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Date Available
5-1-2015
Year of Publication
2015
Document Type
Master's Thesis
Degree Name
Master of Science (MS)
College
Agriculture, Food and Environment
Department/School/Program
Veterinary Science
Faculty
Dr. Edward L. Squires
Faculty
Dr. Daniel K. Howe
Abstract
The objectives of this thesis were: (1) to evaluate the downregulation of the stallion hypothalamic-pituitary-gonadal (HPG) axis by a GnRH antagonist (acyline) based upon endocrine, seminal, testicular and behavioral effects, and (2) to assess recovery after treatment. Stallions were treated for 50 days (n=4; 330µg/kg acyline q 5d) and controls (n=4) received vehicle alone. Stallions were assessed pre-treatment and for 72 days after last treatment. Treatment induced declines (p<0.05) in FSH, LH, testosterone (to castrate levels) and estrone sulfate. Gonadotropins and testosterone returned to control values within nine days and estrone sulfate by 14 days after treatment discontinuation. Acyline-treated stallions failed to respond with FSH, LH and testosterone increase after exogenous GnRH stimulation (25µg gonadorelin, IV) compared to pre-treatment and control stimulation. Total sperm numbers and motility were reduced in acyline-treated stallions, as well as total seminal plasma protein and testicular volume (p<0.05). Time to ejaculation was increased in acyline group (p<0.5). Testicular, sexual behavior and most seminal parameters regained normal levels within 72 days after treatment ceased. Sperm output of acyline-treated stallions was regained within seven months after ending treatment. Acyline reversibly suppressed the stallion HPG axis, thus has potential for treating the androgen-dependent Equine-Arteritis-Virus carrier state and as behavior modulator.
Recommended Citation
Monteiro Davolli, Gabriel, "REVERSIBLE DOWNREGULATION OF HYPOTHALAMIC-PITUITARY-GONADAL AXIS IN THE STALLION WITH A THIRD-GENERATION GNRH ANTAGONIST" (2015). Theses and Dissertations--Veterinary Science. 22.
https://uknowledge.uky.edu/gluck_etds/22
Included in
Large or Food Animal and Equine Medicine Commons, Veterinary Infectious Diseases Commons, Veterinary Preventive Medicine, Epidemiology, and Public Health Commons, Veterinary Toxicology and Pharmacology Commons
