Activation of myocardial protein kinase C by plasmalogenic diglycerides

1990 ◽  
Vol 258 (1) ◽  
pp. C30-C36 ◽  
Author(s):  
D. A. Ford ◽  
R. W. Gross
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Myocardial Ischemia ◽  
Molecular Species ◽  
High Performance ◽  
Ischemic Myocardium ◽  
Phosphorylation Of Proteins ◽  
Kinase C ◽  
Protein Kinase C Activity ◽  
Activate Protein Kinase

Recently, we have demonstrated that myocardial sarcolemma is predominantly comprised of plasmalogen molecular species and that the plasmalogen metabolite 1-O-alk-1'-enyl-2-acyl-sn-glycerol (AAG) accumulates during myocardial ischemia despite substantial decreases in 1,2-diacyl-sn-glycerol (DAG) content. To elucidate the physiological significance of AAG accumulation during myocardial ischemia, rabbit myocardial protein kinase C was partially purified by DE-52 and high-performance hydroxylapatite chromatographies, and the potency of AAG as an activator of myocardial protein kinase C was assessed. Both AAG and 1-O-alkyl-2-acyl-sn-glycerol are potent activators of myocardial protein kinase C with obligatory requirements for physiological increments in free Ca2+ concentration. In contrast, a substantial amount of myocardial protein kinase C activity elicited by DAG was calcium independent. Concentration dependence of ATP for protein kinase C-mediated phosphorylation was identical utilizing either ether-linked diglycerides or DAG as activators, with maximal phosphorylation manifest at ATP concentrations two orders of magnitude less than those found in ischemic myocardium. Thus accumulation of AAG in ischemic myocardium in conjunction with increases in intracellular free Ca2+ concentration may synergistically activate protein kinase C and therefore modulate phosphorylation of proteins in specific subcellular loci.

Activation of protein kinase C inhibits synthesis and release of decidual prolactin

1986 ◽  
Vol 251 (2) ◽  
pp. E172-E177
Author(s):  
I. Harman ◽  
A. Costello ◽  
B. Ganong ◽  
R. M. Bell ◽  
S. Handwerger
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phorbol Esters ◽  
Dependent Manner ◽  
Prolactin Release ◽  
Kinase C ◽  
Protein Kinase C Activity ◽  
Decidual Cells ◽  
Prolactin Synthesis ◽  
Activate Protein Kinase

Activation of calcium-activated, phospholipid-dependent protein kinase C by diacylglycerol and phorbol esters has been shown to mediate release of hormones in many systems. To determine whether protein kinase C activation is also involved in the regulation of prolactin release from human decidua, we have examined the effects of various acylglycerols and phorbol esters on the synthesis and release of prolactin from cultured human decidual cells. sn-1,2-Dioctanoylglycerol (diC8), which is known to stimulate protein kinase C in other systems, inhibited prolactin release in a dose-dependent manner with maximal inhibition of 53.1% (P less than 0.01) at 100 microM. Diolein (100 microM), which also stimulates protein kinase C activity in some systems, inhibited prolactin release by 21.3% (P less than 0.05). Distearin and dipalmitin, which are much less effective in activating protein kinase C, and monopalmitin and tripalmitin, which do not activate protein kinase C, had no significant effect on prolactin release. Phorbol 12-myristate 13-acetate (PMA), phorbol 12,13-didecanoate, and 4 beta-phorbol 12,13-dibutyrate, which activate protein kinase C in other systems, also inhibited the release of prolactin, while the protein kinase C inactivate 4 alpha-phorbol-12,13-didecanoate was without effect. The inhibition of prolactin release was secondary to a decrease in prolactin synthesis. The amounts of prolactin synthesized by cells exposed to diC8 (300 microM) or PMA (10(-7) M) for 30 min were 56.3 and 50.0% less than that synthesized by control cells (P less than 0.01 in each instance).(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic treatment by the calcium channel blocker ± PN 200-110 in the rat counteracts the stimulations of pituitary weight, prolactin release and pituitary C-kinase activity induced by a chronic estradiol treatment, in vivo

1990 ◽  
Vol 122 (3) ◽  
pp. 403-408
Author(s):  
Ph. Touraine ◽  
P. Birman ◽  
F. Bai-Grenier ◽  
C. Dubray ◽  
F. Peillon ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Calcium Channel ◽  
Calcium Channel Blocker ◽  
Channel Blocker ◽  
Plasma Prolactin ◽  
Estradiol Treatment ◽  
Kinase C ◽  
Protein Kinase C Activity

Abstract In order to investigate whether a calcium channel blocker could modulate the protein kinase C activity in normal and estradiol pretreated rat pituitary, female Wistar rats were treated or not (controls) with ± PN 200-110 (3 mg · kg−1 · day−1, sc) for 8 days or with estradiol cervical implants for 8 or 15 days, alone or in combination with PN 200-110 the last 8 days. Estradiol treatment induced a significant increase in plasma prolactin levels and pituitary weight. PN 200-110 administered to normal rats did not modify these parameters, whereas it reduced the effects of the 15 days estradiol treatment on prolactin levels (53.1 ± 4.9 vs 95.0 ±9.1 μg/l, p<0.0001) and pituitary weight (19.9 ± 0.4 vs 23.0 ± 0.6 mg, p <0.001), to values statistically comparable to those measured after 8 days of estradiol treatment. PN 200-110 alone did not induce any change in protein kinase C activity as compared with controls. In contrast, PN 200-110 treatment significantly counteracted the large increase in soluble activity and the decrease in the particulate one induced by estradiol between day 8 and day 15. We conclude that PN 200-110 opposed the stimulatory effects of chronic in vivo estradiol treatment on plasma prolactin levels and pituitary weight and that this regulation was related to a concomitant modulation of the protein kinase C activity.

Swainsonine Modulation of Protein Kinase C Activity in Murine Peritoneal Macrophages

1990 ◽  
Vol 2 (10) ◽  
pp. 333-338 ◽  
Author(s):  
Pascal Breton ◽  
Amha Asseffa ◽  
Krzysztof Grzegorzewski ◽  
Steven K. Akiyama ◽  
Sandra L. White ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Peritoneal Macrophages ◽  
Kinase C ◽  
Protein Kinase C Activity ◽  
Murine Peritoneal Macrophages
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