Estrogen therapy attenuates adiposity markers in spontaneously hypertensive rats

Ovarian hormones modulate the metabolism of adipose cells and present a protective effect against hypertension. The aim of this study was to compare the effect of estradiol on adiposity markers in spontaneously hypertensive rats. Ovariectomized spontaneously hypertensive rats treated with estradiol (5 μg/100 g/day), three weeks after ovariectomy, presented decreased blood pressure and insulin levels and increased hepatic glycogen content. Periuterine or mesenteric adipocytes from treated animals were smaller as compared to vehicle treated group, whereas no differences were observed in relation to the number of cells. Basal rates of glycerol release were higher only in periuterine adipocytes of treated rats. The increment of glycerol release over basal values in response to isoproterenol was 400% and 440%, 283% and 330% for vehicle and estradiol treated periuterine and mesenteric adipocytes, respectively. The estradiol treated group was more sensitive to insulin inhibition of isoproterenol-stimulated lipolysis than the control animals. The lipoprotein lipase activity decreased after treatment, only in periuterine adipose tissue. Estradiol administration increased basal and insulin-stimulated rates of glucose transport in adipocytes of both sites, although the values obtained by periuterine were higher than those observed for mesenteric adipocytes. Both adipose tissues from treated animals exhibited a decreased expression of the peroxisome proliferator-activated receptor-γ, but an increased expression of peroxisome proliferator-activated receptor-α in liver. These findings suggest that estrogen administration attenuates adiposity markers of spontaneously hypertensive rats as a result of the decreased expression levels of peroxisome proliferator-activated receptor-γ in adipose tissue and increased expression of peroxisome proliferator-activated receptor-α in liver.