title: Gender-specific effects of dexamethasone treatment on rat diaphragm structure and function.
abstract: The effects of long-term dexamethasone treatment on diaphragm muscle were studied in female and male rats. Compared with pair-fed control animals, dexamethasone treatment did not significantly affect estrous cycling or peak serum estradiol levels; however, testosterone levels were significantly increased in females and decreased in males. Dexamethasone significantly reduced body and costal diaphragm weights, but to a lesser extent in females than in males. Reductions in diaphragm weight were proportional to reductions in body weight. In females and males, dexamethasone treatment significantly decreased diaphragm fiber (types I and II) cross-sectional area and the relative expression of myosin heavy chain isoform 2B. With the exception of type I fiber atrophy, these changes occurred to a lesser extent in females. Dexamethasone did not significantly affect specific forces. Dexamethasone significantly increased twitch one-half relaxation time and fatigue resistance indexes in males but not in females. In conclusion, the effects of long-term dexamethasone treatment were gender specific, with significantly fewer effects in females, and changes in serum testosterone levels were associated with these findings.
authors.affiliation: Department of Medicine, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York 10467, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Prezant
authors.forename: M L
authors.initials: ML
authors.lastname: Karwa
authors.forename: B
authors.initials: B
authors.lastname: Richner
authors.forename: D
authors.initials: D
authors.lastname: Maggiore
authors.forename: E I
authors.initials: EI
authors.lastname: Gentry
authors.forename: J
authors.initials: J
authors.lastname: Cahill
mesh_terms: D000818:Animals; D003907:Dexamethasone / Q000494:pharmacology*; D003964:Diaphragm / Q000187:drug effects* / Q000502:physiology*; D005260:Female; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012727:Sex Characteristics
chemical_list: D003907:Dexamethasone