[Involvement of SH-groups in the regulation of adenylate cyclase signal system by isoproterenol and serotonin in cultured murine fibroblasts L (subline LSM)]. 
The adenylyl cyclase system (ACS) plays a key role in transduction of a hormonal signal into eukaryotic cells.  The functional activity of the system depends on SH-groups of proteins involved in the ACS: receptor, G-protein, and enzyme adenylyl cyclase (AC).  We studied the influence of thiols and SH-blockers on the regulation of AC activity by nonhormonal (NaF and Gpp[NH]p) and hormonal (biogenic amines isoproterenol and serotonin) agents in homogenates of cultured murine fibroblasts of line L (subline LSM).  In the presence of thiols 2-mercaptoethanol (5 mM) and dithiothreitol (1 mM) the basal AC activity somewhat increased, whereas the stimulating effects of NaF, Gpp[NH]p, and hormones decreased.  No potentiating action of Gpp[NH]p on hormonal effect in this case was found.  The SH-blockers 25 mkM p-chloromercuribenzoic acid (CMBA) and 0.2 mM N-ethylmaleimide significantly inhibited both the basal AC activity and that stimulated by different agents.  Thiols partially restored CMBA inhibited AC activity (in the case of N-ethylmaleimide restoring effects of thiols were insignificant).  This, the ACS of murine fibroblasts of subline LSM is SH-sensitive.  The forms of SH-groups in proteins involved in the ACS determine their functional activities and a possibility of transduction of the hormonal signal on the effector systems.