WE have previously characterized the expression of the cystic fibrosis transmembrane conductance regulator protein (CFTR) gene, mRNA and protein in rat brain with reverse transcriptase (RT)-PCR amplification,in situhybridization and immunocytochemistry. We now report that the CFTR mRNA is expressed in the human anterior hypothalamus, an area involved in regulation of appetite, resting energy expenditure and sexual differentiation. Expression of CFTR in neurons localized to this region may elucidate the pathogenesis of other non-pulmonary manifestations of cystic fibrosis which commonly are observed in children with CF, including congenital absence of the vas deferens. Neuron-specific expression of CFTR in brain may be involved in the regulation of homeostatic functions including reproductive function and fertility through effects on neurosecretion, i.e. GnRH release. Dysregulation of normal neuropeptide vesicle trafficking by mutant CFTR in brain my lead to alteration in physiological function.