Ist die Alpha-Adrenorezeptorendichte an intakten Thrombozyten bei statisch trainierten Athleten erhöht?

Summary Alpha-adrenoreceptors were determined as an equivalent to³H-dihydroergocryptine (DHE) specifically bound on intact thrombocytes in five untrained volunteers (I), eight non-staticly trained sportsmen (II), and eight intensively staticly trained athletes (III). B_max was 933±363 (I), 982±373 (II), and 1796±539 fmol DHE·10^–9 thrombocytes (III). K_D was 1.28±0.49 (I), 2.94±1.12 (II), and 3.58±1.07 nmol·1^–1 (III). The number of binding sites per cell amounted to 561±202 (I), 589±224 (II), and 1078±323 (III). The thrombocytes of the staticly trained athletes showed a significantly higher number of binding sites and a slightly higher affinity (K_D) than the other groups (p < 0.01). However, a wide range of overlapping has to be considered. The biologic significance of these results and their transferability to other organs are open at present. It is the question whether an altered adrenoreceptor density may be one factor of a higher prevalence of hypertension in staticly trained athletes on which our research group has reported recently.

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Abkürzungen B_max. maximale spezifische Bindung des Radioliganden, basierend auf dem Scatchard-Plot - K_D Dissoziationskonstante ermittelt aus der Scatchard Analyse - VO_{2 max.} maximale Sauerstoffaufnahmefähigkeit - DHE Dihydroergocryptin Mit Unterstützung des Bundesinstitutes für Sportwissenschaft, Köln-Lövenich