Ribonucleic acid expression of the CLA-1 gene, a human homolog to mouse high density lipoprotein receptor SR-BI, in human adrenal tumors and cultured adrenal cells.
Human CLA-1 is homologous to the mouse SR-BI gene, which was recently identified as a high density lipoprotein receptor involved in selective cholesterol uptake in rodent adrenal cells. We screened 42 normal and pathological adrenal samples by Northern blotting and found abundant expression of CLA-1 messenger ribonucleic acid (mRNA) in normal adult and fetal adrenals, adrenocortical adenomas, and hyperplasias. Adrenocortical carcinomas and the adrenals adjacent to Cushing's adenomas contained less CLA-1 mRNA than normal adrenals. CLA-1 mRNA was also highly expressed in a Leydig cell tumor, but much less in liver, kidney, and pheochromocytomas. The accumulation of CLA-1 mRNA in primary cultures of normal adrenocortical cells was up-regulated by ACTH in a dose- and time-dependent manner. Both dibutyryl cAMP and staurosporine increased the basal expression of CLA-1 mRNA. Although there was no additive effect of ACTH and dibutyryl cAMP, staurosporine slightly enhanced the stimulatory effect of ACTH on the expression of CLA-1 mRNA. The abundant expression of CLA-1 mRNA and its regulation by the physiological hormone ACTH in human adrenal cells suggest that CLA-1 has a role in adrenal steroidogenesis, probably as a lipoprotein receptor mediating the selective cholesterol uptake in these cells.
Liu
J
J
Department of Pathology, University of Helsinki, Finland. Jiangi.Liu@helsinki.fi
Voutilainen
R
R
Heikkilä
P
P
Kahri
A I
AI
D000302:Adrenal Cortex / Q000473:pathology; D000306:Adrenal Cortex Neoplasms / Q000235:genetics*; D000311:Adrenal Glands / Q000737:chemistry*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000818:Animals; D015152:Blotting, Northern; D003994:Bucladesine / Q000494:pharmacology; D018955:CD36 Antigens / Q000235:genetics*; D002478:Cells, Cultured; D003480:Cushing Syndrome; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D006965:Hyperplasia; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis*; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D051122:Scavenger Receptors, Class B; D019311:Staurosporine / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D018955:CD36 Antigens; D008565:Membrane Proteins; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; C495124:SCARB1 protein, human; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; D003994:Bucladesine; D000324:Adrenocorticotropic Hormone; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate