TIME-COURSE OF ERYTHROPOIETIN, TRIIODOTHYRONINE, THYROXINE, AND THYROID-STIMULATING HORMONE AT 2,315 M

Time course of erythropoietin, triiodothyronine, thyroxine, and thyroi d-stimulating hormone at 2,315 m. J. Appl. Physiol. 76(3): 1068-1072, 1994. - Erythropoietin (EPO), triiodothyronine, thyroxine, thyroid-sti mulating hormone (TSH), hemoglobin (Hb), reticulocytes, packed cell vo lume, and plasma volume changes were studied in 29 male Austrian mount ain rescue soldiers before and several days after an ascent from 744 t o 2,315 m in the Alps. EPO concentrations showed a remarkable increase 48 h after the ascent (P < 0.01). No significant changes were found i n triiodothyronine, thyroxine, and TSH. Reticulocytes increased only s lightly. Hb decreased during the week (P < 0.01). Packed cell volume d id not change, whereas plasma volume showed a slight decrease for 48 h after the ascent but then increased constantly (P < 0.01). It seems t hat thyroid hormones, TSH, and Hb play only a minor role in the regula tion of EPO production and release under mild hypobaric-hypoxic condit ions (2,315 m).