title: Transcriptional regulation of episodic glucocorticoid secretion.
abstract: Circadian and ultradian variations of basal glucocorticoid secretion and transient elevations during stress are essential for homeostasis. Using intronic qRT-PCR to measure changes in primary transcript (hnRNA) we have shown that secretory events induced by stress or ACTH injection are followed by episodic increases in transcription of rate limiting steroidogenic proteins, such as steroidogenic acute regulatory protein (StAR), cytochrome P450 side chain cleavage and melanocortin receptor associated protein. These transcriptional episodes imply rapid turnover of steroidogenic proteins and the need of de novo synthesis following each secretory event. In addition to episodic ACTH secretion, it is likely that intracellular feedback mechanisms at the adrenal fasciculata level contribute to the generation of episodes of transcription. The time relationship between activation and translocation of the CREB co-activator, transducer of regulated CREB activity (TORC) to the nucleus preceding transcriptional episodes suggest the involvement of TORC in the transcriptional activation of StAR and other steroidogenic proteins.
authors.affiliation: Section on Endocrine Physiology, National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Lorna I
authors.initials: LI
authors.lastname: Smith
authors.forename: Victoria
authors.initials: V
authors.lastname: Huang
authors.forename: Victoria
authors.initials: V
authors.lastname: Poon
authors.forename: Ana
authors.initials: A
authors.lastname: Coello
authors.forename: Mark
authors.initials: M
authors.lastname: Olah
authors.forename: Francesca
authors.initials: F
authors.lastname: Spiga
authors.forename: Stafford L
authors.initials: SL
authors.lastname: Lightman
authors.forename: Greti
authors.initials: G
authors.lastname: Aguilera
mesh_terms: D000311:Adrenal Glands / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein; D005786:Gene Expression Regulation; D005938:Glucocorticoids / Q000378:metabolism*; D006801:Humans; D010750:Phosphoproteins / Q000096:biosynthesis; D044101:Receptors, Melanocortin / Q000096:biosynthesis; D013256:Steroids / Q000096:biosynthesis*; D013312:Stress, Physiological; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: C115163:CREB1 protein, human; D017362:Cyclic AMP Response Element-Binding Protein; D005938:Glucocorticoids; D010750:Phosphoproteins; D044101:Receptors, Melanocortin; D013256:Steroids; D000098682:Steroidogenic Acute Regulatory Protein; D000324:Adrenocorticotropic Hormone