A modified competitive protein-binding assay for the measurement of adenosine-3′,5′-monophosphate is desribed. The procedure allows measurement of adenosine-3′,5′-monophosphate in unextracted plasma samples. The mean plasma values in 25 normal, fasting and ambulatory subjects were 22.7 ± 4.7 pmol/ml (mean ± sd) (range 13–31 pmol/ml. The mean urinary content was 3.2 ± 1.0 μmol per g creatinine (mean ± sd) (n=24).

Cyclic AMP, glucose and cortisol in plasma were measured before, during and after major surgery (hysterectomy, six patients) and minor surgery (tympanoplasty, 10 patients). During major surgery cyclic AMP as well as glucose and cortisol showed a pronounced increase. During minor surgery cyclic AMP, glucose and cortisol levels were significantly lower than in the group undergoing major surgery. It is concluded that the increase of plasma cyclic AMP during operative procedures is related to the severity of the trauma.

Serum insulin and blood sugar were investigated in ten normal-weight diabetics with maturity-onset diabetes and in 12 controls before and after intravenous injection of 25 gm dglucose without and during simultaneous infusion of isoprenaline 2 /-&g/min. A significant increase in serum insulin concentration was found after isoprenaline in both groups, both before and after injection of glucose. The increase in serum insulin level in the diabetics after isoprenaline was found to be normal, although the increase in insulin concentration following glucose was greatly reduced. It is concluded that in patients with maturity-onset diabetes there is presumably a defect of the glucose turnover in the B ceUs, whereas the process of insulin secretion itself is normal.

Bone resorption, intestinal absorption of calcium, and urinary calcium excretion were studied in young rats given prolonged calcitonin treatment. The animals soon developed a resistance to the hypocalcaemic effect of calcitonin, probably due to a secondary hyperparathyroidism. In one of the experiments the rats were given 45Ca 2 weeks before the start of the calcitonin treatment in order to label the deep parts of bone. The release of isotope from bone was inhibited after the first injections of the hormone, but even after a few days of calcitonin treatment no differences could be detected between the treated animals and their corresponding controls. An increased release of isotope from bone was registered as soon as the treatment was interrupted, indicating the presence of a secondary hyperparathyroidism. No conclusive changes could be detected in the intestinal absorption of calcium. A transitory reduction in the excretion of calcium in the urine was followed by a considerable loss of calcium.

The glucagon stimulated increase in plasma cyclic AMP has been studied in 17 healthy subjects, in 13 hyperthyroid and in 14 hypothyroid patients. Six hyperthyroid and 2 hypothyroid patients were re-investigated after at least 15 months of treatment. The results show:1) The glucagon stimulated cyclic AMP response is significantly increased in hyperthyroid patients considered as a group, and is reduced in patients with hypothyroidism. 2) Three hyperthyroid and 4 hypothyroid patients showed a normal response to iv glucagon, indicating that the plasma cyclic AMP response to iv glucagon is not a sensitive test for the evaluation of peripheral thyroid states. This suggests that the effects of thyroid hormones in the liver does not necessarily follow the effects in other tissues.3) Re-investigation of treated patients showed that the cyclic AMP response can be normalized by treatment, both in hyperthyroidism and in hypothyroidism. However, in patients treated for hyperthyroidism a hyper-response to glucagon can continue after blood levels of thyroid hormones are reduced to normal. This suggests an inertia in the loss of the hyper-response to glucagon, once a hyperfunction has been induced. A similar inertia in the loss of glucagon sensitivity in hypothyroidism could explain the large number of normal tests in hypothyroid patients.