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The accurate quantification of aldosterone (ALD) in adrenal tributary venous serum/plasma collected by a super-selective adrenal venous sampling (ssAVS) technique has become a definitive procedure to identify the forms (laterality) of primary aldosteronism (PA) and the location of the affected segment(s), and to subsequently make the treatment decision. In this study, a stable isotope-dilution LC/ESI-MS/MS-based method was developed and validated for the determination of the ALD concentrations of the six ssAVS serum samples during a single run. A sextet of Girard reagents was used to convert ALD to the derivatives having different masses for each sample. Based on the validation tests, satisfactory specificity, precision and accuracy were observed and the matrix effect was found to be acceptable. The developed method was used for the analysis of the ssAVS serum samples from eight PA patients. The batch analysis of the six samples permitted the direct comparison of the ALD concentrations between the samples and enhanced to determine the laterality and location of the affected segment(s). The total analysis time after the sample purification was also reduced to 1/3 for the 24 samples by the sample-sextuplex procedure, which was also an advantage of the developed method.

Our group previously purified human and rat aldosterone synthase (CYP11B2 and Cyp11b2, respectively) from their adrenals and verified that it is distinct from steroid 11β-hydroxylase (CYP11B1 or Cyp11b1), the cortisol- or corticosterone-synthesizing enzyme. We now describe their distributions immunohistochemically with specific antibodies. In rats, there is layered functional zonation with the Cyp11b2-positive zona glomerulosa (ZG), Cyp11b1-positive zona fasciculata (ZF), and Cyp11b2/Cyp11b1-negative undifferentiated zone between the ZG and ZF. In human infants and children (

Cortisol (CRT), the main glucocorticoid in humans, plays a crucial role in many physiological processes, therefore, the measurement of its serum level is of great clinical significance. Matrix-assisted laser desorption/ionization-tandem mass spectrometry (MALDI-MS/MS) might be an effective approach for the quantification of CRT in serum due to its attractive properties, i.e., high specificity, ease of use, ruggedness and rapid analysis. In this study, we developed a method to quantify the serum CRT by MALDI-MS/MS. This method employed the derivatization using a Girard-type reagent, 1-(hydrazinocarbonylmethyl)isoquinolinium chloride, which compensated for the lack of sensitivity. This method enabled the reproducible quantification of the serum CRT using a 20-μL sample (intra- and inter-assay relative standard deviations, 7.4% or lower), and the measurable range was 25–500 ng/mL. The serum CRT concentrations determined by the newly-developed MALDI-MS/MS method agreed well with those by liquid chromatography/electrospray ionization-MS/MS or electrochemiluminescence immunoassay. The MALDI-MS/MS method was used for the analysis of peripheral venous serum samples of healthy subjects and adrenal venous serum samples of patients with primary aldosteronism, and satisfactory results were obtained.

We recently identified hundreds of transcripts with differential expression in rat zona glomerulosa (zG) and zona fasciculata. Although the genes up-regulated in the zG may be playing important roles in aldosterone production, the relationship between most of these genes and aldosterone production has not been uncovered. Because aldosterone, in the presence of a high sodium diet, is now considered a significant cardiovascular risk factor, in this review we performed gene ontology and pathway analyses on the same microarray data to better define the genes that may influence zG function. Overall, we identified a number of genes that may be involved in aldosterone production through transforming growth factor β (TGF-β), WNT, calcium, potassium, and ACTH signaling pathways. The list of genes we present in the current report may become an important tool for researchers working on primary aldosteronism and aldosterone-related cardiovascular diseases.

We report a case of non-familial juvenile primary aldosteronism (PA). Super-selective adrenal venous sampling identified less aldosterone production in the right inferior adrenal segment than others. Bilateral adrenalectomy sparing the segment normalized blood pressure and improved PA. Both adrenals had similar histologies, consisting of a normal adrenal cortex and aldosterone synthase-positive hyperplasia/adenoma. An aldosterone-driving KCNJ5 mutation was detected in the lesions, but not in the histologically normal cortex. After taking into account that the two adrenal glands displayed a similar histological profile, as well as the fact that hyperplastic lesions in both glands exhibited a common KCNJ5 mutation, we conclude that the specific mutation may have occurred at an adrenal precursor mesodermal cell, at an early stage of development; its daughter cells were mixed with non-mutant cells and dispersed into both adrenal glands, resulting into a form of the condition known as genetic mosaicism.

It is well known that during diarrhea episodes decreased cyclosporine and tacrolimus levels are often observed, usually requiring an increase in dose. An increase in tacrolimus trough levels is infrequently recognized as a potential cause of the adverse effect of severe diarrhea. Herein, we report the case of a renal transplant patient who displayed increased tacrolimus trough levels during an episode of gastroenteritis with severe diarrhea. The patient is 32-year-old male who received a renal transplant from his mother. Immunosuppression was initiated with tacrolimus in combination with mycophenolate mofetil and prednisone. The postoperative course was uneventful. The function of the transplanted kidney was normal. Eight months after transplantation he presented to our hospital with a history of high fever, abdominal pain, nausea and severe diarrhea. He was admitted with a diagnosis of enterocolitis of unknown etiology. The blood trough level of tacrolimus had increased from 6.7 ng/mL to 28.7 ng/mL after the onset of diarrhea. A therapeutic trough level of tacrolimus was reached 6 weeks after complete relief of diarrhea. Tacrolimus shows large variability in bioavailability after oral administration, both due to intestinal metabolism by cytochrome P450 (CYP3A4) and active secretion from enterocyte into intestinal lumen by P-glycoprotein. The epithelial cells of the intestine, may be destroyed abrogating P-glycoproteins during the course of enterocolitis, thereby increasing the levels of tacrolimus. It is recommended to monitor trough levels of tacrolimus during severe diarrhea of any nature to prevent tacrolimus-related complications.