Correlates of venous catecholamine concentrations in patients with type 1 diabetes during a cold pressor test.

In some patients with type 1 diabetes, various physiologic reactions during a cold pressor test (CPT) are impaired. Whether this is caused by diabetic autonomic neuropathy, disturbed secretion of catecholamines, or disturbed blood glucose control is unknown. The authors, therefore, performed CPTs in patients with type 1 diabetes and in control subjects. They measured blood glucose concentrations, insulin concentrations, cardiac autonomic reflexes, and (before and after the CPT) venous catecholamine concentrations and analyzed correlations between these variables. Twenty-two patients with type 1 diabetes (17 men, 5 women; mean age +/- SD, 26.6 +/- 6.5 y; diabetes duration, 7.6 +/- 0.7 y; glycosylated hemoglobin concentration, 7.7 +/- 2.4%) and 35 control subjects with comparable age and gender distributions were studied. Venous catecholamines were measured before and at the end of a 5-minute CPT. In patients with diabetes, only noradrenaline concentrations increased during the CPT, whereas adrenaline concentrations that were already increased at rest did not change. Adrenaline concentrations correlated inversely with insulin concentrations. In control subjects, both adrenaline and noradrenaline increased significantly during the CPT. In both groups, the magnitude of the individual change in catecholamine concentrations was inversely correlated with the respective resting concentration. Changes in catecholamines, cardiovascular reflex tests, and blood glucose concentrations did not correlate with blood pressure changes. The authors conclude that, in patients with diabetes, resting adrenaline concentrations are related to insulin concentrations. Contrary to control subjects, in patients with diabetes, only noradrenaline increased during CPTs. In both groups, changes in catecholamine concentrations after the CPT were inversely related to the respective resting concentrations.

Effects of intravenous and oral clonidine on hemodynamic and plasma-catecholamine response due to endotracheal intubation.

STUDY OBJECTIVE: To investigate the effects of intravenous (IV) versus oral clonidine on alterations of heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), and plasma-catecholamines due to endotracheal intubation. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: University hospital surgery operating room. PATIENTS: 33 ASA physical status I patients were randomly assigned to either receive clonidine 3 micrograms/kg IV immediately prior to anesthesia induction, clonidine 4 micrograms/kg orally 90 minutes prior to anesthesia induction, or placebo. INTERVENTIONS: Insertion of a 14 G cannula in a large cubital vein for the determination of plasma-catecholamines using local anesthesia. Insertion of a radial artery catheter for measuring blood pressure (BP) using local anesthesia. Transthoracic echocardiography determined CO. MEASUREMENTS AND MAIN RESULTS: Heart rate, MAP, CO, and plasma-catecholamine concentrations were measured. Measurements were performed prior to induction, during intubation, and 10 minutes after intubation. During endotracheal intubation, MAP was significantly lower in the IV clonidine group compared with the placebo and the oral clonidine groups. Cardiac output was significantly lower in the IV clonidine group only. In contrast to the placebo group, norepinephrine plasma concentrations did not increase in either clonidine group. Significant alterations of epinephrine plasma concentrations due to intubation were not observed in either group. Hemodynamics after intubation were not impaired by clonidine treatment. CONCLUSIONS: In conclusion, IV clonidine reduced stress response to endotracheal intubation compared with placebo. Oral clonidine at the dose used was less effective in blunting hemodynamic stress response than IV clonidine.

Diagnostic considerations in pheochromocytoma and chronic hemodialysis: case report and review of the literature.

We present a patient on long-term hemodialysis (LTH) discovered to have a pheochromocytoma. A thorough workup pertaining his catecholamine status was performed, and intraoperative catecholamine changes were monitored. This condition poses some analytical difficulties as both interpretation of plasma catecholamine measurements and determination of their metabolic products are impaired. The literature about catecholamines with respect to hemodialysis is reviewed, and the known cases of pheochromocytoma in LTH patients are discussed. Predialysis norepinephrine concentrations were almost consistently elevated though less than 3-fold when compared to normal controls. Epinephrine is not significantly different in both groups. At least a 3.3-fold increase of epinephrine or norepinephrine in LTH patients with adrenal pheochromocytomas is observed. We conclude that plasma epinephrine elevations can be evaluated in the conventional manner, and norepinephrine concentrations beyond a 3-fold elevation should raise the suspicion of a pathological catechol excess syndrome. The interpretation of plasma homovanillic acid and vanillylmandelic acid in this condition is complicated by the lack of data in LTH patients without pheochromocytoma. Markedly elevated baseline concentrations for these parameters are assumed.

Quantification of urinary catecholamines, their abundant metabolites, and 5-hydroxyindoleacetic acid by high performance liquid chromatography and electrochemical detection, using a single mobile phase and uniform isocratic conditions.

A simple and flexible isocratic HPLC procedure was developed for the measurement of catecholamines and their abundant metabolites ( e.g. nor- metanephrine, metanephrine, methoxy-tyramine, vanillylmandelic acid, homovanillic acid) and 5-hydroxyindolacetic acid by ion-pair reversed phase chromatography on C18 columns, using a single mobile phase containing both sodium octane sulphonate and diethylamine as ion-pairing reagents.

Hypothalamic-pituitary activation does not differ during human and porcine insulin-induced hypoglycemia in insulin-dependent diabetes mellitus.

Although pituitary hormones play only a minor role in acute hormonal counterregulation during insulin-induced hypoglycemia, their concomitant secretion with the profound sympathoadrenal response provides an indicator of hypothalamic-pituitary activation. The release of different amounts of beta-endorphin, growth hormone, and adrenocorticotropin during human (HI) and porcine (PI) insulin-induced hypoglycemia would serve as a pointer to a different insulin species effect on hypothalamic-pituitary response. We performed a controlled, double-blind study with randomization to either HI or PI to compare insulin effects during developing and established hypoglycemia. The glucose clamp technique was used to lower the blood glucose concentration stepwise (3.3, 2.2, 1.7 mmol/l) over similar periods in ten patients with insulin-dependent diabetes mellitus. beta-endorphin, growth hormone, and adrenocorticotropin levels were determined by radioimmunoassay from arterialized blood at the above plateaus. A different action of HI or PI on peripheral glucose metabolism was not found. Pituitary hormones increased significantly during hypoglycemia (analysis of variance for hypoglycemic effects: beta-endorphin, P < 0.02; growth hormone, P < 0.04; adrenocorticotropin, P < 0.05). No insulin species effect was detected. Hypothalamic-pituitary activation during insulin-induced hypoglycemia is independent of the insulin species used, which supports earlier observations of an identical sympathoadrenal response during HI- and PI-induced hypoglycemia.

Catecholamine response during human and pork insulin-induced hypoglycemia in IDDM patients.

OBJECTIVE: To evaluate the catecholamine response during human and pork insulin-induced hypoglycemia. RESEARCH DESIGN AND METHODS: Ten insulin-dependent diabetes mellitus (IDDM) patients without any signs of autonomic neuropathy received either human or pork insulin in a randomized crossover fashion on 2 nonconsecutive days. The glucose clamp technique was applied to achieve stable glycemic plateaus of 5.6, 3.3, 2.2, and 1.7 mM. RESULTS: The effect of both types of insulin on glucose metabolism and circulating catecholamines was almost identical. There was a sharp rise of both epinephrine (P less than 0.05) and norepinephrine (P less than 0.02) during hypoglycemia, which did not depend on the type of insulin applicated. Symptom awareness increased significantly during the decrease of blood glucose concentration. Only during developing hypoglycemia (3.3-mM plateau), was this effect more pronounced (cumulative symptom score 2 vs. 26, P less than 0.05) with pork insulin. CONCLUSIONS: AN attenuated catecholamine secretion seems not to be the putative mechanism of a reduced awareness of human insulin-induced hypoglycemia.

[Circadian rhythm of parathyrin and calcitonin concentrations in the serum]. / Circadiane Rhythmik der Konzentrationen von Parathyrin und Calcitonin im Serum.

The circadian variations of serum intact parathyrin, C-terminal parathyrin (65-84), mid-region parathyrin (44-68) fragments, calcitonin, total calcium, ionized calcium, albumin and phosphate were measured in five healthy subjects. Intact parathyrin, parathyrin (44-68) and calcitonin show a synchronous diurnal fluctuation with a nocturnal increase to a maximum between 24.00 and 2.00 hours. Whereas phosphate has a marked circadian rhythmicity with a zenith between 1.00 and 8.00 hours, total calcium and albumin show a tendency to decrease between 20.00 and 6.00 hours. Ionized calcium concentration remains constant over the whole day.

Comparison of 20-oxosteroids and cortisol in urine as parameters of adrenocortical function.

The coefficient of correlation between values for urinary 20-oxosteroids and urinary cortisol was 0.75 in 106 24-hours urines. Urinary cortisol was usually the more specific and sensitive parameter for the evaluation of adrenocortical function. With an analysis time of 4-5 hours for 100 samples, the method for cortisol was also faster and cheaper. Furthermore, the intra- and interassay variances of 2.7 and 8.2%, respectively, indicate high precision.