Steroid hormones control on nucleic acid biosynthesis in skeletal muscle.

The medical, agricultural and scientific interest of the muscular tissue is well established in the literature. Its formation and function are essential for survival. It is also known that steroid hormones are involved in the growth, development and maturation of skeletal muscles (sexual hormones) as well as in the process of body adjustment to the stress factors in the environment (glucocorticoid hormones). Starting from these considerations, our experiment has made an attempt to clarify part of the mechanisms involved in the action of steroid hormones at muscle level. On this purpose, 3H thymidine and 3H uridine incorporation was followed up in various types of skeletal muscles (femoral biceps, diaphragmatic, psoas) from rats treated with steroid hormones. Though known as anabolic hormones, sexual hormones did not induce significant and persistent changes in the nucleic acid synthesis (NAS), except for testosterone which enhanced RNA synthesis only in the level femoral muscle after 21 days of administration. Progesterone and the glucocorticoid hormones are known as hormones of proteic catabolism but it seems that this effect is more marked in muscles whose structure predominantly consists of white fibres (rapid muscles), as confirmed by our experiment.