title: Effects of beta-endorphin and naloxone on corticosterone and cortisol release in the newt (Triturus carnifex): studies in vivo and in vitro.
abstract: The effects of beta-endorphin and its receptor antagonist, naloxone, on corticosterone and cortisol production in male and female Triturus carnifex were studied in vivo and in vitro. In the in-vivo experiment, the animals were injected s.c. with beta-endorphin and/or naloxone, and killed after 15, 30, 90 and 360 min. In the in-vitro experiment, interrenal tissues, with and without added pituitary, were incubated with beta-endorphin and/or naloxone for 15, 30, 60 and 120 min. The data obtained in vivo and in vitro from males and females were in agreement. Treatment with beta-endorphin caused a significant decrease in corticosterone and cortisol release, while naloxone induced an increase in the two corticosteroids at the same times as the decrease caused by beta-endorphin. The combined beta-endorphin plus naloxone treatment did not change corticosterone and cortisol levels. These results suggest that, in Triturus carnifex, opioids are involved in the regulation of the hypothalamo-pituitary-interrenal axis. In particular, the in-vitro results indicate a direct effect of opioids on interrenal steroidogenesis.
authors.affiliation: Department of Molecular, Cellular and Animal Biology, University of Camerino, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Zerani
authors.forename: A
authors.initials: A
authors.lastname: Gobbetti
mesh_terms: D000818:Animals; D003345:Corticosterone / Q000378:metabolism; D046508:Culture Techniques; D005260:Female; D006854:Hydrocortisone / Q000378:metabolism; D006889:Hydroxycorticosteroids / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000378:metabolism; D007668:Kidney / Q000187:drug effects*; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D010902:Pituitary Gland; D012455:Salamandridae; D001615:beta-Endorphin / Q000494:pharmacology*
chemical_list: D006889:Hydroxycorticosteroids; D009270:Naloxone; D001615:beta-Endorphin; D003345:Corticosterone; D006854:Hydrocortisone