[Relationships between thyrotropin, growth hormone and insulin in hypothyroidism]

Since growth hormone has been found to be inhibited in many cases of untreated primary hypothyroidism, we tried to investigate whether the high thyrotropin levels or the lack of thyroid hormones is the responsible factor. Six primary hypothyrotic patients were kept euthyroid by means of high and constant doses of thyroid extract. Growth hormone immunoassays were performed before and after three days of thyrotropin stimulation. Immunoassayable insulin was also investigated under the same experimental conditions. Although a moderate inhibition of growth hormone after thyrotopin stimulation was observed, the magnitude of this inhibition was not as marked as it has bee described in untreated primary hypothyrotics. There was no difference in insulin production before and after thyrotropin administration.