+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Triacylglycerol lipase activity in the rabbit renal medulla

Biochimica et Biophysica Acta 921(3): 449-456

Triacylglycerol lipase activity in the rabbit renal medulla

Although the renal medulla is rich in triacylglycerols, the lipolysis of these intracellular triacylglycerols by a renomedullary triacylglycerol lipase has not been directly demonstrated. The present study demonstrates triacylglcyerol lipase activity localized in the particulate subcellular fractions of rabbit renal medullae. Renomedullary triacylglycerol lipase activity, as determined by the hydrolysis of [14C]triolein to [14C]oleic acid, was observed to have a pH optimum of 5.8. Addition of cAMP/ATP'magnesium acetate resulted in an 80% activation of crude homogenate triacylglycerol lipase activity; addition of exogenous cAMP-dependent protein kinase resulted in a further activation of lipolysis. 3 mM CaCl2 had no effect on basal triacylglycerol lipase activity. 1 M NaCl did not inhibit lipolysis, suggesting that the lipase activity measured was not due to lipoprotein lipase. Endogenous renomedullary triacylglycerols were hydrolysed by a lipase in the 100,000 7x g pellet of renomedullary homogenates, resulting in the release of free fatty acids including arachidonic and adrenic acids. Dispersed renomedullary cells were prepared to monitor hormone-sensitive triacylglycerol lipase activity in intact cells. Addition of 10 .mu.M forskolin and 10 .mu.M epinephrine resulted in 8-fold and 50-fold increases in triacylglycerol lipase activity, respectively, as defined by release of free glycerol from the cells. These studies demonstrate that a cAMP-dependent hormone-sensitive triacylglycerol lipase is present in the renal medulla, and is responsible for the hydrolysis of renomedullary triacylglycerols.

Accession: 006840440

PMID: 2822129

DOI: 10.1016/0005-2760(87)90071-3

Download PDF Full Text: Triacylglycerol lipase activity in the rabbit renal medulla

Related references

Fujita T.; Shimada S.; Fujimoto Y., 1990: Triacylglycerol lipase mediated release of arachidonic acid for prostaglandin synthesis in rabbit kidney medulla microsomes. European Journal of Pharmacology 183(6): 2078

Klimov A.N.; Serrano D.S.; Nikul'cheva N.G.; Soliternova I.B., 1985: Comparison of the effects of homologous and heterologous albumins on the activity of blood plasma lipoprotein lipase and hepatic triacylglycerol lipase in rabbit brain. Changes in the activity of blood plasma lipoprotein lipase (EC, LPL and hepatic triacylglycerol lipase EC, H-TGL) were studied in rabbits injected intravenously by homologous and heterologous albumins (bovine, fraction Y, Sigma, B...

Jackson, R.L.; Ponce, E.; McLean, L.R.; Demel, R.A., 1986: Comparison of the triacylglycerol hydrolase activity of human post-heparin plasma lipoprotein lipase and hepatic triacylglycerol lipase. A monolayer study. Interfacial catalysis of hepatic triacylglycerol lipase (H-TGL) and lipoprotein lipase (LpL) isolated from human post-heparin plasma was investigated with mixed monolayers of trioleoylglycerol (TO) and egg phosphatidylcholine. Rates of enzyme cata...

Miller W.C.; Palmer W.K.; Arnall D.A.; Oscai L.B., 1987: Effect of cholera toxin on triacylglycerol lipase activity and triacylglycerol content of rat heart. This study was performed to reexamine the effects of cholera toxin on total and intracellular alkaline lipoprotein lipase (LPL) activity in rat heart. In addition, the relationship between intracellular triacylglycerol (TG) lipase activity and TG...

K.A.K.nno; I.R.mirez; D.L.S.verson, 1984: Lipolysis and neutral triacylglycerol lipase activity in triacylglycerol enriched cardiac myocytes. Journal of Molecular and Cellular Cardiology 16(supp-S2): 21-21

Erman A.; Azuri R.; Raz A., 1981: Enzymatic coupling of phospho lipase a 2 and prostaglandin synthase activities in sub cellular fractions from renal rabbit medulla. Israel Journal of Medical Sciences 17(6): 498-499

Kobayashi, J.; Kusunoki, M.; Murase, Y.; Kawashiri, M.; Higashikata, T.; Miwa, K.; Katsuda, S.; Takata, M.; Asano, A.; Nohara, A.; Inazu, A.; Mabuchi, H., 2005: Relationship of lipoprotein lipase and hepatic triacylglycerol lipase activity to serum adiponectin levels in Japanese hyperlipidemic men. Objective: The aim of this study was to determine how lipoprotein lipase (LPL) and hepatic triacylglycerol lipase (HTGL) activity relate to serum adiponectin levels. Research design and methods: Fifty-five hyperlipidemic Japanese men were recruite...

Fujimoto Y.; Akamatsu N.; Hattori A.; Fujita T., 1984: Stimulation of prostaglandin e 2 synthesis by exogenous phospho lipase a 2 and phospho lipase c in rabbit kidney medulla slices. The effects of phospholipase A2 and C on the synthesis of prostaglandin [PG] E2 in rabbit kidney medulla and the release of fatty acids from the medulla slices were investigated. Exogenous phospholipase A2 [from Naja naja (Indian cobra) venom] and...

Kanemitsu, H.; Sasaki, S.; Akiba, T.; Marumo, F., 1990: Ureteral obstruction decreases ATP dependent H(+)-pump activity of rabbit renal outer medulla. Ureteral obstruction has been known to cause a renal acidification defect. To determine the underlying mechanisms of this defect, vacuolar-type H(+)-pump activity of the membrane vesicles taken from the rabbit renal outermedulla was measured in 24...

Dimand, R.J.; Bradbury, E.M.; Cox, K.L., 1989: Determination of triacylglycerol lipase activity using carbon-13-labeled triacylglycerols and nuclear magnetic resonance spectroscopy: evidence that hepatic lipase hydrolyzes medium-chain triacylglycerols. Triacylglycerol lipase activity was studied using glycerol [1-13C]trioctanoate mixed with postheparin rat plasma. 13C NMR spectroscopy demonstrated triacylglycerol hydrolysis into free fatty acids with no difference at the 1,3 or 2 glycerol positi...