Effect of. cap alpha. /sub 1/-adrenergic stimulation on phosphoinositide metabolism and protein kinase C (PK-C) in rat cardiomyocytes
Alpha/sub 1/-adrenergic stimulation is known to enhance membrane phospholipid metabolism resulting in increases in inositol phosphates (IP's) and diacylglycerol (DAG). Cardiomyocytes prelabeled with /sup 3/H-myo-inositol were treated with norepinephrine (NE) for 1-15 min, acid extracted, and IP's separated by ion exchange chromatography. Addition of NE (10/sup -5/M) in the presence of propranolol (10/sup -5/ M) and LiCl (9 mM) enhanced the accumulation of IP's, linearly with time up to 15 min, and reached 7.3, and 1.5-fold at 15 min for IP/sub 1/, IP/sub 2/, and IP/sub 3/, respectively. KCl at 30 mM had no effect on accumulation of IP's, but augmented the effect of NE. PK-C activity was measured in both cytosol (S) and particulate (P) fractions of treated cells. NE alone had a negligible effect on membrane PK-C, while 30 mM KCl caused a small increase. However, pretreatment with KCl followed by NE produced a significant increase above that seen with KCl alone. Dioctanoylglycerol also stimulated membrane association of PK-C in these cells. These data suggest that ..cap alpha../sub 1/-adrenergic stimulation of membrane association of myocardial PK-C is mediated by DAG but may be dependent on membrane potential and/or the extent of Ca/sup 2 +/ loading.
- OSTI ID:
- 5435771
- Report Number(s):
- CONF-8604222-; TRN: 86-026655
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:3; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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CELL MEMBRANES
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HEART
ION EXCHANGE CHROMATOGRAPHY
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550501* - Metabolism- Tracer Techniques