title: Gastrin releasing peptide, but not pentagastrin, stimulates ACTH and cortisol secretion in conscious dogs.
abstract: Gastrin releasing peptide (GRP) is the mammalian equivalent of bombesin. Bombesin has been shown to stimulate canine ACTH and cortisol secretion in a dose-related manner. In the present study, following a 30-40 min saline infusion, a progressively-increasing, stepwise infusion of GRP (60, 600, 1200 pmol/kg per h) or pentagastrin (PG) (2, 4, 8 micrograms/kg per h) was administered. Each drug dose was infused for 40-45 min and blood samples were drawn at 20-22.5 min intervals. GRP caused significant, dose-dependent increases in plasma ACTH (145 +/- 6%, 242 +/- 49%, 270 +/- 78% of control) and cortisol (158 +/- 16%, 218 +/- 26%, 250 +/- 62% of control). The dose of GRP required for a half-maximal cortisol response was 120 pmol/kg per h, while that for ACTH was 140 pmol/kg per h. PG had no effect on either ACTH or cortisol. While PG is apparently not involved in GRP/bombesin release of ACTH or cortisol, similar mechanisms of action for GRP and bombesin are suggested by their equimolar potencies.
authors.affiliation: Department of Physiology, Meharry Medical College, Nashville, TN 37208.
authors.forename: L D
authors.initials: LD
authors.lastname: Sander
authors.forename: R M
authors.initials: RM
authors.lastname: Thomas
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000818:Animals; D003243:Consciousness; D004285:Dogs; D005260:Female; D019886:Gastrin-Releasing Peptide; D006854:Hydrocortisone / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D007262:Infusions, Intravenous; D008297:Male; D010418:Pentagastrin / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology*; D010913:Pituitary-Adrenal System / Q000502:physiology; D011863:Radioimmunoassay; D013997:Time Factors
chemical_list: D010455:Peptides; D019886:Gastrin-Releasing Peptide; D000324:Adrenocorticotropic Hormone; D010418:Pentagastrin; D006854:Hydrocortisone