Effect of the dietary exposure of rat to di(2-ethyl hexyl) phthalate on their metabolic efficiency.

The nutritional impact of di(2-ethyl hexyl) phthalate (DEHP), specifically its energy efficiency and nitrogen utilization, was studied in the experimental rat. Groups of male Wistar rats were fed over 21 days with a standard diet alone or a standard diet supplemented with 2% (w/w) DEHP. Food intake, body weight and nitrogen compounds excretion were measured daily. The composition and energetic content of the carcass were determined in animals of both dietary groups after the feeding period, as well as in a separate group on day 0. The food and energy intakes were similar in both groups, however, the efficiencies of energy and nitrogen use were significantly reduced in the DEHP-fed rat. These alterations were reflected by a reduction of 31% on carcass energy retention and a decrease of 26% on cumulative nitrogen balance, without changes in the body composition. The increase of urinary nitrogen excretion, mainly as urea compound, is the major contributing factor to the lower nitrogen retention. These results indicate that DEHP decreases energy efficiency and nitrogen utilization, leading to a pronounced reduction in body weight gain. In addition, this study provides a possible conceptual framework that could explain the metabolic changes induced by DEHP and related compounds in experimental animals.

Effects of chronic di(2-ethylhexyl) phthalate intake on the secretion and removal rate of triglyceride-rich lipoproteins in rats.

This work intends to characterize the nature of the plasma triglyceride level decrease in male Wistar rats fed with diets supplemented with 2% (w/w) di(2-ethylhexyl) phthalate (DEHP), a packaged-food chemical contaminant. After being fed for 21 days, the animals were assessed to determine plasma and liver lipids or to quantify the in vivo hepatic secretion and in vitro plasma removal of triglyceride-rich lipoproteins. The liver cholesterol and triglyceride contents in DEHP-fed rats were closely similar to those found in controls, co-existing with a decrease in plasma cholesterol (19%), phospholipid (14%) and triglyceride (36%) levels. The decrease of the plasma triglyceride pool size was not associated with a reduction in hepatic secretion of triglyceride. The total triglyceride lipase activity rose (32%) due to a remarkable increase (100%) of the extrahepatic lipoprotein lipase activity. We can conclude that extrahepatic lipoprotein lipase activity accounts for the hypotriglyceridaemic effect of DEHP through an increase of triglyceride removal rate.

[Chronic consumption of brominated vegetable oils: their effect on liver secretion and catabolism of plasma lipoproteins]. / Ingesta crónica de aceites vegetales bromados: su acción sobre la secreción hepática y catabolismo de lipoproteínas plasmáticas.

We have previously reported that normal Wistar rats fed during 105 days with standard laboratory chow, supplemented with 0.5g of brominated vegetable oil (olive, sunflower) per 100 g of diet showed a significant increase of triglyceride and cholesterol content in both heart and liver. This was accompanied by a significant decrease of plasma lipid levels. Fluctuations in plasma triglyceride concentrations may be a result of either variations in the liver secretion rate of very low density lipoprotein-triglyceride (VLDL-TG), or changes in their removal rate by extrahepatic tissues or both. In the present work we have studied the contribution of both VLDL-TG secretion, and removal rates of plasma TG in the decrease of plasma TG levels, in rats fed during 105 days with a standard laboratory chow supplemented with 0.5 g per 100 g of brominated vegetable oil. VLDL-TG secretion was estimated by measuring the accumulation of plasma TG following the injection of TRITON WR 1339 and the removal rate of plasma TG by assaying plasma post-heparin lipolytic total (PHLA) and hepatic (H-TGL) lipase activities. In addition, the major lipid composition of plasma lipoprotein fractions were measured. Results were compared to those of a control group fed a laboratory chow diet during the same period of time. Our results show a decrease in both VLDL-TG secretion and plasma TG pool size accompanied by normal PHLA and H-TGL activities in animals fed the diet supplemented with brominated oils. However, the proportion of the major lipid components of the plasma lipoproteins fractions were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Colesterol en las fracciones lipoproteicas en mujeres obesas normolipemicas con o sin disminucion de la tolerancia glucida. / Cholesterol in lipoprotein fraction in normolipemic obese women with or without reduction of glucose tolerance

De acuerdo al indice ponderal y al resultado de la prueba de tolerancia a la glucosa, 92 mujeres normolipemicas fueron clasificadas en controles; obesas con tolerancia normal y obesas con disminucion de la tolerancia glucida. Segun las edades, se agruparon en menores (A) y mayores (B) de 40 anos. Se cuantifico el contenido de colesterol (C) en las fracciones lipoproteicas - aisladas por precipitacion con polianiones - y se realizaron los cocientes Cr/C alfa y C alfa/C beta + Cpre-beta considerados indices mas precisos del riesgo de enfermedad coronaria isquemica.Se encontro una disminucion significativa del C alfa en las obesas con disminucion de la tolerancia glucida frente a los controles. El cociente C alfa /C beta + Cpre-beta mostro un comportamiento similar y para A y B, respectivamente. La relacion Cr/C alfa incremento con una significacion p < 0.001 para ambos grupos.En los obesos con tolerancia normal solo se encontro modificacion en el cociente C alfa /C beta + Cpre-beta para A. Nuestros resultados demuestran una alteracion en la distribucion del colesterol entre los distintos grupos de pacientes obesas clasificadas como normolipemicas, particularmente acentuada en las que tienen disminucion de la tolerancia glucida

Colesterol en las fracciones lipoproteicas en mujeres obesas normolipemicas con o sin disminucion de la tolerancia glucida. / Cholesterol in lipoprotein fraction in normolipemic obese women with or without reduction of glucose tolerance

De acuerdo al indice ponderal y al resultado de la prueba de tolerancia a la glucosa, 92 mujeres normolipemicas fueron clasificadas en controles; obesas con tolerancia normal y obesas con disminucion de la tolerancia glucida. Segun las edades, se agruparon en menores (A) y mayores (B) de 40 anos. Se cuantifico el contenido de colesterol (C) en las fracciones lipoproteicas - aisladas por precipitacion con polianiones - y se realizaron los cocientes Cr/C alfa y C alfa/C beta + Cpre-beta considerados indices mas precisos del riesgo de enfermedad coronaria isquemica.Se encontro una disminucion significativa del C alfa en las obesas con disminucion de la tolerancia glucida frente a los controles. El cociente C alfa /C beta + Cpre-beta mostro un comportamiento similar y para A y B, respectivamente. La relacion Cr/C alfa incremento con una significacion p < 0.001 para ambos grupos.En los obesos con tolerancia normal solo se encontro modificacion en el cociente C alfa /C beta + Cpre-beta para A. Nuestros resultados demuestran una alteracion en la distribucion del colesterol entre los distintos grupos de pacientes obesas clasificadas como normolipemicas, particularmente acentuada en las que tienen disminucion de la tolerancia glucida