Two types of mRNAs for neuroendocrine protein 7B2 were deduced from the sequence of cDNAs clones isolated from a human pituitary cDNA library. One type lacks an Ala100 codon present in the other. The difference is located at an intron site within the human 7B2 gene and can be explained by the transcriptional utilization of two alternate acceptor splice sites, three nucleotides apart. Heteroduplex analysis of DNA fragments amplified by the polymerase chain reaction indicated that this 7B2 mRNA dimorphism occurs in several human endocrine tissues as well as in other species, suggesting that the alternate processing of 7B2 gene transcripts may be an intrinsic mechanism of its expression and could underlie some yet unknown biological functions.