Stimulation of adrenocorticotropin/beta-endorphin release by synthetic ovine corticotropin-releasing factor in vitro. Enhancement by various vasopressin analogs.
Vasopressin analogs, which markedly differed in the ratio of pressor versus antidiuretic activity and also in ACTH/beta-endorphin-releasing activity, were used in the present study. The ability of vasopressin and these analogs to enhance the release of adrenocorticotropin-(ACTH-IR) and beta-endorphin-like immunoreactivity (beta-EI) induced by synthetic ovine corticotropin-releasing factor -CRF-(1-41)- was studied in vitro using incubated rat anterior pituitary quarters. Arginine vasopressin (AVP) potentiated the action of CRF-(1-41) 2- to 4-fold. Vasopressin analogs, which possess direct CRF-like activity when given alone, also enhanced beta-EI release caused by CRF-(1-41); the lowest concentration able to potentiate CRF-(1-41) activity was closely correlated with the ED50 value of these analogs for direct CRF-like activity. The vasopressin analog 1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid)-2-(O-methyl)tyrosine-8-arginine-vasopressin blocked the release of ACTH-IR induced by AVP; however, this analog failed to prevent the potentiation by AVP of ACTH-IR release caused by CRF-(1-41), but enhanced itself the action of CRF-(1-41). Two analogs, which exhibited no direct CRF-like activity and which also did not antagonize the CRF-like activity of AVP, markedly enhanced the ACTH-IR and beta-EI response to CRF-(1-41).(ABSTRACT TRUNCATED AT 250 WORDS)
D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D003346:Corticotropin-Releasing Hormone; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004723:Endorphins / Q000378:metabolism*; D008297:Male; D010455:Peptides / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical; D013329:Structure-Activity Relationship; D014667:Vasopressins / Q000494:pharmacology*; D001615:beta-Endorphin
D004723:Endorphins; D010455:Peptides; D014667:Vasopressins; D001127:Arginine Vasopressin; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D000242:Cyclic AMP