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Objectives: Survey on effects of serotonin agonist on the
plasma concentrations of growth hormone (GH) and
thyroid hormones (T3 and T4TH)
Design: Repeated measures (GLM) were used.
Animals: Twenty Kurdish lambs 3-4 months old. Procedure: Animals were randomly divided into four
groups. The first group (control) received 2 ml normal
saline. The second, third and fourth groups received 120,
240 and 480 mg/kg body weight L-tryptophan through
jugular vein, respectively. Blood samples were collected in
three periods including before (days 1, 4, 5 and 6), during
(days 7, 8, 9, 10, 11, 12, 13, 14, 15, 18, 22, 26, 30’ and 34)
and after (days 36, 37 and 38) injections. Plasma concentrations of these hormones in unextracted samples
was analyzed by radioimmunoassay kit (Tabeshyarnoor
kits company, Tehran, Iran).
Results: Injection of serotonin agonist increased mean
plasma concentration (MPC) of GH (P<0.01). There are no significant differences in MPC of GH within the treated groups. Effects of blood sampling times, period (before,
during, after injection) and their interaction with treatment
on MPC of GH were significant (P<0.01). MPC of TH (T3
and T4) in all of the treated groups was significantly
increased compare with control one (P<0.01). There are no
significant differences in MPC of TH within the treated
groups. Effects of blood sampling times and period
(before, during and after injection) and also their
interactive effects with treatment were significant.
Conclusion: According to statistical analysis of data we can suggest that serotonin agonist stimulates GH and TH
secretion simultaneously. J. Fac. Vet.Med. Univ. Tehran.
61,2:175-179,2006.