cosyntropin and Insulin-Resistance

There is still uncertainty about what is the most appropriate test for assessment of the integrity of the hypothalamo-pituitary-adrenal (HPA) axis. Many advocate the insulin tolerance test (ITT), but this is unpleasant and resource intensive, and may occasionally give misleading results. The conventional [250 microg tetracosactrin, ACTH-(1-24)] short synacthen test (SST) has been used as a simple alternative to the ITT, but it has produced some falsely reassuring results with potentially serious consequences. A low dose [1 microg tetracosactrin, ACTH-(1-24)] short synacthen test (LDSST) has recently been advocated as a more reliable and safer alternative to ITT. Some studies, however, have failed to demonstrate any difference between SST and LDSST. The purpose of this study was to assess the clinical usefulness of LDSST compared to SST and ITT in patients with pituitary disease. We studied 64 patients with suspected or proven pituitary disease. All patients underwent SST and LDSST. Forty-two patients underwent ITT. There was a high correlation between the ITT and LDSST peak cortisol responses (r = 0.89; P < 0.0001), the ITT and SST 30 min cortisol levels (r = 0.83; P < 0.0001), and the LDSST peak cortisol response and the SST 30 min cortisol level (r = 0.85; P < 0.0001). In the LDSST, all but six patients achieved maximal cortisol response by 30 min. A plasma cortisol cut-off of 600 nmol/L is more helpful than 500 nmol/L for clinical decision-making using either the SST 30 min cortisol level or the LDSST peak cortisol response. The sensitivity of the LDSST was 100% (cortisol response of >600 nmol/L indicates intact HPA axis), with no falsely reassuring results. SST (pass cortisol level, >600 nmol/L) was less sensitive than LDSST, it produced 2 of 64 (3%) falsely reassuring results. Even the ITT (pass cortisol level, >500 nmol/L) failed to identify one patient with clinically evident cortisol deficiency. The results of this study indicate that both SST and LDSST, at a cortisol cut-off of 600 nmol/L, are safe for the purpose of clinical decision-making with regard to steroid replacement therapy in patients with pituitary disease. As the LDSST produced no falsely reassuring decisions, we suggest that this could replace the SST and ITT for initial evaluation of the HPA axis in patients with pituitary disease. We suggest administering 1 microg tetracosactrin, i.v., with sampling at 0, 20, and 30 min.

Topics: Adult; Aged; Cosyntropin; Dose-Response Relationship, Drug; Evaluation Studies as Topic; Humans; Hypothalamo-Hypophyseal System; Insulin; Insulin Resistance; Middle Aged; Pituitary Diseases; Pituitary-Adrenal System

Criteria for the evaluation of the insulin tolerance test (ITT) and Synacthen test are still a matter of debate. The objective of the study was to make a comparison of serum and salivary cortisol during four stimulation tests. Sixty four healthy volunteers underwent the ITT, the Synacthen test with 1 (LDST), 10 (MDST) and 250 (HDST) microg dose of ACTH. Maximum serum cortisol response was observed at the 90 min of the ITT (49 %), HDST (89 %) and MDST (56 %) and at the 40 min of the LDST (44 %). Results expressed as 95 % confidence intervals: 408.0-843.6 and 289.5-868.1 nmol/l in the IIT at 60 and 90 min. In the HDST and the MDST serum cortisol reached the maximum at 90 min 542.6-1245.5 and 444.2-871.3 nmol/l. Levels of salivary cortisol followed the same pattern as serum cortisol. Salivary cortisol reached the maximum response in the HDST and the MDST at 90 min and at 40 min in the LDST. We confirmed good reliability of all tests with respect to timing of response and maximum response compared to the ITT. We proved that the MDST test can provide the similar response in serum cortisol to the HDST. Measuring either salivary cortisol or ACTH levels did not provide any additional benefit then measuring serum cortisol by itself.

Topics: Adult; Cosyntropin; Female; Humans; Hydrocortisone; Hypothalamo-Hypophyseal System; Insulin; Insulin Resistance; Male; Pituitary-Adrenal System; Reference Standards; Reproducibility of Results; Saliva

Determination of response of cortisol and its metabolites to different stimuli may be important for adrenal gland disorders. To date, only one metabolite, cortisone, has been followed in stimulation tests of the adrenal gland. We aimed to describe a response of cortisol metabolites to the standard short Synacthen test (HDST), insulin tolerance test (ITT), low dose Synacthen test (LDST) and medium dose Synacthen test (MDST). Sixty healthy subjects were investigated: 30 men and 30 women. Plasma for measurements of cortisol and its metabolites was obtained before and 30th and 60th min after Synacthen and insulin administration. The cut-off 500 nmol/l of cortisol was reached after stimulation in all of tests, the maximal stimulation level was reached in 60th min in all of the tests except for LDST. The response of cortisol and its metabolites at 30th and 60th min strongly correlated in all of the tests except for LDST. Cortisol and its metabolites increased after stimulation; in contrast, cortisone and its metabolites decreased. We showed that the response of the cortisol metabolites during the Synacthen tests and ITT well correlated, and the MDST showed similar response compared to HDST. The decrease in cortisone metabolites may correspond to the regeneration of cortisol from cortisone in response to stimulation test.

Topics: Adult; Cortisone; Cosyntropin; Female; Humans; Hydrocortisone; Insulin; Insulin Resistance; Male; Middle Aged

The aim of this study was to investigate the phenotypic parameters and associated factors characterizing the development of glucose intolerance in polycystic ovary syndrome (PCOS). Among the 121 PCOS female subjects from the Mediterranean region, 15.7 and 2.5% displayed impaired glucose tolerance and type 2 diabetes, respectively. These subjects were included in a single group of overweight or obese subjects presenting with glucose intolerance (GI) states. PCOS women with normal glucose tolerance (81.8%) were subdivided into two groups: those who were overweight or obese and those of normal weight. Metabolic and hormonal characteristics of the GI group included significantly higher fasting and glucose-stimulated insulin levels, more severe insulin resistance, hyperandrogenemia, and significantly higher cortisol and androstenedione responses to 1-24 ACTH stimulation. One important finding was that lower birth weight and earlier age of menarche were associated with GI in PCOS women. Frequency of hirsutism, oligomenorrhea, acne, and acanthosis nigricans did not characterize women with GI. Our findings indicate that PCOS patients with GI represent a subgroup with specific clinical and hormonal characteristics. Our observations may have an important impact in preventative and therapeutic strategies.

Topics: Adolescent; Adult; Androstenedione; Blood Glucose; Cohort Studies; Cosyntropin; Diabetes Mellitus; Diabetes Mellitus, Type 2; Family Health; Feeding Behavior; Female; Glucose Intolerance; Humans; Hydrocortisone; Insulin; Insulin Resistance; Mediterranean Region; Obesity; Phenotype; Physical Fitness; Polycystic Ovary Syndrome; Sex Hormone-Binding Globulin

An adolescent female with type B insulin resistance and hyperandrogenemia is described. Evidence presented suggests that hyperinsulinemia leads to an increase in serum total and free testosterone. Support for this hypothesis is noted during an in vivo experiment in which large doses of regular insulin (305 U/kg-day) were infused iv, and multiple serum total testosterone measurements obtained. After 35 days of iv insulin therapy, the serum total testosterone values rose from 4.9 nmol/L (142 ng/dL) to 22.8 nmol/L (660 ng/dL), and the ovarian volume increased 2-fold. Basal (9.8 nmol/L; 282 ng/dL) and stimulated (16.8 nmol/L; 481 ng/dL) androstenedione measurements were elevated, and the dehydroepiandrosterone/androstenedione ratio was low, suggesting increased 3 beta-hydroxysteroid dehydrogenase activity. After resolution of the insulin-resistant state and the concomitant hyperinsulinemia, the serum total testosterone values returned to normal. This case illustrates that long term hyperinsulinemia leads to elevation of serum total testosterone.

Topics: Adolescent; Androgens; Autoantibodies; Cosyntropin; Dose-Response Relationship, Drug; Female; Gonadotropin-Releasing Hormone; Humans; Injections, Intravenous; Insulin; Insulin Resistance; Luteinizing Hormone; Receptor, Insulin