Correlation of serum leptin and insulin levels of pregnant protein-restricted rats with predictive obesity variables

Abstract

During pregnancy and protein restriction, changes in serum insulin and leptin levels, food intake and several metabolic parameters normally result in enhanced adiposity. We evaluated serum leptin and insulin levels and their correlations with some predictive obesity variables in Wistar rats (90 days), up to the 14th day of pregnancy: control non-pregnant (N = 5) and pregnant (N = 7) groups (control diet: 17% protein), and low-protein non-pregnant (N = 5) and pregnant (N = 6) groups (low-protein diet: 6%). Independent of the protein content of the diet, pregnancy increased total (F 1,19 = 22.28, P < 0.001) and relative (F 1,19 = 5.57, P < 0.03) food intake, the variation of weight (F 1,19 = 49.79, P < 0.000) and final body weight (F 1,19 = 19.52, P < 0.001), but glycemia (F 1,19 = 9.02, P = 0.01) and the relative weight of gonadal adipose tissue (F 1,19 = 17.11, P < 0.001) were decreased. Pregnancy (F 1,19 = 18.13, P < 0.001) and low-protein diet (F 1,19 = 20.35, P < 0.001) increased the absolute weight of brown adipose tissue. However, the relative weight of this tissue was increased only by protein restriction (F 1,19 = 15.20, P < 0.001) and the relative lipid in carcass was decreased in low-protein groups (F 1,19 = 4.34, P = 0.05). Serum insulin and leptin levels were similar among groups and did not correlate with food intake. However, there was a positive relationship between serum insulin levels and carcass fat depots in low-protein groups (r = 0.37, P < 0.05), while in pregnancy serum leptin correlated with weight of gonadal (r = 0.39, P < 0.02) and retroperitoneal (r = 0.41, P < 0.01) adipose tissues. Unexpectedly, protein restriction during 14 days of pregnancy did not alter the serum profile of adiposity signals and their effects on food intake and adiposity, probably due to the short term of exposure to low-protein diet.

Protein restriction during pregnancy affects maternal liver lipid metabolism and fetal brain lipid composition in the rat

“…During the first half of normal pregnancy, progressive accumulation of maternal fat depots occurs due to increased adipose tissue lipogenesis and glycerolneogenesis (27). In this study, although there were not differences in maternal body and liver weights, there was a significant decrease in maternal body and liver lipid content as well as on fetal body weight; similar results have been reported with severe protein restriction (6%) (21).…”

A low-protein diet during pregnancy prevents modifications in intercellular communication proteins in rat islets

“…Pregnancy also produces hyperphagia [ 41 – 43 ], and the pregnant rats in this study exhibited a higher food intake that resulted in significant body weight gain and a consequent higher final body weight in comparison to the non-pregnant rats. Thus, a short duration of mild protein restriction during pregnancy did not alter the food-related behavior or somatic profile of the rats, corroborating previous observations [ 44 ].…”

The Role of Maternal Dietary Proteins in Development of Metabolic Syndrome in Offspring

“…Low protein diet: A low protein content of the diet significantly influences body composition in rats. A low protein diet during pregnancy increased body weight and absolute weight of brown adipose tissue [ 72 ]. Brown adipose tissue has a significant role in the regulation of energy balance because it is a site of facultative thermogenesis that is mediated by uncoupling protein 1 (UCP1), a mitochondrial inner membrane protein [ 73 ].…”