Cortisol cut-points for the glucagon stimulation test in the evaluation of hypothalamic pituitary adrenal axis

Diagnosis of adrenal insufficiency requires evaluation by dynamic stimulation tests. The insulin tolerance test (ITT) is accepted as the gold-standard test for the evaluation of hypothalamo-pituitary-adrenal (HPA) axis but the test is unpleasant and dangerous. Although it takes more time, glucagon stimulation test (GST) is a good alternative to ITT. The primary aim of this study was to compare the ITT and GSTs in the evaluation of HPA axe in patients with pituitary disorders. We conducted a prospective study in which ITT and GST were performed within 7 days in 81 patients. Serum cortisol was measured. We divided our population in Group 1 (G1): Adrenal Insufficiency (Peak cortisol under ITT <200 ng/mL) and Group 2 (G2): normal response (Peak cortisol under ITT >200 ng/mL). Receiver-operating characteristic (ROC) analysis was performed to identify the thresholds for GST. The mean peak of cortisol under GST was not significantly different from that obtained after ITT in the whole cohort (182.67 ± 89.07 ng/mL vs. 179.75 ± 79.01 ng/mL), and it was significantly reduced in patients of G1 (p < 10^-3). ROC curve analysis showed that the best diagnostic accuracy was obtained with a peak cortisol cut-off to GST of 167 ng/mL (sensitivity, 89%; specificity, 79%). Using this cut-off, 86.4% of the patients were correctly classified. In our prospective series, GST is a potential accurate and safe alternative test for the assessment HPA. Test-specific cut-offs should be applied to avoid misinterpretation.

Effects of dermal sub-chronic exposure of pubescent male rats to permethrin (PRMT) on the histological structures of genital tract, testosterone and lipoperoxidation

Short-term effects of pyrethroids on human health are better and well identified, whereas long-term risk's estimation remains difficult, especially those affecting the reproductive function. The present study, carried out in male rats, is a contribution to explore some effects underlying permethrin (PRMT) toxicity. The aim of the present work was to investigate the effect of different subcutaneous treatments with PRMT low doses on testes and epididymides histopathology, testosterone and oxidative stress in pubescent male rats. Groups of six animals were treated with a dermal daily dose of 0.013, 0.13, or 1.3 mg/kg b.w/day of PRMT in 70% ethanol for 30, 45, and 60 days, respectively. Macroscopic studies showed an influence of PRMT on the testes, the epididymides and body weight. The pyrethroid induces a testis disturbance traduced by a deregulation of spermatogenesis and an epididymis dysfunction by the appearance of strong deformations into the microstructure of the epididymides. A hormonal disruption was evidenced by the measurement of the plasma testosterone concentrations. The findings of the present investigation mentioned a significant increase (p≤0.05) in lipoperoxidation, after 45 or 60 days, when we measured the plasma malondialdehyde (MDA) concentrations. In conclusion the study shows that subcutaneous PRMT treatment causes an arrest of spermatogenesis, and a significant disharmony in testosterone concentration and MDA levels. These effects are related to dose, length of treatment and to the lipid peroxidation, which may be one of the molecular mechanisms involved in PRMT-induced gonads and epididymides toxicity.