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Crouse MS, Trotta RJ, Freetly HC, Lindholm-Perry AK, Neville BW, Oliver WT, Hammer CJ, Syring JG, King LE, Neville TL, Reynolds LP, Dahlen CR, Caton JS, Ward AK, Cushman RA. Disrupted one-carbon metabolism in heifers negatively affects their health and physiology. J Anim Sci 2024; 102:skae144. [PMID: 38770669 PMCID: PMC11176977 DOI: 10.1093/jas/skae144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 05/20/2024] [Indexed: 05/22/2024] Open
Abstract
The objective of this study was to determine the dose-dependent response of one-carbon metabolite (OCM: methionine, choline, folate, and vitamin B12) supplementation on heifer dry matter intake on fixed gain, organ mass, hematology, cytokine concentration, pancreatic and jejunal enzyme activity, and muscle hydrogen peroxide production. Angus heifers (n = 30; body weight [BW] = 392.6 ± 12.6 kg) were individually fed and assigned to one of five treatments: 0XNEG: total mixed ration (TMR) and saline injections at days 0 and 7 of the estrous cycle, 0XPOS: TMR, rumen-protected methionine (MET) fed at 0.08% of the diet dry matter, rumen-protected choline (CHOL) fed at 60 g/d, and saline injections at days 0 and 7, 0.5X: TMR, MET, CHOL, 5-mg B12, and 80-mg folate injections at days 0 and 7, 1X: TMR, MET CHOL, 10-mg vitamin B12, and 160-mg folate at days 0 and 7, and 2X: TMR, MET, CHOL, 20-mg vitamin B12, and 320-mg folate at days 0 and 7. All heifers were estrus synchronized but not bred, and blood samples were collected on days 0, 7, and at slaughter (day 14) during which tissues were collected. By design, heifer ADG did not differ (P = 0.96). Spleen weight and uterine weight were affected cubically (P = 0.03) decreasing from 0XPOS to 0.5X. Ovarian weight decreased linearly (P < 0.01) with increasing folate and B12 injection. Hemoglobin and hematocrit percentage were decreased (P < 0.01) in the 0.5X treatment compared with all other treatments. Plasma glucose, histotroph protein, and pancreatic α-amylase were decreased (P ≤ 0.04) in the 0.5X treatment. Heifers on the 2X treatment had greater pancreatic α-amylase compared with 0XNEG and 0.5X treatment. Interleukin-6 in plasma tended (P = 0.08) to be greater in the 0XPOS heifers compared with all other treatments. Lastly, 0XPOS-treated heifers had reduced (P ≤ 0.07) hydrogen peroxide production in muscle compared with 0XNEG heifers. These data imply that while certain doses of OCM do not improve whole animal physiology, OCM supplementation doses that disrupt one-carbon metabolism, such as that of the 0.5X treatment, can induce a negative systemic response that results in negative effects in both the dam and the conceptus during early gestation. Therefore, it is necessary to simultaneously establish an optimal OCM dose that increases circulating concentrations for use by the dam and the conceptus, while avoiding potential negative side effects of a disruptive OCM, to evaluate the long-term impacts of OCM supplementation of offspring programming.
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Affiliation(s)
- Matthew S Crouse
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933, USA
| | - Ronald J Trotta
- Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40546, USA
| | - Harvey C Freetly
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933, USA
| | | | - Bryan W Neville
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933, USA
| | - William T Oliver
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933, USA
| | - Carrie J Hammer
- Department of Animal Sciences, and Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND 58108, USA
| | - Jessica G Syring
- Department of Animal Sciences, and Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND 58108, USA
| | - Layla E King
- Department of Agriculture and Natural Resources, University of Minnesota Crookston, Crookston, MN 56716, USA
| | - Tammi L Neville
- Department of Animal Sciences, and Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND 58108, USA
| | - Lawrence P Reynolds
- Department of Animal Sciences, and Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND 58108, USA
| | - Carl R Dahlen
- Department of Animal Sciences, and Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND 58108, USA
| | - Joel S Caton
- Department of Animal Sciences, and Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND 58108, USA
| | - Alison K Ward
- Department of Veterinary Biomedical Science, University of Saskatchewan, Saskatoon, SK S7N5A2, Canada
| | - Robert A Cushman
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933, USA
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Hurlbert JL, Menezes ACB, Baumgaertner F, Bochantin-Winders KA, Jurgens IM, Kirsch JD, Amat S, Sedivec KK, Swanson KC, Dahlen CR. Vitamin and mineral supplementation to beef heifers during gestation: impacts on morphometric measurements of the neonatal calf, vitamin and trace mineral status, blood metabolite and endocrine profiles, and calf organ characteristics at 30 h after birth. J Anim Sci 2024; 102:skae116. [PMID: 38666437 PMCID: PMC11121445 DOI: 10.1093/jas/skae116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 04/23/2024] [Indexed: 05/26/2024] Open
Abstract
To examine the effects of feeding a vitamin and mineral supplement to beef heifers throughout gestation on mineral status and hormone/endocrine profiles in the dam and calf, and morphometric characteristics and organ mass of the calf at 30 h after birth, Angus-based heifers (n = 72, 14 to 15 mo of age, initial body weight [BW] = 380.4 ± 50.56 kg) were estrus synchronized and artificially inseminated (AI) with female-sexed semen. Heifers were blocked by BW and randomly assigned to receive either a basal diet (CON; n = 36) or a basal diet plus a vitamin and mineral supplement (VTM; n = 36) via an individual feeding system beginning at breeding, with both diets targeting BW gains of 0.45 kg heifer-1·d-1. Heifers not pregnant after the first AI (CON, n = 19; VTM, n = 18) were rebred via AI 60 d after treatment initiation, and heifers gestating female fetuses (CON, n = 7; VTM, n = 7) received treatments throughout gestation and were experimental units for this study. Calves were separated from their dams and fed colostrum replacer within 2 h of birth and euthanized 30 h after the first feeding. Calf morphometrics were recorded, and tissues were weighed and sampled. Serum from the dam at calving and serum, liver, and muscle from the calf at 30 h were analyzed for concentrations of minerals. Serum from the dam and calf were analyzed for concentrations of leptin, vitamins A, D, and E, cortisol, growth hormone, and insulin-like growth factor 1. All response variables were analyzed using the MIXED procedure of SAS. Calf body morphometrics and BW of the dam at calving (P ≥ 0.32), calf organ weights (P ≥ 0.21), and calf ovarian follicle counts (P ≥ 0.13) were not affected by maternal treatment. Concentrations of Se and Co in calf serum and Se in calf liver were increased (P ≤ 0.02) in VTM. Serum concentrations of Co and vitamin A in the dam were greater (P ≤ 0.01) in supplemented compared with nonsupplemented dams, and serum concentrations of vitamin D were greater (P ≤ 0.0003) in supplemented dams and calves compared with the nonsupplemented cohort. Maternal supplementation supported vitamin and mineral status in the neonate, yet had no discernable impact on BW, organ mass, or circulating hormones/metabolites in the calf. Evaluating offspring at later postnatal time points is warranted to determine if prenatal vitamin and mineral supplementation affects performance, health, metabolism, and efficiency of energy utilization in key metabolic tissues in the calf.
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Affiliation(s)
- Jennifer L Hurlbert
- Department of Animal Sciences, Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND, 58108, USA
| | - Ana Clara B Menezes
- Department of Animal Sciences, Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND, 58108, USA
| | - Friederike Baumgaertner
- Department of Animal Sciences, Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND, 58108, USA
- Central Grasslands Research Extension Center, North Dakota State University, Streeter, ND, 58483, USA
| | - Kerri A Bochantin-Winders
- Department of Animal Sciences, Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND, 58108, USA
| | - Isabella M Jurgens
- Department of Animal Sciences, Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND, 58108, USA
| | - James D Kirsch
- Department of Animal Sciences, Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND, 58108, USA
| | - Samat Amat
- Department of Microbiological Sciences, North Dakota State University, Fargo, ND, 58108, USA
| | - Kevin K Sedivec
- Central Grasslands Research Extension Center, North Dakota State University, Streeter, ND, 58483, USA
| | - Kendall C Swanson
- Department of Animal Sciences, Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND, 58108, USA
| | - Carl R Dahlen
- Department of Animal Sciences, Center for Nutrition and Pregnancy, North Dakota State University, Fargo, ND, 58108, USA
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Abedal-Majed MA, Abuajamieh M, Al-Qaisi M, Sargent KM, Titi HH, Alnimer MA, Abdelqader A, Shamoun AI, Cupp AS. Sheep with ovarian androgen excess have fibrosis and follicular arrest with increased mRNA abundance for steroidogenic enzymes and gonadotropin receptors. J Anim Sci 2023; 101:skad082. [PMID: 37061806 PMCID: PMC10184696 DOI: 10.1093/jas/skad082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 03/15/2023] [Indexed: 04/17/2023] Open
Abstract
An androgen excess ovarian micro-environment may limit follicle progression in sheep. Two populations of ewes with divergent follicular fluid androstenedione (A4) were identified in a flock in Jordan: High A4; (A4) ≥ 30 ng/mL, (N = 12) or Control A4 (Control); A4 ≤ 15 ng/mL; (N = 12). We hypothesized High A4 ewes would have increased steroidogenic enzyme mRNA abundance, inflammation, and follicular arrest. Messenger RNA abundance for steroidogenic enzymes StAR, CYP17A1, CYP11A1, and HSD3B1 were increased in theca cells while CYP17A1, CYP19A1, and HSD3B1 were increased in granulosa cells in High A4 ewes compared to Control. Gonadotropin receptor mRNA expression for LHCGR was increased in theca and FSHR in granulosa in High A4 ewes. Messenger RNA expression of FOS when reduced, increases expression of CYP17A1 which was observed in High A4 granulosa cells compared to Control. Furthermore, High A4 ewes had greater numbers of primordial follicles (P < 0.001) and fewer developing follicles compared to Control before, and after 7 d of culture, indicating follicular arrest was not alleviated by cortex culture. Increased fibrosis in the ovarian cortex was detected in High A4 ewes relative to Control (P < 0.001) suggesting increased inflammation and altered extracellular matrix deposition. Thus, this High A4 ewes population has similar characteristics to High A4 cows and women with polycystic ovary syndrome suggesting that naturally occurring androgen excess occurs in multiple species and may be a causative factor in follicular arrest and subsequent female sub- or infertility.
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Affiliation(s)
- Mohamed A Abedal-Majed
- Department of Animal Production, School of Agriculture, The University of Jordan, Amman 11942, Jordan
| | - Mohannad Abuajamieh
- Department of Animal Production, School of Agriculture, The University of Jordan, Amman 11942, Jordan
| | - Mohmmad Al-Qaisi
- Department of Animal Production, School of Agriculture, The University of Jordan, Amman 11942, Jordan
| | - Kevin M Sargent
- Department of Agriculture, Southeast Missouri State University, Cape Girardeau, MO 63701, USA
| | - Hosam H Titi
- Department of Animal Production, School of Agriculture, The University of Jordan, Amman 11942, Jordan
| | - Mufeed A Alnimer
- Department of Animal Production, School of Agriculture, The University of Jordan, Amman 11942, Jordan
| | - Anas Abdelqader
- Department of Animal Production, School of Agriculture, The University of Jordan, Amman 11942, Jordan
| | - Ahmad I Shamoun
- Department of Animal Production, School of Agriculture, The University of Jordan, Amman 11942, Jordan
| | - Andrea S Cupp
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln (UNL), Nebraska 68583, USA
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Cushman RA, Soares ÉM, Yake HK, Patterson AL, Rosasco SL, Beard JK, Northrop EJ, Rich JJJ, Miles JR, Chase CC, Gonda MG, Perry GA, McNeel AK, Summers AF. Brangus cows have ovarian reserve parameters more like Brahman than Angus cows. Anim Reprod Sci 2019; 209:106170. [PMID: 31514925 DOI: 10.1016/j.anireprosci.2019.106170] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/15/2019] [Accepted: 08/19/2019] [Indexed: 11/18/2022]
Abstract
Bos indicus females have more surface antral follicles than Bos taurus females; however, histological studies demonstrated no difference in total number of primordial follicles between these two biological types of cattle. Primordial follicle density in the ovary was less in Nelore ovaries compared to Angus ovaries, but no studies have examined the primordial follicle density in Bos indicus cross-bred females. It, therefore, was hypothesized that primordial follicle density in the ovary would decrease as percentage Bos indicus increased. Ovaries were collected from cross-bred Angus (n = 32, no Bos indicus influence), Brangus (n = 15), or Brahman (n = 9) cows and prepared for histological evaluation. There was no difference in total number of primordial follicles per ovary between breeds (P > 0.10). When numbers of primordial follicles were expressed on a per gram of ovarian tissue basis, there were fewer primordial follicles per gram of ovarian tissue in Brangus and Brahman cows than in Angus cows (P < 0.05). Brangus cows did not differ from Brahman cows in primordial follicle density (P > 0.10). Differences in primordial follicle density could indicate differences in capacity of ovarian stroma to produce factors necessary for oogonial proliferation and primordial follicle formation among breeds. Identifying these factors could improve the aprroach for culturing pre-antral follicles of cattle. Furthermore, these results explain why ultrasonographic antral follicle counts may need to be adjusted to a greater threshold to predict size of the ovarian reserve and determine ovarian reserve related reproductive traits in Bos indicus females.
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Affiliation(s)
- Robert A Cushman
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE, USA.
| | - Émerson M Soares
- Federal University of Santa Maria, Animal Science Department, Santa Maria, RS, Brazil
| | - Hannah K Yake
- University of Tennessee, Animal Science Department, Knoxville, TN, USA
| | | | - Shelby L Rosasco
- New Mexico State University, Department of Animal and Range Sciences, Las Cruces, NM, USA
| | - Joslyn K Beard
- New Mexico State University, Department of Animal and Range Sciences, Las Cruces, NM, USA
| | - Emmalee J Northrop
- South Dakota State University, Department of Animal Science, Brookings, SD, USA
| | - Jerica J J Rich
- South Dakota State University, Department of Animal Science, Brookings, SD, USA
| | - Jeremy R Miles
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE, USA
| | - Chadwick C Chase
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE, USA
| | - Michael G Gonda
- South Dakota State University, Department of Animal Science, Brookings, SD, USA
| | - George A Perry
- South Dakota State University, Department of Animal Science, Brookings, SD, USA
| | - Anthony K McNeel
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE, USA
| | - Adam F Summers
- New Mexico State University, Department of Animal and Range Sciences, Las Cruces, NM, USA.
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Maternal age influences the number of primordial follicles in the ovaries of yearling Angus heifers. Anim Reprod Sci 2018; 200:105-112. [PMID: 30563721 DOI: 10.1016/j.anireprosci.2018.12.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 12/05/2018] [Accepted: 12/11/2018] [Indexed: 01/17/2023]
Abstract
The number of antral follicles detectable by ultrasonography in heifers is influenced by age of the dam, because daughters of primiparous cows have fewer antral follicles than daughters of mature cows. We, therefore, hypothesized that heifers with primiparous dams would have fewer primordial follicles in their ovaries than heifers born to mature (4+ y) cows. Angus heifers (n = 464) were submitted for ultrasonographic evaluation of antral follicle number at 325, 355, and 385 d of age. Ovaries were collected from a random subset of heifers (n = 79) and processed for histological evaluation to determine number of primordial follicles. A greater percentage of heifers with primiparous dams had a corpus luteum at first ultrasonographic examination; however, a greater percentage of heifers with multiparous dams had ovulated by the start of breeding (P < 0.01). Heifers with primiparous dams had fewer antral follicles detectable by ultrasonography (P < 0.01). Heifers with primparous dams had fewer surface antral follicles on their ovaries (P < 0.01), and the number of primordial follicles per histological section was less for heifers with primiparous dams (P = 0.02). These data indicate that the lesser number of antral follicles detectable by ultrasonography in heifers with primparous dams is due to less ovarian follicle reserves. Selecting replacement heifers from mature dams may result in daughters with greater fertility and reproductive longevity; however, further research is necessary to determine if interactions between size of the ovarian follicle reserve and age at puberty influence fertility and reproductive longevity in replacement heifers.
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Timing of transcriptomic and proteomic changes in the bovine placentome after parturition. Theriogenology 2017; 100:1-7. [PMID: 28708523 DOI: 10.1016/j.theriogenology.2017.05.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 11/11/2016] [Accepted: 05/24/2017] [Indexed: 11/22/2022]
Abstract
Proper post-partum reproductive performance is important for reproductive efficiency in beef cows, and dystocia decreases post-partum fertility. Crossbred beef cows (n = 1676) were evaluated for lifetime performance based on degree of dystocia at presentation of the first calf. Cows that experienced moderate or severe dystocia produced fewer calves during their productive life (P < 0.01). The exact mechanism is unclear, but may be due to the contributions of dystocia to abnormal placental separation. Proteolytic activity is hypothesized to contribute to placental separation in ruminants; however, when ovine placentomes were collected following caesarian section, no proteolytic activity was detected. We hypothesized that stage 2 of parturition was necessary to stimulate proteolysis and initiate placental separation. Serial placentome collections were performed on mature cows (n = 21 initiated; 7 with complete sampling) at hourly intervals for the first 2 h after expulsion of the calf. An intact piece of each placentome was fixed for histological evaluation, and a separate piece of caruncular and cotyledonary tissue from each placentome was frozen for transcriptomic and proteolytic analysis. A full set of placentomes was collected from only 7 of 21 cows at 0, 1, and 2 h, and all cows had expelled fetal membranes by 6 h. Histological, transcriptomic and proteolytic analysis was performed on placentomes from cows from which three placentomes were collected (n = 7). The microscopic distance between maternal and fetal tissues increased at 1 h (P = 0.01). Relative transcript abundance of matrix metalloprotease 14 (MMP14) tended to increase with time (P = 0.06). The relative transcript abundance of plasminogen activator urokinase-type (PLAU) was greater in caruncles than cotyledons (P = 0.01), and tended (P = 0.10) to increase in the caruncle between 0 and 2 h while remaining unchanged in the cotyledon over the same span of time. Greater PLAU and plasminogen activator tissue-type (PLAT) proteolytic activity was detected by zymography in the caruncle than the cotyledon immediately post-partum (P < 0.01). From these findings we conclude that 1) dystocia during the first parity decreases lifetime productivity in beef cattle, 2) the PA system is present at both the transcript and protein level in the bovine plactentome during parturition and 3) proteolytic activity is localized to the caruncular aspect of the placentome.
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Gandra JR, Verdurico LC, Mingoti RD, Takiya CS, Gardinal R, Vendramini THA, Barletta RV, Visintin JA, Rennó FP. Whole flaxseed, raw soybeans, and calcium salts of fatty acids supplementation for transition cows: follicle development and embryo quality. ITALIAN JOURNAL OF ANIMAL SCIENCE 2017. [DOI: 10.1080/1828051x.2017.1302823] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | | | | | - Caio Seiti Takiya
- Department of Animal Nutrition and Production, University of Sao Paulo, Pirassununga, Brazil
| | - Rodrigo Gardinal
- Department of Animal Nutrition and Production, University of Sao Paulo, Pirassununga, Brazil
| | | | - Rafael Villela Barletta
- Department of Animal Nutrition and Production, University of Sao Paulo, Pirassununga, Brazil
| | | | - Francisco Palma Rennó
- Department of Animal Nutrition and Production, University of Sao Paulo, Pirassununga, Brazil
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Amundson OL, Fountain TH, Larimore EL, Richardson BN, McNeel AK, Wright EC, Keisler DH, Cushman RA, Perry GA, Freetly HC. Postweaning nutritional programming of ovarian development in beef heifers1,2. J Anim Sci 2015; 93:5232-9. [DOI: 10.2527/jas.2015-9067] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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9
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Cushman RA, Tait RG, McNeel AK, Forbes ED, Amundson OL, Lents CA, Lindholm-Perry AK, Perry GA, Wood JR, Cupp AS, Smith TPL, Freetly HC, Bennett GL. A polymorphism in myostatin influences puberty but not fertility in beef heifers, whereas µ-calpain affects first calf birth weight1. J Anim Sci 2015; 93:117-26. [DOI: 10.2527/jas.2014-8505] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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10
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Freetly HC, Vonnahme KA, McNeel AK, Camacho LE, Amundson OL, Forbes ED, Lents CA, Cushman RA. The consequence of level of nutrition on heifer ovarian and mammary development1,2. J Anim Sci 2014; 92:5437-43. [DOI: 10.2527/jas.2014-8086] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- H. C. Freetly
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933
| | - K. A. Vonnahme
- Department of Animal Sciences, North Dakota State University, Fargo 58108
| | - A. K. McNeel
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933
| | - L. E. Camacho
- Department of Animal Sciences, North Dakota State University, Fargo 58108
| | - O. L. Amundson
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933
| | - E. D. Forbes
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933
| | - C. A. Lents
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933
| | - R. A. Cushman
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933
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Summers AF, Pohlmeier WE, Sargent KM, Cole BD, Vinton RJ, Kurz SG, McFee RM, Cushman RA, Cupp AS, Wood JR. Altered theca and cumulus oocyte complex gene expression, follicular arrest and reduced fertility in cows with dominant follicle follicular fluid androgen excess. PLoS One 2014; 9:e110683. [PMID: 25330369 PMCID: PMC4199720 DOI: 10.1371/journal.pone.0110683] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 09/19/2014] [Indexed: 12/18/2022] Open
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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Affiliation(s)
- Adam F. Summers
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - William E. Pohlmeier
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Kevin M. Sargent
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Brizett D. Cole
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Rebecca J. Vinton
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Scott G. Kurz
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Renee M. McFee
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Robert A. Cushman
- USDA-ARS Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, Nebraska, United States of America
| | - Andrea S. Cupp
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
- * E-mail:
| | - Jennifer R. Wood
- Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
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Araújo VR, Gastal MO, Figueiredo JR, Gastal EL. In vitro culture of bovine preantral follicles: a review. Reprod Biol Endocrinol 2014; 12:78. [PMID: 25117631 PMCID: PMC4148547 DOI: 10.1186/1477-7827-12-78] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 08/08/2014] [Indexed: 11/11/2022] Open
Abstract
Preantral follicles are the majority of the ovarian follicle population and their use as a source of homogeneous oocytes for bovine reproductive biotechnologies could result in a substantial advance in this field. However, while in other species embryos and offspring have been produced, in bovine species the results have been limited to the follicular activation of small (primordial) preantral follicles and formation of early antral follicles from large (secondary) preantral follicles after in vitro culture. Therefore, this review will highlight the basic aspects of bovine folliculogenesis by focusing on preantral follicles, the methods of harvesting preantral follicles, the main results from in vitro follicular culture during the last 20 years, and the potential candidate substances (basic supplements, growth factors, and hormones) for improving the efficiency of in vitro follicle growth.
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Affiliation(s)
- Valdevane R Araújo
- Department of Animal Science, Food and Nutrition, Southern Illinois University, 1205 Lincoln Drive, MC 4417, Carbondale, IL 62901 USA
- Laboratory of Manipulation of Oocytes and Preantral Follicles (LAMOFOPA), Veterinary Faculty, State University of Ceará, Av. Paranjana 1700, Campus do Itaperi, Fortaleza, CE 60740-903 Brazil
| | - Melba O Gastal
- Department of Animal Science, Food and Nutrition, Southern Illinois University, 1205 Lincoln Drive, MC 4417, Carbondale, IL 62901 USA
| | - José R Figueiredo
- Laboratory of Manipulation of Oocytes and Preantral Follicles (LAMOFOPA), Veterinary Faculty, State University of Ceará, Av. Paranjana 1700, Campus do Itaperi, Fortaleza, CE 60740-903 Brazil
| | - Eduardo L Gastal
- Department of Animal Science, Food and Nutrition, Southern Illinois University, 1205 Lincoln Drive, MC 4417, Carbondale, IL 62901 USA
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13
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Abstract
The somatotropic axis – consisting of growth hormone (GH), the insulin-like growth factors 1 and 2 (IGF1 and IGF2), GH binding protein (GHBP), IGF binding proteins (IGFBPs) 1 to 6, and the cell-surface receptors for GH and the IGFs – has major effects on growth, lactation and reproduction. The primary target tissues for GH are involved in growth and metabolism. The functionality of the somatotropic axis depends in part on the expression of liver GH receptor (GHR), which determines the amount of IGF1 released from the liver in response to GH. The IGF1 acts as a pleiotropic growth factor and also serves as the endocrine negative feedback signal controlling pituitary GH secretion. Growth hormone and IGF1 undergo dynamic changes throughout the life cycle, particularly when animals are either growing, early post partum or lactating. Cells within the reproductive tract can respond directly to GH but to a lesser degree than the primary target tissues. The major impact that GH has on reproduction, therefore, may be secondary to its systemic effects on metabolism (including insulin sensitivity) or secondary to the capacity for GH to control IGF1 secretion. Insulin-like growth factor 1 and IGFBP are also synthesised within the ovary and this local synthesis is a component of the collective IGF1 action on the follicle. Future studies of GH should focus on its direct effects on the follicle as well as its indirect effects mediated by shifts in nutrient metabolism, insulin sensitivity, IGF1 and IGFBP.
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14
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Burkhart MN, Juengel JL, Smith PR, Heath DA, Perry GA, Smith MF, Garverick HA. Morphological development and characterization of aromatase and estrogen receptors alpha and beta in fetal ovaries of cattle from days 110 to 250. Anim Reprod Sci 2009; 117:43-54. [PMID: 19299095 DOI: 10.1016/j.anireprosci.2009.02.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 02/04/2009] [Accepted: 02/11/2009] [Indexed: 11/15/2022]
Abstract
To better understand the role of estradiol-17beta in fetal ovarian development, presence and localization of cytochrome P450 aromatase (P450arom) and estrogen receptors alpha (ERalpha) and beta (ERbeta) proteins were characterized in fetal ovaries of cattle using immunohistochemistry. Fetal cattle ovaries were collected from an abattoir and sorted into fetal age groups (days 110, 130, 150, 170, 190, 210, 230, 250+) based on crown-rump length. In addition to immunohistochemistry, morphological analysis of ovarian and follicular formation was made. Ovaries appeared lobular at day 110, but by the end of gestation (day 250+) ovaries were oval-shaped similar to those found in adult animals. Ovarian structures within different lobes appeared to be at different developmental stages. At day 110, oocytes and pre-granulosa cells were observed in ovigerous cords that were still open to the surface epithelium. Most ovigerous cords appeared to be closed to the surface epithelium on day 130, all closed by day 150 and were no longer present at day 210. Ovarian follicles were classified as follows: Type 1(primordial): single layer of flattened granulosa cells, Type 1a (transitory): single layer of mixed flattened and cuboidal granulosa cells, Type 2 (primary): at least one but less than two layers of cuboidal granulosa cells, Type 3 (small preantral): two to three layers of granulosa cells, Type 4 (large preantral): four to six layers of granulosa, and the theca layer is forming around the follicle, Type 5 (antral): contain greater than six layers of granulosa cells, several layers of theca cells and the antrum has formed. Type 1 follicles were observed in day 110 ovaries. Follicle Types 1a and 2 were first observed on day 130. Type 3 follicles were first observed on day 150 and Types 4 and 5 were first observed on day 170. P450arom protein was localized in granulosa cells of follicle Types 2-5 and cells of rete tubules throughout the experimental period. There was punctate expression within stroma and rete masses. There was ERalpha protein localization in pre-granulosa cells and germ cells of ovigerous cords and all surface epithelial cells. There was also localization in granulosa cells and oocytes of all follicle types and cells of rete tubules. There was punctate ERalpha protein expression in stroma and rete masses. ERbeta protein was localized in pre-granulosa cells and germ cells of ovigerous cords. Expression was also localized to granulosa cells of all follicle types and cells of rete tubules. ERbeta protein was punctate in oocytes of follicles, surface epithelial cells, stroma and rete masses. Thus, the fetal ovary of cattle has the steroidogenic enzyme (P450arom) to convert androgens to estradiol-17beta, and estrogen receptors alpha and beta to facilitate an estrogen response within the fetal ovary.
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Affiliation(s)
- M N Burkhart
- University of Missouri, Division of Animal Sciences, 920 E. Campus Drive, Columbia, MO 65211, USA
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Wang C, Prossnitz ER, Roy SK. G protein-coupled receptor 30 expression is required for estrogen stimulation of primordial follicle formation in the hamster ovary. Endocrinology 2008; 149:4452-61. [PMID: 18499747 PMCID: PMC2553386 DOI: 10.1210/en.2008-0441] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Estradiol-17beta (E2) plays an important role in the formation and development of primordial follicles, but the mechanisms remain unclear. G protein-coupled receptor 30 (GPR30) can mediate a rapid and transcription-independent E2 signaling in various cells. The objectives of this study were to examine whether GPR30 was expressed in the neonatal hamster ovary and whether it could mediate estrogen action during the formation of primordial follicles. GPR30 mRNA levels decreased from the 13th day of gestation (E13) through the second day of postnatal (P2) life, followed by steady increases from P3 through P6. Consistent with the changes in mRNA levels, GPR30 protein expression decreased from E13 to P2 followed by a significant increase by P7, the day before the first appearance of primordial follicles in the hamster ovary. GPR30 was expressed both in the oocytes and somatic cells, although the expression in the oocytes was low. GPR30 protein was located primarily in the perinuclear endoplasmic reticulum, which was also the site of E2-BSA-FITC (E2-BSA-fluorescein isothiocyanate) binding. E2 or E2-BSA increased intracellular calcium in neonatal hamster ovary cells in vitro. Exposure to GPR30 small interfering RNA in vitro significantly reduced GPR30 mRNA and protein levels in cultured hamster ovaries, attenuated E-BSA binding to cultured P6 ovarian cells, and markedly suppressed estrogen-stimulated primordial follicle formation. These results suggest that a membrane estrogen receptor, GPR30, is expressed in the ovary during perinatal development and mediates E2 action on primordial follicle formation.
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MESH Headings
- Animals
- Animals, Newborn
- Cells, Cultured
- Cricetinae
- Embryo, Mammalian
- Estradiol/metabolism
- Estradiol/pharmacology
- Female
- Gene Expression Regulation, Developmental/physiology
- Ovarian Follicle/drug effects
- Ovarian Follicle/growth & development
- Ovarian Follicle/metabolism
- Ovary/drug effects
- Ovary/metabolism
- Ovary/physiology
- Protein Binding
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Small Interfering/pharmacology
- Receptors, G-Protein-Coupled/antagonists & inhibitors
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, G-Protein-Coupled/physiology
- Tissue Distribution
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Affiliation(s)
- Cheng Wang
- Department of Obstetrics-Gynecology, University of Nebraska Medical Center, Omaha, Nebraska 68198-4515, USA
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Abstract
The role of E2 on primordial follicle formation was examined by treating neonatal hamsters with 1 or 2 microg estradiol cypionate (ECP) at age postnatal d 1 (P1) and P4 or by in vitro culture of embryonic d 15 (E15) ovaries with 1, 5, or 10 ng/ml estradiol-17beta (E2). The specificity of E2 action was examined by ICI 182,780. One microgram of ECP maintained serum levels of E2 within the physiological range, significantly reduced apoptosis, and stimulated the formation and development of primordial follicles. In contrast, 2 microg ECP increased serum E2 levels to 400 pg/ml and had significantly less influence on primordial follicle formation. In vivo, ICI 182,780 significantly increased apoptosis and caused a modest reduction in primordial follicle formation. The formation and development of primordial follicles in vitro increased markedly with 1 ng/ml E2, and the effect was blocked by ICI 182,780. Higher doses of E2 had no effect on primordial follicle formation but significantly up-regulated apoptosis, which was blocked by ICI 182,780. CYP19A1 mRNA expression occurred by E13 and increased with the formation of primordial follicles. P4 ovaries synthesized E2 from testosterone, which increased further by FSH. Both testosterone and FSH maintained ovarian CYP19A1 mRNA, but FSH up-regulated the expression. These results suggest that neonatal hamster ovaries produce E2 under FSH control and that E2 action is essential for the survival and differentiation of somatic cells and the oocytes leading to the formation and development of primordial follicles. This supportive action of E2 is lost when hormone levels increase above a threshold.
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Affiliation(s)
- Cheng Wang
- Department of Obstetrics, Durham Research Center, University of Nebraska Medical Center, 984515 Nebraska Medical Center, Omaha, Nebraska 68198-4515, USA
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17
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Slot KA, Kastelijn J, Bachelot A, Kelly PA, Binart N, Teerds KJ. Reduced recruitment and survival of primordial and growing follicles in GH receptor-deficient mice. Reproduction 2006; 131:525-32. [PMID: 16514195 DOI: 10.1530/rep.1.00946] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
GH influences female fertility. The goal of the present study was to obtain more insight into the effect of loss of GH signalling, as observed in humans suffering from Laron syndrome, on ovarian function. Therefore, serial paraffin sections of ovaries of untreated and IGF-I-treated female GH receptor knock-out (GHR/GHBP-KO) mice were examined to determine the follicular reserve and the percentage of follicular atresia in each ovary. Our observations demonstrate that the amount of primordial follicles was significantly elevated in GHR/GHBP-KO mice, while the numbers of primary, preantral and antral follicles were lower compared with wild-type values. The reduced number of healthy growing follicles in GHR/GHBP-KO mice was accompanied by a significant increase in the percentage of atretic follicles. IGF-I treatment of GHR/GHBP-KO mice for 14 days resulted in a reduced number of primordial follicles, an increased number of healthy antral follicles, and a decreased percentage of atretic follicles. The results of the present study suggest that GH may play a role, either directly or indirectly, via for instance IGF-I, in the recruitment of primordial follicles into the growing pool. Furthermore, GH seems to protect antral follicles, directly or indirectly from undergoing atresia.
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Affiliation(s)
- Karin A Slot
- Department of Animal Sciences, Human and Animal Physiology Group, Wageningen University, Haarweg 10, 6709 PJ Wageningen, The Netherlands
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18
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Spicer LJ. Effects of estradiol on bovine thecal cell function in vitro: dependence on insulin and gonadotropins. J Dairy Sci 2006; 88:2412-21. [PMID: 15956304 DOI: 10.3168/jds.s0022-0302(05)72919-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The objective of this study was to evaluate the influence of estradiol (E2) on proliferation and steroid production by thecal cells obtained from large (> or =8 mm) follicles of cattle. Five experiments evaluated the effect of various doses of E2 during a 2-d exposure in serum-free medium on hormone-induced steroidogenesis and cell proliferation. In LH-treated thecal cells of experiment 1, 300 ng/mL of E2 decreased progesterone production by 30% and increased androstenedione production to 5.8-fold of controls. In the absence of LH, both 3 and 300 ng/mL of E2 increased progesterone production. In experiment 2, in the presence of insulin and LH, 3, 30, and 300 ng/mL of E2 decreased progesterone production (by 17 to 36%), whereas 3 ng/mL of E2 decreased and 300 ng/mL of E2 increased androstenedione production. Doses of LH (3 to 30 ng/mL) tested in experiment 3 increased (to as much as 3.7-fold) progesterone production by thecal cells and E2 attenuated this stimulatory effect by 40%. In contrast, E2 amplified the stimulatory effect of LH on androstenedione production in experiment 3. In experiment 4, E2 (300 ng/mL) decreased IGF-I- and insulin-induced thecal cell progesterone production by 70 to 77%, whereas E2 increased basal, IGF-I, and insulin-induced androstenedione production. In experiment 5, in the presence of insulin, 10 to 1000 ng/mL of E2 had no effect on [(125)I]-IGF-I binding to thecal cells, whereas 10 and 100 ng/mL of E2 increased and 1000 ng/mL of E2 decreased progesterone production by thecal cells. Estradiol had no consistent effect on thecal cell numbers among the 5 experiments. These results support the hypothesis that E2 may act as a paracrine factor to directly regulate hormone-induced steroid production by thecal cells without affecting cell numbers or numbers of insulin-like growth factor type I receptors.
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Affiliation(s)
- L J Spicer
- Department of Animal Science, Oklahoma State University, Stillwater, 74078, USA.
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19
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Sirotkin AV. Control of reproductive processes by growth hormone: extra- and intracellular mechanisms. Vet J 2006; 170:307-17. [PMID: 16266845 DOI: 10.1016/j.tvjl.2004.05.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2004] [Indexed: 10/26/2022]
Abstract
Recent data on the association between growth hormone (GH) and male and female reproductive processes, as well as the effects of GH on these processes and on some reproductive and non-reproductive disorders, and possible extra- and intracellular mediators of its action are reviewed. The available data suggest that GH is an important endocrine and autocrine/paracrine regulator of reproduction. It controls proliferation, apoptosis, growth and differentiation and the secretory and generative activities of different reproductive organs. It also regulates their response to gonadotrophin-releasing hormone (GnRH) and gonadotropins. Despite the effects of GH on the IGF/IGFBP (insulin-like growth factor binding protein) system, oxytocin, steroids, activin, gonadotropin and gonadotropin receptors, the majority of GH's actions on the reproductive processes are probably mediated not by these substances but by specific GH receptors acting through cAMP/protein kinase A, protein kinase G, tyrosine kinase-, MAP kinase and CDC2 kinase-dependent intracellular mechanisms. Although GH treatments can increase the risk of some reproductive and non-reproductive disorders, they may be useful in improving gonadal function, inducing superovulation and in embryo production.
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Affiliation(s)
- A V Sirotkin
- Research Institute of Animal Production, Hlohovská 2, 949 92 Nitra, Slovakia.
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20
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Abstract
Antral follicle growth in cattle occurs in two distinct phases; the first 'slow' growth phase spans the time from antrum acquisition to a size of approximately 3 mm detectable by transrectal ultrasound, and the second 'fast' phase is gondadotrophin-dependent and includes cohort growth, dominant follicle (DF) selection, and DF growth. This review summarises current concepts of the relative roles FSH and LH, ovarian and metabolic hormones play mainly in the second phase of antral follicle growth in animals of different reproductive and nutritional states. It is proposed that differential FSH response may enable one cohort follicle to become selected, and that follicular secretions, particularly inhibin, suppress FSH and thus are responsible for DF selection and dominance. Acute dependence of the DF on LH pulses will determine DF lifespan, and the LH pulse profile can be influenced by metabolic hormones such as leptin, providing one possible link for nutritional state and reproduction. Direct ovarian effects of acute and chronic changes in growth hormone, insulin and insulin-like growth factor (IGF)-I have been described on cohort follicles, DF oestrogen activity and on DF growth. Influences of metabolic hormones on early antral follicles undergoing their first 'slow' growth phase are less well described, yet metabolic hormones appear to enhance growth into the cohort available for FSH-induced emergence, and may influence subsequent developmental competence of oocytes.
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Affiliation(s)
- M Mihm
- Department of Veterinary Preclinical Studies, University of Glasgow Veterinary School, Bearsden Road, Glasgow G61 1QH, UK.
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21
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Kezele P, Skinner MK. Regulation of ovarian primordial follicle assembly and development by estrogen and progesterone: endocrine model of follicle assembly. Endocrinology 2003; 144:3329-37. [PMID: 12865310 DOI: 10.1210/en.2002-0131] [Citation(s) in RCA: 200] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The assembly of the developmentally arrested primordial follicle and the subsequent transition of the primordial follicle to the primary follicle are critical processes in normal ovarian physiology that remain to be elucidated. Ovarian follicles do not proliferate and the primordial follicles present in the neonate represent the total number of gametes available to a female throughout her reproductive life. The primordial follicles are oocytes surrounded by less differentiated squamous granulosa cells and are derived from oocyte nests, and primary follicles are oocytes surrounded by a single layer of cuboidal granulosa cells that have initiated follicle development. Abnormalities in primordial follicle assembly, arrest, and development (i.e. primordial to primary follicle transition) can cause pathological conditions such as premature ovarian failure. In this study newborn rat ovaries were cultured for 7 d. The rate of primordial follicle assembly in vivo was identical with the rate in vitro. Interestingly, the rate of primordial follicle transition to the primary follicle was found to be 3 times greater in culture. This abnormal rate of primary follicle development in culture suggests the primordial follicle does not arrest in development as observed in vivo. To investigate this phenomena newborn rat ovaries were cultured in the presence of progesterone, estradiol or calf serum. Estradiol, progesterone, or calf serum significantly reduced the level of initial primordial to primary follicle transition. Approximately 60% of follicles make the primordial to primary follicle transition in control ovaries and about 30% in treated ovaries. Steroids and calf serum had no effect on the primordial to primary follicle transition in ovaries collected and cultured from postnatal 4-d-old rats, suggesting the effects observed are restricted to the initial wave of primordial to primary follicle transition. Interestingly, progesterone was also found to significantly reduce the rate of primordial follicle assembly. All viable oocytes assembled into primordial follicles in control ovaries and approximately 40% remained unassembled in progesterone-treated ovaries. Progesterone was also found to reduce primordial follicle assembly in vivo with 10% of the total follicles remaining unassembled in progesterone injected neonatal animals. Analysis of cellular apoptosis demonstrated that progesterone inhibited the coordinated oocyte apoptosis required for primordial follicle assembly. The hypothesis developed is that high levels of maternal and fetal steroids prevent premature primordial follicle assembly and primordial to primary follicle transition in the embryo. After birth steroid levels fall dramatically and the primordial follicles are free to assemble and initiate development. These observations suggest a novel role for steroids and the maternal-fetal endocrine unit in the control of ovarian primordial follicle assembly and early follicular development.
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Affiliation(s)
- Phillip Kezele
- Center for Reproductive Biology, School of Molecular Biosciences, Washington State University, Pullman, Washington 99164-4231, USA
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