Lipoprotein lipase and hormone-sensitive lipase activity and mRNA in rat adipose tissue during pregnancy (original) (raw)
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Pregnancy Effects on Rat Adipose Tissue Lipolytic Capacity are Dependent on Anatomical Location
Cellular Physiology and Biochemistry, 2005
Pregnancy is characterized by changes in maternal adiposity. The aim of this study was to carry out a detailed analysis of the different steps of the adrenergic pathway, lipoprotein lipase (LPL) levels and adipocyte size, in order to evaluate the response of white adipose tissue (WAT) to the metabolic changes during pregnancy depending on the anatomical location. In general, the levels of the proteins of the lipolytic pathway decreased with pregnancy. In retroperitoneal WAT adenylate cyclase (AC) levels decreased from 100% in controls to 44% by day 13 and 11% by day 20. In mesenteric WAT the α 2A /β 3-adrenergic receptor balance seemed to be one of the main regulatory points of the lipolytic pathway and the reduction in the postreceptor element levels was clearly lower than for the other two depots (PKA levels reduced from 100% in controls to 72% by day 20, while in the other two depots it decreased to 30%, and AC and HSL levels did not show statistically significant changes in this depot). In contrast, the LPL-to-HSL ratio may be a major regulatory point in gonadal WAT. In summary, we describe regional differences in the regulation of WAT metabolism throughout pregnancy, which may be of great importance to determine the role of the different fat depots during late pregnancy. Thus, gonadal and mesenteric WAT changed to a lipolytic state to sustain the rapid foetal growth, although with differences between them in the main regulatory points, while retroperitoneal WAT could have a role later on, during lactation.
Biochemical and Biophysical Research Communications, 1981
To determine whether the reduced lipoprotein lipase activity in adipose tissue in late pregnancy corresponds to parallel changes in the uptake of triglyceride fatty acids, isolated adipocytes from 19-and 21-day pregnant rats and virgin controls were incubated for different periods in the presence of rat plasma triglyceride-rich lipoproteins with their esterified fatty acids of neutral glycerides (triglycerides) labelled with 3H. The hydrolysis of triglycerides and uptake of fatty acids by the adipocytes increased linearly and parabolically with respect to the incubation time and were always lower in cells from pregnant animals than from controls. Addition of heparin to the incubation medium produced similar increases in hydrolysis and uptake in all groups. Results indicate that the diminished uptake of triglyceride fatty acids by adipose tissue contributes to hypertriglyceridemia in late pregnancy which is counteracted by lipogenesis increase tc maintain the mother's augmented body fat.
Adipose tissue lipoprotein lipase Early pregnancy Dietary fatty acids Breast milk Developing brain Long-chain polyunsaturated fatty acids a b s t r a c t Pregnant rats received soybean (SO), olive (OO), fish (FO) and linseed (LO) oil diets from conception to d12 of gestation (early diets) and standard diet thereafter. At d12 and d20 the lipoprotein lipase (LPL) activity was evaluated in maternal adipose tissues (ATs). Fatty Acid (FA) profile was determined in maternal lumbar AT (LAT), in milk and in pup's plasma and brain. LPL activity was higher in ATs at d12 than d20, all groups presenting hypertriglyceridemia at d20. At d12, the LO diet resulted higher LPL activity and incorporation of 18:3 n À 3 into LAT. FA profile in maternal LAT at d20 and colostrum was similar to early diets, reflected also in FA composition of pup's plasma. In FO, brain phospholipids had higher 22:6 n À 3 without affecting arachidonic acid. These results suggest that specifics dietary FA in early pregnancy modulates lipid metabolism and the provision of LC-PUFA in milk and pups brain.
The Journal of Lipid Research, 2005
We examined the presence of hormone-sensitive lipase (HSL) in mammary glands of virgin, pregnant (12, 20, and 21 days), and lactating (1 and 4 days postpartum) rats. Immunohistochemistry with antibody against rat HSL revealed positive HSL in the cytoplasm of both alveolar epithelial cells and adipocytes. In virgin rats, immunoreactive HSL was observed in mammary adipocytes, whereas diffuse staining was found in the epithelial cells. Positive staining for HSL was seen in the two types of cells in pregnant and lactating rats. However, as pregnancy advanced, the staining intensity of immunoreactive HSL increased in the epithelial cells parallel to their proliferation, attaining the maximum during lactation. An immunoreactive protein of 84 kDa and a HSL mRNA of 3.3. kb were found in the rat mammary gland as in white adipose tissue. Both HSL protein and activity were lower in mammary glands from 20 and 21 day pregnant rats than from those of virgin rats, although they returned to virgin values on days 1 and 4 of lactation. Mammary gland HSL activity correlated negatively to plasma insulin levels. Immunoreactive HSL and HSL activity were found in lactating rats' milk. The observed changes indicate an active role of HSL in mammary gland lipid metabolism.
Circulating metabolite utilization by periuterine adipose tissue in situ in the pregnant rat
Metabolism, 1991
To study the use of glucose for lipid synthesis by the periuterine adipose tissue in situ, "C-glucose was infused through the left uterine artery of anesthetized, fed pregnant and virgin control rats. A greater amount of "C-lipid always appeared in the adipose tissue from the left uterine horn than in the tissue from the right uterine horn, indicating direct utilization of the infused "C-glucose by the tissue. Glucose utilization for both glyceride glycerol and fatty acid synthesis increased from day 0 (virgin rats) to day 20 of gestation and then decreased dramatically on day 21. In virgin and 12-day pregnant rats, glucose was incorporated into either lipidic moiety at similar rates, whereas in late pregnant rats glucose utilization for glyceride glycerol synthesis was four to five times greater than for fatty acids. The utilization of circulating fatty acids and the lipoprotein triglyceride-derived fatty acids was studied by infusing %palmitate or "C-triolein-labeled very-low-density lipoprotein (VLDL) through the left uterine artery in both virgin and 20-day pregnant rats. Incorporation of fatty acids from either one of these plasma sources was significantly higher in the pregnant than in virgin rats. This high amount of fatty acid acquisition did not account for the very active glyceride glycerol synthesis observed in pregnant rats and can only be explained by the intracellular reesterification of some lipolitic fatty acids. The results suggest a highly accelerated triacylglycerol/fatty acid substrate cycle in adipose tissue during late pregnancy, which would allow active esterification (contributing to fat accumulation) and responsive lipolysis (permitting rapid fat mobilization) by the mother.
Effect of Starvation on Lipoprotein-Lipase Activity in Different Tissues During Gestation in the Rat
Biochimica Et Biophysica Acta-Lipids and Lipid Metabolism, 1994
This study was addressed to determine whether the tissue-specific LPL activity response to fasting differs between nonpregnant and pregnant rats over the course of pregnancy. Fed and 24-h fasted rats were studied at days 12, 15 or 20 of gestation and were compared to virgin controls. In fed rats at days 15 and 20 of gestation LPL activity decreased in lumbar adipose tissue and the heart and liver, and increased in mammary gland tissue. Fasting decreased LPL activity in lumbar adipose tissue in 12 day pregnant and virgin rats and in mammary gland tissue in pregnant rats at 15 and 20 days of gestation and in virgin rats, whereas it increased LPL activity in heart tissue in rats at day 15 and 20 and in liver at day 20 of gestation. Plasma triacylglycerols were higher in 20 day pregnant rats than in the other groups when fed and this difference was even more noticeable in the fasting condition where the plasma ,B-hydroxybutyrate level also reached the highest value in the 20 day pregnant rats. Since tissue LPL activity controls the hydrolysis and uptake of circulating macylgylcerols, the present results indicate that in fed rats after the 15th day of gestation circulating triacylglycerols are preferentially [taken up by the mammary gland instead of being taken up by adipose tissue and heart. However, after fasting, circulating triacylglycerols ~e driven to the heart and liver in the late pregnant rat, and become a major source for fatty acid oxidation, an effect that seems to be ~pecially evident in the liver of the 20 day pregnant rat where there is an intense increase in LPL activity and the triacylglycerols become preferential substrates for ketone body production.
PPAR-γ, TNF-α Messenger RNA levels and lipase activity in the pregnant and lactating rat
Life Sciences, 2003
Dramatic alternations in maternal metabolism occur during gestation and lactation, especially glucose and fat metabolism. For example, in rats, the amount of body fat mass increases during gestation, then decreases just prior to delivery, and remains low after parturition. To investigate the factors involved in such changes in maternal fat mass, messenger ribonucleic acid (mRNA) levels of adipocytokines, peroxisome proliferatoractivated receptor-g (PPAR-g) and tumor necrosis factor-a (TNF-a), were examined in the intraabdominal adipose tissue of non-pregnant rats, pregnant rats and postpartum rats. We also examined the issue of whether apoptosis, which could be promoted by PPAR-g and TNF-a, is involved in any of the changes in maternal fat mass The activity of lipoprotein lipase (LPL) and hormone sensitive lipase (HSL) in adipose tissue was also measured. PPAR-g and TNF-a mRNA levels remained constant during the gestational and postpartum periods. Apoptosis was not detected at any time as evidenced by DNA laddering and in situ staining. LPL activity was significantly increased at day 5 and remained elevated until day 14 of gestation. HSL activity was significantly increased at day 10 of gestation and then decreased after delivery, at day 10 of lactation. In conclusion, during the gestational and postpartum period of rats, changes in maternal fat mass did not directly correlate with the levels of expression of PPAR-g and TNF-a mRNA. Apoptosis also does not appear to influence on fat mass change. The changes in LPL and HSL activities during gestation suggest that these enzymes might be regulators of maternal adipose tissue level.
Changes in mammary fat pad composition and lipolytic capacity throughout pregnancy
Cell and Tissue Research, 2006
Changes in rat mammary fat pad during pregnancy were assessed by studying differences in the morphology and composition of the pad and in the levels of proteins involved in the accumulation and mobilization of fat stores. During pregnancy, the mammary fat pad weight had increased 1.8-fold by day 20, as compared with control rats. DNA content had increased two-fold by day 13 and remained stable until day 20. Protein content showed a two-fold increase on day 20, compared with control rats. As pregnancy advanced, both the percentage of mammary gland cells with respect to the whole mammary fat pad and the size of the adipocytes increased. The specific content of the different elements of the lipolytic pathway, viz. α 2Aadrenergic receptor (AR), β 3 -AR, cAMP-dependent protein kinase and hormone-sensitive lipase (HSL), underwent a decrease as pregnancy progressed, although adenylate cyclase increased greatly. The lipoprotein lipase (LPL) content per gram of tissue increased with pregnancy and the HSL-to-LPL ratio reflected a continuous increase in triglyceride storage throughout pregnancy. Thus, the mam-mary fat pad undergoes extensive morphological, compositional and metabolic transformation during pregnancy, attributable to the development of the mammary gland. The various elements of the lipolytic pathway and LPL undergo major changes during the development of the mammary gland focused towards the increase of fat stores and allowing the accumulation of lipid droplets in the epithelial mammary cells and an increase in adipocyte size.
Effect of pregnancy and lactation on lipoprotein and cholesterol metabolism in the rat
Journal of lipid research, 1998
Origins of hyperlipidemia and cholestasis that occur during pregnancy were investigated by examining expression of key elements related to plasma and hepatic cholesterol metabolism during pregnancy, lactation, and post-lactation in the rat model. Among major findings were: during pregnancy, the activities of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase, acyl coenzyme A:cholesterol acyltransferase, acyl coenzyme A:diacylglycerol acyltransferase, cholesterol 7alpha-hydroxylase, cholesterol ester hydrolases, low density lipoprotein receptors, LRP, and mdr2 were significantly lower or similar to non-pregnant controls while SR-B1 was elevated. Once lactation began, reductase, cholesterol acyltransferase, 7alpha-hydroxylase activities, low density lipoprotein receptors, and mdr2 increased while SR-B1 decreased. In later stages of lactation most hepatic elements returned to near control levels. Plasma cholesterol levels were higher than control at birth and during lactation with...
Brazilian Journal of Biology, 2018
Aim Obesity during pregnancy is one of the most established risk factors for negative long-term programming. The aim of the present study was to investigate the effects of maternal consumption of a high-fat diet during pregnancy and lactation on the weight gain, visceral adipose tissue and cholesterolemia in neonatal rats. Methods Wistar rats were divided into two groups according to the mother's diet during pregnancy and lactation: Control group (CG, n = 12) were the offspring of rats fed a standard diet (4% lipid) and the Test group (TG, n = 12) were pups rats fed on a high fat diet (23% lipid). The weight of the animals was measured on alternate days until the 22nd day of life, when collected visceral adipose tissue and blood were collected for biochemical analysis. For statistical analysis the Student t test, Sidak´s teste and two way ANOVA was used, with p <0.05. Results the test group showed differences in weight gain, visceral adipose tissue and higher cholesterol. Con...