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. Author manuscript; available in PMC: 2013 Jul 6.
Published in final edited form as: Physiol Behav. 2010 Oct 14;102(1):96–104. doi: 10.1016/j.physbeh.2010.09.025

Figure 8. Plasma levels of total and free testosterone on the first and last day of injection of intact and gonadectomized male rats with testosterone replacement.

Figure 8

Total (A and B) and free (C and D) testosterone levels were measured by radioimmunoassay in INT (white bars) and GDX-T (grey bars) animals. Data are presented as mean ± SEM; N: Total Testosterone: Day 1: Saline: INT = 9, GDX = 8; Cocaine: INT = 8, GDX-T = 9; Day 13: Saline: INT = 22, GDX-T = 21; Cocaine; INT = 32, GDX-T = 33; Free Testosterone: Day 1: Saline: INT = 9, GDX = 8; Cocaine: INT = 8, GDX-T = 9; Day 13: Saline: INT = 10, GDX-T = 9; Cocaine; INT = 10, GDX-T = 10. Values for GDX animals were negligible and not included in the graph. GDX-T animals had higher total and free testosterone levels than intact male rats when treated with saline. A single cocaine injection (Day 1) did not alter total (A) or free (C) testosterone plasma levels when compared to their saline counterpart. Repeated cocaine administration (Day 13; B and D) decreased plasma testosterone of GDX-T compared to their saline counterparts, although only total testosterone reached statistical significance. * p<0.05 compared to INT animals with the same drug treatment; # p < 0.01 compared to the saline counterpart.