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

Summers AF, Pohlmeier WE, Sargent KM, Cole BD, Vinton RJ, Kurz SG, McFee RM, Cushman RA, Cupp AS, Wood JR - PLoS ONE (2014)

Bottom Line: 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.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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America.

ABSTRACT
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.

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HPLC/MS-MS Analysis of Dominant Follicle Sex Steroid Concentrations Collected after Ovariectomy.Differences in concentration of androgens (A) and estrogens (B) was determined by HPLC/MS-MS (Biocrates Life Sciences AG) analysis for High A4 (black bars) and Low (white bars) A4 cows. *, P≤0.05.
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pone-0110683-g002: HPLC/MS-MS Analysis of Dominant Follicle Sex Steroid Concentrations Collected after Ovariectomy.Differences in concentration of androgens (A) and estrogens (B) was determined by HPLC/MS-MS (Biocrates Life Sciences AG) analysis for High A4 (black bars) and Low (white bars) A4 cows. *, P≤0.05.

Mentions: In order to assess the relative concentrations of multiple steroids in a single follicular fluid sample, fluid collected from the E2-active dominant follicles of 7 High A4 (mean A4 = 1293.0±296.6 nM) and 7 Low A4 (mean A4 = 8.2±1.1 nM) cows were subjected to HPLC/MS/MS. Testosterone (T) concentration (Fig. 2A) was increased 30.8-fold (P = 0.002) in High A4 samples; whereas, estrone (E1) concentrations tended to be increased 2.64-fold (P  = 0.11, Fig. 2B). Similar to the individual hormone assays carried out on follicular fluid from all cows in the ovariectomy trial, DHEA, A4, and E2 (Table 1, Fig. 2A and B) concentrations were also increased (P≤0.01) in High A4 samples. Interestingly, when calculating the conversion rates of androgens and estrogens in the follicular fluid, High A4 cows had a 7-fold increase in A4:DHEA (P = 0.0005) compared with Low A4 cows. However the ratio of A4 to T (T:A4) was reduced in High A4 cows (P = 0.05). Similarly High A4 cows had reduced E1:A4 (P = 0.01) and E2:T (P = 0.04) compared with Low A4 cows; suggesting that there was less efficient conversion of androgens to estrogens in dominant follicles of High A4 cows.


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

Summers AF, Pohlmeier WE, Sargent KM, Cole BD, Vinton RJ, Kurz SG, McFee RM, Cushman RA, Cupp AS, Wood JR - PLoS ONE (2014)

HPLC/MS-MS Analysis of Dominant Follicle Sex Steroid Concentrations Collected after Ovariectomy.Differences in concentration of androgens (A) and estrogens (B) was determined by HPLC/MS-MS (Biocrates Life Sciences AG) analysis for High A4 (black bars) and Low (white bars) A4 cows. *, P≤0.05.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4199720&req=5

pone-0110683-g002: HPLC/MS-MS Analysis of Dominant Follicle Sex Steroid Concentrations Collected after Ovariectomy.Differences in concentration of androgens (A) and estrogens (B) was determined by HPLC/MS-MS (Biocrates Life Sciences AG) analysis for High A4 (black bars) and Low (white bars) A4 cows. *, P≤0.05.
Mentions: In order to assess the relative concentrations of multiple steroids in a single follicular fluid sample, fluid collected from the E2-active dominant follicles of 7 High A4 (mean A4 = 1293.0±296.6 nM) and 7 Low A4 (mean A4 = 8.2±1.1 nM) cows were subjected to HPLC/MS/MS. Testosterone (T) concentration (Fig. 2A) was increased 30.8-fold (P = 0.002) in High A4 samples; whereas, estrone (E1) concentrations tended to be increased 2.64-fold (P  = 0.11, Fig. 2B). Similar to the individual hormone assays carried out on follicular fluid from all cows in the ovariectomy trial, DHEA, A4, and E2 (Table 1, Fig. 2A and B) concentrations were also increased (P≤0.01) in High A4 samples. Interestingly, when calculating the conversion rates of androgens and estrogens in the follicular fluid, High A4 cows had a 7-fold increase in A4:DHEA (P = 0.0005) compared with Low A4 cows. However the ratio of A4 to T (T:A4) was reduced in High A4 cows (P = 0.05). Similarly High A4 cows had reduced E1:A4 (P = 0.01) and E2:T (P = 0.04) compared with Low A4 cows; suggesting that there was less efficient conversion of androgens to estrogens in dominant follicles of High A4 cows.

Bottom Line: 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.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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America.

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus