[Effects of sex hormones on sarcoplasmic reticulum Ca2+ -ATPase activity and gene expression in the genioglossal muscle of the aged rats].
OBJECTIVE
To investigate the effects of sex hormones on sarcoplasmic reticulum (SR) Ca(2+)-ATPase activity and gene expression in the genioglossal muscle of the aged rats, and to explore the possible mechanism related to the upper airway stability.


METHODS
Twenty four aged male rats were randomly divided into 3 groups: control group, estrogen group (intramuscular injection of estrogen 0.1 mg/kg, twice a week), androgen group (intramuscular injection of androgen 2.5 mg/kg, twice a week). Ca(2+)-ATPase activity was measured by detecting inorganic phosphorus ion, and SR Ca(2+)-ATPase (SERCA) mRNA level was observed using fluorescence quantitative reverse transcription-polymerase chain reaction (FQ RT-PCR).


RESULTS
Compared with the control group, there were no significant changes in SR Ca(2+)-ATPase activity [34.24+/-6.14 micromol Pi/(mg protein.hour) vs 38.39 +/- 8.49 micromol Pi/(mg protein.hour)] and SERCA mRNA level (0.029,7 +/- 0.014,0 vs 0.031,4+/-0.017,4 ) in estrogen group(P>0.05); while in the androgen group, SR Ca(2+)-ATPase activity [22.91 +/- 4.56 micromol Pi/(mg protein.hour)] was reduced to 67% (P<0.01), and SERCA mRNA level (0.017,2+/-0.008,6) was also significantly reduced (P<0.05).


CONCLUSIONS
Androgen may impair the function of the genioglossal muscle by depressing the SR Ca(2+)-ATPase activity and the SERCA mRNA expression, while estrogen may not have this mechanism in the aged male rats.
Qi
Juan
J
Department of Orthodontics, School of Stomatology, Tongji University, Shanghai 200072, China.
Liu
Yue-hua
YH
D000375:Aging; D000818:Animals; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D007273:Injections, Intramuscular; D008297:Male; D010609:Pharyngeal Muscles / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000235:genetics* / Q000378:metabolism; D013739:Testosterone / Q000008:administration & dosage / Q000494:pharmacology*
D012333:RNA, Messenger; D013739:Testosterone; D004958:Estradiol; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases