Effects of HCG or gonadoreline on seminal parameters and plasma testosterone levels in young male rabbits.
The effect of successive HCG or Gonadoreline injections on some reproductive parameters in 21 young male rabbits, aged from 4 to 4.5 months, has been studied. Animals were randomly allocated in three groups of seven to receive weekly (on each Monday) i.m. injections of 20 mg Gonadoreline, 50 IU HCG, or 0.5 ml Saline solution, respectively. The ejaculate from each male was collected and analysed twice a week (Tuesday and Friday). Higher sperm volumes were observed on the first week after Gonadoreline administration compared to the other groups (p < 0.05), and lower values during the second week in the Control group vs. Gonadoreline group (p < 0.05). Sperm volume increases after the 3rd week in Control animals (p < 0.05). When considering the global period studied, mean sperm volumes achieved after Gonadoreline treatment were higher than in HCG or Control group. Despite the random distribution of the animals to each treatment, and although throughout the experiment more ejaculates were discarded in the Gonadoreline group, the final number of doses obtained per ejaculate was higher in this group followed by HCG treated animals. Globally, the mean sperm concentration of the Control group during the entire studied period was significatively lower compared to the other groups (p < 0.001). No sperm motility differences were detected among the groups (p < 0.1174). HCG injections caused a significative increase in plasma testosterone concentration during the first and second week (p < 0.001) and similar plasma levels were observed in all groups afterwards. No direct plasma testosterone increasing levels owed to Gonadoreline injections were detected, probably due to the frequency of blood sampling (once a week).
Rebollar
P G
PG
Deptos. Producción Animal, E.T.S.I. Agrónomos, UPM, Madrid, Spain. prebollar@pan.etsia.upm.es
Ubilla
E
E
Alvariño
J M
JM
Lorenzo
P L
PL
Silván
G
G
Illera
J C
JC
D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D008297:Male; D011817:Rabbits; D012661:Semen / Q000187:drug effects* / Q000502:physiology; D013076:Sperm Count / Q000187:drug effects; D013081:Sperm Motility / Q000187:drug effects; D013739:Testosterone / Q000097:blood*
D006063:Chorionic Gonadotropin; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone