Neonatal and Infant Reference Intervals for FSH, LH, Testosterone, Estradiol, Cortisol and DHEA-S by Electrochemiluminescence in Argentina.

BACKGROUND: Gonadotropin and steroid concentrations obtained in various laboratories cannot often be compared because of methodological differences. AIMS: to determine reference intervals for FSH, LH, T, E2, F and DHEA-S according to age and sex during the first year of life. METHODS: 1236 healthy infants (1-365 days of age) were recruited at Hospital de Niños in Córdoba, Argentina. Serum samples were analyzed using electrochemiluminescence, Cobas e601 analyzer. Reference Intervals and their confidence limits were estimated. RESULTS: Female FSH levels were higher than in males. LH and T levels were higher in males. E2 levels showed a difference between sexes after 60 days of age. F levels showed a wide variation, without differences between sexes. DHEA-S levels were higher at birth and decreased during the first year. CONCLUSION: These reference intervals may help to increase the diagnostic power for the assessment of endocrine disorders during the first year of life.

Serum levels of adiponectin and leptin in children born small for gestational age: relation to insulin sensitivity parameters.

Children born small for gestational age (SGA) are prone to developing obesity, insulin resistance and type 2 diabetes. Adiponectin and leptin are adipocytokines associated with insulin sensitivity parameters. We aimed to relate serum adiponectin and leptin levels with insulin sensitivity parameters in prepuberal SGA children with and without catch-up growth (SGA+CUG; SGA-CUG, respectively) and to analyze the usefulness of these adipocytokines as early markers of insulin resistance. We analysed adiponectin, proinsulin, leptin, growth factors, insulin, HOMA IR and HOMA beta(cell) in 23 SGA+CUG, 26 SGA-CUG children compared with 48 prepuberal appropiate for gestational age (AGA). SGA children had adiponectin levels comparable to AGA children. Leptin levels were different between sexes, showed to be higher in SGA+CUG group (p=0.040) and these were significantly correlated with insulin sensitivity parameters. These results suggest leptin resistance as an adaptive mechanism to increase energy balance, but an altered functional response of adipocytes cannot be discarded.