Tylosin does not affect GnRH-induced LH secretion in rams.
The aim of this study was to investigate the effect of a therapeutic dose of Tylosin (Tylan 50) on gonadotropin releasing hormone (GnRH)-induced luteinizing hormone (LH) secretion in sheep. A total of 10 mature rams were divided into two groups by balancing body weights (bw) and body condition scores. Five of the rams received 10mg/kg Tylosin intramuscularly (i.m., Tylosin group), while the other five were given placebo (Control group), for 5 days. On Day 5, all the rams were injected intravenously (i.v.) with the GnRH agonist Ovarelin at 0.1 microg/kg bw. Blood samples were collected at -30, 0, 30, 60, 90, 120, 150, 180, 210, 240, and 270 min for measuring LH levels in the plasma. Three days after the cessation of Tylosin application (Day 8) the injection of GnRH was repeated at the same dose. Although LH secretion appeared to be lower on Day 8 compared to Day 5, there were no significant differences between the groups for the mean LH concentrations, total LH secretion, peak LH concentrations, timing of LH peak, duration of LH secretion, and LH secretions on Days 5 and 8. These results indicate the absence of a negative effect of a therapeutic dose of Tylosin on GnRH-induced LH secretion in rams.
Yildiz
Sedat
S
Department of Physiology, Faculty of Veterinary Medicine, University of Kafkas, 36040 Kars, Turkey. yildizsedat@hotmail.com
Ozturkler
Yavuz
Y
Uzun
Metehan
M
Kaya
Mehmet
M
Ucar
Omer
O
D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000378:metabolism*; D008297:Male; D012756:Sheep; D015645:Tylosin / Q000633:toxicity*
D000900:Anti-Bacterial Agents; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D015645:Tylosin