Cellular distribution and hormonal regulation of h-SBP in human hepatoma cells.
The cellular distribution of human Sex Steroid Binding Plasma Protein (h-SBP) was studied in human cells and tissues by indirect immunofluorescence. h-SBP was detected in the cytoplasm of hepatocytes, of prostate and epididymis epithelial cells and in endometrium. Sexual and non-sexual skin, intestine epithelium, striated muscle and some rodent organs were not labelled. The intracellular localization of h-SBP indicate that h-SBP could be taken up from the extracellular compartment or synthesized in situ in sex steroid target organs, where it may play a role in hormone uptake. The hormonal regulation of h-SBP secretion by a human hepatoma cell line, H5A, showed that tri-iodothyronine was more potent than estradiol or tamoxifen, which acted as estrogen agonist, in increasing secreted h-SBP and the combined effect of both thyroid and estrogen hormones resulted in an additive stimulation of h-SBP secretion. As shown by Northern blot analysis, oligonucleotides synthesized from the known sequence of h-SBP hybridized with a RNA of approximately 2 kb which was more represented in H5A cells than in normal human liver, and was increased 2-3 times after hormonal stimulation of the cells. The presence of a poly(A+)RNA coding for h-SBP in the human liver indicated the hepatic synthesis of this protein.
Mercier-Bodard
C
C
Lab. Hormones, Inserm U 33, Bicêtre, France.
Radanyi
C
C
Roux
C
C
Groyer
M T
MT
Robel
P
P
Dadoune
J P
JP
Petra
P H
PH
Jolly
D J
DJ
Baulieu
E E
EE
D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D003907:Dexamethasone / Q000494:pharmacology; D013196:Dihydrotestosterone / Q000378:metabolism; D004717:Endometrium / Q000032:analysis; D004822:Epididymis / Q000032:analysis; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism*; D008297:Male; D051379:Mice; D009132:Muscles / Q000032:analysis; D009363:Neoplasm Proteins / Q000378:metabolism*; D009928:Organ Specificity; D010637:Phenolsulfonphthalein / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology; D011467:Prostate / Q000032:analysis; D051381:Rats; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism*; D012867:Skin / Q000032:analysis; D013629:Tamoxifen / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D014781:Viscera / Q000032:analysis
D009363:Neoplasm Proteins; D012738:Sex Hormone-Binding Globulin; D013196:Dihydrotestosterone; D013629:Tamoxifen; D011374:Progesterone; D003907:Dexamethasone; D010637:Phenolsulfonphthalein