| 1. |
- Lejonklou, Margareta Halin, 1966-, et al.
(författare)
-
Effects of Low-Dose Developmental Bisphenol A Exposure on Metabolic Parameters and Gene Expression in Male and Female Fischer 344 Rat Offspring.
- 2017
-
Ingår i: Journal of Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 125:6
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Bisphenol A (BPA) is an endocrine-disrupting chemical that may contribute to development of obesity and metabolic disorders. Humans are constantly exposed to low concentrations of BPA, and studies support that the developmental period is particularly sensitive.OBJECTIVES: The aim was to investigate the effects of low-dose developmental BPA exposure on metabolic parameters in male and female Fischer 344 (F344) rat offspring.METHODS: Pregnant F344 rats were exposed to BPA via their drinking water, corresponding to (BPA0.5; ) or (BPA50; ), from gestational day (GD) 3.5 until postnatal day (PND) 22, and controls were given vehicle (). Body weight (BW), adipose tissue, liver (weight, histology, and gene expression), heart weight, and lipid profile were investigated in the 5-wk-old offspring.RESULTS: Males and females exhibited differential susceptibility to the different doses of BPA. Developmental BPA exposure increased plasma triglyceride levels ( compared with , females BPA50 ; compared with , males BPA0.5 ) in F344 rat offspring compared with controls. BPA exposure also increased adipocyte cell density by 122% in inguinal white adipose tissue (iWAT) of female offspring exposed to BPA0.5 compared with controls ( number of adipocytes/HPF compared with number of adipocytes/HPF; ) and by 123% in BPA0.5 females compared with BPA50 animals ( number of adipocytes/high power field (HPF) compared with number of adipocytes/HPF; ). In iWAT of male offspring, adipocyte cell density was increased by 129% in BPA50-exposed animals compared with BPA0.5-exposed animals ( number of adipocytes/HPF compared with number of adipocytes/HPF; ). Furthermore, the expression of genes involved in lipid and adipocyte homeostasis was significantly different between exposed animals and controls depending on the tissue, dose, and sex.CONCLUSIONS: Developmental exposure to of BPA, which is 8-10 times lower than the current preliminary EFSA (European Food Safety Authority) tolerable daily intake (TDI) of and is within the range of environmentally relevant levels, was associated with sex-specific differences in the expression of genes in adipose tissue plasma triglyceride levels in males and adipocyte cell density in females when F344 rat offspring of dams exposed to BPA at were compared with the offspring of unexposed controls.
|
|
| 2. |
- Rönn, Monika, 1965-
(författare)
-
Environmental Contaminants and Obesity
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Obesity is a worldwide problem affecting both children and adults. Genetic, physiological, environmental, psychological, social and economic factors interact in varying degrees, influencing body weight and fat distribution and the progress of obesity. Moreover, some anthropogenic chemicals have proven to be endocrine disrupting chemicals (EDCs) with the potential to interfere with different actions of hormones in the body. EDCs may thereby disrupt homeostasis, modifying developmental, behavioral and immune functions in humans and animals, and also promoting adiposity. Because hormones generally act at low concentrations, small changes in the endocrine system may lead to extensive effects. Based on data from experimental and epidemiological studies this thesis elucidates the relationship between a large number of environmental contaminants and obesity.The experimental studies demonstrated that fructose supplementation in the drinking water resulted in unfavorable metabolic alterations such as a higher liver somatic index (LSI), an increase in plasma triglycerides and increased plasma levels of apo A-I. Fructose in combination with exposure to bisphenol A (BPA) increased liver fat content and plasma levels of apo A-I in juvenile female Fischer 344 rats. The experimental studies also showed that the retro-peritoneal fat, which in rats is a distinct fat depot easy to distinguish and dissect, correlated well with the measurements of total fat mass analyzed with MRI, and could therefore be used as a substitute for total fat mass in rats.The epidemiological studies showed that circulating levels of persistent organic pollutants (POPs) were related to fat mass measured by DXA. OCDD, HCB, TNC, DDE and the less chlorinated PCBs were positively related to fat mass, while the more highly chlorinated PCBs showed a negative association. Further, circulating levels of BPA were positively associated with levels of the hormones adiponectin and leptin, but negatively related with ghrelin, hormones which are involved in the regulation of hunger and satiety. However, serum BPA levels were not related to measures of fat mass in the elderly individuals in the PIVUS cohort.This thesis concludes that environmental contaminants such as BPA and POPs most likely are contributors, along with genetic, social and behavioral factors, to the development of obesity.
|
|
