Differences in the actions of adrenaline and noradrenaline with regard to glucose intolerance in patients with pheochromocytoma.

Glucose intolerance is often observed in patients with pheochromocytoma. However, it remains controversial issue that glucose intolerance on pheochromocytoma is caused by impaired insulin secretion and/or by increased insulin resistance. We aimed to reveal the mechanism of glucose intolerance on pheochromocytoma with regard to the type and amount of catecholamines released. We evaluated 12 individuals diagnosed with pheochromocytoma and who underwent surgery to remove it. We examined glycemic parameters before and after surgery and investigated the association between the change of parameters of insulin secretion (homeostasis model assessment of ß-cell function (HOMA-ß)), insulin resistance (homeostasis model assessment of insulin resistance (HOMA-IR)) and that of urinary levels of metanephrine/normetanephrine before and after surgery. Overall, fasting plasma glucose, glycated hemoglobin (HbA1c), HOMA-ß, and HOMA-IR were improved significantly after surgery. Regression analysis showed that the improvement in HOMA-ß from before to after surgery was significantly positively associated with an improvement in urinary levels of metanephrine from before to after surgery and showed a significantly negative association with improvement in urinary levels of normetanephrine from before to after surgery. The improvement in HOMA-IR from before to after surgery was significantly positively associated with an improvement in urinary levels of normetanephrine from before to after surgery. Our results showed that pheochromocytoma extirpation improved glycemic parameters. Furthermore, the different effects elicited by excess amounts of adrenaline and noradrenaline on glucose intolerance were demonstrated.

Clinical Investigation of Adrenal Incidentalomas in Japanese Patients of the Fukuoka Region with Updated Diagnostic Criteria for Sub-clinical Cushing's Syndrome.

Objectives We retrospectively investigated the clinical and endocrinological characteristics of adrenal incidentalomas. Methods We studied 61 patients who had been diagnosed with adrenal incidentalomas and had undergone detailed clinical and endocrinological evaluations while hospitalized. We used common criteria to diagnose the functional tumors, but for sub-clinical Cushing's syndrome, we used an updated set of diagnosis criteria: serum cortisol ≥1.8 µg/dL after a positive response to a 1-mg dexamethasone suppression test if the patient has a low morning adrenocorticotropic hormone (ACTH) level (<10 pg/mL) and a loss of the diurnal serum cortisol rhythm. Results Of the 61 patients, none (0%) had malignant tumors, 8 (13.1%) had pheochromocytoma, and 15 (24.6%) had primary aldosteronism; when diagnosed by our revised criteria, 13 (21.3%) had cortisol-secreting adenomas (Cushing's syndrome and sub-clinical Cushing's syndrome), and 25 (41.0%) had non-functional tumors. Compared with the non-functional tumor group, the primary aldosteronism group and the cortisol-secreting adenoma group were significantly younger and had significantly higher rates of hypokalemia, whereas the pheochromocytoma group had significantly larger tumors and a significantly lower body mass index. Conclusion Our study found a larger percentage of functional tumors among adrenal incidentalomas than past reports, partly because we used a lower serum cortisol level after a dexamethasone suppression test to diagnose sub-clinical Cushing's syndrome and because all of the patients were hospitalized and could therefore receive more detailed examinations. Young patients with hypokalemia or lean patients with large adrenal tumors warrant particularly careful investigation.