Thyroid function in leukaemia patients after allogeneic bone marrow transplantation

The effect of calcitonin on growth hormone secretion in man

To determine whether human calcitonin inhibits GH secretion in man, as has been described for salmon calcitonin, the effect of an i.v. bolus of human calcitonin or saline on GH release after either insulin-induced hypoglycaemia or the administration of GH-releasing hormone (GHRH) or saline was studied. After the injection of calcitonin, no spontaneous GH surges were seen; the GH response to hypoglycaemia was diminished and the response to GHRH almost completely suppressed. Administration of calcitonin also caused a small and transient rise in plasma PRL and TSH but not LH levels, and no change in the integrated PRL or TSH response. Calcium and magnesium levels did not change. It is concluded that human calcitonin suppresses GH secretion in man, but not by suppressing GHRH and probably not by increasing somatostatin release. In addition, calcitonin has limited PRL and TSH-releasing activity.

The significance of the initial FT4-index for the management of single daily dose methimazole treatment of hyperthyroidism

Since the effectiveness of 30 mg methimazole in a single daily dose in gaining initial control of hyperthyroidism may depend largely on patient characteristics, 52 patients (34 with diffuse and 18 with nodular goitre) were investigated in an attempt to determine the relative importance of a number of pretreatment variables. Return to normal thyroid hormone levels after 2 to 6 weeks of treatment appeared to be the rule, although eight of these patients formed notable exceptions (6-20 weeks). The individual duration of treatment until achievement of biochemical euthyroidism correlated with the initial free thyroxine index (r = 0.75, P less than 0.001) and the free triiodothyronine index (r = 0.70, P less than 0.001). For patients with a diffuse goitre it was also related to the thyroid volume estimated by ultrasound (r = 0.73, P less than 0.001). According to multiple linear regression analysis however these variables were found to have no independent prognostic value. The decrease in thyroid volume during initial therapy, the nature of the goitre, a medication compliance score and various other patient variables did not correlate with the effect of treatment. In 12 cases perchlorate discharge tests were performed. The results suggest continued hormone synthesis in patients with highly active iodine trapping as an important mechanism of the postponed attainment of euthyroidism.