title: Levels of messenger RNA encoding ovarian receptors for FSH and LH in cattle during superovulation with equine chorionic gonadotrophin versus FSH.
abstract: This study tested the hypothesis that luteal LH receptor (LHr) and follicular LHr and FSH receptor (FSHr) steady-state mRNA levels are greater during superovulation with equine chorionic gonadotrophin (eCG) compared with that with FSH. Heifers were stimulated with eCG (n = 10) or FSH (n = 10), and ovaries were recovered the day before and at 12 and 24 h after luteolysis was induced with prostaglandin F2 alpha (PGF2 alpha). Total RNA was purified from individual follicles and corpora lutea. Steady-state levels of LHr and FSHr mRNA were assessed by slot blot analysis employing homologous cDNA probes. There were no differences in luteal LHr between FSH- and eCG-stimulated animals before luteolysis, and hybridization signals were detected in only one of six animals by 12 h after injection of PGF2 alpha. After PGF2 alpha injection, steady-state levels of follicular LHr were 4-fold lower (P < 0.05) and follicular FSHr mRNA levels were 2.4-fold lower (P < 0.05) in eCG- compared with FSH-treated cattle. In eCG-treated animals, induction of luteolysis led to a significant increase in follicular LHr mRNA levels (P < 0.01) and a significant decrease in follicular FSHr mRNA levels (P < 0.01). There was no such effect of luteolysis in FSH-treated animals. We conclude that superovulation with eCG, compared with FSH, results in lower follicular levels of LHr and FSHr mRNA but does not affect luteal LHr mRNA levels.
authors.affiliation: Centre de Recherche en Reproduction Animale, Faculté de Médecine Véterinaire, Université de Montréal, Quebec, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Soumano
authors.forename: J G
authors.initials: JG
authors.lastname: Lussier
authors.forename: C A
authors.initials: CA
authors.lastname: Price
mesh_terms: D000818:Animals; D002417:Cattle; D015237:Dinoprost / Q000494:pharmacology; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D006064:Gonadotropins, Equine / Q000494:pharmacology*; D010053:Ovary / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism*; D011962:Receptors, FSH / Q000235:genetics*; D011974:Receptors, LH / Q000235:genetics*; D013268:Stimulation, Chemical; D013480:Superovulation / Q000378:metabolism*
chemical_list: D006064:Gonadotropins, Equine; D012333:RNA, Messenger; D011962:Receptors, FSH; D011974:Receptors, LH; D005640:Follicle Stimulating Hormone; D015237:Dinoprost