Somatostatin (somatotropin release-inhibiting factor, SRIF) interacts with G-protein coupled receptors (sst) designated sst1 through sst5. In PC12 and GC cells, SRIF binding sites were identified and mRNA receptor expression was evaluated. SRIF binding sites were expressed at a much lower density in PC12 (Kd = 21.2 +/- 3.9 nM; Bmax = 31 +/- 8 fmol/mg protein) than in GC cells (Kd = 6.4 +/- 1.6 nM; Bmax = 643 +/- 29 fmol/mg protein). sst3 receptor mRNA (81% of the total) was mainly expressed in PC12 cells, while sst1/2 receptor mRNAs were mostly expressed in GC cells (64 and 29%, respectively). In PC12 cells, adenylyl cyclase (AC) activity was unaffected by SRIF-14 (binding all SRIF receptors), octreotide (specific for sst2/3/5 receptors), BIM 23056 (binding sst3/5 receptors) or CH275 (specific for sst1 receptors), 1 microM each. In GC cells, SRIF-14 or octreotide, but not the two other peptides, significantly inhibited AC activity.
Expression and coupling of somatostatin receptors in rat adrenal (PC12) and pituitary (GC) cell lines.
TRAINA, Giovanna;
1998
Abstract
Somatostatin (somatotropin release-inhibiting factor, SRIF) interacts with G-protein coupled receptors (sst) designated sst1 through sst5. In PC12 and GC cells, SRIF binding sites were identified and mRNA receptor expression was evaluated. SRIF binding sites were expressed at a much lower density in PC12 (Kd = 21.2 +/- 3.9 nM; Bmax = 31 +/- 8 fmol/mg protein) than in GC cells (Kd = 6.4 +/- 1.6 nM; Bmax = 643 +/- 29 fmol/mg protein). sst3 receptor mRNA (81% of the total) was mainly expressed in PC12 cells, while sst1/2 receptor mRNAs were mostly expressed in GC cells (64 and 29%, respectively). In PC12 cells, adenylyl cyclase (AC) activity was unaffected by SRIF-14 (binding all SRIF receptors), octreotide (specific for sst2/3/5 receptors), BIM 23056 (binding sst3/5 receptors) or CH275 (specific for sst1 receptors), 1 microM each. In GC cells, SRIF-14 or octreotide, but not the two other peptides, significantly inhibited AC activity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
