title: Progestin priming before gonadotrophin stimulation and AI improves embryo development and normalises luteal function in the cat.
abstract: Exogenous gonadotrophins administered before AI can adversely alter endocrine dynamics and inhibit embryo development in felids. In the present study, we tested the hypothesis that priming the domestic cat ovary with progestin mitigates the negative influence of gonadotrophin therapy by normalising early embryogenesis and luteal function. Queens were given either: (1) progestin pretreatment plus chorionic gonadotrophins (n=8; primed); or (2) gonadotrophins only (n=8; unprimed). Ovulatory response was assessed laparoscopically, and cats with fresh corpora lutea (CL) were inseminated in utero. Ovariohysterectomy was performed 3 days later to recover intra-oviductal embryos for in vitro culture; one ovary was prepared for histology, and CL from the remaining ovary were excised and assessed for progesterone content and targeted gene expression. Of the six primed and seven unprimed queens inseminated, embryo(s) were recovered from five individuals per group. Embryos from progestin-primed donors more closely simulated normal stage in vivo development (P<0.05). No 2- or 4-cell embryos from either group developed beyond 16-cells in vitro; however, 50% of unprimed and 66.7% of primed (P>0.05) 5-16-cell embryos progressed to morulae or blastocysts by Day 4 of culture. Although histological characteristics were unaffected by progestin priming (P>0.05), luteal progesterone was unusually high (P<0.05) in unprimed compared with primed cats (72.4±5.8 vs. 52.2±5.5 ng mg(-1), respectively). Two genes associated with progesterone biosynthesis (luteinising hormone receptor and 3β-hydroxysteroid dehydrogenase) were upregulated in unprimed versus primed individuals (P=0.05 and P<0.05, respectively), indicating potential mechanistic pathways for the protective influence of pre-emptive progestin treatment. Building on earlier findings that progestin priming prevents spontaneous ovulation, increases ovarian sensitivity to gonadotrophins and ensures a normative endocrine environment, the present study demonstrates that pretreatment with this steroid also benefits embryo development and normalisation of early luteal function.
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, Front Royal, VA 22630, USA.
authors.forename: Rosemary A
authors.initials: RA
authors.lastname: Stewart
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, Front Royal, VA 22630, USA.
authors.forename: Adrienne E
authors.initials: AE
authors.lastname: Crosier
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, Front Royal, VA 22630, USA.
authors.forename: Katharine M
authors.initials: KM
authors.lastname: Pelican
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, Front Royal, VA 22630, USA.
authors.forename: Budhan S
authors.initials: BS
authors.lastname: Pukazhenthi
authors.affiliation: Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA.
authors.forename: Brandon D
authors.initials: BD
authors.lastname: Sitzmann
authors.affiliation: Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA.
authors.forename: Tom E
authors.initials: TE
authors.lastname: Porter
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, Front Royal, VA 22630, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Wildt
authors.affiliation: Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA.
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Ottinger
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, Front Royal, VA 22630, USA.
authors.forename: JoGayle
authors.initials: J
authors.lastname: Howard
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism; D000177:Acrosome / Q000502:physiology; D000818:Animals; D002415:Cats; D003338:Corpus Luteum / Q000187:drug effects* / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D046149:Embryo Culture Techniques / Q000662:veterinary; D047108:Embryonic Development / Q000187:drug effects* / Q000502:physiology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006062:Gonadotropins / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary*; D008297:Male; D011247:Pregnancy; D011374:Progesterone / Q000378:metabolism; D011372:Progestins / Q000494:pharmacology*; D011974:Receptors, LH / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013076:Sperm Count / Q000662:veterinary; D013081:Sperm Motility / Q000502:physiology; D018709:Statistics, Nonparametric
chemical_list: D017931:DNA Primers; D006062:Gonadotropins; D011372:Progestins; D011974:Receptors, LH; D011374:Progesterone; D015096:3-Hydroxysteroid Dehydrogenases