Effects of acetylcholine on the turnover of phosphoryl units in individual phospholipids of pancreas slices and brain cortex slices

Hokin, Lowell E.; Hokin, Mabel R.

doi:10.1016/0006-3002(55)90013-5

Cited by 254 publications

(46 citation statements)

References 17 publications

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“…The highest specific activities were attained by the component believed to be phosphatidic acid and by a phosphoinositide which probably has the structure of phosphatidylinositol. These findings are similar to those of Dawson (36) using guinea pig brain and those of Hokin and Hokin (37,38) using pigeon pancreas and guinea pig brain. Rowe (9) reported that cephalin was the most highly labeled phospholipid component in whole blood incubated with P32.…”

Section: Resultssupporting

confidence: 91%

The Incorporation of Radioactive Phosphorus Into the Phospholipids of Human Leukemic Leukocytes and Platelets*

Firkin¹,

Williams²

1961

J. Clin. Invest.

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The phospholipid composition of human platelets and erythrocytes has been reported by several investigators (1-4) and the metabolism of phospholipids in human blood has been studied in some detail (5-9). Recent investigations of phospholipid metabolism of leukocytes have been reported (6, 10) but we are not aware of similar studies on platelets.In this laboratory, investigation of the biochemical characteristics of leukemic leukocytes is being carried out, and as part of this program an examination of the phospholipid metabolism of these cells was undertaken. In this report are presented data on the phospholipid composition of platelets and leukocytes from leukemic patients, and the results of studies on the incorporation of P32-labeled orthophosphate (P32) into the phospholipids of these formed elements in vivo and in vitro.The phospholipid composition was similar in leukocytes and platelets from chronic leukemia and in leukocytes from acute leukemia. The pattern of incorporation into leukocyte phospholipids of p32 administered therapeutically to patients with chronic myelocytic leukemia was studied, and it was found that rapid incorporation of P32 could be demonstrated in lecithin, phosphatidylethanolamine, phosphatidylserine, inositol phosphatide, and sphingomyelin. In the course of this work it was * This study was supported in part by Research Grant E-2813 from the National Institute of Allergy and Infectious Diseases, Bethesda, Md. and by Research Grant P-143B from the American Cancer Society. A preliminary report of the work has been published (Fed. Proc. 1960, 19, 72 MATERIALS AND METHODSPaticets studied. Two patients with acute myelocytic leukemia, 2 with chronic lymphocytic leukemia, and 9 with chronic myelocytic leukemia were utilized in this study. Seven of the patients had not been treated previously for their leukemia. Six of the patients, all with chronic myelocytic leukemia, had been treated previously by chemotherapy or with P'3, but were in relapse with leukocyte counts above 100,000 per mm3 at the time of the study. There was no apparent difference in the results obtained from previously treated or untreated patients, although the series is too small to permit definite conclusions on this point.Separation of the formed elements of the blood. Leukocytes were isolated from patients with acute or chronic myelocytic or lymphocytic leukemia with white blood cell counts greater than 100,000 per mm3. Five hundred ml of blood wvas collected in a plastic platelet pack (Fenw-al) containing 50 ml of 3 per cent ethylenediamine tetraacetic acid (USP) as anticoagulant. All subsequent operations were performed at 40 C. The blood was stored for 1.5 hours to permit sedimentation of the erythrocytes. The plasma layer containing platelets and leukocytes was removed by syphoning into a plastic transfer pack (Fenwal) and then centrifuged in silicone-coated (G.E. Drifilm) 40 ml centrifuge tubes at 180 G for 15 minutes to sediment the leukocytes. The leukocytes were washed 3 times with twice their volume of 0.85 ...

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Section: Resultssupporting

confidence: 91%

The Incorporation of Radioactive Phosphorus Into the Phospholipids of Human Leukemic Leukocytes and Platelets*

Firkin¹,

Williams²

1961

J. Clin. Invest.

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“…Yet, it is clear from these (Figs. [3][4][5] and previous studies (18) that medium osmolarity cannot be ignored while probing for metabolic activities in platelet suspensions. Although a biochemical explanation of the observed phenomena must await further study, it is useful for a start to consider some of the more obvious consequences of manipulating medium osmolarity.…”

Section: Discussionmentioning

confidence: 99%

“…Proof of the active turnover of the inositol lipids in tissues other than brain began in 1955 with the studies of Hokin and Hokin (4) on the stimulation by acetylcholine of 'Pt incorporation into phosphoinositide of pancreas slices. Later, it became apparent that in various other tissues, liver (5,6), erythrocytes (7,8), leukocytes (9)(10)(11), and kidney (5,12), the in vitro incorporation of 'Pt was at a very high rate in the inositides.…”

Section: Introductionmentioning

confidence: 99%

Quantification of human platelet inositides and the influence of ionic environment on their incorporation of orthophosphate-32P

Cohen¹,

Broekman²,

Verkley³

et al. 1971

J. Clin. Invest.

112

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A B S T R A C T Platelets are a rich source for the study of inositol lipids in man. The substitution of an EDTAKCl solution for the water component of the Bligh and Dyer procedure permitted quantitative extraction of polyphosphoinositides. The latter, with monophosphoinositide, were found to comprise, on a molar basis, 6.7% of total platelet phospholipids. Study of the incorporation of orthophosphate-'P into platelet phospholipids was further simplified by separating eight 'P-labeled lipids, including the inositides, with a single chromatographic development on formaldehyde-treated paper. Particular attention was paid to the influence of ionic environment on the pattern and degree of labeling.In 300 mOsm media major phospholipids other than the inositides were not labeled. Small amounts of label appeared in certain trace phospholipids, notably phosphatidic acid. In 150 mOsm media, labeling of inositides was moderately increased, that of trace phospholipids enormously so. The increased labeling was not solely due to thrombocytolysis since (a) platelet disruption by sonication or freeze-thawing abolished 'P incorporation into phospholipids and (b) in timed studies, restoration of osmolarity to 300 mOsm by addition of hypertonic sorbitol blunted the enhancement effect of previous 150 mOsm exposure. Lowering K and compensatorily increasing Na concentration of 300 mOsm media also stimulated aP labeling of inositides and, to a lesser extent, the trace phospholipids. However, the pattern and degree of stimulation were not as strikingly altered as in the osmolarity studies.

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“…In the early 1950s, Hokin and Hokin ( 1,2 ) discovered that addition of acetylcholine to brain slices stimulated the incorporation of phosphate and inositol but not glycerol into lipids; the major products of this incorporation were phosphatidylinositol (PI) and phosphatidic acid. Subsequent studies defi ned the reactions of the PI cycle and showed that the initial event was receptor-meditated activation of a phospholipase C (PLC), which hydrolyzes phosphatidylinositol 4,5-bisphosphate (PI-4,5-P 2 ) to 1,2-diacylglycerol (DG) and inositol 1,4,5-trisphosphate (IP 3 ).…”

Section: The Pi Cyclementioning

confidence: 99%

Phosphoinositide 3-kinase signaling in the vertebrate retina

Rajala

2010

Journal of Lipid Research

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This article is available online at http://www.jlr.org was established by Streb et al. ( 3 ) in their classic paper that showed elevations in IP 3 caused intracellular release of bound calcium. Subsequently, 1,2-DG was found to stimulate protein kinase C (PKC), a serine/threonine kinase that phosphorylates a number of cellular proteins ( 4 ). Activation of the PLC/PKC cascade affects a variety of cellular events, including secretion, phagocytosis, smooth muscle contraction, proliferation, neurotransmission, and metabolism [see reviews by Rhee ( 5 ), Rhee and Choi ( 6 ), and Berridge ( 7 ) THE PI CYCLEIn the early 1950s, Hokin and Hokin ( 1, 2 ) discovered that addition of acetylcholine to brain slices stimulated the incorporation of phosphate and inositol but not glycerol into lipids; the major products of this incorporation were phosphatidylinositol (PI) and phosphatidic acid. Subsequent studies defi ned the reactions of the PI cycle and showed that the initial event was receptor-meditated activation of a phospholipase C (PLC), which hydrolyzes phosphatidylinositol 4,5-bisphosphate (PI-4,5-P 2 ) to 1,2-diacylglycerol (DG) and inositol 1,4,5-trisphosphate (IP 3 ). This increase in lipid synthesis reported by the Hokins was a recovery reaction that rapidly replenished PI separate from de novo PI synthesis. The role of 1,4, This work was supported by grants

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Effects of acetylcholine on the turnover of phosphoryl units in individual phospholipids of pancreas slices and brain cortex slices

Cited by 254 publications

References 17 publications

The Incorporation of Radioactive Phosphorus Into the Phospholipids of Human Leukemic Leukocytes and Platelets*

The Incorporation of Radioactive Phosphorus Into the Phospholipids of Human Leukemic Leukocytes and Platelets*

Quantification of human platelet inositides and the influence of ionic environment on their incorporation of orthophosphate-32P

Phosphoinositide 3-kinase signaling in the vertebrate retina

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