Faculty Collaboration Database

Effect of intraventricular beta-endorphin and morphine on hypothalamic-pituitary-adrenal activity and the release of pituitary beta-endorphin. Neuroendocrinology 1981 Sep;33(3):170-5

Date

09/01/1981

Pubmed ID

6270585

DOI

10.1159/000123224

Scopus ID

2-s2.0-0019418744 (requires institutional sign-in at Scopus site)   62 Citations

Abstract

The effects of intraventricular (i.v.t.) morphine sulfate (MS) and beta-endorphin (beta-EP) on pituitary-adrenal activity and the release of pituitary beta-EP were studied in rats. Pituitary-adrenal activity was monitored by measuring plasma corticosterone (CS) levels. 45 min after i.v.t. injection, both MS and beta-EP caused dose-related increases in plasma CS, with beta-EP being approximately ten times more potent on a molar basis. MS injected i.v.t. at 0.3, 1.0, 3.0 and 10.0 microgram did not cause a significant reduction in pituitary immunoreactive (i.r.) beta-EP, but did cause an increase in plasma i.r. beta-EP at 3 microgram of MS. beta-EP injected i.v.t. at 1.5 microgram caused a reduction of pituitary i.r. beta-EP. Since i.v.t.-injected beta-EP may have contributed to the measured plasma i.r. beta-EP, a nonimmunoreactive analog (Des-Asn20-beta c-EP) was used to assess the change in plasma i.r. beta-EP. 5 microgram of DES-Asn20-beta c-EP injected i.v.t. caused increases in plasma i.r. beta-EP and CS, as well as a 40% reduction in pituitary i.r. beta-EP. The concomitant intraperitoneal (i.p.) injection of naloxone HCl (10 mg/kg) significantly blocked the increase in plasma CS induced by 5 microgram of beta-EP. When naloxone HCl, 10 mg/kg was injected alone, a significant increase in plasma CS was found. The results indicate that i.v.t. beta-EP is more potent than MS in causing the release of pituitary ACTH and beta-EP. These findings are consistent with a role for brain endorphins in the regulation of CRF release.

Author List

Haracz JL, Bloom AS, Wang RI, Tseng LF

Author

Alan Bloom PhD, MA Emeritus Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Corticosterone
Dose-Response Relationship, Drug
Endorphins
Hypothalamo-Hypophyseal System
Injections, Intraventricular
Male
Morphine
Naloxone
Pituitary Gland
Pituitary-Adrenal System
Rats
Rats, Inbred Strains
beta-Endorphin