title: The mare as a model for luteinized unruptured follicle syndrome: intrafollicular endocrine milieu.
abstract: Luteinized unruptured follicle (LUF) syndrome is a recurrent anovulatory dysfunction that affects up to 23% of women with normal menstrual cycles and up to 73% with endometriosis. Mechanisms underlying the development of LUF syndrome in mares were studied to provide a potential model for human anovulation. The effect of extended increase in circulating LH achieved by administration of recombinant equine LH (reLH) or a short surge of LH and decrease in progesterone induced by prostaglandin F2α (PGF2α) on LUF formation (Experiment 1), identification of an optimal dose of COX-2 inhibitor (flunixin meglumine, FM; to block the effect of prostaglandins) for inducing LUFs (Experiment 2), and evaluation of intrafollicular endocrine milieu in LUFs (Experiment 3) were investigated. In Experiment 1, mares were treated with reLH from Day 7 to Day 15 (Day 0=ovulation), PGF2α on Day 7, or in combination. In Experiment 2, FM at doses of 2.0 or 3.0 mg/kg every 12 h and human chorionic gonadotropin (hCG) (1500 IU) were administered after a follicle ≥32 mm was detected. In Experiment 3, FM at a dose of 2.0 mg/kg every 12 h plus hCG was used to induce LUFs and investigate the intrafollicular endocrine milieu. No LUFs were induced by reLH or PGF2α treatment; however, LUFs were induced in 100% of mares using FM. Intrafollicular PGF2α metabolite, PGF2α, and PGE2 were lower and the ratio of PGE2:PGF2α was higher in the induced LUF group. Higher levels of intrafollicular E2 and total primary sex steroids were observed in the induced LUF group along with a tendency for higher levels of GH, cortisol, and T; however, LH, PRL, VEGF-A, and NO did not differ between groups. In conclusion, this study reveals part of the intrafollicular endocrine milieu and the association of prostaglandins in LUF formation, and indicates that the mare might be an appropriate model for studying the poorly understood LUF syndrome.
authors.forename: S T
authors.initials: ST
authors.lastname: Bashir
authors.forename: M O
authors.initials: MO
authors.lastname: Gastal
authors.affiliation: Department of Animal ScienceFood and Nutrition, Southern Illinois University, 1205 Lincoln Drive, MC 4417, Carbondale, Illinois 62901, USAEquiBreed OzWarnervale, New South Wales, AustraliaDepartment of PhysiologySouthern Illinois University, Carbondale, Illinois, USADepartamento de Medicina y Cirugía AnimalFacultad de Veterinaria, Universidad CEU Cardenal Herrera, Valencia, SpainDepartment of ObstetricsGynecology and Reproductive Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: S P
authors.initials: SP
authors.lastname: Tazawa
authors.forename: S G S
authors.initials: SG
authors.lastname: Tarso
authors.affiliation: Department of Animal ScienceFood and Nutrition, Southern Illinois University, 1205 Lincoln Drive, MC 4417, Carbondale, Illinois 62901, USAEquiBreed OzWarnervale, New South Wales, AustraliaDepartment of PhysiologySouthern Illinois University, Carbondale, Illinois, USADepartamento de Medicina y Cirugía AnimalFacultad de Veterinaria, Universidad CEU Cardenal Herrera, Valencia, SpainDepartment of ObstetricsGynecology and Reproductive Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: D B
authors.initials: DB
authors.lastname: Hales
authors.affiliation: Department of Animal ScienceFood and Nutrition, Southern Illinois University, 1205 Lincoln Drive, MC 4417, Carbondale, Illinois 62901, USAEquiBreed OzWarnervale, New South Wales, AustraliaDepartment of PhysiologySouthern Illinois University, Carbondale, Illinois, USADepartamento de Medicina y Cirugía AnimalFacultad de Veterinaria, Universidad CEU Cardenal Herrera, Valencia, SpainDepartment of ObstetricsGynecology and Reproductive Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Cuervo-Arango
authors.affiliation: Department of Animal ScienceFood and Nutrition, Southern Illinois University, 1205 Lincoln Drive, MC 4417, Carbondale, Illinois 62901, USAEquiBreed OzWarnervale, New South Wales, AustraliaDepartment of PhysiologySouthern Illinois University, Carbondale, Illinois, USADepartamento de Medicina y Cirugía AnimalFacultad de Veterinaria, Universidad CEU Cardenal Herrera, Valencia, SpainDepartment of ObstetricsGynecology and Reproductive Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: A R
authors.initials: AR
authors.lastname: Baerwald
authors.forename: E L
authors.initials: EL
authors.lastname: Gastal
mesh_terms: D000818:Animals; D000858:Anovulation / Q000209:etiology*; D003002:Clonixin / Q000031:analogs & derivatives; D015237:Dinoprost / Q000502:physiology*; D004195:Disease Models, Animal; D005260:Female; D006736:Horses; D007986:Luteinizing Hormone / Q000502:physiology*
chemical_list: C014558:flunixin meglumine; D007986:Luteinizing Hormone; D015237:Dinoprost; D003002:Clonixin