Effects of salsolinol and its antagonistic analogue, 1-MeDIQ, on growth hormone release in nursing sheep.
Suckling induces a GH surge simultaneously to that of prolactin, so we tested whether salsolinol, a dopamine derivative (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline), participates in the regulatory process of GH secretion in lactating sheep. A series of intracerebroventricular (i.c.v.) infusions of salsolinol, in two doses, was performed in nursing sheep, without suckling, during the fifth week of lactation. In other suckling sheep, we infused i.c.v. a structural analogue of salsolinol-1-methyl-3,4-dihydroisoqinoline (1-MeDIQ), which is able to antagonize salsolinol's action. Intracerebroventricular treatment of nursing sheep with a lower dose of salsolinol (total 50 ng) significantly increased plasma GH concentration, as compared with the concentrations noted before the infusion and in nursing controls. A higher dose of salsolinol (total 5 micrograms) did not affect GH release significantly. Intracerebroventricular treatment with 1-MeDIQ (total 300 micrograms) significantly reduced basal GH release, not affecting a pattern of GH surge in response to suckling. In conclusion, salsolinol may affect the regulatory process of GH secretion in lactating sheep, but its role seems not to be major.
Górski
Konrad
K
Department of Endocrinology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jablonna n/Warsaw, Poland.
Romanowicz
Katarzyna
K
Molik
Edyta
E
Fulop
Ferenc
F
Misztal
Tomasz
T
D000704:Analysis of Variance; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004333:Drug Administration Routes; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D007546:Isoquinolines / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D007774:Lactation / Q000187:drug effects*; D011247:Pregnancy; D012756:Sheep; D013391:Sucking Behavior / Q000187:drug effects
C486859:1-methyl-3,4-dihydroisoquinoline; D007546:Isoquinolines; D013006:Growth Hormone; C036617:salsolinol