Number of type A spermatogonia following 10ρg (A), 1ηg (B) and 1µg (C) doses after 2, 4, 6, 8, 10 and 12 days of alone kisspeptin treatment. Type A spermatogonia decreased significantly in 1ηg and 1µg treatment groups only after 12 days of treatment. Values are expressed as mean ± SE (n=7). *p< 0.05, **p < 0.01.