Opposite regulations by androgenic and thyroid hormones of V1 myosin expression in the two types of rabbit striated muscle: skeletal and cardiac

Abstract

The finding that VI cardiac myosin is expressed in masticatory skeletal muscles of the rabbit [1] provided a unique opportunity for comparing the hormonal regulation of VI in skeletal and cardiac muscles. Thyroid hormones had no significant effect on the postnatal expression of VI in masticatory muscles, but increased this expression in cardiac ventricles. In contrast, androgenic hormones reduced VI expression in masticatory muscles, but did not affect it significantly in cardiac ventricles. Modulation of VI gene transcription in striated muscle is thus shown here to depend both on the target muscle and on the hormone.