Effect of Sex Hormones on Non-Esterified Fatty Acids, Intra-Abdominal Fat Accumulation, and Hypertension Induced by Sucrose Diet in Male Rats

Abstract

Sucrose-fed rats (1) had higher intra-abdominal fat mass and plasma non-esterified fatty acids and lower testosterone levels, (2) were hypertensive, and (3) had lower plasma NO metabolites than controls. The lack of testosterone by castration of sucrose-fed rats decreased high blood pressure and circulating non-esterified fatty acids and increased NO metabolites. The administration of testosterone to castrated sucrose-fed rats restored hypertension, fat accumulation, and high-circulating non-esterified fatty acids, and lowered NO metabolite levels whereas estradiol treatment did not significantly affect these variables in castrated animals. This study proposes that the low levels of testosterone found in sucrose-fed rats are sufficient to maintain central obesity and increased circulating non-esterified fatty acids, which contribute to the development of hypertension in sucrose-fed rats by modulating the biosynthesis of NO.

Modulation of aortic vascular reactivity by sex hormones in a male rat model of metabolic syndrome

“…Some of the mechanisms responsible for this could be the absence of androgens, since they are required to induce hypertension in fructose-fed rats, a variant of the sucrose-fed rats (Song et al, 2004) as observed in our model, and high blood pressure reappears when MS castrated animals receive treatment with testosterone (El Hafidi et al, 2006).…”

“…In our laboratory, recent work has shown that Int MS rats sustain an increase of free saturated fatty acids, such as palmitic, stearic and oleic, and that this increase is positively correlated with the reduction of serum NO 3 − and NO 2 − concentration (El Hafidi et al, 2006). We can speculate that the free fatty acids have a direct effect on endothelial nitric oxide synthase (eNOS) (Davda et al, 1995).…”

“…In our model, these metabolic and functional abnormalities are induced in Wistar rats by chronic administration of sucrose in the drinking water, which additionally induces altered vascular reactivity in vitro i.e. hypercontractility to norepinephrine and a decreased relaxation in response to acetylcholine (Baños et al, 1997), accumulation of intraabdominal adipose tissue, an altered lipid profile (El Hafidi et al, 2006) and severe nephropathy (Baños and El Hafidi, 2005), among other pathological features.…”

“…However, the physiological mechanisms responsible for the differences in outcome associated with the sex of the individual, and their possible participation in the incidence of arterial hypertension have not been fully elucidated. Recently, we have described that testosterone administered to castrated, sucrose-fed rats restores hypertension and intraabdominal fat accumulation (El Hafidi et al, 2006). Also androgens may aid the onset of hypertension in spontaneously hypertensive rats, through the increased activity of the tyrosinehydroxylase enzyme (Kumai et al, 1995), which primarily increases the levels of norepinephrine (NE) in the blood.…”

Variações metabólicas e endócrinas de cachaços híbridos (Landrace x Large White) durante o primeiro ano de vida e sua relação com o estabelecimento da puberdade

“…Os maiores níveis de NEFA observados no período pré-puberdade podem ser explicados parcialmente pelos menores níveis de testosterona neste período, concordando com os resultados obtidos por Hafidi et al (2006), que observaram a ocorrência de obesidade e aumento nos níveis circulantes de NEFA em ratos com baixos níveis de testosterona, porém, não foi observada correlação entre estes parâmetros neste estudo (P = 0,27). Os maiores níveis de NEFA no período pré-puberdade também podem justificar os níveis mais altos de GGT neste mesmo período, em comparação à puberdade, pois o maior aporte de NEFA provavelmente acarretou uma maior atividade hepática (GONZALEZ et al, 2011).…”