Characteristics of the Hormonal Status of Young Schoolchildren in the European North

Abstract

It is known that the secretory activity of the hypophysis and peripheral glands determines the functional development of the body, organogenesis, and maturation of receptor mechanisms. This is of particular importance in childhood and most significant in prepuberty and puberty, when the genital system begins to develop to maturity. Data are available on sex- and agerelated levels of sex hormones in healthy children of various regions [6-8]. Some authors note the absence of any significant sex- and age-related changes in the hormonal status between 6 and 10 years. According to others, this age is characterized by an increase in the concentration of gonadotropic hormones and sex steroids [9-10]. However, the development of the hormonal profile of children of the European North remains almost unstudied. The aim of this work was to analyze the endocrine status and endocrine relationships at the beginning of sexual development, which is extremely important for the understanding of the mechanisms of endocrine development. Virtually healthy children were examined, 79 boys and 81 girls aged 9-10 years, living in the Komi Republic (Syktyvkar, Sosnogorsk). We determined the levels of hypophyseal hormones (thyrotropin, TSH; folliclestimulating hormone, FSH; and luteinizing hormone, LH) and hormones of the peripheral glands (cortisol; triiodothyronme, T 3; thyroxine, T 4; testosterone; and progesterone) by radioimmunoas says using Immunotech (Czech Republic) and Beloris (Belarus) reagent kits. Statistical analysis of the data was conducted using software packages Excel 7.0 and Statistica 5.5 (StatSoft, USA). The analysis of the data revealed significant alterations of the hormone levels between 9 and 10 years of age. Concentrations of almost all hormones studied increased. In our study, the largest increases were in the levels of gonadotropine and sex steroids (table). For example, boys were characterized by a significant (p < 0.05) increase in the LH level, by almost a factor of 2. Also, there was a tendency toward higher FSH levels. In girls, this pattern was even more pronounced. The level of LH more than doubled (p < 0.01), and FSH increased by half (p < 0.05). At the same time, concentrations of gonadotropins were subject to large individual differences. It should be noted that the variability of the FSH was reduced in the children studied. Alterations in the levels of sex steroids also tended to increase. A significant increase in the testosterone concentration (p < 0.05) and a moderate increase in progesterone (p < 0.01) were observed in boys. Girls were characterized by a significant increase in the progesterone level (p < 0.01). Cortisol slightly increased with age in both girls and boys. Analysis of the frequency distribution of steroid hormone concentrations indicated a shift