title: Inactive hepatic lipase in rat plasma.
abstract: Hepatic lipase activity is detectable in liver but also in adrenal glands, ovaries, and plasma. The subunit size of hepatic lipase in liver, adrenal glands, and nonheparin plasma was compared. Hepatic lipase in liver and adrenal glands appeared as a 55 kDa band. In liver, a faint band of lower size was also detected. In nonheparin plasma, hepatic lipase appeared as a doublet of 57 kDa and 59 kDa. When activity/mass ratio was calculated, similar values were obtained for liver and adrenal glands. In plasma this value was much lower. After heparin administration in vivo, hepatic lipase activity in plasma increased nearly 100-fold with appearance of an additional 55 kDa band in postheparin plasma. This band coeluted with activity after preparative polyacrylamide gel electrophoresis. Differences in size persisted after digestion with peptide-N-glycosidase F. A progressive increase in 57 kDa and 59 kDa in postheparin plasma followed disappearance of the 55 kDa band, suggesting that these larger bands originate from the smaller form. In plasma, both smaller and larger forms were associated with HDL, but not with LDL or VLDL. We conclude that rat plasma contains a larger form of hepatic lipase that is inactive in in vitro assay.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 645, E-08071 Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Galan
authors.forename: Julia
authors.initials: J
authors.lastname: Peinado-Onsurbe
authors.forename: Josep
authors.initials: J
authors.lastname: Julve
authors.forename: David
authors.initials: D
authors.lastname: Ricart-Jané
authors.forename: Monique Q
authors.initials: MQ
authors.lastname: Robert
authors.forename: Miquel
authors.initials: M
authors.lastname: Llobera
authors.forename: Ignasi
authors.initials: I
authors.lastname: Ramírez
mesh_terms: D000311:Adrenal Glands / Q000201:enzymology; D000818:Animals; D008049:Lipase / Q000097:blood* / Q000302:isolation & purification; D008075:Lipoproteins, HDL / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood; D008079:Lipoproteins, VLDL / Q000097:blood; D008099:Liver / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D008049:Lipase