Figure 7.

GnRH2 stimulates secretion of testosterone similar to GnRH1 despite reduced luteinizing hormone (LH) release in mature male pigs. Plasma concentrations of LH (A) and testosterone (B) after intravenous administration of [d-ala⁶] GnRH1 (solid line; n = 8) or [d-ala⁶] GnRH2 (dotted line; n = 6) to cannulated adult males. After pretreatment sampling, treatments were administered (arrow; 0 min) and blood was serially collected. Data are presented as the Least Squares Means (±SEM). For LH, Treatment, P < 0.001; Time, P < 0.0001; Treatment × Time, P < 0.03. For testosterone, Treatment, P = 0.1929; Time, P < 0.002; Treatment × Time, P = 0.7190. *Within treatment, concentrations differ from pre-injection levels (P < 0.05). GnRH1 differences are indicated above error bars and GnRH2 differences are labeled below error bars. Reprinted from Desaulniers et al. (35) with permission from Oxford University Press.