Phospholipase C activation and Ca2+ mobilization by cloned human somatostatin receptor subtypes 1–5, in transfected COS‐7 cells
Open Access
- 11 July 1994
- journal article
- Published by Wiley in FEBS Letters
- Vol. 348 (2) , 192-196
- https://doi.org/10.1016/0014-5793(94)00603-2
Abstract
We transfected the COS‐7 cells with cDNAs encoding different human somatostatin receptor (hSSTR) subtypes, and found that hSSTR subtypes mediate not only the inhibition of forskolin‐induced cAMP accumulation but also the stimulation of phospholipase C (PLC) and Ca2+ mobilization. Activation of PLC by 1 μM somatostatin (SRIF) was in the order of: hSSTR5 ⪢ hSSTR2 ⪢ hSSTR3 ⪢ hSSTR4 ⪢ hSSTR1. Pertussis toxin (PTX) treatment completely or partially reversed the PLC activation. 1 nM SRIF was equally effective for adenylate cyclase (AC) inhibition in a PTX‐sensitive manner, in all the cells expressing different hSSTRs, except for hSSTR1. Nevertheless, SRIF stimulated AC even in the presence of forskolin at higher doses of SRIF in PTX‐treated hSSTR5‐expressing cells. We conclude that the cloned hSSTRs differentially couple to PTX‐sensitive and ‐insensitive G‐proteins to modulate PLC, Ca2+ mobilization and AC.Keywords
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