Adenylate cyclase activity and steroidogenesis in phenotypic revertants of an ACTH-insensitive adrenal tumour cell line

Nature ◽  
1976 ◽  
Vol 259 (5543) ◽  
pp. 482-483 ◽  
Author(s):  
BERNARD P. SCHIMMER
1995 ◽  
Vol 312 (3) ◽  
pp. 769-774 ◽  
Author(s):  
L Zeng ◽  
M D Houslay

Incubation of hepatocytes or the SV40-DNA-immortalized hepatocyte P9 cell line with cholera toxin led to a time-dependent activation of adenylate cyclase activity, which occurred after a defined lag period. When added together with cholera toxin, each of the hormones insulin and vasopressin was capable of attenuating the maximum stimulatory effect achieved by cholera toxin over a period of 60 min through a process which could be blocked by the compounds staurosporine and chelerythrine. Attenuating effects on cholera-toxin-stimulated adenylate cyclase activity could also be elicited by using either the protein kinase C (PKC)-stimulating phorbol ester PMA (phorbol 12-myristate 13-acetate) or the protein phosphatase inhibitor okadaic acid. Alkaline phosphatase treatment of membranes reversed the inhibitory effect of PMA. Cholera toxin also stimulated the adenylate cyclase activity of intact CHO (Chinese-hamster ovary) and NIH-3T3 cells, but this activity was insensitive to the addition of PMA. Overexpression of various PKC isoforms in CHO cell lines did not confer sensitivity to inhibition by PMA upon cholera-toxin-stimulated adenylate cyclase activity. Rather, overexpression of the gamma isoform of PKC allowed PMA to stimulate adenylate cyclase activity in CHO cells. It is suggested that the PKC-mediated phosphorylation of a membrane protein attenuates cholera-toxin-stimulated adenylate cyclase activity in hepatocytes and P9 cells. The cellular selectivity of such an action may be due to the target for this inhibitory action of PKC being a particular isoform of adenylate cyclase which provides the major activity in hepatocytes and P9 cells, but not in either CHO or NIH-3T3 cells.


Lipids ◽  
1993 ◽  
Vol 28 (8) ◽  
pp. 727-730 ◽  
Author(s):  
Lido Calorini ◽  
Gabriele Mugnai ◽  
Antonella Mannini ◽  
Salvatore Ruggieri

FEBS Letters ◽  
1988 ◽  
Vol 242 (1) ◽  
pp. 61-64 ◽  
Author(s):  
Jean Luc Scemama ◽  
Patrick Robberecht ◽  
Magali Waelbroeck ◽  
Philippe De Neef ◽  
Lucien Pradayrol ◽  
...  

Author(s):  
L.S. Cutler

Many studies previously have shown that the B-adrenergic agonist isoproterenol and the a-adrenergic agonist norepinephrine will stimulate secretion by the adult rat submandibular (SMG) and parotid glands. Recent data from several laboratories indicates that adrenergic agonists bind to specific receptors on the secretory cell surface and stimulate membrane associated adenylate cyclase activity which generates cyclic AMP. The production of cyclic AMP apparently initiates a cascade of events which culminates in exocytosis. During recent studies in our laboratory it was observed that the adenylate cyclase activity in plasma membrane fractions derived from the prenatal and early neonatal rat submandibular gland was retractile to stimulation by isoproterenol but was stimulated by norepinephrine. In addition, in vitro secretion studies indicated that these prenatal and neonatal glands would not secrete peroxidase in response to isoproterenol but would secrete in response to norepinephrine. In contrast to these in vitro observations, it has been shown that the injection of isoproterenol into the living newborn rat results in secretion of peroxidase by the SMG (1).


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