title: Endocrine effects of the GnRH antagonist, acyline, in domestic dogs.
abstract: Gonadotrophin-releasing hormone (GnRH) antagonists may have a future role in the control of canine reproductive function. In this study, the effects of a single dose of the potent GnRH antagonist, acyline, on serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) were evaluated in male dogs. Blood samples were drawn before (Day -1) and after (30, 60, and 90 min, 3, 6, 9, 12, and 24h, and 3, 6, 9, 14, 22, and 29 d) treatment with acyline (330 microg/kg, sc); serum concentrations of FSH, LH, and T varied throughout the study period (P<0.01, <0.05, and <0.01, respectively). Gonadotrophins decreased below pretreatment concentrations 60 min after injection, whereas T took 90 min to decrease below baseline (P>0.05). Follicle-stimulating hormone, LH and T decreased until Day 9, when they reached their nadir at 2.0 +/-1.1 ng/mL (P<0.01), 1.2+/-0.2 ng/mL (P>0.05), and 0.5+/-0.2 ng/mL (P<0.05), respectively. Both gonadotrophins and T began increasing on Day 14 after treatment, although FSH and T serum concentrations still remained below baseline on that day (P>0.05). Follicle-stimulating hormone and T rebounded above baseline on Day 29, whereas LH reached concentrations were similar to baseline at this time (P>0.05). No local or systemic side effects were detected in any dog following acyline treatment. In conclusion, a single acyline treatment safely and reversibly decreased serum gonadotrophin and T concentrations in dogs for 9 d.
authors.affiliation: Laboratory of Reproductive Physiology, Faculty of Veterinary Medicine, National University of La Plata - National Research Council, 60 y 118 La Plata (1900), Argentina.
authors.forename: G
authors.initials: G
authors.lastname: García Romero
authors.forename: C
authors.initials: C
authors.lastname: Valiente
authors.forename: D
authors.initials: D
authors.lastname: Aquilano
authors.forename: Y
authors.initials: Y
authors.lastname: Corrada
authors.forename: C
authors.initials: C
authors.lastname: Gobello
mesh_terms: D000818:Animals; D000829:Animals, Domestic / Q000097:blood / Q000502:physiology; D004285:Dogs / Q000097:blood / Q000502:physiology; D004703:Endocrine System / Q000187:drug effects* / Q000502:physiology; D005640:Follicle Stimulating Hormone / Q000097:blood; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors*; D006727:Hormone Antagonists / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology*; D013739:Testosterone / Q000097:blood
chemical_list: D006727:Hormone Antagonists; D009842:Oligopeptides; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; C109238:acyline