The analysis of fatty acids and their derivatives in the liver of C57BL/6 mice with long-term caloric restrictions.

Caloric restriction (CR) is a dietetic intervention based on the reduction of daily calorie intake by 10-30 %. When subjected to CR, the organism adjusts its metabolism to the changing availability of key nutrients. However, fatty acids' content in organisms subjected to long-term CR has not been evaluated. The aim of the research was to analyze the influence of long-term CR on the contents of medium- and long-chain fatty acids, as well as on the contents of fatty acid derivatives in liver. The study was performed on C57BL female (n = 12) and male (n = 12) mice subjected to lifelong 30 % calorie restriction. Fatty acids were analyzed using gas chromatography, while fatty acid derivatives were analyzed with liquid chromatography. The dynamics of change of the lipid profile of the labeled fatty acids observed in the liver tissue confirms that lipolysis actively takes place in this organ when hungry. Moreover, it is highly possible that de novo synthesis of acids takes place, with the aim to ensure energy substrates to the body. Moreover, an increase of concentration was observed for fatty acid derivatives, those with anti-inflammatory properties (resolvin, LTX A4). However, there was no increase in the concentration of pro-inflammatory eicosanoids. The results suggest that it is important to take into consideration the introduction of appropriate supplements when using CR.

Soy isoflavones administered pre- and postnatally may affect the ERα and ERß expression and elements' content in bones of mature male rats.

The aim of this study was to assess the influence of soy isoflavones, administered pre- and later postnatally, on the estrogen receptor α (ERα) and ß (ERß) expression in bones and to examine the mineral metabolism of the skeletal system in male rats. In bones, ERs were examined with an immunohistochemical method; in blood, estradiol with chemiluminescence immunoassay and in blood and bones, calcium and magnesium with atomic absorption spectrometry and fluorides with a potentiometric method were examined. Decreased immunoexpression of ERα and the increased intensity of immunofluorescence of ERß in osteocytes in the femur of experimental rats were observed. In the serum of treated rats, a significantly higher concentration of estradiol and lower calcium were observed. The content of magnesium and fluoride were significantly higher in the bones of the examined animals. The data presented show that pre- and postnatal supplementation of male rats with soy isoflavones may considerably increase the concentration of estrogens in serum, with a concurrent effect on the mineral composition of bones.