Fig. 5.

Changes in laryngeal muscle fiber number in both males and females after treatment with exogenous testosterone (TP-treatment). Animals were treated for five week starting at PM0 (A) or at PM2 (B). Experimental and control animals whose fibers were counted after these five weeks are represented as PM0+ and PM2+, respectively. Note that the effects of TP-treatment depend on both age and sex of the animal. Females have significantly more fibers than control females when treated with TP at PM0 (P≤0.05) but there is no effect at PM2. Conversely, there is no effect in males treated with TP at PM0 while fiber number actually decreases in males treated at PM2 (P≤0.05).