Glycine intake decreases plasma free fatty acids, adipose cell size, and blood pressure in sucrose-fed rats

Abstract

os. Glycine intake decreases plasma free fatty acids, adipose cell size, and blood pressure in sucrose-fed rats. Am J Physiol Regul Integr Comp Physiol 287: R1387-R1393, 2004. First published August 26, 2004 doi:10.1152/ajpregu.00159.2004The study investigated the mechanism by which glycine protects against increased circulating nonesterified fatty acids (NEFA), fat cell size, intra-abdominal fat accumulation, and blood pressure (BP) induced in male Wistar rats by sucrose ingestion. The addition of 1% glycine to the drinking water containing 30% sucrose, for 4 wk, markedly reduced high BP in sucrose-fed rats (SFR) (122.3 Ϯ 5.6 vs. 147.6 Ϯ 5.4 mmHg in SFR without glycine, P Ͻ 0.001). Decreases in plasma triglyceride (TG) levels (0.9 Ϯ 0.3 vs. 1.4 Ϯ 0.3 mM, P Ͻ 0.001), intra-abdominal fat (6.8 Ϯ 2.16 vs. 14.8 Ϯ 4.0 g, P Ͻ 0.01), and adipose cell size were observed in SFR treated with glycine compared with SFR without treatment. Total NEFA concentration in the plasma of SFR was significantly decreased by glycine intake (0.64 Ϯ 0.08 vs. 1.11 Ϯ 0.09 mM in SFR without glycine, P Ͻ 0.001). In control animals, glycine decreased glucose, TGs, and total NEFA but without reaching significance. In SFR treated with glycine, mitochondrial respiration, as an indicator of the rate of fat oxidation, showed an increase in the state IV oxidation rate of the ␤-oxidation substrates octanoic acid and palmitoyl carnitine. This suggests an enhancement of hepatic fatty acid metabolism, i.e., in their transport, activation, or ␤-oxidation. These findings imply that the protection by glycine against elevated BP might be attributed to its effect in increasing fatty acid oxidation, reducing intra-abdominal fat accumulation and circulating NEFA, which have been proposed as links between obesity and hypertension. obesity; mitochondrial oxygen uptake; fatty acid oxidation OBESITY is a significant human health problem; its incidence is reaching epidemic proportions in many Western countries (2, 31). Obesity with fat accumulation predominantly in the abdominal cavity is more frequently associated with disorders of glucose and lipid metabolism than is subcutaneous fat obesity (6, 17). It is well known that increased intra-abdominal fat accumulation is also associated with elevated circulating nonesterified fatty acids (NEFA) (33), resulting from the increased lipolytic activity in adipose tissue. High levels of circulating NEFA have been assumed to be a possible link between intra-abdominal fat accumulation and elevated blood pressure (BP) (9,34,46,49).Several factors are known to be involved in the development of intra-abdominal adiposity in both humans and animals, including genetic and environmental factors, such as excessive fat or carbohydrate intake and lack of physical exercise (8, 44). Thus several animal models of obesity have been developed to investigate the mechanism by which obesity induces hypertension, hyperinsulinemia, and insulin resistance.In our laboratory, we developed an animal model of intraabdominal fat accumulation, indu...

Identification of Serum Metabolites Associated With Incident Hypertension in the European Prospective Investigation Into Cancer and Nutrition–Potsdam Study

“…27,28 The second identified amino acid glycine is known to reduce oxidative stress because of an enhancement of the bioavailability of nitric oxide. 22,23 As seen in the partial plot of glycine, an increase of glycine concentrations of ≈150 to 250 µmol/L was closely associated with an improvement of 10-year hypertension-free survival time. A recent study showed that glycine concentrations of around 200 µmol/L are required to activate glycine-gated chloride channels which, inter alia, occur in macrophages, monocytes, and endothelial cells.…”

“…Nevertheless, the observed results are supported by recent research indicating that supplementation with serine as well as glycine may have BP-lowering effects. [20][21][22][23] Moreover, antiinflammatory and antioxidant properties were attributed to serine and glycine, 20,[23][24][25][26] which may contribute to protective effects regarding the development of hypertension.…”

“…Nevertheless, the observed results are supported by recent research indicating that supplementation with serine as well as glycine may have BP-lowering effects. [20][21][22][23] Moreover, antiinflammatory and antioxidant properties were attributed to serine and glycine, 20,[23][24][25][26] which may contribute to protective effects regarding the development of hypertension.In this study, a nonlinear positive association of serine concentrations with 10-year hypertension-free survival was observed, whereby serine concentrations of 100 µmol/L were most protective regarding 10-year hypertension-free survival. This is confirmed by a study of Mishra et al 20 describing serine-induced vasodilation in endothelium-intact vessels as a result of increasing serine concentrations.…”

Consumption of Pork-Liver Protein Hydrolysate Reduces Body Fat in Otsuka Long-Evans Tokushima Fatty Rats by Suppressing Hepatic Lipogenesis

“…Recently, Hafidi et al reported that 10 g/l drinking water glycine reduces adipose tissue accumulation and plasma fatty acids. 31) It has been also reported that the content of glycine in soy protein and buckwheat protein, known as an anti-obesity factor, [3][4][5][6] is also higher than that in casein. 32) Both glycine and alanine can readily be metabolized to pyruvate, which has been reported to have an anti-obesity effect.…”

Non-steroidal anti-inflammatory drugs attenuate the vascular responses in aging metabolic syndrome rats

“…The increase in abdominal fat was most likely accompanied by a decrease in muscle mass as reported by other groups [39] because body weight did not significantly increase. In our model, we have not determined a difference in muscle mass between the Control and MS rats, but sucrose fed animals have been shown to consume less solid food, which means less protein and mineral intake [40] . Although obesity is a risk factor for sarcopenia, its pathophysiology is complex, and multiple factors, including lifestyle, endocrine, and immunological factors, can play a role.…”