INFLUENCE OF OESTROGENS ON THYROID FUNCTION. I.

Abstract

The effect of oestrogens on thyroid function has interested many investigators throughout the years. When reviewing the literature it appears that despite much work in this field, no unanimous conception has emerged: data on stimulation of the thyroid gland alternate with reports on inhibition, without there being any explanation for these discrepancies based on differences in animal species used or on experimental procedure. More accurate analysis of the data from the literature, however, suggests that oestrogens influence the thyroid gland in at least two counterbalancing ways: on the one hand via an inhibition of thyrotrophin (TSH) release by the pituitary gland, on the other, by a direct action on the thyroid gland, viz., a potentiation of TSH action. The total effect on the thyroid function then may be the algebraic sum of these two actions. In this way small quantitative differences in both aspects of action, e. g. caused by differences in experimental condition, might lead to the variable results found in the literature. The result of our investigations was that a sensitization of the thyroid for TSH under the influence of oestrogens, only suggested by the data in the literature, could actually be demonstrated.