Influence of catecholamines, prostaglandins and thyroid hormones on growth hormone secretion by chicken pituitary cells in vitro.
In young chickens plasma concentrations of growth hormone (GH) are depressed by prostaglandins (PG) E1 and E2, epinephrine, norepinephrine, alpha 2 and beta agonists or thyroid hormones. A primary culture of chicken adenohypophyseal cells was used to examine the direct effects of these agents at the level of the pituitary as evaluated by GH release in the presence and absence of growth hormone releasing factor (GRF). Following collagenase dispersion and culture (preincubation, 48 hr) cells were exposed (incubation, 2 hr) to test agents, except for thyroid hormones which were added during the preincubation, and incubation period. Growth hormone release was increased (P less than .05) in the presence of PGE1 (10(-8)M by 34%; 10(-7)M by 54%), PGE2 (10(-8)M by 29%; 10(-7)M by 29%), PGF2 alpha (10(-8)M by 28%), and the beta agonist isoproterenol (10(-7)M by 46%). Basal GH release from chicken pituitary cells was not affected by dopamine, norepinephrine, epinephrine, thyroxine (T4), triiodothyronine (T3), or alpha adrenergic agonists. Growth hormone releasing factor stimulated GH release was not affected by the presence of prostaglandins E1, E2 or F2 alpha in the incubation media. However, GRF stimulated GH release was reduced by high doses of catecholamines: dopamine (10(-6)M by 34%), norepinephrine (10(-6)M by 74%), epinephrine (10(-8)M by 47%; 10(-7)M by 41%; 10(-6)M by 89%), and by the alpha 1 adrenergic agonist, phenylephrine (10(-7)M by 52%), the alpha 2 agonist, clonidine (10(-8)M by 34%; 10(-7)M by 83%) and the beta agonist, isoproterenol (10(-7)M by 64%).(ABSTRACT TRUNCATED AT 250 WORDS)
Donoghue
D J
DJ
Department of Animal Sciences, Rutgers, State University, New Brunswick, NJ 08903.
Perez
F M
FM
Diamante
B S
BS
Malamed
S
S
Scanes
C G
CG
D000818:Animals; D002395:Catecholamines / Q000494:pharmacology*; D002478:Cells, Cultured; D002645:Chickens; D004298:Dopamine / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D013006:Growth Hormone / Q000378:metabolism*; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011453:Prostaglandins / Q000494:pharmacology*; D013963:Thyroid Hormones / Q000494:pharmacology*; D013974:Thyroxine / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology
D002395:Catecholamines; D011453:Prostaglandins; D013963:Thyroid Hormones; D014284:Triiodothyronine; D013006:Growth Hormone; D013974:Thyroxine; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine