In variations related to the thyroid gland, rarely have both the thyroid and TSH levels been determined in the blood of the same individual. This relates to the fact that endocrine patterns have not been investigated. It is also interesting to note that the findings indicate that the thyroid activity and the TSH activity of the blood vary somewhat independently. For example, in 10 cases of hypothyroidism the thyroid activity of the blood was low, but the TSH values varied widely – 0.000 to 0.005. In 10 hyperthyroid cases, the thyroid hormone levels were high but the TSH levels showed a “normal” variation. It appears, therefore, that high thyroid activity may be promoted in some cases by high TSH activity, but that in other cases the thyroids are active without outside stimulation of a high order. Likewise, it would seem plausible to suppose that low thyroid activity is due in some cases to deficiencies in the thyroid gland itself, but that in other cases the thyroid glands are ample and would function satisfactorily were it not for a deficiency of TSH.
TSH + The Thyroid