Mechanisms of CCK regulation of monitor peptide mRNA expression in pancreatic acinar AR42J cells

We explored the mechanism(s) by which cholecystokinin (CCK) stimulation of AR42J rat pancreatoma cells results in increased mRNA expression of a CCK-releasing peptide [monitor peptide (MP)]. With the use of a newly established reverse transcription-polymerase chain reaction assay system, CCK was shown to increase the level of MP mRNA by about ninefold. When protein synthesis was blocked by addition of cycloheximide, the MP mRNA level remained unchanged in the presence of CCK. Inhibition of transcription with actinomycin D resulted in a half-life for MP mRNA of approximately 17 h, and this rate remained unchanged after CCK treatment, suggesting that CCK may regulate the MP mRNA level by influencing gene transcription. A-23187, bombesin, substance P, and carbachol increased the MP mRNA level. CoCl(2) abolished actions of both CCK and A-23187 on MP mRNA expression. Dibutyryl-adenosine 3',5'-cyclic monophosphate, forskolin, secretin, and vasoactive intestinal polypeptide had no effect on MP mRNA expression. 12-O-tetradecanoylphorbol-13-acetate and phorbol 12,13-dibutyrate also failed to increase MP mRNA. It was therefore proposed that CCK stimulates MP mRNA expression of AR42J cells in a Ca2+-dependent and protein kinase C-independent manner.

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Detection of protein kinase C subspecies expression at the mRNA level using a reverse transcriptase-polymerase chain reaction approach

Biochemical Society Transactions ◽

10.1042/bst021379s ◽

1993 ◽

Vol 21 (4) ◽

pp. 379S-379S

Author(s):

Leigh M. Eastwood ◽

Martin G. Rumsby ◽

F. Arthur McMorris

Keyword(s):

Polymerase Chain Reaction ◽

Protein Kinase C ◽

Protein Kinase ◽

Reverse Transcriptase ◽

Mrna Level ◽

Chain Reaction ◽

Polymerase Chain Reaction Approach ◽

Kinase C ◽

Polymerase Chain

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PKC-independent inhibition of cardiac L-type Ca2+ channel current by phorbol esters

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1996.270.2.h620 ◽

1996 ◽

Vol 270 (2) ◽

pp. H620-H627 ◽

Cited By ~ 2

Author(s):

T. Asai ◽

L. M. Shuba ◽

D. J. Pelzer ◽

T. F. McDonald

Keyword(s):

Protein Kinase C ◽

Phorbol Esters ◽

Ventricular Myocytes ◽

Inhibitory Effect ◽

Independent Action ◽

Independent Manner ◽

Channel Current ◽

Kinase C ◽

Channel Currents ◽

Stimulation Of

Active and inactive phorbol esters were applied to guinea pig ventricular myocytes to study the responses of L-type Ca2+ (ICa,L) and L-type Na+ (INa,L) currents. Phorbol 12-myristate 13-acetate (PMA) (10-100 rM) never stimulated ICa,L or INa,L and frequently depressed them by 5-30% in a voltage-independent manner. However, the phorbol ester consistently activated delayed-rectifying K+ (IK) and Cl- currents. The inhibition of ICa,L occurred approximately 3 times faster than comonitored stimulation of IK, and ICa,L and INa,L were unaffected by two interventions that suppressed IK stimulation [pretreatment with 50 microM 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) and dialysis with pCa 11 versus standard pCa 9 solution]. Inactive phorbol esters 4 alpha-phorbol 12,13-didecanoate (alpha-PDD) and 4 alpha-phorbol had little effect on IK, but alpha-PDD had a PMA-like inhibitory effect on Ca2+ channel currents. We conclude that, unlike the stimulation of IK by PMA, inhibition of Ca2+ channel current by phorbol esters is a protein kinase C-independent action.

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Murine and Pediatric Myocardial Growth Factor mRNA Expression Using Reverse Transcription–Polymerase Chain Reaction

Biochemical and Molecular Medicine ◽

10.1006/bmme.1996.0002 ◽

1996 ◽

Vol 57 (1) ◽

pp. 10-13 ◽

Cited By ~ 7

Author(s):

Robert E. Shaddy ◽

Y.Lynda Zhang ◽

William L. White

Keyword(s):

Polymerase Chain Reaction ◽

Growth Factor ◽

Mrna Expression ◽

Reverse Transcription ◽

Chain Reaction ◽

Polymerase Chain

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Calcium mobilization and protein kinase C activation are required for cholecystokinin stimulation of pancreatic cholesterol esterase secretion

Biochemical Journal ◽

10.1042/bj3060605 ◽

1995 ◽

Vol 306 (2) ◽

pp. 605-608 ◽

Cited By ~ 3

Author(s):

J Brodt-Eppley ◽

D Y Hui

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Digestive Enzyme ◽

Calcium Mobilization ◽

Cholesterol Esterase ◽

Ionophore A23187 ◽

Prolonged Incubation ◽

Ar42j Cells ◽

Kinase C ◽

Stimulation Of

The bile salt-stimulated cholesterol esterase is a digestive enzyme synthesized by the acinar cells of the pancreas. Previous results have shown that cholesterol esterase biosynthesis and secretion in the AR42J pancreatoma cells could be increased 3-5-fold by intestinal hormones such as cholecystokinin (CCK). The purpose of the current study is to explore the signalling mechanism by which CCK stimulation of AR42J cells results in increased biosynthesis and secretion of the cholesterol esterase. The results showed that the CCK-induced cholesterol esterase secretion could be mimicked by addition of the Ca2+ ionophore A23187 or by transient incubation of AR42J cells with the protein kinase C activator phorbol 12-myristate 13-acetate (PMA). Cholesterol esterase stimulation by CCK, A23187 and PMA could be abolished by the calcium chelator BAPTA or by specific protein kinase C inhibitors such as chelerythrine. Additionally, prolonged incubation of AR42J cells with PMA to reduce the protein kinase C level, also reduced CCK-stimulated cholesterol esterase secretion to a level similar to that observed in control cells. Taken together, these data suggested that CCK activation of cholesterol esterase secretion may be mediated by a Ca(2+)-dependent protein kinase C pathway, requiring increases in calcium mobilization and activation of protein kinase C.

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