Passive immunization of rams (Ovis aries) against GnRH: effects on antibody titer, serum concentrations of testosterone, and sexual behavior.
The effect of immunoneutralization of gonadotropin-releasing hormone (GnRH) on serum concentrations of testosterone and sexual behavior was evaluated in sexually mature male sheep. In Experiment 1, GnRH1 rams (n=16) were passively immunized against GnRH (300 ml antiserum), control rams were either passively immunized against keyhole limpet hemocyanin (KLH, n=15) or surgically castrated (Wethers1, n=4). Sexual performance of the rams was assessed weekly for 3 weeks before and 6 weeks after immunization, using ovarihystertomized ewes actively immunized against GnRH. Experiment 2 evaluated the effects of repeated immunization. Rams were immunized with two aliquots (400 and 300 ml, respectively) of anti-GnRH sera (GnRH, n=5) or normal sheep serum (NSS, n=4), 2 weeks apart. Surgically castrated animals were used as a second control group (Wethers2). Administration of anti-GnRH sera, but neither anti-KLH nor NSS sera, resulted in marked reduction (P<0.05) in serum concentrations of testosterone. Sexual behavior was not consistently affected by administration of one aliquot of anti-GnRH sera, however repeated immunizations resulted in more persistent reduction in serum concentrations of testosterone and more consistent suppression of sexual behavior.
Parthasarathy
V
V
Department of Animal Science, University of California, Davis, CA 95616, USA. valli@arches.uga.edu
Price
E O
EO
Orihuela
A
A
Dally
M R
MR
Adams
T E
TE
D000818:Animals; D000906:Antibodies / Q000097:blood*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000276:immunology* / Q000502:physiology; D007116:Immunization, Passive; D007700:Kinetics; D008297:Male; D009919:Orchiectomy / Q000662:veterinary; D010052:Ovariectomy / Q000662:veterinary; D012726:Sexual Behavior, Animal; D012756:Sheep / Q000502:physiology*; D013739:Testosterone / Q000097:blood*
D000906:Antibodies; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone