ELECTRO-MYOGRAPHIC STUDY OF SEXUAL AND OTHER HORMONES ON SKELETAL MUSCLES

Using a fair number of adult females (at different stages of menstruation and oophorectomization) and males (normal and castrated), the action of sexual and other hormones was investigated electro-myographically. M. bulbocavernosus and obliquus abdominis were employed. Beside those, certain efforts were. made to trace the site of the sex-hormonal action. 1. In the normal female, M. bulb. showed a weak cyclic change, simultaneously with the menstruation cycle-eakening or vanishing of the electrical discharge during bleeding, and a few days before and after this perid. The muscle responded to ‘anti-bearing down effort’ with quickened discharges. 2. Inhibitory action of progesterone was domonstrated on M. bulb. The intravenous administration seemed to be quicker in action and less durable than the intramuscular. These were seen in both muscles. 3. The depressive action of chorionic gonadotrophin and the enhancing influence of serum gonadotrophin were demonstrated. 4. Cortisone showed an enchancing action on M. bulb. and the abdominal muscle, but desoxycorticosterone had no such effect. 5. The action of oxytocin was transitory and very peculiar. To the abdominal muscle it gave an enhacement effect, while to M. bulb. a definitedepressive. The other hormone of the posterior lobe of pituitary body, vasopressin, reacted upon both muscles with a transitory and rather weak enhancement. 6. A thyroid gland extract showed a temporary enhancement in M. bulb., but on the abdominal muscle a weak increase or often none. 7. A salivary gland extract had fairly durable enhancing influences on the two muscles. 8. Adrenaline or thymus extract seemed to have very little to do with the muscles. 9. Bromvaleryl urea, chloral hydrate and morhpine were found to be unable to change the discharge pattern of the abdominal muscle. Sodium isoamylethylbarbiturate and sodium phenobarbiturate showed specific preference to the female subjects, reducing the discharge activities of both muscles. Testosterone or estradiol acted inhibitorily against the bariturate action. 10. In the animal experiments, the sexual hormones were shown to be reactive on the whole field of nervous system below mesencephalon (the more higher parts being not investigated), but less so on the peripheral. General discussions are given with regard to the hormonal environment of the body and the antagonisms between the hormones.