Modulation of steroidogenic enzymes by orphan nuclear transcriptional regulation may control diverse production of cortisol and androgens in the human adrenal.
The capacity of the adrenal to produce cortisol is controlled in part by 21-hydroxylase (CYP21) and the production of androgens by 17-hydroxylase/17-20-lyase (CYP17), in response to secretagogues including ACTH, angiotensin-II (A-II) and insulin. In this study we examined the capacity of human adrenocortical cells to produce cortisol and androgens in response to these secretagogues and their ability to regulate the expression of CYP21 and CYP17. In H-295 cells, forskolin and A-II were found to stimulate production of cortisol relative to androstenedione and a similar pattern of steroid production was noted in primary human adrenocortical cells. Both mRNA and protein expression of CYP21 was upregulated with forskolin and A-II alone and in combination, as detected by Northern and Western blotting. Whereas expression of CYP17 mRNA and protein was up regulated in the presence of forskolin and forskolin in combination with insulin. The ability of steroidogenic factor-1 (SF-1) and nur77 to regulate transcription of these enzymes was examined. Forskolin, A-II and insulin increased the protein expression of SF-1. Increased binding of SF-1 to its response element in the presence of forskolin, A-II and insulin was observed. Nur77 was expressed primarily in the zona glomerulosa and fasciculata. Increased protein expression of nur77 and the greatest binding of nur77 to its response element was seen when cells were stimulated with A-II in combination with forskolin. These data indicate that nur77 may preferentially regulate steroid enzyme genes relevant to cortisol production and thereby regulate differential cortisol and adrenal androgen production.
Kelly
Sinead N
SN
Department of Surgery, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Ireland.
McKenna
T Joseph
TJ
Young
Leonie S
LS
D000311:Adrenal Glands / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000728:Androgens / Q000096:biosynthesis*; D000804:Angiotensin II / Q000494:pharmacology; D015152:Blotting, Northern / Q000379:methods; D015153:Blotting, Western / Q000379:methods; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000032:analysis; D024202:Electrophoretic Mobility Shift Assay; D004789:Enzyme Activation; D051717:Fushi Tarazu Transcription Factors; D005786:Gene Expression Regulation; D006801:Humans; D006854:Hydrocortisone / Q000096:biosynthesis*; D007150:Immunohistochemistry / Q000379:methods; D007328:Insulin / Q000494:pharmacology; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D012333:RNA, Messenger / Q000032:analysis; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D013254:Steroid 17-alpha-Hydroxylase / Q000378:metabolism; D013255:Steroid 21-Hydroxylase / Q000378:metabolism; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000032:analysis
D000728:Androgens; D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D007328:Insulin; C539821:NR4A1 protein, human; C515057:NR5A1 protein, human; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; D000804:Angiotensin II; D005576:Colforsin; D000324:Adrenocorticotropic Hormone; D013255:Steroid 21-Hydroxylase; D013254:Steroid 17-alpha-Hydroxylase; D006854:Hydrocortisone