title: Androgen locally regulates rat bulbocavernosus and levator ani size.
abstract: Adult male rats were gonadectomized, and small Silastic capsules filled with hormone were sutured to each bulbocavernosus and levator ani muscle complex (BC/LA). In the first experiment, one capsule contained testosterone (T), while the capsule on the contralateral muscles contained the antiandrogen hydroxyflutamide (hFl). The intent of this treatment was to provide a focus of androgenic stimulation to the muscles on one side. After 30 days, animals were sacrificed, and the BC/LA muscle pairs were removed, weighed, and compared. BC/LAs receiving T treatment were heavier than those receiving hFl treatment (p less than 0.0001), with an average weight difference of 12%. Muscle fibers from T-treated BCs were significantly larger in diameter than those from contralateral, hFl-treated BCs. These results indicate that androgen exerts its anabolic effect by acting locally upon a cell population within or near the BC/LA. When hFl and blank capsules were implanted in castrated males, the hFl-treated muscles were significantly heavier (by 9%), demonstrating an anabolic effect of hFl in the absence of androgen, and refuting the idea that hFl may have caused local toxic effects in the first experiment. Gonadectomized animals given T versus blank capsules had T-treated muscles that were 8% heavier than the blank-treated side. Muscle weights were also compared in animals receiving bilateral denervation of the BC/LA at the time of T and hFl capsule implantation and gonadectomy; local testosterone treatment failed to affect BC/LA weights in these denervated muscles.
authors.affiliation: Department of Psychology, University of California, Berkeley 94720.
authors.forename: M N
authors.initials: MN
authors.lastname: Rand
authors.forename: S M
authors.initials: SM
authors.lastname: Breedlove
mesh_terms: D000818:Animals; D002772:Cholera Toxin; D004343:Drug Implants; D005485:Flutamide / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D006735:Horseradish Peroxidase; D008297:Male; D024510:Muscle Development; D009132:Muscles / Q000033:anatomy & histology / Q000187:drug effects; D009919:Orchiectomy; D009929:Organ Size / Q000187:drug effects; D010413:Penis / Q000033:anatomy & histology / Q000187:drug effects / Q000254:growth & development*; D051381:Rats; D011919:Rats, Inbred Strains; D013739:Testosterone / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D004343:Drug Implants; C052635:cholera toxin, B subunit-horseradish peroxidase; C014290:hydroxyflutamide; D013739:Testosterone; D005485:Flutamide; D002772:Cholera Toxin; D006735:Horseradish Peroxidase