title: Steroid regulation of early postnatal development in the corpus epididymidis of pigs.
abstract: Development of the epididymis including blood-epididymal barrier formation is not required until sperm reach the epididymis peripuberally. Regulation of this development in the early postnatal period is largely unknown. The current objectives were to evaluate potential roles of endogenous estrogen and androgen signaling during early development of the corpus epididymidis and to determine the timing of formation of the blood-epididymal barrier in the pig. Effects of endogenous steroids were evaluated using littermates treated with vehicle, an aromatase inhibitor (letrozole) to reduce endogenous estrogens, an estrogen receptor antagonist (fulvestrant) or an androgen receptor antagonist (flutamide). Phosphorylated histone 3 immunohistochemistry was used to identify proliferating epithelial cells. Lanthanum nitrate and electron microscopy were used to analyze formation of the blood barrier in the corpus epididymidis. Reducing endogenous estrogens increased the number of proliferating corpus epithelial cells at 6 and 6.5 weeks of age compared with vehicle-treated boars (P<0.01 and P<0.001 respectively). Blocking androgen receptors did not alter proliferation rate at 6.5 weeks of age. Although barrier formation was similar between 6 and 6.5 weeks of age in vehicle-treated animals, intercellular barriers increased in letrozole-treated littermates at 6.5 weeks of age. Fulvestrant treatment, which should mimic aromatase inhibition for regulation through ESR1 and ESR2 signaling but potentially stimulate endogenous estrogen signaling through the G protein-coupled estrogen receptor (GPER), had the opposite effect on aromatase inhibition. These responses in conjunction with the presence of GPER in the corpus epididymidis suggest early corpus epididymal development is regulated partially by GPER.
authors: Departments of Animal SciencePopulation Health and ReproductionUniversity of California, Davis, One Shields Avenue, Davis, California 95616, USA.
authors: Kimberley D
authors: KD
authors: Katleba
authors: Departments of Animal SciencePopulation Health and ReproductionUniversity of California, Davis, One Shields Avenue, Davis, California 95616, USA.
authors: Erin L
authors: EL
authors: Legacki
authors: Departments of Animal SciencePopulation Health and ReproductionUniversity of California, Davis, One Shields Avenue, Davis, California 95616, USA.
authors: Alan J
authors: AJ
authors: Conley
authors: Departments of Animal SciencePopulation Health and ReproductionUniversity of California, Davis, One Shields Avenue, Davis, California 95616, USA tberger@ucdavis.edu.
authors: Trish
authors: T
authors: Berger
mesh_terms: D059002:Androgen Receptor Antagonists / Q000494:pharmacology; D000818:Animals; D001141:Aromatase / Q000737:chemistry / Q000378:metabolism*; D047072:Aromatase Inhibitors / Q000494:pharmacology; D001814:Blood-Testis Barrier / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D004822:Epididymis / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D065171:Estrogen Receptor Antagonists / Q000494:pharmacology; D005485:Flutamide / Q000494:pharmacology; D000077267:Fulvestrant; D000077289:Letrozole; D008297:Male; D046529:Microscopy, Electron, Transmission / Q000662:veterinary; D009570:Nitriles / Q000494:pharmacology; D020033:Protein Isoforms / Q000037:antagonists & inhibitors / Q000378:metabolism; D011944:Receptors, Androgen / Q000737:chemistry / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors / Q000378:metabolism; D046468:Sexual Development / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D034421:Sus scrofa / Q000254:growth & development* / Q000502:physiology; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D014230:Triazoles / Q000494:pharmacology
chemical_list: D059002:Androgen Receptor Antagonists; D047072:Aromatase Inhibitors; D065171:Estrogen Receptor Antagonists; D009570:Nitriles; D020033:Protein Isoforms; D011944:Receptors, Androgen; D011960:Receptors, Estrogen; D043562:Receptors, G-Protein-Coupled; D014230:Triazoles; D000077267:Fulvestrant; D004958:Estradiol; D005485:Flutamide; D000077289:Letrozole; D001141:Aromatase
keywords: GPER; aromatase; blood–epididymal barrier; boar; estradiol