Pubertal upregulation of erythropoiesis in boys is determined primarily by androgen.

@article{citeulike:113125, abstract = {OBJECTIVES: To study the relative roles of androgens and the growth hormone-insulin-like growth factor I (GH-IGF-I) system in the regulation of erythropoiesis in boys during puberty. STUDY DESIGN: We treated 23 boys with constitutional delay of puberty with low-dose testosterone (T), in combination with either a potent aromatase inhibitor, letrozole (Lz; 2.5 mg/d), or placebo (P). The study design was randomized, double-blinded, and placebo-controlled between the treated groups. Treatment with T + Lz was associated with high T and low IGF-I concentrations, whereas treatment with T + P resulted in moderately increased T and high IGF-I concentrations. RESULTS: The blood hemoglobin concentration increased by 1.6 g/dL in T + Lz-treated boys, despite their low IGF-I concentrations. The estimated red blood cell volume increased more in T + Lz-treated than in T + P-treated boys (349 vs 174 mL, respectively, P = .01). Serum T concentrations during the treatment period correlated with the 12-month increments in hemoglobin and red blood cell volume. The changes in blood hemoglobin concentration and RBC in T + Lz-treated boys were similar to those we observed in a population of normal adolescent boys in the late stages of puberty. CONCLUSIONS: The pubertal increase in hemoglobin concentration in boys is related to direct androgen effects.}, address = {Hospital for Children and Adolescents, University of Helsinki, Helsinki, Finland.}, author = {Hero, M. and Wickman, S. and Hanhij\"{a}rvi, R. and Siimes, M. A. and Dunkel, L. }, citeulike-article-id = {113125}, doi = {http://dx.doi.org/10.1016/j.jpeds.2004.09.002}, issn = {0022-3476}, journal = {J Pediatr}, keywords = {androgen, erythropoiesis}, month = {February}, number = {2}, pages = {245--252}, posted-at = {2005-03-03 13:10:26}, priority = {2}, title = {Pubertal upregulation of erythropoiesis in boys is determined primarily by androgen.}, url = {http://dx.doi.org/10.1016/j.jpeds.2004.09.002}, volume = {146}, year = {2005} }

TY - JOUR ID - citeulike:113125 L3 - citeulike-article-id:113125 TI - Pubertal upregulation of erythropoiesis in boys is determined primarily by androgen. JF - J Pediatr VL - 146 IS - 2 SP - 245 EP - 252 AD - Hospital for Children and Adolescents, University of Helsinki, Helsinki, Finland. SN - 0022-3476 N2 - OBJECTIVES: To study the relative roles of androgens and the growth hormone-insulin-like growth factor I (GH-IGF-I) system in the regulation of erythropoiesis in boys during puberty. STUDY DESIGN: We treated 23 boys with constitutional delay of puberty with low-dose testosterone (T), in combination with either a potent aromatase inhibitor, letrozole (Lz; 2.5 mg/d), or placebo (P). The study design was randomized, double-blinded, and placebo-controlled between the treated groups. Treatment with T + Lz was associated with high T and low IGF-I concentrations, whereas treatment with T + P resulted in moderately increased T and high IGF-I concentrations. RESULTS: The blood hemoglobin concentration increased by 1.6 g/dL in T + Lz-treated boys, despite their low IGF-I concentrations. The estimated red blood cell volume increased more in T + Lz-treated than in T + P-treated boys (349 vs 174 mL, respectively, P = .01). Serum T concentrations during the treatment period correlated with the 12-month increments in hemoglobin and red blood cell volume. The changes in blood hemoglobin concentration and RBC in T + Lz-treated boys were similar to those we observed in a population of normal adolescent boys in the late stages of puberty. CONCLUSIONS: The pubertal increase in hemoglobin concentration in boys is related to direct androgen effects. KW - androgen KW - erythropoiesis AU - Hero, M AU - Wickman, S AU - Hanhijärvi, R AU - Siimes, MA AU - Dunkel, L PY - 2005/02// UR - http://dx.doi.org/10.1016/j.jpeds.2004.09.002 ER -