Search Results
You are looking at 1 - 4 of 4 items for
- Author: Rafael R Domingues x
- Refine by access: All content x
Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
Eutheria Foundation, Cross Plains, Wisconsin, USA
Search for other papers by Rafael R Domingues in
Google Scholar
PubMed
Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
Search for other papers by O J Ginther in
Google Scholar
PubMed
Search for other papers by Mateus Z Toledo in
Google Scholar
PubMed
Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
Search for other papers by Milo C Wiltbank in
Google Scholar
PubMed
Understanding the impacts of nutrition on reproductive physiology in cattle are fundamental to improve reproductive efficiency for animals under different nutritional conditions. Starting on Day 0 (day of ovulation) until next ovulation, Holstein heifers (n = 24) were fed: low energy diet (ad libitum grass hay; LED) and high energy diet (ad libitum grass hay + concentrate supplement; HED). Heifers on HED gained more weight (average daily gain: 0.824 ± 0.07 vs 0.598 ± 0.09 kg/day) and had increased insulin concentrations. The dominant follicle of wave 1 in HED had greater growth rate overall from Days 0 to 8 and on Days 6–7 and 8–9 and started atresia later. The dominant follicle of wave 2 in HED had greater growth rate overall from Day 9 to 18 and on Days 14–15 and 15–16. In two-wave patterns, there was no difference in estradiol or progesterone concentrations but concentrations of FSH were lower in HED on Days 15 and 16. Estradiol concentrations increased earlier in two-wave patterns in association with earlier luteolysis. The frequency of two follicular waves was greater in HED than LED (11/12 vs 6/11; 92.7% vs 54.5%). In conclusion, an acute increase in dietary energy altered not only growth rate of the dominant follicle but also follicular wave pattern in heifers by increasing frequency of two follicular waves. The hypotheses were supported that an acute increase in dietary energy (1) prolongs growth period of dominant follicles and (2) alters follicular wave pattern in heifers.
Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, USA
Search for other papers by Rafael R Domingues in
Google Scholar
PubMed
Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, USA
Search for other papers by OJ Ginther in
Google Scholar
PubMed
Eutheria Foundation, Cross Plains, Wisconsin, USA
Search for other papers by Victor Gomez-Leon in
Google Scholar
PubMed
Search for other papers by Polyana Nunes da Silva in
Google Scholar
PubMed
Search for other papers by Thadeu Castro in
Google Scholar
PubMed
Search for other papers by August Hoppmann in
Google Scholar
PubMed
Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, USA
Search for other papers by Milo C Wiltbank in
Google Scholar
PubMed
In brief
Endometrial and luteal synthesis of prostaglandin F2alpha (PGF2A) occurs before and during luteolysis and is critical for luteal regression. This study demonstrates that PGF2A stimulates further PGF2A synthesis (autoamplification) apparently from the corpus luteum.
Abstract
Understanding the endocrine profile of prostaglandin F2alpha (PGF2A) autoamplification is fundamental to comprehend luteal and endometrial responses to PGF2A. On day 10 of postovulation (preluteolysis), heifers (n = 6/group) were treated intrauterine with saline or PGF2A (0.5 mg; hour 0). A third group received flunixin meglumine + PGF (FM+PGF) to prevent endogenous synthesis of PGF2A. Exogenous PGF2A was metabolized at hour 2 as measured by PGF2A metabolite (PGFM). From hours 5 to 48, concentrations of PGFM were greatest in the PGF group, smallest in the FM+PGF, and intermediate in the control suggesting endogenous synthesis of PGF2A only in PGF group. Progesterone (P4) concentrations decreased transiently between hours 0 and 1 in PGF and FM+PGF groups but rebounded to pretreatment concentrations by hours 6 and 4, respectively. No control or FM+PGF heifers underwent luteolysis during the experimental period. Conversely, in the PGF group, one heifer had complete luteolysis (P4 < 1 ng/mL), two heifers had partial luteolysis followed by P4 and CL resurgence by hour 48, and three heifers did not undergo luteolysis. Endogenous PGF2A appears to be of luteal origin due to the lack of pulsatile pattern of PGFM and lack of endometrial upregulation of oxytocin receptor (typical of endometrial synthesis of PGF2A), whereas luteal downregulation of PGF receptor and HPGD indicates a classic luteal response to PGF2A signaling although other specific mechanisms were not investigated. The hypothesis was supported that a single PGF2A treatment simulating the peak of a natural luteolytic pulse and the uteroovarian transport of PGF2A stimulates measurable endogenous PGF2A production.
Department of Dairy Science, University of Wisconsin-Madison (UW-Madison), Madison, Wisconsin, USA
Department of Veterinary Medicine, Universidade Federal de Viçosa, Viçosa, Brazil
Search for other papers by Victor E Gomez-León in
Google Scholar
PubMed
Department of Pathobiological Science, School of Veterinary Medicine, UW-Madison, Madison, Wisconsin, USA
Search for other papers by O J Ginther in
Google Scholar
PubMed
Department of Pathobiological Science, School of Veterinary Medicine, UW-Madison, Madison, Wisconsin, USA
Search for other papers by Rafael R Domingues in
Google Scholar
PubMed
Search for other papers by José D Guimarães in
Google Scholar
PubMed
Search for other papers by Milo C Wiltbank in
Google Scholar
PubMed
Previous research demonstrated that acute treatment with GnRH antagonist, Acyline, allowed follicle growth until ~8.5 mm and no dominant follicle was selected. This study evaluated whether deficient LH was the underlying mechanism for Acyline effects by replacing LH action, using human chorionic gonadotropin (hCG), during Acyline treatment. Holstein heifers (n = 24) during first follicular wave were evaluated by ultrasound and randomized into one of three treatments: Control (saline treatments), Acyline (5 µg/kg Acyline), or Acyline+hCG (Acyline plus 50 IU of hCG at start then 100 IU every 12 h). Pulses of LH were present in Control heifers (9 Pulses/10 h) but not during Acyline treatment. Data were normalized to the transition to diameter deviation (day 0; F1 ~7.5 mm). Diameter deviation of the largest (F1) and the second largest (F2) follicle was not observed in Acyline-treated heifers, whereas control heifers had decreased growth of F2 at F1 ~7.5 mm, indicating deviation. Selection of a single dominant follicle was restored by providing LH activity in Acyline+hCG heifers, as evidenced by F1 and F2 deviation, continued growth of F1, and elevated circulating estradiol. Separation of F1 and F2 occurred 12 h (~7.0 mm) earlier in Acyline+hCG heifers than Controls. Circulating FSH was greater in Acyline than Controls, but lower in Acyline+hCG than Controls after day 1.5. In conclusion, dominant follicle selection and growth after follicle deviation is due to LH action as shown by inhibition of this process during ablation of GnRH-stimulated LH pulses with Acyline and restoration of it after replacement of LH action by hCG treatment.
Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, USA
Search for other papers by Rafael R Domingues in
Google Scholar
PubMed
Departamento de Reprodução e Avaliação Animal, Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil
Search for other papers by Fabiana S Andrade in
Google Scholar
PubMed
Departamento de Reprodução e Avaliação Animal, Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, Brazil
Search for other papers by Joao Paulo N Andrade in
Google Scholar
PubMed
Search for other papers by Sadrollah M Moghbeli in
Google Scholar
PubMed
Current address: Department of Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, USA
Search for other papers by Victor Gomez-Leon in
Google Scholar
PubMed
Search for other papers by Guilherme Madureira in
Google Scholar
PubMed
Search for other papers by Marco R B Mello in
Google Scholar
PubMed
Search for other papers by Brian W Kirkpatrick in
Google Scholar
PubMed
Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, USA
Search for other papers by Milo C Wiltbank in
Google Scholar
PubMed
In brief
Follicle selection is a key event in monovular species. In this manuscript, we demonstrate the role of SMAD6 in promoting decreased granulosa cell proliferation and follicle growth rate in carriers vs noncarriers of the Trio allele and after vs before follicle deviation.
Abstract
Cattle are generally considered a monovular species; however, recently, a bovine high fecundity allele, termed the Trio allele, was discovered. Carriers of Trio have an elevated ovulation rate (3–5), while half-sibling noncarriers are monovular. Carriers of the Trio allele have overexpression in granulosa cells of SMAD6, an inhibitor of oocyte-derived regulators of granulosa cell proliferation and differentiation. In experiment 1, follicle size was tracked for each follicle during a follicular wave. Follicle growth rate was greater before vs after follicle deviation in both carriers and noncarriers. Additionally, follicle growth rate was consistently less in carriers vs noncarriers. In experiment 2, we collected granulosa cells from follicles before and after deviation for evaluation of granulosa cell gene expression. Granulosa cell proliferation was less in carriers vs noncarriers and after vs before follicle deviation (decreased expression of cell cycle genes CCNB1 and CCNA2). The decreased granulosa cell proliferation in noncarriers after deviation was associated with increased SMAD6 expression. Similarly, in experiment 3, decreased expression of SMAD6 in granulosa cells of noncarriers cultured in vitro for 60 h was associated with increased expression of cell cycle genes. This suggests that SMAD6 may not just be inhibiting follicle growth rate in carriers of Trio but may also play a role in the decreased follicle growth after deviation in noncarriers. The hypotheses were supported that (1) follicle growth and granulosa cell proliferation decrease after deviation in both carriers and noncarriers and that (2) granulosa cell proliferation is reduced in carriers compared to noncarriers.
