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The adrenal gland is among the organs with the highest concentration of vitamin C in the body. Interestingly, both the adrenal cortex and the medulla accumulate such high levels of ascorbate. Ascorbic acid is a cofactor required both in catecholamine biosynthesis and in adrenal steroidogenesis. Here we provide an overview on the role of vitamin C in the adrenal cortex and medulla derived from in vitro and in vivo studies. In addition, recent insights gained from an animal model with a deletion in the gene for the ascorbic acid transporter will be summarized. Mutant mice lacking the plasma membrane ascorbic acid transporter(SVCT2) have severely reduced tissue levels of ascorbic acid and die soon after birth. There is a significant decrease of tissue catecholamine levels in the adrenals. On the ultrastructural level, adrenal chromaffin cells in SVCT2 null mice show depletion of catecholamine storage vesicles, signs of apoptosis, and increased glycogen storage. Decreased plasma levels of corticosterone and altered morphology of mitochondrial membranes indicate additional effects of the deficiency on adrenal cortical function. The data derived from these animal models and various cell culture studies confirm a crucial role for vitamin C for both the adrenal cortex as well as the adrenal medulla further underlining the interdependence of the two endocrine systems united in one gland. [ABSTRACT FROM AUTHOR]

Adrenal computed tomography with determination of Hounsfield units has proved to be sensitive and specific in the differential diagnosis of benign vs. malign adrenal lesions. On the other hand, computed tomography may fail in patients with small adrenal masses of less than 1.0 cm. However, especially in patients with diagnosed malignancies and small adrenal masses which were discovered during the diagnostic staging procedure it is important to determine the origin of the adrenal lesion. An augmented increase in 17α-hydroxyprogesterone (17-OHP) levels following corticotropin (1-24) stimulation has been noted in incidentally discovered adrenal masses by several groups. Therefore, we tested the hypothesis that elevated ACTH-stimulated 17-OHP (Δ > 2.6 ng/mL) can predict primary adrenal lesions. We evaluated the use of the ACTH test in 85 patients with adrenocortical tumors and in 16 patients who underwent abdominal imaging for staging of a carcinoma other than of adrenal origin. We found an augmented 17-OHP response in 70 (> 82%) of patients with known adrenocortical tumors and in 10 (> 62%) of patients with adrenal masses and diagnosed malignancies. Results in the latter group have been confirmed in histological studies after operation or puncture. In the group of patients who suffered from a solid malignant tumor and had an adrenal mass, it was thus possible to separate primary from secondary adrenal lesions in 100%. In the group of patients with known adrenocortical tumors, it failed to differentiate between benign and malignant adrenocortical lesion in one case. We therefore think that the ACTH test is a valuable biochemical tool to distinguish primary adrenal tumors from adrenal metastasis derived from other malignancies. [ABSTRACT FROM AUTHOR]