[Hindlimb antigravity muscles' reaction in male and female rats to the deficit of functional loading].
Histological and histomorphometric comparison of the antigravity muscles of rats of both sexes was performed following 30-d unloading of their hind limbs by head-down suspension. It was shown that growth rate of control males was higher as compared to control females. This is attributed to the synergic effects of somatotropin and testosterone on metabolism and growth of males and only somatotropin in females. Load deprivation of the hind limbs inhibited body mass gain in all animals; however, this inhibition was twice as great in males. Increase of the soleus and gastrocnemius in the control males in this experiment was slightly ahead of the muscle mass gain in the females. The histomorphometric investigation of the cross-section area of myofibers did not reveal differences between males and females either in the control or suspension. No difference was found in percent of various types of fibers in the control males and females. In the soleus of the suspended rats, a part of slow fibers had transformed into fast ones without any sex-related particularities. The conclusion was made that despite the significant difference in the hormonal profile, the reaction of males and females to insufficient weight loading of the antigravity muscles was alike.
Il'ina-Kakueva
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D000818:Animals; D015992:Body Mass Index; D005260:Female; D006112:Gravitation; D018476:Hypokinesia / Q000175:diagnosis / Q000503:physiopathology; D007866:Leg / Q000503:physiopathology*; D008297:Male; D018485:Muscle Fibers, Skeletal; D018482:Muscle, Skeletal / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar