Effects of castration, testosterone and immobilization on the activities of choline acetyltransferase and cholinesterase in rat limb muscles.
Thirteen months after castration of male rats the weight of their soleus muscles was lowered to 82% and their choline acetyltransferase (ChAc) activity to 83% of control values. The administration of testosterone lasting 5 weeks increased the weight of the soleus muscles of castrated animals by 19% and their ChAc activity bu 37%. Changes in the activity of cholinesterase occurring after castration and testosterone treatment were not statistically significant. It is assumed taht the effect of testosterone on the activity of ChAc was mainly due to an increase in the functional activity of the motoneurones innervating the muscle. Rapid developmental increase of ChAc activity was observed in the muscles of intact rats between the age of 48 and 82 days. During this period of development the activity of ChAc rose faster than the weight of the muscles. Testosterone had no effect on the weight and ChAc activity of the soleus and extensor digitorum longus muscles of non-castrated rats after 1 week's administration; after 5 weeks' administration the weight of the muscles and their ChAc activity were diminished. After the soleus muscles of non-castrated rats had been immobilized for 10 days, their ChAc activity was 56% and their weight 51% of control values. The administration of testosterone did not alter the effect of immobilization on the ChAc and weight of the muscle.
D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D002369:Castration; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D002802:Cholinesterases / Q000378:metabolism*; D007103:Immobilization; D008297:Male; D009132:Muscles / Q000187:drug effects / Q000201:enzymology*; D009929:Organ Size; D051381:Rats; D013739:Testosterone / Q000494:pharmacology*
D013739:Testosterone; D000123:Acetyltransferases; D002795:Choline O-Acetyltransferase; D002802:Cholinesterases