Ascorbic acid (vitamin C) is a cofactor required in catecholamine synthesis for conversion of dopamine to norepinephrine by dopamine beta-hydroxylase. Mutant mice lacking the plasma membrane ascorbic acid transporter (SVCT2) have severely reduced tissue levels of ascorbic acid and die after birth. We therefore investigated whether these mice might have impaired synthesis of catecholamines. Levels of catecholamines in brain were unaffected by SVCT2 deficiency. In heart, the only evidence for impaired dopamine beta-hydroxylase activity was a twofold increase in tissue dopamine. An influence of the deficiency on tissue catecholamines was most prominent in the adrenals where norepinephrine was decreased by 50% and epinephrine, by 81%. On the ultrastructural level, adrenal chromaffin cells in SVCT2 null mice showed depletion of catecholamine storage vesicles, increased amounts of rough endoplasmic reticulum, signs of apoptosis, and increased glycogen storage. Decreased plasma levels of corticosterone indicated additional effects of the deficiency on adrenal cortical function. These data show that deranged catecholamine system function in SVCT2 null mice is largely restricted to the adrenal medulla and cannot account for the lethality in these animals. The data, however, establish a crucial role for ascorbic acid in adrenal chromaffin cell function.

Corticotropin-releasing hormone (CRH) is both a main regulator of the hypothalamic-pituitaryadrenocortical axis and the autonomic nervous system. CRH receptor type 1 (CRHR1)-deficient mice demonstrate alterations in behavior, impaired stress responses with adrenocortical insufficiency and aberrant neuroendocrine development, but the adrenal medulla has not been analyzed in these animals. Therefore we studied the production of adrenal catecholamines, expression of the enzyme responsible for catecholamine biosynthesis neuropeptides and the ultrastructure of chromaffin cells in CRHR1 null mice. In addition we examined whether treatment of CRHR1 null mice with adrenocorticotropic hormone (ACTH) could restore function of the adrenal medulla. CRHR1 null mice received saline or ACTH, and wildtype or heterozygous mice injected with saline served as controls. Adrenal epinephrine levels in saline-treated CRHR1 null mice were 44% those of controls (P Ͻ0.001), and the phenylethanolamine N-methyltransferase (PNMT) mRNA levels in CRHR1 null mice were only 25% of controls (P Ͻ0.001). ACTH treatment increased epinephrine and PNMT mRNA level in CRHR1 null mice but failed to restore them to normal levels. Proenkephalin mRNA in both saline-and ACTH-treated CRHR1 null mice were higher than in control animals (215.8% P Ͻ0.05, 268.9% P Ͻ0.01) whereas expression of neuropeptide Y and chromogranin B did not differ. On the ultrastructural level, chromaffin cells in saline-treated CRHR1 null mice exhibited a marked depletion in epinephrine-storing secretory granules that was not completely normalized by ACTH-treatment. In conclusion, CRHR1 is required for a normal chromaffin cell structure and function and deletion of this gene is associated with a significant impairment of epinephrine biosynthesis. Molecular Psychiatry (2002) 7, 967-974.

A 56-yr-old man was admitted to our university hospital for severe back pain one month after a resection for lung adenocarcinoma (stage IIIA) without evidence of the adrenal mass. Computed tomography (CT) of the abdomen showed bilateral bleeding of adrenal tumors. Endocrinological laboratory studies showed high plasma ACTH and normal serum cortisol levels with the loss of circadian rhythm. Although plasma ACTH levels increased, there was no cortisol response to administration of human corticotropichormone (hCRH). Core-needle biopsy was performed on the right adrenal tumor and revealed adenocarcinoma cells mimicking a primary lung tumor previously examined. We diagnosed retroperitoneal hemorrhage due to bilateral adrenal gland metastasis from lung adenocarcinoma with adrenal insufficiency. Adrenal metastases most commonly originate from a primary lung tumor, followed by stomach, esophagus and liver/bile ducts. Bilateral adrenal metastases were noted in approximately half of all adrenal metastases patients. Clinically significant adrenal hemorrhage by metastasis is exceedingly rare and non-specific symptoms, such as abdominal, chest or back pain, nausea and vomiting, confusion, weakness, hypotension, shock and high fever, are often observed in these patients. We present a case of massive retroperitoneal hemorrhage and adrenal insufficiency due to adrenal gland metastasis from adenocarcinoma of lung.