No direct nuclear effect of progesterone in the inner ear: other possible pathways.
CONCLUSIONS
No nuclear progesterone receptors were found in human or rat stria vascularis, organ of Corti or spiral ganglion with immunohistochemistry or polymerase chain reaction (PCR). Progesterone receptor B (PR-B) was found with Western blot in the cochlea, probably representing the staining in the cochlear bone. The effect of progesterone on hearing is therefore most likely not due to a direct action on the inner ear.


OBJECTIVE
Studies suggest that progesterone as a component in hormone replacement therapy has a negative effect on hearing thresholds and otoacoustic emissions in pre- and postmenopausal women and mice. This study was designed to examine the presence of PRs in the cochlea of humans and rats.


METHODS
Immunohistochemical staining of PR protein in humans and rats, PCR of PR-B mRNA expression, and Western blot of PR-A and PR-B protein in rats was performed.


RESULTS
No nuclear staining could be found for any PR in human or rat inner ear except the PR-B staining in the cochlear bone. No mRNA expression was detected by PCR. PR-B could be detected in Western blot performed on the whole cochlea including bone.
Division of ENT Diseases, Department of Clinical Sciences, Intervention and Technology, Karolinska Institutet.
Asa
A
Bonnard
Lena
L
Sahlin
Malou
M
Hultcrantz
Rusana
R
Simonoska
D000818:Animals; D015153:Blotting, Western; D003051:Cochlea / Q000187:drug effects / Q000378:metabolism*; D004195:Disease Models, Animal; D005260:Female; D005786:Gene Expression Regulation; D006319:Hearing Loss, Sensorineural / Q000139:chemically induced / Q000235:genetics* / Q000378:metabolism; D020249:Hormone Replacement Therapy / Q000009:adverse effects; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008875:Middle Aged; D017084:Otoacoustic Emissions, Spontaneous / Q000187:drug effects*; D016133:Polymerase Chain Reaction; D011374:Progesterone / Q000009:adverse effects*; D011372:Progestins / Q000009:adverse effects; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011980:Receptors, Progesterone / Q000096:biosynthesis / Q000235:genetics*
D011372:Progestins; D012333:RNA, Messenger; D011980:Receptors, Progesterone; C097314:progesterone receptor B; D011374:Progesterone