TY - JOUR
T1 - Inducing effects of chronic administration of isoproterenol on 1-acyl-sn-glycero-3-phosphate and 1-acyl-sn -glycero-3-phosphocholine acyltransferases in rat parotid salivary gland
AU - Koji, Yashiro
AU - Yasunaga, Kameyama
AU - Masako, Mizuno
AU - Yutaka, Yokota
N1 - Funding Information:
I-acyl-GPC acyltransferasesd etermined at suboptimal condition varied dependingo n the concentration of acyl acceptorin the presenceo f them ixture of acyl-CoAs in rat liver microsomes.I ncomplete agreementb etweent he fatty acid composition and the specificityo f I-acyl-GPC acyltransferasme ay be due to complexe ffectso f thesef actors. In hypertrophiedp arotidg land of IPR-treated rat, thes ubstrates pecificityf or acyl-CoAs wasn ot greatly changedi n I-acyl-GPC acyltransferaseIn. contrast, that of 1-acyl-GP acyltransferasew as remarkably alteredb y the administrationo f IPR. In the altered specificityf or acyl-CoAs, a decreaseo f 20:4 at the sn-2 position of PC was correlatedw ith a decreaseo f specificity of I-acyl-GP acyltransferase for 20:4-CoA. Furthermore, the elevation rate of I-acyl-GP acyltransferasea ctivity was greatert han that of 1-acyl-GPC acyltransferaseT. herefore, the alteration of unsaturatedf atty acid compositiona t the sn -2 position of PC wasa t leasti n part due to the changeo f activity and specificityo f I-acyl-GP acyl-transferaseH. owever,t herea re partial discrepancies betweent he fatty acid compositiona t the sn-2 position of PC and the substrates pecificityo f I-acyl-GP acyltransferasefo r acyl-CoAs. The involvemento f I-acyl-GPC acyltransferasein the change of un-saturatedf atty acid composition, especiallyi n in-creaseo f 18: 2, by IPR treatmentis also considerable because the specific activity and preference of 1-acyl-GPC acyltransferasef or unsaturated acyl-CoAs were still higher than that of I-acyl-GP acyl-transferasein IPR-treated rat. De Gomez Dumm et al. (1978) described that single injection of epinephrine or IPR produced a decreasein the con-versiono f [l-‘4C]linoleica cid to y-linolenic acid in the presenceo f ATP and CoA, Acyl-CoA desaturdtion system is also thought to be important for lyso- phospholipid acylation as it is concernedw ith the of arachidonica cid. On the basiso f theser esults,t he supplyo f acyl donor. The increaseo f 18: 2 at thes n - 1 propertieso f the two differenta cyl transfere nzymes position as well as at the sn-2 position observedi n which introducef atty acids into the sn-2 position of this study may be due to the changeo f acyl-CoA phosphatidylcholine were characterized in iso-availability. proterenol-treaterda t parotid gland microsomesa nd The specific activities of lysophospholipida cyl-compared with the control. Acyl-CoA: l-acyl-sn-transferasesin parotid gland microsomesw ere re-glycero-3-phosphocholine(l-acyl-GPC)O-acyltrans-markably increasedb y administrationo f IPR. How-ferasea ctivity was higher than acyl-CoA : 1-acyl-sn-ever, activity of glucose-6-phosphatasoen, e of the glycero-3-phosphate(l-acyl-GP0)-acyltransferasein microsomalm arkere nzymesw, as not increasedb ut, microsomes,a nd the former was preferablet o un-converselyd, ecreasewd ith the samet reatmentT. hese saturateda cyl-CoAs. On the other hand, I-acyl-GP resultss uggestth at the increasesin the specifica ctiv-acyltransferashea d a lower specificityf or acyl-CoAs. ities of the acyltransferaseosb servedi n IPR-treated When both enzymea ctivitiesw erec omparedb etween rat parotid gland in which hypertrophya nd hyper-isoproterenol-treateadn d control rat parotid glands, plasia is occurring did not result from the loss of the activities of I-acyl-GP and 1-acyl-GPC acyl-other microsomale nzymep roteinsb ut rather repre-transferasesw ere increased approx. 3-g-fold and sented an actual increase in total acyltransferase 2-fold, in the isoproterenol-treategdl and. However, levels.K awashima et al. (1985 1986)d escribedt hat one of the marker enzymeso f microsomalf raction, microsomal lysophospholipida cyltransferasea ctiv-glucose-6-phosphatasaec tivity, remained the same ities were induced in rat liver, kidney and intestinal one. These results suggestt hat the increasesin the mucosa by clofibric acid-feed which is known as specifica ctivitieso f the acyltransferaseosb servedin hypolipidemica nd anticholesteremiacn d also stimu-isoproterenol-treaterda t parotid gland represented lates the pcroxisomal proliferation (Svoboda and an actual increasei n total acyltransferasele vels.I n Azarnoff, 1966).I n addition, increaseda ctivity of addition, the preferenceo f I-acyl-GP acyltransferase I-acyl-GPC acyltransferaseco mparingto host liver for arachidonoyl-CoA was decreasedb y adminis-activity was observedin Morris hepatomab y Waite tration of isoproterenol.A lteration of the fatty acid et al. (1977)T. hesec hangeso f acyltransferasaec tivity composition at the sn-2 position of phos-suggestth at lysophosphohpida cyltransferassey stems phatidylcholinew as explained at least in part by somehowp lay an important role in proliferation of changeso f activity and substrates pecificityf or acyl-cells and organellesI.n severalt umor cells including CoAs of thesea cyltransferases. the above cells, increase of oligoenoic acids and decreaseo f polyenoic acids in phospholipidsw ere Acknowledgements-We thank Mr Akihiko Okada and also observed as well as in the hypertrophiedp arotid MS Teruyo Tanahashif or their helpful assistanceT. his gland by IPR (Waite et al., 1977; Albert and studyw as supportedin part by Grant-in-Aid for Scientific Anderson, 1977;R uggieria nd Fallani, 1979;H artz et Culture,J apan, and by a grant from Miyata ScienceR e-Researchf rom the Ministry of Education, Sciencea nd al., 1982).H artz et al. (1982)r eportedt hat increased searchF oundationo f Asahi University,G ifu, Japan. contents of 16:1 , 18: 1 and 18:2 and decreased content of polyunsaturateda cids with four or more double bonds correspondedw ith the cell growthr ate in Morris hepatomaT. he changeso f fatty acid composition may be an essentialp roperty of growing cells, and this also suggestst he involvemento f ly-sophospholipida cyltransferassey stemsin cell growth or proliferation. In order to clarify the enzymaticr egulationo f the fatty acid composition of PC completely,f urther study on availability of acyl-CoA will be necessary. Furthermore,p urificationo f the acyltransferasewsi ll be necessaryto clarify whethert hec hangeso f activity and specificity of the lysophospholipid acyl-transferasesa re due to the alteration of catalytic faculty or isozymep attern.
PY - 1988
Y1 - 1988
N2 - 1. 1. In rat parotid gland, chronic administration of isoproterenol caused significant increase of linoleic acid and decrease of arachidonic acid at the sn-2 position of phosphatidylcholine. 2. 2. The activities of 1-acyl-sn-glycero-3-phosphate and 1-acyl-sn-glycero-3-phosphocholine acyl-transferases were increased 3-8-fold and 2-fold, respectively, in the parotid gland microsomes of isoproterenol-treated rat. 3. 3. Furthermore, the specificity of these two enzymes for various acyl-CoAs was also changed by administration of isoproterenol. 4. 4. The alteration of unsaturated fatty acid composition at the sn-2 position of phosphatidylcholine was at least in part due to the change of activity and substrate specificity of lysophospholipid acyltransferases.
AB - 1. 1. In rat parotid gland, chronic administration of isoproterenol caused significant increase of linoleic acid and decrease of arachidonic acid at the sn-2 position of phosphatidylcholine. 2. 2. The activities of 1-acyl-sn-glycero-3-phosphate and 1-acyl-sn-glycero-3-phosphocholine acyl-transferases were increased 3-8-fold and 2-fold, respectively, in the parotid gland microsomes of isoproterenol-treated rat. 3. 3. Furthermore, the specificity of these two enzymes for various acyl-CoAs was also changed by administration of isoproterenol. 4. 4. The alteration of unsaturated fatty acid composition at the sn-2 position of phosphatidylcholine was at least in part due to the change of activity and substrate specificity of lysophospholipid acyltransferases.
UR - https://www.scopus.com/pages/publications/0023933054
UR - https://www.scopus.com/pages/publications/0023933054#tab=citedBy
U2 - 10.1016/0742-8413(88)90017-5
DO - 10.1016/0742-8413(88)90017-5
M3 - Article
C2 - 2903000
AN - SCOPUS:0023933054
SN - 0306-4492
VL - 90
SP - 397
EP - 402
JO - Comparative Biochemistry and Physiology. Part C, Comparative
JF - Comparative Biochemistry and Physiology. Part C, Comparative
IS - 2
ER -