Inhibins, activins, and follistatins: expression of mRNAs and cellular localization in tissues from men with benign prostatic hyperplasia.
BACKGROUND
The transforming growth factor beta (TGF beta) superfamily of growth factors includes activins and inhibins, which have been shown to be present in the rat ventral prostate, and human prostate tumor cell lines, although their localization in benign prostatic hyperplasia (BPH) tissue is currently unknown.


METHODS
BPH tissues were obtained at surgery, and the mRNA expression for the inhibin alpha, beta A, beta B subunits, the putative activin beta C subunit, the activin type II receptor (ActRII), and the activin binding protein, follistatin, was determined by reverse transcription polymerase chain reaction (RT-PCR) and Southern blot analysis. Antibodies specific for alpha, beta A, beta B, activin A, and follistatin were used to determine the localization of these proteins in BPH tissue specimens.


RESULTS
Southern blot analysis confirmed that mRNA for ActRII, beta C subunit, and follistatin was present in all biopsy samples assayed. However, alpha, beta A, and beta B subunit mRNA expression was variable between patient samples. Immunohistochemistry demonstrated the predominant localization of beta A, beta B, and activin A proteins to the epithelium of BPH tissues. No immunoreactivity for the inhibin alpha subunit was detected; follistatin immunoreactivity was localized to the fibroblastic stroma.


CONCLUSIONS
The compartmentalization of activin subunit proteins to the epithelium, and of follistatin to the stroma, suggests that a paracrine interaction occurs between the activin ligands and follistatin-binding proteins in BPH tissue.
Thomas
T Z
TZ
Institute of Reproduction and Development, Monash Medical Center, Clayton, Victoria, Australia.
Chapman
S M
SM
Hong
W
W
Gurusingfhe
C
C
Mellor
S L
SL
Fletcher
R
R
Pedersen
J
J
Risbridger
G P
GP
D029404:Activin Receptors; D028341:Activins; D000818:Animals; D038681:Follistatin; D015870:Gene Expression; D006023:Glycoproteins / Q000032:analysis* / Q000235:genetics; D006801:Humans; D028322:Inhibin-beta Subunits; D007265:Inhibins / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D009842:Oligopeptides; D010455:Peptides / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D011470:Prostatic Hyperplasia / Q000378:metabolism* / Q000473:pathology; D029584:Prostatic Secretory Proteins; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D017978:Receptors, Growth Factor / Q000032:analysis / Q000235:genetics
D038681:Follistatin; D006023:Glycoproteins; D009842:Oligopeptides; D010455:Peptides; D029584:Prostatic Secretory Proteins; D012333:RNA, Messenger; D017978:Receptors, Growth Factor; C044147:activin B; C043076:beta-microseminoprotein; C103008:inhibin beta A subunit; C094377:inhibin-alpha subunit; D028341:Activins; C048617:myelopeptides; D007265:Inhibins; D028322:Inhibin-beta Subunits; D029404:Activin Receptors