Published-Ahead-of-Print April 4, 2007, DOI:10.2164/jandrol.107.002634
Journal of Andrology, Vol. 28, No. 5, September/October 2007
Copyright © American Society of Andrology
DOI: 10.2164/jandrol.107.002634
Microvillar Size and Espin Expression in Principal Cells of the Adult Rat Epididymis Are Regulated by Androgens
NADIA PRIMIANI*,
MARY GREGORY
,
JULIE DUFRESNE
,
CHARLES E. SMITH
,
YE LAUREN LIU*,
JAMES R. BARTLES
,
DANIEL G. CYR*,
AND
LOUIS HERMO*
From the * Department of Anatomy and Cell Biology,
McGill University, Montreal, Canada;
INRS-Institut Armand Frappier,
Université du Québec, Pointe-Claire, Canada;
Département de Stomatologie,
Université de Montréal, Montreal, Canada; and
Department of Cell and Molecular Biology,
Feinberg School of Medicine, Northwestern University, Chicago, Illinois.
|
Correspondence to: Dr Louis Hermo, Department of Anatomy and Cell Biology,
McGill University, 3640 University St, Montreal, Quebec, H3A 2B2 (e-mail:
louis.hermo{at}mcgill.ca). |
Principal cells of the epididymis are the most prominent cell type and are
noted for an apical cell surface studded with microvilli. The latter contain
channel proteins that condition the microenvironment of epididymal lumen and
promote sperm maturation; however, the regulation of the structure and
integrity of microvilli is not well known. Espins are a family of proteins
implicated in microvillar growth. The objectives of this study were to assess
the regulation of espin in epididymal principal cells both in vitro and in
vivo. Treatment of immortalized rat caput epididymal (RCE) cells with
increasing doses of a homogenized testicular extract revealed a dose-dependent
increase in the size of microvilli. Reverse transcriptase–polymerase
chain reaction (RT-PCR) of adult rat epididymal RNA using espin-specific
primers indicated the presence of a band at about 290 base pairs (bp) in all
regions. Western blot analysis using affinity-purified espin antibody
confirmed the presence of an approximately 110-kDa band in the epididymis,
corresponding to espin isoform 1. In adult rats, immunocytochemistry revealed
espin expression over principal cells. In orchidectomized rats, espin
expression was significantly reduced, whereas ligation of the efferent ducts
resulted in a decrease of espin expression but not to the extent of
orchidectomy. The fact that espin expression was restored to control levels in
orchidectomized rats supplemented with high levels of testosterone indicated
that its expression was dependent on androgens and not on other lumicrine
factors derived from the testis. Taken together, these data indicate that
espin is expressed in the epididymis and is regulated by androgens.
Key words: RT-PCR, immunocytochemistry, RCE cell line, orchidectomy, testicular extract
Copyright © 2007 by The American Society of Andrology.