Major depression increases cardiovascular risk despite lower cholesterol levels. Little is known about effects of antidepressants on metabolic risk factors. We studied lipoprotein composition, insulin sensitivity (quantitative insulin sensitivity check index), and saliva cortisol in 78 depressed patients before and after 35 days of amitriptyline or paroxetin treatment. Data were analyzed by principal component factor analyses and analysis of variance (ANOVA). At baseline, quantitative insulin sensitivity check index was inversely correlated with cortisol (r = -0.46; P = 0.005) in normal weight patients, with body mass index in overweight patients (r = -0.50; P < 0.001). In overweight patients, hypercortisolemia correlated inversely with total and low density lipoprotein cholesterol (eg, cortisol at 4:00 PM and low density lipoprotein cholesterol: r = -0.49, P = 0.002). After treatment, quantitative insulin sensitivity check index was unchanged. Triglycerides increased in responders to amitriptyline only (P < 0.05). Parameters of cholesterol metabolism improved slightly without differences between treatment groups (eg, high density lipoprotein: pre 43.5 +/- 12.0; post 47.6 +/- 13.0 mg/dL; P = 0.01; low density lipoprotein triglycerides, a measure of low density lipoprotein atherogenicity: pre 458 +/- 120; post 415 +/- 130 mg/g; P < 0,01). The inverse correlation of cortisol and cholesterol, at least in the obese subgroup, proposes a mechanism for the known association of depression with low cholesterol. As determinants of plasma lipids in major depression, we identified body mass index, insulin sensitivity, and cortisol. Although uncontrolled, our data suggest that treatment of depression exerts a mainly beneficial effect on lipid regulation.

In 13 healthy, male nonsmokers (mean age: 25.7 ± 2.4 years) with normal fasting triglycerides we investigated postprandial changes of triglycerides in several lipoprotein fractions. After a 12-hour overnight fast they ingested a standardized lipid load (1,017 kcal) including 30,000 IU retinyl palmitate. Postprandially, total triglycerides increased significantly (p < 0.001) to a peak value of 221 ± 81 mg/dl at 5 h. Two subjects had an exceptionally strong triglyceride response (peak values: 363 and 390 mg/dl). They had the highest levels of retinyl palmitate in the chylomicron and the nonchylomicron fraction, and one of them showed elevated intermediate-density lipoprotein values throughout the test period. In addition, they showed an altered early and an increased late postprandial insulin response. Thus, our data provide evidence that an exaggerated postprandial triglyceride response may point to an increased atherogenic risk even in healthy subjects with normal fasting triglycerides.

SummaryThe clonal rat rhabdomyosarcoma cell line BA-HAN-IC was tested for its susceptibility to differentiation induction with different polar compounds. This cell line is composed of proliferating mononuclear tumour cells, some of which spontaneously fuse to form terminally differentiated postmitotic myotubelike giant cells. Exposure of BA-HAN-IC cells to dimethylsulphoxide (DMSO), hexamethylene bisacetamide (HMBA), sodium butyrate (NaBut) and N-monomethylformamide (NMF) resulted in a significant inhibition of proliferation (P<0.001) and in a simultaneous increase in differentiation. The response was most pronounced after exposure to NMF as evidenced by a marked increase in the creatine kinase activity used as a biochemical marker of differentiation (P<0.05) and the number of terminally differentiated myotube-like giant cells (P <0.001). Furthermore, about 5% of the mononuclear cells exhibited thick and thin myofilaments which were never observed in the mononuclear cells of the control. In contrast, the effects of DMSO, HMBA and NaBut were exclusively confined to a significant increase in biochemical differentiation (P<0.05), whereas no increase in morphological differentiation was observed and the number of myotube-like giant cells even significantly (P<0.001) decreased. This heterogeneous response to differentiation induction with different polar compounds probably indicates different mechanisms of action and suggests that the induction of biochemical differentiation might be independently regulated from events leading to cell fusion and terminal differentiation.

Lipoprotein(a) [(Lp(a)], a low-density lipoprotein (LDL)-like particle, contains in addition to LDL a specific protein component, apolipoprotein(a) [apo(a)]. Conventionally, Lp(a) has been measured by immunological methods that distinguish between Lp(a) and LDL by dealing with apo(a) as an antigen. We describe a new method to determine Lp(a) on the basis of its cholesterol content. Very-low-density lipoproteins were removed from serum by preparative ultracentrifugation at a density of 1.006 kg/L. The infranate was subjected to agarose gel electrophoresis to separate Lp(a) and LDL. Lp(a) cholesterol was then determined by direct enzymatic staining for cholesterol. On electrophoresis of the &gt; 1.006 kg/L (bottom) fraction, Lp(a) migrates to the pre-beta position, regardless of the genetic apo(a) isoform. The interassay CVs of Lp(a) cholesterol determinations ranged from 6.9% to 11.5%, and the results correlated well with the Lp(a) concentrations measured by immunonephelometry (r = 0.937). There was an inverse relation between the molecular mass of the genetically determined apo(a) isoforms and Lp(a) cholesterol concentrations. Patients with angiographically proven coronary artery disease (CAD) had significantly more Lp(a) cholesterol than healthy controls did. The ratio of Lp(a) cholesterol to immunologically determined Lp(a) tended to be lower in CAD patients, suggesting that Lp(a) particles contained less cholesterol than apo(a). In addition, the new method allows determination of LDL cholesterol without contamination by Lp(a).

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