Bioassay of thyroid stimulating hormone using the f goldfish.

A new method for the bioassay of thyroid stimulating hormone using goldfish is described. The technique can detect thyroid stimulating substances in euthyroid unconcentrated plasma. Early results show that the method compares well with other techniques. Some evidence has been obtained which suggests that in primary myxoedema there may be some impairment of the thyropituitary "servo-mechanism" in older patients.