Effect of denervation on the androgen-induced expression of actin and CPK mRNAs in the levator ani muscle of the rat

In the adult male rat, the castration-induced atrophy of the levator ani (LA) muscle was found to be associated with a decrease in the relative levels of both actin and creatine phosphokinase (CPK) mRNAs. The typical recovery of these two sequences following 5 days of testosterone propionate (TP) replacement therapy was not impaired by the bilateral denervation of the LA. This indicated that TP was the sole trophic factor regulating the plasticity of these two mRNAs and challenged the hypothesis that androgen action might be neuronally mediated. The observation that denervation led to a severe repression of both actin and CPK messages only in the absence of TP replacement therapy suggested that the nerve impulse could play an accessory role in the control of their expression.