Enzymes of phospholipid biosynthesis in rat alveolar type II cells

Hoehn, Susan K.; Lesperance, Esther; Klass, Daniel J.

doi:10.1007/bf02713868

Cited by 16 publications

(2 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The activity of this enzyme in the cytosol of type I1 cells was fivefold that of whole lung (Table 1). Earlier, Hoehn et al [21] reported an enrichment of choline kinase in sonicates of type I1 cells. Gilfillan et al [22] could not confirm these results.…”

Section: Discussionmentioning

confidence: 97%

Synthesis of Phosphatidylcholines in Ozone-Exposed Alveolar Type II Cells Isolated from Adult Rat Lung: Is Glycerolphosphate Acyltransferase a Rate-Limiting Enzyme?

Haagsman¹,

Schuurmans²,

Batenburg³

et al. 1988

Experimental Lung Research

View full text Add to dashboard Cite

Type II cells were exposed to ozone by gas diffusion through the thin Teflon bottom of culture dishes. The rate of phosphatidylcholine synthesis by type II cells, monitored by the incorporation of [Me-14C]choline, was impaired by ozone at concentrations that did not affect other cellular parameters. The enzymes choline kinase and cholinephosphate cytidylyltransferase were not susceptible to inactivation by ozone at concentrations at which the activity of glycerolphosphate acyltransferase was decreased. The enzyme activity of lactate dehydrogenase increased after ozone exposure. The specific activity of choline kinase in the cytosolic fraction of type II cells was fivefold that in whole lung. The metabolism of [Me-14C]choline was studied as a function of the choline concentration. Maximal rates of phosphatidylcholine synthesis were already attained at a concentration of 20 microM choline. Exposure of type II cells to ozone did not affect the recovery of label from [Me-14C]choline in choline phosphate and CDP choline. However, the maximal rate of phosphatidylcholine synthesis decreased after ozone exposure, which indicates that the decreased apparent activity of glycerolphosphate acyltransferase limits the supply of diacylglycerols and thereby the rate of phosphatidylcholine synthesis. If the flux through the diacylglycerol pathway was stimulated by the addition of palmitic acid, a higher maximal rate of phosphatidylcholine synthesis was observed. The uptake of [Me-14C]choline and the recovery of label in CDPcholine were not altered by the addition of different concentrations of palmitate. It is concluded that type II cells take up choline very efficiently, probably due to the high specific activity of choline kinase. At low choline concentrations the rate of phosphatidylcholine synthesis is determined by the supply of CDPcholine. At concentrations of choline in the upper physiological range, the rate of phosphatidylcholine synthesis is determined by the availability of diacylglycerols, which in turn is limited by the apparent activity of glycerolphosphate acyltransferase.

show abstract

Section: Discussionmentioning

confidence: 97%

Synthesis of Phosphatidylcholines in Ozone-Exposed Alveolar Type II Cells Isolated from Adult Rat Lung: Is Glycerolphosphate Acyltransferase a Rate-Limiting Enzyme?

Haagsman¹,

Schuurmans²,

Batenburg³

et al. 1988

Experimental Lung Research

View full text Add to dashboard Cite

show abstract

“…51 The increase in the quantity of phospholipids in BALF can be ascribed to the stimulation of type II pneumocytes. 52,53 The phospholipid content and rate of synthesis in the lung are determined by number and variety of type II cells, being influenced by numerous toxicants. 54 Inflammatory cells play a major role in the stimulation of type II cells to produce surfactant phospholipids but the mechanism was not appropriately clear.…”

Section: Discussionmentioning

confidence: 99%

Pulmonary toxicity of dust generated during weaving of carpets

Ameen¹,

Ahmad

Rahman

2002

Hum Exp Toxicol

View full text Add to dashboard Cite

The dust generated during weaving (carpet dust) tibbati, knotted and tuffted carpets in carpet industry was studied for its toxicity in vitro and in vivo. Carpet dust (0.5, 1.0, 2.5 and 5.0 mg/1£10 6 cells) caused in vitro cytotoxicity in rat alveolar macrophages (AM) in a concentration-dependent manner. The cytotoxic, inflammatory and oxidative responses were observed in bronchoalveolar lavage fluid (BALF) of rats at 1, 4, 8 and 16 days after exposure. Rats were intratracheally exposed at 5 mg/rat individually to all three types of carpet dust. All types of carpet dusts produced increased AM, lymphocytes (PMN) population in BALF suggesting their inflammatory reactions. Cytotoxic nature of carpet dust was shown by the increased activities of lactate dehydrogenase (LDH) and acid phosphatase (AP) in BALF. Increased AM population and in vitro cytotoxicity due to carpet dusts have shown some correlation with the levels of LDH and AP activities in BALF. The gradual enhanced profile of hydrogen peroxide (H2O2) and nitric oxide (NO) along with depletion of reduced glutathione (GSH) in AM due to these carpet dusts are suggestive of their oxidant nature. The enzyme activities of both glutathione peroxidase (GPx) and glutathione reductase (GR) in AM were marginally reduced in exposed rats. In conclusion, the data suggest the cytotoxic, inflammatory and oxidant nature of carpet dusts. It is extrapolated that health effects on carpet weavers would be associated with the concentration and nature of airborne dust generated during weaving of carpets

show abstract

Biochemical and metabolic properties of bovine type II pneumocytes in primary culture

Augustin¹,

Schoon²,

Gerull³

et al. 1989

Lung

View full text Add to dashboard Cite

Bovine type II pneumocytes were isolated from lungs of adult cattle by enzymatic tissue dissociation and subsequent purification by density gradient centrifugation on a 1.040 g/ml Percoll gradient. By quantitative and qualitative high-performance liquid chromatographic (HPLC) analysis of freshly isolated, highly purified bovine type II pneumocytes, six phospholipid components (phosphatidylcholine, phosphatidylglycerol, phosphatidyl-ethanolamine, phosphatidylinositol, phosphatidylserine, and sphingomyelin) were detected regularly and their composition was compared to that of whole lung homogenates. Total phospholipid content of 10(6) bovine type II cells was 34.7 micrograms (quantitative HPLC). Suspended and adherent bovine type II cells incorporated [14C]choline into their phospholipids. The rate of synthesis of suspended cells (289 pmol/h x 10(6) cells) was constant for at least 4 h, while adherent type II cells incorporated [14C]choline with a constant rate of 160 pmol/h x 10(6) cells for at least 20 h. These data further establish the use of cultured bovine type II pneumocytes as a high-purity model for the in vitro investigation of the surfactant system.

show abstract

Enzymes of phospholipid biosynthesis in rat alveolar type II cells

Cited by 16 publications

References 23 publications

Synthesis of Phosphatidylcholines in Ozone-Exposed Alveolar Type II Cells Isolated from Adult Rat Lung: Is Glycerolphosphate Acyltransferase a Rate-Limiting Enzyme?

Synthesis of Phosphatidylcholines in Ozone-Exposed Alveolar Type II Cells Isolated from Adult Rat Lung: Is Glycerolphosphate Acyltransferase a Rate-Limiting Enzyme?

Pulmonary toxicity of dust generated during weaving of carpets

Biochemical and metabolic properties of bovine type II pneumocytes in primary culture

Contact Info

Product

Resources

About