Androgen regulation of a laryngeal-specific myosin heavy chain mRNA isoform whose expression is sexually differentiated

Androgen controls the expression of the laryngeal-specific myosin heavy chain responsible for the fast twitch in the laryngeal muscles (LM) of male Xenopus laevis frogs. Females express LM in a few fast-twitch muscle fibres. The number of muscle fibres expressing LM and the expression of LM increases in juvenile females treated with androgen. In juvenile males all the muscle fibres express LM and the expression increases on treatment with androgen. Castrated males show a decrease in the expression of LM. Androgen probably activates the large number of its receptors present in the larynx.