reduce some of the inhibitory effects of beauvericin on GC function.

Changes in fibroblast growth factor receptors-1c, -2c, -3c, and -4 mRNA in granulosa and theca cells during ovarian follicular growth in dairy cattle

The various fibroblast growth factors (FGF) regulate their function via binding to 4 main FGF receptor (FGFR) subtypes and their splice variants, FGFR1b, FGF1c, FGFR2b, FGFR2c and FGFR3c and FGFR4, but which of these FGFR are expressed in the granulosa (GC) and theca cells (TC), the 2 main cell layers of ovarian follicles, or change during follicular development is unknown. We hypothesized that FGFR1c, FGFR2c and FGFR3c (but not FGFR4) gene expression in GC (but not TC) would change with follicular development. Hence, the objective of this study was to determine if abundance of FGFR1c, FGFR2c, FGFR3c, and FGFR4 mRNA change according to follicular size, steroidogenic status, and days post-ovulation during growth of first-wave dominant follicles in Holstein cattle exhibiting regular estrous cycles. Estrous cycles of non-lactating dairy cattle were synchronized, and ovaries were collected on either d 3 to 4 (n = 8) or d 5 to 6 (n = 8) post-ovulation for GC and TC RNA extraction from small (1-5 mm), medium (5.1 to 8 mm) or large (8.1-18 mm) follicles for real-time PCR analysis. In GC, FGFR1c and FGFR2c mRNA relative abundance was greater in estrogen (E2)-inactive (ie, concentrations of E2 < progesterone, P4) follicles of all sizes than in GC from large E2-active follicles (ie, E2 > P4), whereas FGFR3c and FGFR4 mRNA abundance did not significantly differ among follicle types or days post-estrus. In TC, medium E2-inactive follicles had greater FGFR1c and FGFR4 mRNA abundance than large E2-active and E2-inactive follicles on d 5 to 6 post-ovulation whereas FGFR2c and FGFR3c mRNA abundance did not significantly differ among follicle types or day post-estrus. In vitro experiments revealed that androstenedione increased abundance of FGFR1c, FGFR2c and FGFR4 mRNA in GC whereas estradiol decreased FGFR2c mRNA abundance. Neither androstenedione nor estradiol affected abundance of the various FGFR mRNAs in cultured TC. Taken together, the findings that FGFR1c and FGFR2c mRNA abundance was less in GC of E2-active follicles and FGFR1c and FGFR4 mRNA was greater in TC of medium inactive follicles at late than at early growing phase of the first dominant follicle support an anti-differentiation role for FGF and their FGFR as well as support the idea that steroid-induced changes in FGF and their receptors may regulate selection of dominant follicles in cattle.

Effects of transforming growth factor β1 on steroidogenesis of feline granulosa cells cultured in vitro

CONTEXT

Little is known about the hormonal regulation of feline ovarian granulosa cell proliferation and steroidogenesis.

AIMS

To determine if transforming growth factor β1 (TGFB1), activin, epidermal growth factor (EGF), follicle stimulating hormone (FSH), luteinizing hormone (LH), melatonin, and insulin-like growth factor 1 (IGF1) regulate granulosa cell steroidogenesis and proliferation in cats, three experiments were conducted in winter season.

METHODS

Granulosa cells were isolated and treated in vitro with various hormones in serum-free medium for 48h after an initial 48h plating in 10% fetal calf serum.

KEY RESULTS

Treatment with IGF1 and FSH increased (P<0.05) estradiol production by 2.3- and 1.33-fold, respectively. In contrast, TGFB1 blocked (P<0.05) IGF1-induced estradiol production and inhibited FSH-induced estradiol production by 60%. Combined with FSH or FSH plus IGF1, TGFB1 inhibited (P<0.05) cell proliferation, whereas TGFB1 increased progesterone production by 2.8-fold in the presence of FSH plus IGF1. EGF decreased (P<0.05) FSH plus IGF1-induced estradiol production by 89% but did not affect progesterone production or cell numbers. Activin did not affect (P>0.10) cell numbers or steroidogenesis in the presence of FSH plus IGF1. Melatonin and LH decreased (P<0.05) estradiol production 53% and 59%, respectively, without affecting progesterone production or cell proliferation.

CONCLUSIONS

The present study has identified TGFB1 as a major regulator of feline ovarian function, in addition to EGF, IGF1, melatonin, LH and FSH.

IMPLICATIONS

These studies will provide useful information for future development of fertility control in feline species.

Emerging mycotoxins and reproductive effects in animals: A short review

Emerging Fusarium mycotoxins beauvericin (BEA), enniatins (ENNs) and moniliformin (MON) are gaining increasing interest due to their wide presence especially in cereals and grain-based products. In vitro and in vivo studies indicate that Fusarium mycotoxins can be implicated in reproductive disorders in animals. Of these mycotoxins BEA may affect reproductive functions, impairing the development of oocytes in pigs and sheep. Studies show dramatic inhibitory effects of BEA and ENNA on bovine granulosa cell steroidogenesis. ENNs also inhibit boar sperm motility and cause detrimental effects on embryos in mice and pigs. Although little data are reported on reproductive effects of MON, in vitro studies show inhibitory effects of MON on Chinese hamster ovary cells. The present review aims to summarize the reproductive toxicological effects of emerging Fusarium mycotoxins BEA, ENNs and MON on embryo development, ovarian function, and testicular function of animals. In vitro and in vivo toxicological data are reported although additional studies are needed for proper risk assessment.

Effects of bone morphogenetic protein 4, gremlin, and connective tissue growth factor on estradiol and progesterone production by bovine granulosa cells

Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-β family of proteins that have been implicated in the paracrine regulation of granulosa cell (GC) function, but whether responses to BMPs change with follicular size or interact with connective tissue growth factor (CTGF) or BMP antagonists (e.g., gremlin [GREM]) to directly affect GC function of cattle is unknown. Therefore, to determine the effects of BMP4 on proliferation and steroidogenesis of GCs and its interaction with GREM or CTGF, experiments were conducted using bovine GC cultures. In vitro, BMP4 (30 ng/mL) inhibited (P < 0.05) follicle-stimulating hormone (FSH) plus insulin-like growth factor 1 (IGF1)-induced progesterone and estradiol production by large- and small-follicle GCs, but the inhibitory effect of BMP4 on estradiol production was much more pronounced in large-follicle GCs. In small-follicle GCs, BMP4 had no effect (P > 0.10) on IGF1-induced proliferation, but GREM inhibited (P < 0.05) cell proliferation and estradiol and progesterone production in IGF1 plus FSH-treated GCs. In large-follicle GCs, BMP4 (10 to 30 ng/mL) increased (P < 0.05) GC numbers and GREM (100 ng/mL) blocked this effect. In large-follicle GCs, CTGF inhibited (P < 0.05) FSH plus IGF1-induced progesterone and estradiol production, and CTGF blocked the stimulatory effect of BMP4 on GC proliferation. These results indicate that BMP4, GREM, and CTGF inhibit GC aromatase activity and progesterone production. Also, the stimulatory effect of BMP4 on GC proliferation and the inhibitory effects of BMP4 on GC steroidogenesis are more pronounced in large vs. small follicles.

PSVIII-14 Effect of Certillus, a direct-fed microbial, on milk yield, milk components, and feed intake in primi- and multiparous lactating Holstein cows

To determine the effect of Certillus on milk production, milk components and feed efficiency, primiparous (n = 13) and multiparous (n = 12) Holstein cows were assigned to one of two dietary groups starting from 8 to 120 days of lactation. The controls (n = 13) received regular TMR ration, and treated cows (n =12) received control TMR plus 2 x 109 cfu/head of Certillus (Church & Dwight Co., Inc., Waukesha, WI). Cows were housed in an open-air free-stall barn with 16 Insentec electronic feeders (8 feeders/group) to record daily feed events and intake (DMI). Cows were provided with ad libitum TMR fed twice daily and were milked twice daily. Milk samples were taken weekly during successive a.m./p.m. milkings and analyzed for percentage milk fat, protein, lactose, and milk urea nitrogen (MUN). Data were analyzed using a repeated-measures 2 x 2 factorial ANOVA. Daily milk production (4%FCM) was influenced (P &lt; 0.05) by treatment x parity, week and parity, averaging 11% greater (P &lt; 0.05) in Certillus-fed than control cows. Milk fat percentage increased (P &lt; 0.005) from 4.02 to 4.41 + 0.09% with Certillus feeding. Milk lactose was influenced (P &lt; 0.05) by week and treatment x parity. Milk protein was affected by week (P &lt; 0.001) only. Certillus decreased (P &lt; 0.05) MUN levels such that MUN was 1.0 mg/dL greater (P &lt; 0.001) in Certillus-fed than control cows. Feed intake was reduced by 9% (P &lt; 0.01) and feed efficiency (kg 4%FCM/kg DMI) was improved by 14% (P &lt; 0.05) in Certillus-fed versus control cows. We conclude that Certillus may hold potential as an effective direct-fed microbial to increase feed efficiency and milk production.

257 Awardee Talk: Pursuit of Novel Factors that Regulate Ovarian Follicular Function

As follicles grow, theca cells (TC) and granulosa cells (GC) must proliferate with minimal differentiation while thecal vascularization increases so that follicles do not prematurely ovulate or luteinize before the oocyte is fully mature. In the early 2000s we used Affymetrix microarrays to discover several unique genes involved in ovarian follicular development. Thrombospondin and fibroblast growth factor (FGF) 2 receptor genes were stimulated by IGF1 in porcine GC. We compared GC gene expression in bovine cystic versus normal follicles and discovered several novel genes including Indian hedgehog protein (IHH), FGF9, brain ribonuclease (BRB), and G protein-coupled receptor 34 (GPR34), leading to identification of roles for these proteins in ovarian follicular development. During the past 10 years, follow-up TC microarray and mechanistic studies have identified FGF9 control of cell cycle proteins, tight junction proteins, and microRNA 221 (MIR221), and that the mitogenic and steroidogenic responses to the major trophic hormones of the ovary (including IGF1, LH and FSH) are altered by overexpression of MIR221 in GC. In addition, we discovered that: 1) FGF9 stimulates GC and TC mitosis while inhibiting steroidogenesis; 2) FGF9 induces E2 transcription factor (E2F)-1, E2F-8 and cyclin D1 (CCND1), and that both IGF1 and vascular endothelial growth factor-A (VEGFA) synergize with FGF9 to further induce E2F8 and CCND1 mRNA; 3) FGF9 induces the nuclear protein UHRF1; and 4) an E2F inhibitor blocks the stimulatory and inhibitory effects of FGF9 on GC proliferation and steroidogenesis, respectively, and down-regulates UHRF1 mRNA and up-regulates VEGFA mRNA. Thus, aberrant production of FGF9 and the factors it induces/inhibits may lead to vascular dysfunction and ovarian disorders such as ovarian cysts. With additional research, knowledge about these newly identified factors may be used to help the livestock industry improve reproductive efficiency via new treatments for estrous synchronization, superovulation and cystic ovaries.

Wingless-type mouse mammary tumor virus integration site regulation of bovine theca cells

Ovarian paracrine mediation by components of the wingless-type mouse mammary tumor virus integration site ligands (WNT1 to 11) and their receptors, frizzled family members (FZD1 to 10), has been proposed. Secreted truncated forms of FZD proteins (e.g., secreted frizzled-related protein 4 [SFRP4]) block the action of WNT ligands. Dickkopf-1 (DKK1) is another WNT antagonist, and R-spondin-1 (RSPO1) is one of a group of four secreted proteins that enhance WNT/β-catenin signaling. Our hypothesis was that granulosa cells signal theca cells (TCs) via SFRP4, DKK1, RSPO1, and WNT secretion to regulate TC differentiation and proliferation. Therefore, in vitro experiments were conducted to study the effects of WNT family member 3A (WNT3A), WNT5A, RSPO1, DKK1, insulin-like growth factor 1 (IGF1), bone morphogenetic protein 7 (BMP7), Indian hedgehog (IHH), and fibroblast growth factor 9 (FGF9) on bovine TC proliferation and steroidogenesis. TCs of large (8 to 20 mm) and small (3 to 6 mm) follicles were collected from bovine ovaries; TC monolayers were established in vitro and treated with various doses of recombinant human WNT3A, WNT5A, RSPO1, DKK1, IGF1, FGF9, BMP7, IHH, and/or ovine luteinizing hormone (LH) in serum-free medium for 48 h. In experiment 1, using LH-treated TC, IGF1, IHH, and WNT3A increased (P < 0.05) cell numbers and androstenedione production, whereas WNT3A and BMP7 inhibited (P < 0.05) progesterone production. In experiment 2, FGF9 blocked (P < 0.05) the WNT3A-induced increase in androstenedione production in LH plus IGF1-treated TC. In experiment 3, RSPO1 further increased (P < 0.05) LH plus IGF1-induced progesterone and androstenedione production. In experiment 4, SFRP4 and DKK1 alone had no significant effect on TC proliferation or progesterone production of large-follicle TC but both blocked the inhibitory effect of WNT5A on androstenedione production. In contrast, DKK1 alone inhibited (P < 0.05) small-follicle TC androstenedione production whereas SFRP4 was without effect. We conclude that the ovarian TC WNT system is functional in cattle, with WNT3A increasing proliferation and androstenedione production of TC.

Postpartum nutrition affects the insulin-like growth factor system in dominant follicles and plasma of anestrous beef cows

Effects of nutrition on insulin-like growth factor-I (IGF-I), IGF binding proteins (IGFBP), and insulin in plasma and dominant follicles were evaluated at day 72 and 56 (Exp. 1, n = 12 and Exp. 2, n = 28, respectively) postpartum in anovulatory primiparous beef cows. Cows were stratified based on body condition score at calving and randomly assigned to nutritional treatments: maintain (M), 2.27 kg of a 40 % CP supplement per day and ad libitum hay; or gain (G), ad libitum access to a 50 % concentrate diet and ad libitum hay. Blood samples were collected twice weekly starting 30 days postpartum. Ovarian follicles were evaluated using ultrasonography commencing 42 (Exp. 1) or 30 (Exp. 2) days postpartum. Body weight and condition score were greater (P < 0.05) for cows of G than M groups and postpartum interval to luteal function was longer for cows of the M than G group. Insulin and IGF-I concentrations in follicular fluid (FF) and plasma were greater (P < 0.05) for cows of the G than M group at follicular aspiration. Plasma and FF IGFBP4 and IGFBP5 concentrations were greater (P <  0.05) in Exp. 2, and IGFBP5 was greater in Exp. 1 for cows of the G than M group. Treatment did not affect FF steroid concentrations or granulosal cell CYP19A1, PAPPA, IGFBP4, and IGFBP5 mRNA abundance. These results indicate concentrations of IGF-I, insulin, IGFBP4, and IGFBP5 in FF and plasma are affected by nutritional intake and may be related to follicular function.

Effects of selected hormones and their combination on progesterone and estradiol production and proliferation of feline granulosa cells cultured in vitro

Little is known about the hormonal regulation of feline ovarian granulosa cell proliferation and steroidogenesis. The present study aimed to develop a hormone responsive granulosa cell culture system to measure steroidogenic and cell proliferation responses to help identify factors that might regulate ovarian function in queens. Five experiments were conducted each with 75 or more ovaries, three in spring and two in fall seasons. Granulosa cells were isolated and treated in vitro with various hormones in serum-free medium for 48 h after an initial 48 h plating in 10% fetal calf serum. In granulosa cells isolated from spring and fall collected feline ovaries, IGF1 alone and combined with FSH stimulated (P < 0.05) cell proliferation, whereas FSH alone had no effect (P > 0.10) on cell proliferation. Also, in granulosa cells collected in spring and fall, IGF1 alone and FSH alone increased (P < 0.05) estradiol production by severalfold, and a combination of FSH and IGF1 increased (P < 0.05) estradiol production above either FSH or IGF1 treatment alone. The FSH plus IGF1 treatment increased (P < 0.05) CYP19A1 mRNA abundance by 27-fold. In contrast, EGF decreased (P < 0.05) FSH plus IGF1-induced estradiol production by over 80% in granulosa cells of both spring and fall collected ovaries. In granulosa cells isolated from spring and fall collected ovaries, IGF1 plus FSH inhibited (P < 0.05) progesterone production. Melatonin increased (P < 0.05) FSH plus IGF1-induced cell proliferation and amplified (P < 0.05) the FSH plus IGF1-induced inhibition of progesterone production. However, melatonin and GH had no effect (P > 0.10) on estradiol production either alone or in combination with FSH plus IGF1 in both spring and fall. Prolactin, FGF9 and activin had no effect (P > 0.10) on cell proliferation or steroidogenesis. FGF2 decreased (P < 0.05) estradiol production without affecting progesterone production or cell numbers. Growth differentiation factor 9 (GDF9) increased (P < 0.05) progesterone production but had no effect (P > 0.10) on granulosa cell proliferation or estradiol production. In conclusion, the in vitro system described herewithin may be useful to assess and evaluate ovarian function in feline species and has identified EGF, FSH and IGF1 as major regulators of feline ovarian follicular function.

Discovery of a possible role of asprosin in ovarian follicular function

Asprosin is a novel fasting-induced protein encoded by fibrillin-1 (FBN1) gene, produced when FBN1 is cleaved by the enzyme furin, and is associated with insulin resistance and polycystic ovarian syndrome in humans. To characterize mRNA abundance of FBN1, FURIN, and the presumed asprosin receptor, olfactory receptor family 4 subfamily M member 1 (OR4M1) in granulosa (GC) and theca cells (TC), and identify hormones regulating FBN1 mRNA expression, GC and TC from small (1-5 mm; SM) and large (>8 mm; LG) follicles were collected from ovaries of heifers obtained at an abattoir and used for real-time PCR gene expression analysis or in vitro evaluation of hormone regulation and asprosin effects. SMTC had 151-fold greater (P < 0.05) FBN1 mRNA abundance than SMGC, and LGTC had 50-fold greater FBN1 mRNA than LGGC. In contrast, OR4M1 mRNA was 81-fold greater in SMGC than LGGC and did not differ from SMTC, but LGTC had 9-fold greater OR4M1 mRNA than LGGC. FURIN mRNA was 2.6-fold greater in SMTC than SMGC, but did not differ among follicular sizes. In cultured TC, leptin, insulin, LH, IGF1 and steroids did not affect FBN1 mRNA, but TGFB1 increased (P < 0.05) FBN1 mRNA by 2.2-fold; EGF and FGFs increased FBN1 mRNA by 1.3- to 1.5-fold. Asprosin enhanced LH-induced TC androstenedione production, reduced IGF1-induced TC proliferation, and had no effect on progesterone production. Developmental regulation of FBN1, FURIN and OR4M1 along with direct effects of asprosin on TC suggests that asprosin may be a novel regulator of ovarian follicular function.

Developmental and hormonal regulation of ubiquitin-like with plant homeodomain and really interesting new gene finger domains 1 gene expression in ovarian granulosa and theca cells of cattle

Ubiquitin-like with plant homeodomain and really interesting new gene finger domains 1 (UHRF1) is a multi-domain nuclear protein that plays an important role in epigenetics and tumorigenesis, but its role in normal ovarian follicle development remains unknown. Thus, the present study evaluated if UHRF1 mRNA abundance in bovine follicular cells is developmentally and hormonally regulated, and if changes in UHRF1 are associated with changes in DNA methylation in follicular cells. Abundance of UHRF1 mRNA was greater in granulosa cells (GC) and theca cells (TC) from small (<6 mm) than large (≥8 mm) follicles and was greater in small-follicle GC than TC. In GC and TC, fibroblast growth factor 9 (FGF9) treatment increased (P < 0.05) UHRF1 expression by 2-fold. Also, luteinizing hormone (LH) and insulin-like growth factor 1 (IGF1) increased (P < 0.05) UHRF1 expression in TC by 2-fold, and forskolin (an adenylate cyclase inducer) alone or combined with IGF1 increased (P < 0.05) UHRF1 expression by 3-fold. An E2F transcription factor inhibitor (E2Fi) decreased (P < 0.05) UHRF1 expression by 44% in TC and by 99% in GC. Estradiol, progesterone, and dibutyryl-cAMP decreased (P < 0.05) UHRF1 mRNA abundance in GC. Treatment of GC with follicle-stimulating hormone (FSH) alone had no effect but when combined with IGF1 enhanced the UHRF1 mRNA abundance by 2.7-fold. Beauvericin (a mycotoxin) completely inhibited the FSH plus IGF1-induced UHRF1 expression in small-follicle GC. Treatments that increased UHRF1 mRNA (i.e., FGF9) in GC tended to decrease (by 63%; P < 0.10) global DNA methylation, and those that decreased UHRF1 mRNA (i.e., E2Fi) in GC tended to increase (by 2.4-fold; P < 0.10) global DNA methylation. Collectively, these results suggest that UHRF1 expression in both GC and TC is developmentally and hormonally regulated, and that UHRF1 may play a role in follicular growth and development as well as be involved in ovarian epigenetic processes.

Regulation of the transcription factor E2F1 mRNA in ovarian granulosa cells of cattle

The E2F family of transcription factors plays an important role in the control of the cell cycle, cell proliferation, and differentiation, and their role in ovarian function is just emerging. Although some evidence suggests a possible role of E2F1 in ovarian follicular development, what regulates its production in ovarian cells is unknown. Objectives of this study were to determine whether: (i) E2F1 gene expression in granulosa cells (GCs) and theca cells (TCs) change with follicular development and (ii) E2F1 mRNA abundance in TC and GC is hormonally regulated. Using real-time PCR, E2F1 mRNA abundance in GC was 5.5-fold greater (P < 0.05) in small (SM; 1 to 5 mm) than large (LG; >8 mm) follicles, but in TC, E2F1 expression did not differ among follicle sizes. SM-follicle GC had 2.1-fold greater (P < 0.05) E2F1 mRNA than TC. In SM-follicle GC, FGF9 induced a 7.6-fold increase in E2F1 mRNA abundance; however, FGF9 did not affect (P > 0.10) abundance of E2F1 mRNA in LG-follicle TC or GC. Follicle-stimulating hormone (FSH) had no effect (P > 0.10) on E2F1 gene expression in SM- or LG-follicle GC. SM-follicle GC were concomitantly treated with insulin-like growth factor 1 (30 ng/mL), FSH (30 ng/mL), and either 0 or 30 ng/mL of FGF9 with or without 50 µM of an E2F inhibitor (E2Fi; HLM0064741); FGF9 alone increased (P < 0.05) GC numbers, whereas E2Fi alone decreased (P < 0.05) GC numbers, and concomitant treatment of E2Fi with FGF9 blocked (P < 0.05) this stimulatory effect of FGF9. Estradiol production was inhibited (P < 0.05) by FGF9 alone and concomitant treatment of E2Fi with FGF9 attenuated (P < 0.05) this inhibitory effect of FGF9. SM-follicle GC treated with E2Fi decreased (P < 0.05) E2F1 mRNA abundance by 70%. Collectively, our studies show that GC E2F1 mRNA is developmentally and hormonally regulated in cattle. Inhibition of E2F1 reduced FGF9-induced GC proliferation and attenuated FGF9-inhibited estradiol production, indicating that E2F1 may be involved in follicular development in cattle.

Regulation of the transcription factor E2F8 gene expression in bovine ovarian cells

Overexpression of the transcription factor, E2F8, has been associated with ovarian cancer. Objectives of this study were to determine: 1) if E2F8 gene expression in granulosa cells (GC) and theca cells (TC) change with follicular development, and 2) if E2F8 mRNA abundance in TC and GC is hormonally regulated. Using real-time PCR, E2F8 mRNA abundance in GC and TC was greater (P < 0.05) in small than large follicles. FGF9 induced an increase (P < 0.05) in E2F8 mRNA abundance by 1.6- to 7-fold in large-follicle (8-20 mm) TC and GC as well as in small-follicle (1-5 mm) GC. Abundance of E2F8 mRNA in TC was increased (P < 0.05) with FGF2, FGF9 or VEGFA treatments alone in vitro, and concomitant treatment of VEGFA with FGF9 increased (P < 0.05) abundance of E2F8 mRNA above any of the singular treatments; BMP4, WNT3A and LH were without effect. IGF1 amplified the stimulatory effect of FGF9 on E2F8 mRNA abundance by 2.7-fold. Collectively, our studies show for the first time that follicular E2F8 is developmentally and hormonally regulated indicating that E2F8 may be involved in follicular development.

Effects of N-carbamylglutamate and L-arginine on gonadotrophin-releasing hormone (GnRH) gene expression and secretion in GT1-7 cells

Recent studies have shown that N-carbamylglutamate (NCG) and arginine (ARG) supplementation improves reproductive performance in livestock. The objectives of the present study were to evaluate the effects of NCG and ARG on GT1-7 cell gonadotrophin-releasing hormone (GnRH) secretion, gene expression and cell proliferation. GT1-7 cells were treated in vitro with different concentrations of NCG (0-1.0mM) or ARG (0-4.0mM) in serum-free medium for 12 or 24h. For GnRH secretion and cell proliferation, GT1-7 cells were more sensitive to NCG than ARG. NCG treatment after 12h increased cell numbers and inhibited GnRH secretion in a dose-dependent manner (P<0.05), although there was no significant effect of NCG on these parameters after 24h culture. ARG treatment decreased GnRH secretion after 24h (P<0.05), whereas it had no effect after 12h. GT1-7 cells express GnRH, Kiss-1 metastasis-suppressor (Kiss1), G-protein coupled receptor 54 (GPR54), neuronal nitric oxide synthase (nNOS) and estrogen receptor α (ERα) genes. High concentrations of NCG (1.0mM) and ARG (4.0mM) inhibited (P<0.05) GnRH and nNOS mRNA abundance in GT1-7 cells. ARG treatment decreased Kiss1 and increased ERα mRNA abundance. Thus, high concentrations of NCG (1.0mM) and ARG (4.0mM) may act both directly and indirectly to regulate GnRH neuron function by downregulating genes related to GnRH synthesis and secretion to slow GnRH production while stimulating GT1-7 cell proliferation.

Hormonal regulation of vascular endothelial growth factor A (VEGFA) gene expression in granulosa and theca cells of cattle1

Vascular endothelial growth factor A (VEGFA) stimulates angiogenesis and is associated with increased vascularity in ovarian follicles of cattle. The objectives of this study were to investigate the developmental and hormonal regulation of VEGFA expression in ovarian granulosa and theca cells (TC) of cattle. Bovine ovaries were collected from a local slaughterhouse and granulosa cells (GC) and TC were collected from small (SM; 1 to 5 mm) and large (LG; 8 to 20 mm) follicles. Cells were collected fresh or cultured in serum-free medium and treated with various factors that regulate angiogenesis and follicular development. RNA was collected for analysis of VEGFA mRNA abundance via quantitative PCR. In SM-follicle GC (SMGC), prostaglandin E2 (PGE2) and FSH decreased (P < 0.05) VEGFA mRNA abundance by 30 to 46%, whereas in LG-follicle GC (LGGC), PGE2 and FSH were without effect (P > 0.10). In SMGC, dihydrotestosterone (DHT), sonic hedgehog (SHH), and growth differentiation factor-9 (GDF9) decreased (P < 0.05) VEGFA expression by 30 to 40%. Fibroblast growth factor-9 (FGF9) and estradiol (E2) were without effect (P > 0.10) on VEGFA mRNA in both SMGC and LGGC, whereas progesterone increased (P < 0.05) VEGFA mRNA in LGGC but had no effect in LGTC. Bone morphogenetic protein-4 (BMP4), LH, and FGF9 increased (P < 0.05) abundance of VEGFA mRNA by 1.5- to 1.9-fold in LGTC. Insulin-like growth factor-1 (IGF1) was without effect (P > 0.10) on VEGFA mRNA in both TC and GC. An E2F transcription factor inhibitor, HLM0064741 (E2Fi), dramatically (i.e., 8- to 13-fold) stimulated (P < 0.01) the expression of VEGFA mRNA expression in both SMGC and LGTC. Abundance of VEGFA mRNA was greater (P < 0.05) in LGGC and SMGC than in LGTC. Also, SMTC had greater (P < 0.05) abundance of VEGFA mRNA than LGTC. In conclusion, VEGFA mRNA abundance was greater in GC than TC, and VEGFA expression decreased in TC during follicle development. Some treatments either suppressed, stimulated, or had no effect on VEGFA expression depending on the cell type. The inhibition of E2F transcription factors had the greatest stimulatory effect of all treatments evaluated, and thus, E2Fs may play an important role in regulating angiogenesis during follicle growth in cattle.

Effects of N-carbamylglutamate and arginine on steroidogenesis and proliferation of pig granulosa cells in vitro

Results of in vivo studies indicate dietary N-carbamylglutamate (NCG) and arginine (ARG) can enhance reproductive performance in gilts. It was hypothesized that both NCG and ARG will alter hormone-induced estradiol (E2) production by granulosa cells (GC), explaining why these compounds could improve reproductive performance in pigs. The objective of these studies, therefore, was to evaluate the direct effects of NCG and ARG on porcine GC proliferation and steroidogenesis, using an in vitro cell culture system. The GC from small (SM; 1-5 mm) and large (LG; >5 mm) pig follicles were cultured for 2 days in 5% fetal bovine serum and 5% porcine serum-containing medium followed by 2 days in serum-free medium containing 500 ng/mL of testosterone (as an E2 precursor), and NCG or ARG at various doses in the presence of either follicle-stimulating hormone (FSH; 30 ng/mL), insulin-like growth factor-1 (IGF1; 30 ng/mL), or both. Numbers of GC were determined at the end of the experiment and concentrations of progesterone (P4) and E2 in culture medium were determined. Results indicated that LG-follicle GC were more responsive to NCG and ARG than SM-follicle GC. Specifically, in LG-follicle GC, NCG inhibited (P <  0.05) basal and FSH-induced P4 and E2 production but stimulated cell numbers; whereas ARG inhibited FSH-induced E2 production and cell numbers. In SM-follicle GC, treatment with NCG and ARG decreased IGF1 plus FSH induced P4 production, but E2 production and cell proliferation were not affected. These studies indicate that NCG and ARG may directly affect follicular function in pigs.

The effects of protein supplementation of fall calving beef cows on pre- and postpartum plasma insulin, glucose and IGF-I, and postnatal growth and plasma insulin and IGF-I of calves

Fall calving (September to October) cows (n = 189 calvings in 5 replications; body weight [BW] = 626 ± 6 kg, body condition score [BCS] = 4.76 ± 0.06) grazing native dormant range were used to determine the effects of protein supplementation on performance and endocrine function of cows and calves. Cows were individually fed either a control (CON; 1.82 kg/d of 38% crude protein [CP]) or restricted (RES; 0.2 kg/d of 8% CP) protein supplement from mid-November to mid-March for 6 consecutive years. During each year, cows were reassigned dietary treatments according to calving date and BCS, and half of the CON and half of the RES cows remained on the same diets as the previous year and the other halves were assigned to the other diet. Statistical analyses were performed with the general linear model procedure utilizing a 2 × 2 factorial arrangement and a complete randomized design. Cows on CON diets lost less BW from November to January compared with RES cows (-25.9 ± 2.6 and -45.0 ± 2.6 kg, respectively; P < 0.001). Protein supplementation increased plasma concentrations of insulin of CON compared with RES cows during treatment (P < 0.05). Calf birth weight did not differ between prenatal supplemention of CON and RES (P = 0.87). A prenatal × postnatal effect was detected for BW of calves; prenatal RES and postnatal CON calves (RES-CON; 189.4 ± 4.2, P = 0.05) had greater 205-d adjusted weaning weights compared with prenatal RES and postnatal RES (RES-RES) and prenatal CON and postnatal RES (CON-RES) calves (163.0 ± 4.2 and 177.8 ± 4.2 kg, respectively). There was a prenatal × postnatal effect on gain of calves from January to weaning (P = 0.05); RES-CON gained more than RES-RES and CON-RES calves. Adjusted yearling 365-d BW was least (P = 0.02) for RES-RES calves. Prenatal protein supplementation of cows decreased (P = 0.03) final BW of calves at harvest (23 mo). Prenatal and postnatal supplementation of cows did not influence carcass characteristics of calves (P > 0.10). In conclusion, increasing protein supplementation of fall calving beef cows from November to March, during breeding and early pregnancy, reduced BW loss of cows, decreased the interval from calving to pregnancy, increased plasma concentrations of insulin in December, January, and March, and increased plasma insulin-like growth factor-I in December without alteration in pregnancy rate. Reduced protein supplementation prenatally increased BW of calves at harvest.

MicroRNA 221 expression in theca and granulosa cells: hormonal regulation and function

Small noncoding RNA molecules (miRNA) regulate protein levels in a post-transcriptional manner by partial base pairing to the 3'-UTR of target genes thus mediating degradation or translational repression. Previous studies indicate that numerous miRNA regulate the biosynthesis of intraovarian hormones, and emerging evidence indicates that one of these, miRNA-221 (MIR221), may be a modulator of ovarian function. However, the hormonal control of ovarian MIR221 is not known. The objectives of this study were to investigate the developmental and hormonal regulation of MIR221 expression in granulosa (GC) and theca cell (TC) and its possible role in regulating follicular function. Bovine ovaries were collected from a local abattoir and GC and TC were obtained from small (<6 mm) and large (≥8 mm) follicles. In Exp. 1, GCs of small follicles had 9.7-fold greater (P < 0.001) levels of MIR221 than those of large follicles, and TCs of large follicles had 3.7-fold greater (P < 0.001) levels of MIR221 than those of small follicles. In large follicles, abundance of MIR221 was 66.6-fold greater (P < 0.001) in TCs than in GCs. In small follicles, MIR221 abundance did not differ (P = 0.14) between GC and TCs. In vitro Exp. 2, 3, and 4 revealed that treatment of bovine TCs with various steroids, phytoestrogens, IGF1, forskolin, and dibutyryl cyclic adenosine monophosphate had no effect (P > 0.35) on MIR221 expression, whereas treatment with fibroblast growth factor 9 (FGF9) and FGF2 increased (P < 0.001) TC MIR221 abundance 1.7- to 2.5-fold. In Exp. 5, FGF9 increased (P < 0.05) GC MIR221 abundance by 1.7- and 2.0-fold in small and large follicles, respectively. The role of MIR221 in GC steroidogenesis was investigated in Exp. 6 and it was found that transfection with a MIR221 mimic reduced (P < 0.01) GC estradiol and progesterone production induced by FSH and IGF1, whereas transfection with MIR221 inhibitor had little or no effect. We conclude that thecal MIR221 expression is increased by FGF9 and increased MIR221 may act to inhibit GC steroidogenesis in cattle.

Fusarium Molds and Mycotoxins: Potential Species-Specific Effects

This review summarizes the information on biochemical and biological activity of the main Fusarium mycotoxins, focusing on toxicological aspects in terms of species-specific effects. Both in vitro and in vivo studies have centered on the peculiarity of the responses to mycotoxins, demonstrating that toxicokinetics, bioavailability and the mechanisms of action of these substances vary depending on the species involved, but additional studies are needed to better understand the specific responses. The aim of this review is to summarize the toxicological responses of the main species affected by Fusarium mycotoxins.

Transcriptome profiling of bovine ovarian theca cells treated with fibroblast growth factor 9

We reported previously that fibroblast growth factor 9 (FGF9) acts as an antidifferentiation factor, stimulating proliferation of granulosa cells (GCs) and theca cells (TCs) while suppressing hormone-induced steroidogenesis of these cells. How FGF9 acts to simultaneously suppress steroidogenesis and stimulate proliferation remains to be fully elucidated. Thus, this study was undertaken to clarify the effects of FGF9 on the TC transcriptome. Ovaries were obtained from beef heifers at a local abattoir, TCs were isolated from large antral follicles, and cultured with or without 30 ng/mL of FGF9 for 24 h in the presence of LH and IGF-1. After treatment, total RNA was extracted from TC and processed for microarray using Affymetrix GeneChip Bovine Genome Arrays (n = 4/group). Transcriptome analysis comparing FGF9-treated TC with control TC using 1.3-fold cutoff, and a P < 0.05 significance level identified 355 differentially expressed transcripts, with 164 elements upregulated and 191 elements downregulated by FGF9. The ingenuity pathway analysis (IPA) was used to investigate how FGF9 treatment affects molecular pathways, biological functions, and the connection between molecules in bovine TC. The IPA software identified 346 pathways in response to FGF9 in TC involved in several biological functions and unveiled interesting relationships among genes related to cell proliferation (eg, CCND1, FZD5, and MYB), antioxidation/cytoprotection (eg, HMOX1 and NQO1), and steroidogenesis (eg, CYP11A1 and STAR). Overall, genes, pathways, and networks identified in this study painted a picture of how FGF9 may regulate folliculogenesis, providing novel candidate genes for further investigation of FGF9 functions in ovarian follicular development.

The role of tight junction proteins in ovarian follicular development and ovarian cancer

Tight junctions (TJ) are protein structures that control the transport of water, ions and macromolecules across cell layers. Functions of the transmembrane TJ protein, occluding (OCLN) and the cytoplasmic TJ proteins, tight junction protein 1 (TJP1; also known as zona occludens protein-1), cingulin (CGN) and claudins (CLDN) are reviewed, and current evidence of their role in the ovarian function is reviewed. Abundance of OCLN, CLDNs and TJP1 mRNA changed during follicular growth. In vitro treatment with various growth factors known to affect ovarian folliculogenesis indicated that CGN, OCLN and TJP1 are hormonally regulated. The summarized studies indicate that expression of TJ proteins (i.e., OCLN, CLDN, TJP1 and CGN) changes with follicle size in a variety of vertebrate species but whether these changes in TJ proteins are increased or decreased depends on species and cell type. Evidence indicates that autocrine, paracrine and endocrine regulators, such as fibroblast growth factor-9, epidermal growth factor, androgens, tumor necrosis factor-α and glucocorticoids may modulate these TJ proteins. Additional evidence presented indicates that TJ proteins may be involved in ovarian cancer development in addition to normal follicular and luteal development. A model is proposed suggesting that hormonal downregulation of TJ proteins during ovarian follicular development could reduce barrier function (i.e., selective permeability of molecules between theca and granulosa cells) and allow for an increase in the volume of follicular fluid as well as allow additional serum factors into the follicle that may directly impact granulosa cell functions.

Influence of a Roundup formulation on glyphosate effects on steroidogenesis and proliferation of bovine granulosa cells in vitro

Glyphosate (N-phosphonomethyl-glycine) is a non-selective systemic herbicide widely used worldwide. The purpose of this study is to determine if glyphosate alone (GLPH) or in formulation with Roundup (G-RU) can affect granulosa cell proliferation and steroid production. Four experiments were conducted. In Exp. 1, 10 and 300 μg/mL of GLPH had no effect (P > 0.05) on cell numbers, estradiol or progesterone production, whereas 10 and 300 μg/mL of G-RU dramatically decreased (P < 0.05) cell numbers and estradiol and progesterone production. In Exp. 2, G-RU at 0.1 μg/mL had no significant effect whereas G-RU at 10 μg/mL decreased (P < 0.05) GC numbers, progesterone and estradiol production. In the absence of IGF1 but presence of FSH, 1 μg/mL of G-RU decreased (P < 0.05) estradiol production, whereas in the presence of IGF1 and FSH, 1 μg/mL of G-RU increased (P < 0.05) cell numbers, progesterone and estradiol production. In Exp. 3, IGF1 significantly increased cell numbers (by 2.8-fold) and estradiol (by 17.8-fold) and progesterone (by 6.1-fold) production. GLPH at 10 μg/mL alone had no significant effect on FSH-induced (i.e., basal) or FSH plus IGF1-induced cell numbers, estradiol or progesterone production. However, G-RU at 10 μg/mL significantly inhibited FSH plus IGF1-induced cell numbers, estradiol and progesterone production by 65%-91%. In Exp. 4, 48 h treatment of G-RU had no significant effect on viability of attached cells. In conclusion, the present studies demonstrate that GLPH and particularly G-RU may have the potential to impair reproductive function in cattle.

A Review of the Mycotoxin Enniatin B

Mycotoxin enniatin B (ENN B) is a secondary metabolism product by Fusarium fungi. It is a well-known antibacterial, antihelmintic, antifungal, herbicidal, and insecticidal compound. It has been found as a contaminant in several food commodities, particularly in cereal grains, co-occurring also with other mycotoxins. The primary mechanism of action of ENN B is mainly due to its ionophoric characteristics, but the exact mechanism is still unclear. In the last two decades, it has been a topic of great interest since its potent mammalian cytotoxic activity was demonstrated in several mammalian cell lines. Moreover, the co-exposure in vitro with other mycotoxins enhances its toxic potential through synergic effects, depending on the concentrations tested. Despite its clear cytotoxic effect, European Food Safety Authority stated that acute exposure to ENNs, such as ENN B, does not indicate concern for human health, but a concern might be the chronic exposure. However, given the lack of relevant toxicity data, no firm conclusion could be drawn and a risk assessment was not possible. In fact, very few studies have been carried out in vivo and, in these studies, no adverse effects were observed. So, research on toxicological effects induced by ENN B is still on-going. Recently, some studies are dealing with new advances regarding ENN B. This review summarizes the information on biochemical and biological activity of ENN B, focusing on toxicological aspects and on the latest advances in research on ENN B.

Effects of N-carbamylglutamate and L-arginine on steroidogenesis and gene expression in bovine granulosa cells

Feeding N-carbamylglutamate (NCG) and arginine (ARG) improves reproductive measures in pigs and reduces systemic steroid levels in pregnant ewes. We hypothesized that the effects of NCG and ARG on reproduction were due to direct effects on the ovary. Thus, the objectives of this study were to investigate the effects of NCG and ARG on granulosa cell (GC) steroidogenesis, gene expression, and cell proliferation in vitro. GC were collected from small (1-5mm) bovine follicles and treated in vitro with NCG or ARG in serum-free medium for 24h to 48h. Both NCG and ARG inhibited (P<0.05) IGF1- and FSH-induced GC estradiol production but only NCG inhibited (P<0.05) progesterone production. In contrast, NCG and ARG increased (P<0.05) GC numbers induced by IGF1 and FSH. NCG inhibited (P<0.05) StAR, CYP11A1 and CYP19A1 mRNA abundance in small-follicle GC, whereas ARG had no effect (P>0.10) on StAR, CYP11A1 or CYP19A1 mRNA abundance. We conclude that NCG and ARG may act directly on GC and therefore may regulate ovarian function by slowing follicular differentiation via inhibiting IGF1 action, and steroid synthesis while stimulating GC proliferation in cattle.

Evidence that gene expression of ovarian follicular tight junction proteins is regulated in vivo and in vitro in cattle

Tight junctions (TJ) are common paracellular sealing structures that control the transport of water, ions, and macromolecules across cell layers. Because the role of TJ in bovine follicular development is unknown, we investigated the developmental and hormonal regulation of the transmembrane TJ protein, occludin (OCLN), and the cytoplasmic TJ proteins, TJ protein 1 (TJP1) and cingulin (CGN) in bovine granulosa cells (GC) and theca cells (TC). For this purpose, bovine GC and TC were isolated from large (>8 mm) and/or small (1 to 5 mm) follicles and either extracted for real-time PCR (qPCR) or cultured in vitro. The abundances of both and mRNA were greater ( < 0.05) in TC than GC, whereas the mRNA abundance was greater ( < 0.05) in GC than TC. The abundance of mRNA in both GC and TC was greater ( < 0.05) in small follicles compared with large follicles, whereas the GC of large follicles had less ( < 0.05) mRNA abundance than the GC of small follicles. The abundance of mRNA in GC or TC did not differ ( > 0.10) among follicle sizes. In vitro treatment with various growth factors known to affect ovarian folliculogenesis indicated that , , and were hormonally regulated. Fibroblast growth factor 9 (FGF9) decreased ( < 0.05) the and mRNA abundances. Tumor necrosis factor α (TNFα) and vascular endothelial growth factor A (VEGFA) increased ( < 0.05) the mRNA abundance but decreased ( < 0.05) the mRNA abundance. Dexamethasone (DEX) increased ( < 0.05) and mRNA abundances. Epidermal growth factor (EGF) decreased ( < 0.05) and dihydrotestosterone (DHT) increased ( < 0.05) the abundances of , , and mRNA. We propose that the downregulation of OCLN and other TJ proteins during follicular development could reduce barrier function, thereby participating in increasing follicle size by allowing for an increase in the volume of follicular fluid as well as by allowing additional serum factors into the follicular fluid that potentially may directly impact GC functions. The results of the current study indicate the following in cattle: 1) gene expression of TJ proteins (i.e., , , and ) differs between GC and TC and changes with follicle size, and 2) autocrine, paracrine, and endocrine regulators, such as FGF9, EGF, DHT, TNFα, and glucocorticoids, modulate , , and mRNA abundance in TC in vitro.

Current status of the role of endothelins in regulating ovarian follicular function: A review

Endothelins (EDN) are a group of vasoactive 21 amino acid peptides reported to play roles in steroidogenesis, folliculogenesis, and ovulation. EDN1, EDN2 and EDN3 have all been shown to affect granulosa cell (GC) function in a variety of mammalians species. Herewithin, the role of EDN in regulating steroidogenesis and ovarian follicular development is reviewed, focusing on the localization and function of EDN and their receptors in ovarian follicular function emphasizing species differences. For example, in single ovulating species such as humans and cattle, in the presence of trophic hormones such as FSH and IGF1, EDN1 and EDN2 significantly inhibited GC estradiol production in 2 of 4 studies, while no effect was observed for GC progesterone production in 2 of 4 studies. In contrast, EDN1 exhibited inhibitory effects on progesterone production by GC in 3 of 3 studies in pigs and 3 of 4 studies in rats. Also, EDN1 inhibited GC estradiol production in 4 of 5 studies in rats. Altogether, these results indicate that EDN are produced by ovarian follicles and are involved in the regulation of steroidogenesis of GC of several mammalian species including humans, cattle, pigs and rats, but that these effects may vary with species and culture condition.

Evidence for direct effects of glyphosate on ovarian function: glyphosate influences steroidogenesis and proliferation of bovine granulosa but not theca cells in vitro

Glyphosate (GLY) is a common herbicide used worldwide but its effect on ovarian function in mammals is unknown. The aim of this study was to determine the potential endocrine disruptor effects of GLY on ovarian function evaluating cell proliferation, steroidogenesis and gene expression using bovine granulosa cells (GC) and theca cells as in vitro models. GC proliferation was impaired (P < 0.05) after exposure to GLY at 0.5, 1.7 and 5 μg ml-1 . GC progesterone production was not affected (P ≥ 0.05) at all doses tested while estradiol production was inhibited (P < 0.05) by GLY at 5 μg ml-1 . At the same concentration GLY showed no effect (P ≥ 0.05) on theca cell proliferation and steroidogenesis. At higher concentrations (0.01 and 0.3 mg ml-1 ), GLY had no significant effect (P ≥ 0.05) on GC proliferation and steroidogenesis. These studies, for the first time, suggest that GLY may affect the reproductive system in cattle via direct action on ovarian function; however, further studies will be required to understand better the mechanism of action and to determine the in vivo reproductive effects of GLY. Copyright © 2016 John Wiley & Sons, Ltd.

G protein-coupled receptor 34 in ovarian granulosa cells of cattle: changes during follicular development and potential functional implications

Abundance of G protein-coupled receptor 34 (GPR34) mRNA is greater in granulosa cells (GCs) of cystic vs normal follicles of cattle. The present experiments were designed to determine if GPR34 mRNA in granulosa cell [GC] changes during selection and growth of dominant follicles in cattle as well as to investigate the hormonal regulation of GPR34 mRNA in bovine GC in vitro. In Exp. 1, estrous cycles of nonlactating cows were synchronized and then ovariectomized on either day 3-4 or 5-6 after ovulation. GPR34 mRNA abundance in GC was 2.8- to 3.8-fold greater (P < 0.05) in small (1-5 mm) and large (≥8 mm) estrogen-inactive dominant follicles than in large estrogen-active follicles. Also, GPR34 mRNA tended to be greater (P < 0.10) in F2 than F1 follicles on day 3-4 postovulation. In Exp. 2-7, ovaries were collected at an abattoir and GC were isolated and treated in vitro. Expression of GPR34 was increased (P < 0.05) 2.2-fold by IGF1. Tumor necrosis factor (TNF)-α decreased (P < 0.05) the IGF1-induced GPR34 mRNA abundance in small-follicle GC, whereas IGF1 decreased (P < 0.05) GPR34 expression by 45% in large-follicle GC. Treatment of small-follicle GC with either IL-2, prostaglandin E2 or angiogenin decreased (P < 0.05) GPR34 expression, whereas FSH, cortisol, wingless 3A, or hedgehog proteins did not affect (P > 0.10) GPR34 expression. In Exp. 6 and 7, 2 presumed ligands of GPR34, L-a-lysophosphatidylserine (LPPS) and LPP-ethanolamine, increased (P < 0.05) GC numbers and estradiol production by 2-fold or more in small-follicle GC, and this response was only observed in IGF1-treated GC. In conclusion, GPR34 is a developmentally and hormonally regulated gene in GC, and its presumed ligands enhance IGF1-induced proliferation and steroidogenesis of bovine GC.

Fibroblast growth factor 9 (FGF9) regulation of cyclin D1 and cyclin-dependent kinase-4 in ovarian granulosa and theca cells of cattle

To determine the mechanism by which fibroblast growth factor 9 (FGF9) alters granulosa (GC) and theca (TC) cell proliferation, cell cycle proteins that regulate progression through G1 phase of the cell cycle, cyclin D1 (CCND1) and cyclin-dependent kinase-4 (CDK4; CCND1's catalytic partner), were evaluated. Ovaries were obtained from a local abattoir, GC were harvested from small (1-5 mm) and large (8-22 mm) follicles, and TC were harvested from large follicles. GC and TC were plated in medium containing 10% fetal calf serum followed by various treatments in serum-free medium. Treatment with 30 ng/mL of either FGF9 or IGF1 significantly increased GC numbers and when combined, synergized to further increase GC numbers by threefold. Abundance of CCND1 and CDK4 mRNA in TC and GC were quantified via real-time PCR. Alone and in combination with IGF1, FGF9 significantly increased CCND1 mRNA expression in both GC and TC. Western blotting revealed that CCND1 protein levels were increased by FGF9 in TC after 6 h and 12 h of treatment, but CDK4 protein was not affected. A mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway inhibitor, U0126, significantly reduced FGF9-induced CCND1 mRNA expression to basal levels. For the first time we show that CCND1 mRNA expression is increased by FGF9 in bovine TC and GC, and that FGF9 likely uses the MAPK pathway to induce CCND1 mRNA production in bovine TC.

Changes in fibroblast growth factor 9 mRNA in granulosa and theca cells during ovarian follicular growth in dairy cattle

Fibroblast growth factor 9 (FGF9) has been suggested to act as an antidifferentiation factor in cattle by reducing steroidogenesis and increasing cell proliferation in granulosa (GC) and theca (TC) cells. The objective of this study was to characterize FGF9 mRNA abundance in GC and TC during development of dominant follicles in dairy cattle. Estrous cycles of nonlactating dairy cattle were synchronized, and ovaries were collected on either d 3 to 4 (n=8) or 5 to 6 (n=8) postovulation for GC and TC RNA extraction from small (1-5mm), medium (5.1-8mm), and large (8.1-18mm) follicles for PCR analysis. The FGF9 mRNA abundance was greater in GC than in TC. In GC, FGF9 mRNA abundance was greater in small, medium, and large estrogen-inactive [i.e., concentrations of estradiol (E2)<progesterone (P4)] follicles than in large E2-active (i.e., concentrations of E2>P4) follicles at both early (d 3-4) and late (d 5-6) growing phases of first dominant follicle. Abundance of FGF9 mRNA increased in medium-sized follicles from early to late growing phase of the dominant follicle. In TC, FGF9 mRNA abundance was greater in large E2-inactive follicles than in large E2-active follicles on d 3 to 4 postovulation; no significant differences in TC FGF9 mRNA existed among follicle types on d 5 to 6 postovulation. Correlations among levels of follicular fluid hormones and FGF9 mRNA levels revealed significant negative correlations between GC FGF9 mRNA abundance and follicular fluid E2 (r=-0.68), free IGF-1 (r=-0.63), and E2-to-P4 ratio (r=-0.58). In summary, abundance of FGF9 mRNA in GC and TC increases in medium-sized follicles during development of dominant follicles and is less in dominant E2-active than subordinate E2-inactive follicles, suggesting that FGF9 signaling could contribute to normal follicle development and steroidogenesis in dairy cattle.

Changes in brain ribonuclease (BRB) messenger RNA in granulosa cells (GCs) of dominant vs subordinate ovarian follicles of cattle and the regulation of BRB gene expression in bovine GCs

Brain ribonuclease (BRB) is a member of the ribonuclease A superfamily that is constitutively expressed in a range of tissues and is the functional homolog of human ribonuclease 1. This study was designed to characterize BRB gene expression in granulosa cells (GCs) during development of bovine dominant ovarian follicles and to determine the hormonal regulation of BRB in GCs. Estrous cycles of Holstein cows (n = 18) were synchronized, and cows were ovariectomized on either day 3 to 4 or day 5 to 6 after ovulation during dominant follicle growth and selection. Ovaries were collected, follicular fluid (FFL) was aspirated, and GCs were collected for RNA isolation and quantitative polymerase chain reaction. Follicles were categorized as small (1-5 mm; pooled per ovary), medium (5-8 mm; individually collected), or large (8.1-17 mm; individually collected) based on surface diameter. Estradiol (E2) and progesterone (P4) levels were measured by radioimmunoassay (RIA) in FFL. Abundance of BRB messenger RNA (mRNA) in GCs was 8.6- to 11.8-fold greater (P < 0.05) in small (n = 31), medium (n = 66), and large (n = 33) subordinate E2-inactive (FFL E2 < P4) follicles than in large (n = 16) dominant E2-active (FFL E2 > P4) follicles. In the largest 4 follicles, GCs BRB mRNA abundance was negatively correlated (P < 0.01) with FFL E2 (r = -0.65) and E2:P4 ratio (r = -0.46). In experiment 2, GCs from large (8-22 mm diameter) and small (1-5 mm diameter) follicles were treated with insulin-like growth factor 1 (IGF1; 0 or 30 ng/mL) and/or tumor necrosis factor alpha (0 or 30 ng/mL); IGF1 increased (P < 0.05) BRB mRNA abundance, and tumor necrosis factor alpha decreased (P < 0.001) the IGF1-induced BRB mRNA abundance in large-follicle GCs. In experiment 3 to 6, E2, follicle-stimulating hormone, fibroblast growth factor 9, cortisol, wingless 3A, or sonic hedgehog did not affect (P > 0.10) abundance of BRB mRNA in GCs; thyroxine and luteinizing hormone increased (P < 0.05), whereas prostaglandin E2 (PGE2) decreased (P < 0.05) BRB mRNA abundance in small-follicle GCs. Treatment of small-follicle GCs with recombinant human RNase1 increased (P < 0.05) GCs numbers and E2 production. In conclusion, BRB is a hormonally and developmentally regulated gene in bovine GCs and may regulate E2 production during follicular growth in cattle.

In vitro effects of deoxynivalenol and zearalenone major metabolites alone and combined, on cell proliferation, steroid production and gene expression in bovine small-follicle granulosa cells

The effects of deoxynivalenol (DON) and zearalenone (ZEA) on reproduction in ruminants are unclear. This study was performed to evaluate the impact of DON and ZEA hydroxylated metabolites, α-zearalenol (α-Zol) and β-zearalenone (β-Zol), on cell proliferation, steroidogenesis and gene expression using bovine granulosa cells (GC). Cell proliferation was negatively affected after exposure to β-Zol at 31 μM and after exposure to α-Zol (3.1 μM) alone and combined with DON (3.3 μM). DON and α-Zol decreased steroidogenesis, while β-Zol at high concentration had stimulatory effects. DON and β-Zol increased CYP19A1 mRNA abundance. CYP11A1 mRNA abundance was stimulated by DON, alone and combined with α-Zol and β-Zol, whereas was inhibited by β-Zol alone. Generally mycotoxins effects on cell proliferation, steroidogenesis and gene expression were influenced by the presence or absence of IGF1. In conclusion DON and ZEA metabolites may impair in vitro cell proliferation, steroid production and gene expression in cattle.

Individual and combined effects of deoxynivalenol and α-zearalenol on cell proliferation and steroidogenesis of granulosa cells in cattle

This study was conducted to evaluate the impact of deoxynivalenol (DON) and zearalenone (ZEA) metabolite, α-zearalenol (α-Zol), on cell proliferation and steroidogenesis of bovine large (LG) follicle granulosa cells (GC). LGGC were obtained from bovine ovarian follicles (8-22 mm) and were cultured for 2 days in medium containing 10% fetal bovine serum followed by 1 or 2 days in serum-free medium without (control) or with treatments. Three different experiments were performed using different dosages of DON and α-Zol and in different combinations and a fourth experiment evaluated estradiol effects on granulosa cell proliferation. DON inhibited progesterone (P4) and estradiol (E2) production at high dose. α-Zol alone and in combination with DON increased cell growth. Estradiol inhibited cell growth indicating α-Zol is not acting as an estrogen agonist. This study demonstrates that α-Zol and DON can impact in vitro GC function, however further studies will be required to better understand the mechanism of action and reproductive effects of Fusarium mycotoxins.

Direct effects of the algal toxin, domoic acid, on ovarian function: Bovine granulosa and theca cells as an in vitro model

Domoic acid (DA) is a potent neurotoxin produced by alga Pseudo-nitzschia spp. and has been associated with reproductive disorders in mammals. The aim of this study was to investigate if DA can affect the reproductive system via direct action on ovarian function. Bovine granulosa and theca cells were used as in vitro models for evaluating DA effects on ovarian cell proliferation and steroid production. In small-follicle granulosa cells (SMGC), cell proliferation and estradiol (E2) production was not affected (P>0.05) while progesterone (P4) production was inhibited (P<0.05) by DA at all doses tested. In large-follicle granulosa cells (LGGC), DA had no effect (P>0.05) on cell proliferation or P4 production while E2 production was stimulated by 1 and 5 µg/ml DA (P<0.05). DA (1 µg/ml) attenuated (P<0.05) insulin-like growth factor 1 (IGF-1)-induced P4 production by large-follicle theca cells (LGTC), but did not affect androstenedione (A4) production or proliferation of LGTC. In glutamate-free medium, DA inhibited (P<0.05) SMGC E2 production and this inhibition was similar to inhibition of E2 by trans-(±)-1-amino-1,3-cyclopentanedicarboxylic acid monohydrate (ACPD; a selective metabotropic glutamate receptor subtype agonist) while kainic acid (KA; an ionotropic glutamate receptor subtype agonist) had no effect (P>0.10) on E2 production. Collectively, these results show for the first time that DA has direct effects on ovarian GC and TC steroidogenesis. Because DA inhibited E2 and P4 production, DA has the potential to be an endocrine disruptor.

Maintenance energy requirements of beef cows and relationship with cow and calf performance, metabolic hormones, and functional proteins

Gestating Angus, nonlactating, spring-calving cows were used to determine variation in maintenance energy requirements (MR); to evaluate the relationship among MR and cow and calf performance, plasma concentrations of IGF-I, T4, glucose, insulin, and ruminal temperature; and to describe the LM proteome and evaluate protein abundance in cows with different MR. Cows (4 to 7 yr of age) with a BCS of 5.0 ± 0.2 and BW of 582 ± 37 kg in the second to third trimester of gestation were studied in 3 trials (trial 1, n = 23; trial 2, n = 32; trial 3, n = 38). Cows were individually fed a complete diet in amounts to meet predicted MR (Level 1 Model of NRC), and feed intake was adjusted weekly until constant BW was achieved for at least 21 d (maintenance). Cows were classified on the basis of MR as low (>0.5 SD less than mean, LMR), moderate (±0.5 SD of mean, MMR), or high (>0.5 SD more than mean, HMR) MR. Blood samples were taken at maintenance and at 2 mo postpartum in trial 2. Muscle biopsies were taken from LMR and HMR after cows consumed actual MR for 28 d (trial 2) or 21 d (trial 3). Proteins from LM were separated by 2-dimensional difference gel electrophoresis and were identified, and abundance was quantified and compared. The greatest differences in MR between cows were 29%, 24%, and 25% in trials 1, 2, and 3, respectively. Daily MR (NEm, kcal·BW(-0.75)·d(-1)) averaged 89.2 ± 6.3, 93.0 ± 4.9, and 90.4 ± 4.6 in trials 1, 2, and 3, respectively. Postpartum BW and BCS, calf birth and weaning weights, postpartum luteal activity, and ruminal temperature were not influenced by MR of the cows. Concentrations of IGF-I were greater (P = 0.001) in plasma of MMR compared with LMR cows consuming predicted MR diets, and MR was negatively correlated with concentrations of IGF-I in plasma (r = -0.38; P = 0.05) at 2 mo postpartum. A total of 103 proteins were isolated from LM; 52 gene products were identified. Abundance of specific proteins in the LM was not influenced (P > 0.11) by MR. Variation in MR of cows will make it possible to improve feed efficiency by selection. Identification of biomarkers for MR will allow selection of more efficient cows, which consume less feed and produce calves with similar weaning weights. Productive cows that require less feed for maintenance will improve efficiency of production and enhance sustainability of the environment.

Effects of fibroblast growth factor 9 on steroidogenesis and control of FGFR2IIIc mRNA in porcine granulosa cells

The objectives of this study were to investigate the effects of fibroblast growth factor 9 (FGF9) on hormone-stimulated porcine granulosa cell proliferation and steroid production and to further elucidate the hormonal and developmental control of FGFR2IIIc gene expression in granulosa cells. Porcine ovaries were collected from a local slaughterhouse and granulosa cells were collected from small to medium (1 to 5 mm) follicles for 5 in vitro studies that were conducted. Cells were cultured for 48 h in 5% fetal calf serum plus 5% porcine serum and then treated with various combinations of FSH, IGF-I, FGF9, Sonic hedgehog (SHH), cortisol, PGE2, and/or wingless-type mouse mammary tumor virus integration site family member 5A (WNT5A) in serum-free medium for an additional 24 or 48 h. Medium was collected for analysis of steroid concentration via RIA, or RNA was collected for gene expression analysis of FGFR2IIIc via quantitative reverse transcription PCR. Fibroblast growth factor 9 stimulated (P < 0.05) IGF-I-induced estradiol production in the presence of FSH and testosterone. However, FGF9 had inconsistent effects on progesterone production, stimulating progesterone production in the presence of FSH and testosterone but inhibiting progesterone production in the presence of IGF-I, FSH, and testosterone. Cell numbers were increased (P < 0.05) by FGF9 in the presence of IGF-I and FSH but not in the presence of FSH and absence of IGF-I. For FGFR2IIIc mRNA studies, granulosa cells were treated with FSH, IGF-I, FGF9, SHH, cortisol, PGE2, or WNT5A. Follicle-stimulating hormone alone had no effect (P > 0.10) whereas IGF-I increased (P < 0.05) FGFR2IIIc mRNA abundance. Cortisol, PGE2, SHH, and WNT5A had no effect (P > 0.10) on FGFR2IIIc gene expression whereas FGF9 in the presence of FSH and IGF-I inhibited (P < 0.05) FGFR2IIIc gene expression. In an in vivo study, granulosa cells from large (7 to 14 mm) follicles had greater (P < 0.05) abundance of FGFR2IIIc mRNA than small (1 to 3 mm) or medium (4 to 6 mm) follicles. In conclusion, IGF-I-induced FGFR2IIIc mRNA may be a mechanism for increased responses to FGF9 in FSH plus IGF-I-treated granulosa cells. Fibroblast growth factor 9 and IGF-I may work together as amplifiers of follicular growth and granulosa cell differentiation by stimulating estradiol production and concomitantly stimulating granulosa cell growth in pigs.

Possible role of IGF2 receptors in regulating selection of 2 dominant follicles in cattle selected for twin ovulations and births

Abundance of IGF-2 receptor (IGF2R), FSH receptor (FSHR), and LH receptor (LHCGR) mRNA in granulosa cells (GCs) or theca cells (TCs) or both cells as well as estradiol (E2), progesterone (P4), and androstenedione concentrations in follicular fluid were compared in cows genetically selected (Twinner) or not selected (control) for multiple ovulations and twin births. Cows were slaughtered at day 3 to 4 (day 3) and day 5 to 6 (day 5) of an estrous cycle, and ovaries, follicular fluid, GCs, and TCs were collected. The two largest (F1 and F2) E2-active (EA) and E2-inactive (EI) follicles were selected according to their E2-to-P4 ratio and diameter. Androstenedione levels in EA F1 and F2 follicles were 5-fold greater (P < 0.05) in Twinner cows than in control cows on day 3 but did not differ on day 5. Twinner cows also had greater (P < 0.05) E2 and P4 concentrations, whereas steroid levels in EI follicles did not differ (P > 0.10) between genotypes. In EA F2 follicles, IGF2R levels in GCs were greater (P < 0.05) in control cows than in Twinner cows on day 3 and day 5, whereas IGF2R mRNA in TCs did not differ (P > 0.10). On day 3, FSHR mRNA levels were greater (P < 0.05) in GCs of EA F1 and EI F2 follicles of control cows than of Twinner cows. LH receptor mRNA expression was less in GCs and greater in TCs of EA F2 follicles in control cows than in Twinner cows (P < 0.05). We hypothesize that reduced GC IGF2R expression in F2 follicles of Twinner cows may play a role in the development of 2 or more dominant follicles.