[ANP changes induced by varying TSH].

Aim of our study was estimating if TSH could influence the timing of ANP release. About it we observed 70 male subjects: 40 were euthyroid patients aged 42 +/- 5 years (group A); 20 patients treated by thyroxine in doses sufficient for inhibiting TSH release, aged 45 +/- 7 years (group B). A third group (C) was composed by 10 subjects with high basal levels of serum T3 and T4 with no thyrostatic therapy, aged 40 +/- 9 years. These subjects underwent a TRH test estimating at -30', 0', 30', 60', 120' plasma concentrations of TSH, ANP, T3, T4. In reply to physiological stimulus induced on patients of group A we observed a significant increase of TSH values (max at 60') and ANP levels (max at 120'). No significant variations occurred during the TRH test in T3 and T4 concentrations. In groups B and C no important modifications were observed neither in TSH nor in ANP plasma levels. ANP secretion seems to be dependent from the secretory condition of hypothalamus-pituitary-thyroid axis both in physiological and pathological conditions.