Lipoprotein lipase (LPL) is known to be attached to the luminal surface of vascular endothelial cells in a complex with membrane-bound heparan sulfate, and released into blood stream by heparin. LPL that catalyzes hydrolysis of triglyceride (TGL) on chylomicron and VLDL into two fatty acids and monoacylglycerol, is also implicated to participate in an enhancement of cholesterol uptake by arterial endothelial cells in vitro. But little is known about the LPL-mediated cholesterol uptake in physiological state. In this study, changes in blood lipid composition and levels of lipoproteins were determined after the injection of heparin in human. The level of LPL in plasma was increased from 0 to 11 mU/ml within 30-40 min post-heparin administration and decreased to the basal level within 2 h. The level of TGL in plasma decreased from 70 mg/dl to 20 mg/dl within 1 h and gradually increased to 80 mg/dl within 4 h. However the level of total cholesterol in plasma remained at 140 mg/dl during an experimental period of 4 h. Analysis of Lipoproteins in plasma by NaBr density gradient ultracentrifugation showed that the level of VLDL decreased from 50 mg/dl to 10 mg/dl within 1-2 h and returned to normal plasm level at 4 h. However there were no significant changes in the level of LDL and HDL. These results suggest that, at least, in normo-lipidemic subjects, increased free plasm LPL acts primarily on VLDL and failed to show any significant uptake of cholesterol-rich lipoproteins in human.
Adult ; Cholesterol/blood ; Heparin/pharmacology* ; Heparin/administration & dosage ; Human ; Immunoblotting ; Lipoprotein Lipase/blood* ; Lipoproteins/blood* ; Lipoproteins, HDL/blood ; Lipoproteins, LDL/blood ; Lipoproteins, VLDL/blood ; Triglycerides/blood

MED1 is a key transcription co-activator subunit of the Mediator complex that is essential for RNA polymerase II-dependent transcription. MED1 functions as a co-activator for PPARs and other nuclear receptors and transcription factors, and plays an important role in lipid metabolism. To examine how MED1 might affect plasma lipids, plasma triglyceride, cholesterol levels, and lipoprotein profiles, were measured in MED1(deltaLiv) mice fasted for 24, 48 and 72 hours. Histological changes in liver sections from MED1(deltaLiv) mice after 72 hours of fasting were also examined using H&E staining. There was no fat accumulation in livers of MED1(deltaLiv) mice compared to MED1(fl/fl) and PPARalpha -/- control mice after 72 hours of fasting. Compared with MEDl(fl/fl) mice, plasma triglycerides in MED1(deltaLiv) mice were significantly increased after 24, 48 and 72 hours of fasting, and plasma cholesterol was significantly increased after 48 and 72 hours of fasting. Lipoprotein profiles were similar in fed MED1(fl/fl) and MED1(deltaLiv) mice. However, very low density lipoprotein (VLDL) was significantly increased in MED1(deltaLiv) mice after 24 hours of fasting. We conclude that, hyperlipidemia in MED1(deltaLiv) mice in response to fasting is due to the accumulation of VLDL, which suggests that MED1 plays a pivotal role in the regulation of plasma triglyceride and cholesterol levels.
Animals ; Cholesterol ; blood ; Fasting ; Hyperlipidemias ; blood ; Lipoproteins, VLDL ; blood ; Liver ; chemistry ; Mediator Complex Subunit 1 ; genetics ; physiology ; Mice ; Mice, Knockout ; Triglycerides ; blood

INTRODUCTIONThis study aimed to compare the effects of the two most commonly prescribed atypical antipsychotics, olanzapine and risperidone, on fasting blood sugar and serum lipid profile of the recipients.

METHODSA randomised, comparative, open clinical study was conducted on 60 schizophrenic patients. The patients were divided into two groups, one receiving olanzapine and the other receiving risperidone. The patients were assessed for changes in fasting blood sugar and serum lipid profile (triglycerides [TG], high-density lipoprotein [HDL], low-density lipoprotein [LDL], very-low-density lipoprotein [VLDL] and total cholesterol) eight weeks after starting treatment. The number of patients positive for fasting blood sugar and lipid profile criteria of metabolic syndrome was calculated by applying the modified National Cholesterol Education Programme Adult Treatment Panel III guidelines (NCEP ATP III) criteria at eight weeks.

RESULTSPatients treated with olanzapine showed a highly significant increase in the observed parameters, whereas those treated with risperidone showed a significant increase in fasting blood sugar, HDL and LDL levels, and a highly significant increase in other parameters. Intergroup comparison was insignificant except for TG, VLDL and total cholesterol levels. More men as compared to women fulfilled the NCEP ATP III criteria for metabolic syndrome in both groups.

CONCLUSIONOlanzapine has a higher propensity to cause derangement of some parameters of lipid profile than risperidone. These parameters include TG, VLDL and total cholesterol levels.

Adolescent ; Adult ; Antipsychotic Agents ; pharmacology ; Benzodiazepines ; pharmacology ; Blood Glucose ; drug effects ; Cholesterol ; blood ; Female ; Humans ; Lipids ; blood ; Lipoproteins, HDL ; drug effects ; Lipoproteins, LDL ; blood ; Lipoproteins, VLDL ; drug effects ; Male ; Metabolic Syndrome ; complications ; diagnosis ; Reproducibility of Results ; Risperidone ; pharmacology ; Schizophrenia ; blood ; drug therapy ; Triglycerides ; blood