Intermediate role of adenosine 3′:5′-cyclic monophosphate and protein kinase during gonadotropin-induced steroidogenesis in testicular interstitial cells
AUTOR(ES)
Dufau, Maria L.
RESUMO
Discrepancies between adenosine 3′:5′-cyclic monophosphate (cAMP) and steroid production have been frequently observed in isolated target cells stimulated by low concentrations of trophic hormone. This dissociation is particularly marked in the interstitial cells of the testis, where testosterone production is elicited by gonadotropin concentrations in the picomolar range. Because of these observations, and a disparity between steroidogenesis and protein kinase (ATP: protein phosphotransferase, EC 2.7.1.37) activation in Leydig cells, the role of cAMP as a mediator of the acute steroidogenic response has been questioned. This problem has been further analyzed by assay of free and occupied cAMP-binding sites of the regulatory subunit of protein kinase in basal and hormone-stimulated cells. Free sites were measured by a [3H]-cAMP-binding assay, and occupied sites were measured by radioimmunoassay of endogenous cAMP eluted from receptor protein.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=431588Documentos Relacionados
- Gonadotropin-induced regulation of luteinizing hormone receptors and desensitization of testicular 3':5'-cyclic AMP and testosterone responses.
- Adenosine 3′:5′-cyclic monophosphate- and guanosine 3′:5′-cyclic monophosphate-dependent protein kinases: Possible homologous proteins
- A Protein Binding Assay for Adenosine 3′:5′-Cyclic Monophosphate
- 3′:5′-Cyclic Adenosine Monophosphate Phosphodiesterase: Negative Cooperativity
- Interaction of the Subunits of Adenosine 3′:5′-Cyclic Monophosphate-Dependent Protein Kinase of Muscle
