biostudies-literatureYamamoto HJapan Society for the Promotion of Science1734https://www.ebi.ac.uk/biostudies/studies/S-EPMC12800249biostudies-literatureUnknown16(1)Proopiomelanocortin (POMC), a precursor with multiple bioactive peptides, is expressed by keratinocytes and regulates various pathophysiological responses, including pruritus associated with atopic dermatitis (AD). In the skin, POMC is extracellularly processed into peptides like α-melanocyte-stimulating hormone (α-MSH); however, the processing and functional role of β-endorphin (β-END) remain unclear. Here, we investigated the molecular form and biological activity of β-END generated in the context of AD. We analyzed skin extracts from AD lesions using immunoprecipitation and MALDI-TOF MS, identifying β-END(1-9), a truncated peptide, as a major derivative. To explore opioid receptor expression in fetal rat skin keratinocytes (FRSK) using RT-PCR. Delta opioid receptor (DOR) was detected inScientific reportsExtracellular processing of proopiomelanocortin generates short beta endorphin that regulates rat keratinocytes via the delta opioid receptor.PMC12800249JP23K05029 and JP20K05829Koida AYamamoto HYamada TSawaguchi YfalseExtracellular processing of proopiomelanocortin generates short beta endorphin that regulates rat keratinocytes via the delta opioid receptor.Proopiomelanocortin (POMC), a precursor with multiple bioactive peptides, is expressed by keratinocytes and regulates various pathophysiological responses, including pruritus associated with atopic dermatitis (AD). In the skin, POMC is extracellularly processed into peptides like α-melanocyte-stimulating hormone (α-MSH); however, the processing and functional role of β-endorphin (β-END) remain unclear. Here, we investigated the molecular form and biological activity of β-END generated in the context of AD. We analyzed skin extracts from AD lesions using immunoprecipitation and MALDI-TOF MS, identifying β-END(1-9), a truncated peptide, as a major derivative. To explore opioid receptor expression in fetal rat skin keratinocytes (FRSK) using RT-PCR. Delta opioid receptor (DOR) was detected in2025-01-01T00:00:00Z2025 Dec2026-06-13T04:55:06.295Z2026-06-13T03:08:52.271ZS-EPMC128002494138176710.1038/s41598-025-31279-5