¹Pediatric and Reproductive Endocrinology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA

²Clinical Neurocardiology Section and Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA

³The Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, La Jolla, CA, USA

⁴Institute of Neuroanatomy, Heinrich-Heine University, Düsseldorf, Germany

⁵Department of Anatomy, Heinrich-Heine University, Düsseldorf, Germany

⁶Department of Endocrinology, Heinrich-Heine University, Düsseldorf, Germany

Correspondence to: M Yoshida-Hiroi, Clinical Neurocardiology Section and Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bldg 10, Room 6N252, 10 Center Drive, Bethesda, Maryland 20892-1620, USA. E-mail: hiroim@ninds.nih.gov

Corticotropin-releasing hormone (CRH) is both a main regulator of the hypothalamic-pituitary-adrenocortical 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 wild-type or heterozygous mice injected with saline served as controls. Adrenal epinephrine levels in saline-treated CRHR1 null mice were 44% those of controls (P<0.001), and the phenylethanolamine N-methyltransferase (PNMT) mRNA levels in CRHR1 null mice were only 25% of controls (P <0.001). 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 <0.05, 268.9% P <0.01) 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. doi:10.1038/sj.mp.4001143

CRH receptor type 1; chromaffin cell; catecholamine; ACTH; adrenal; mouse