Inhibitory effects of β-endorphin on cortisol release from goldfish (Carassius auratus) head kidney: an in vitro study.
β-Endorphin (β-END) is an endogenous opioid peptide derived from the common precursor proopiomelanocortin, together with adrenocorticotropic hormone (ACTH) and melanocyte-stimulating hormone (MSH). Although the roles of ACTH and MSH in fish are well known, the roles of circulating β-END have not been elucidated. In the present study, we evaluated the biological roles of β-END in the goldfish. First, we cloned the cDNAs of the delta opioid receptor (DOR), kappa opioid receptor (KOR), and mu opioid receptor (MOR) from the brain of the goldfish. Second, we analyzed the tissues that expressed these genes by using reverse transcription polymerase chain reaction. Among the several tissues that contained the opioid gene transcripts, the mRNAs of DOR, KOR, and MOR were detected in interrenal cells of the head kidney, which produce cortisol. On the basis of these results, the effects of β-END on cortisol release were examined in vitro. β-END alone suppressed the basal release of cortisol in a dose-dependent manner. Moreover, β-END inhibited the cortisol-releasing activity of ACTH1-24. Therefore, it is probable that the role of β-END in the interrenal cells is the suppression of cortisol release. Interestingly, the suppression of cortisol release was not observed with N-acetyl-β-END, indicating that acetylation decreases the activity of β-END in interrenal cells.
School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
Yuki
Y
Kobayashi
School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
Kanta
K
Mizusawa
Kitasato University School of Medicine, Sagamihara, Kanagawa 252-0373, Japan.
Yuta
Y
Arai
School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
Hiroaki
H
Chiba
School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan. Electronic address: akiyoshi@kitasato-u.ac.jp.
Akiyoshi
A
Takahashi
D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D006054:Goldfish; D060226:Head Kidney / Q000187:drug effects* / Q000378:metabolism; D006854:Hydrocortisone / Q000378:metabolism*; D017403:In Situ Hybridization; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D010802:Phylogeny; D011957:Receptors, Opioid / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D001615:beta-Endorphin / Q000494:pharmacology*
D011957:Receptors, Opioid; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone
Adrenocorticotropic hormone; Cortisol release; Opioid receptor; Proopiomelanocortin; β-Endorphin