Glucocorticoid Regulation of ACTH Sensitivity of Adenyl Cyclase in Rat Fat Cell Membranes
AUTOR(ES)
Braun, T.
RESUMO
Plasma membrane sacs of isolated rat fat cells (ghots) possess an adenyl cyclase system, which is activated by lipolytic hormones of disparate molecular structure, including adrenocorticotropin (ACTH), glucagon, and epinephrine. Previous studies indicated that distinctive selectivity units for individual hormones are coupled to the same unit of adenyl cyclase in the fat cell membrane. The present study has shown that ghost cyclase from adrenalectomized and hypophysectomized rats exhibits a striking reduction in response to ACTH, the stimulatory effects of epinephrine, glucagon, or fluoride being unchanged. Pretreatment of adrenalectomized, hypophysectomized, sham operated, or intact rats with the synthetic glucocorticoid, dexamethasone, selectively increased the ACTH response in ghost cyclase preparations. Cortisol, like dexamethasone, increased the ACTH response in ghosts from adrenalectomized rats; 11-deoxycorticosterone was ineffective. The dexamethasone effect to enhance the ACTH response is blocked by actinomycin D or cycloheximide.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=283149Documentos Relacionados
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