Effect of (-)-stepholidine on serum prolactin level of female rats
Abstract
AIM: To study the effect of (-)-stepholidine (SPD) on serum prolactin (PRL) level and elucidate its pharmacological action on dopamine D2 receptors.
METHODS: After i.p. administration of dopamine receptor agonist, antagonist, or SPD, the serum PRL levels were determined by radioimmunoassay.
RESULTS: SPD (24 mg.kg-1, i.p.) caused a rapid rise in serum PRL level, lasting more than 1 h. SPD 0.2-40 mg.kg-1 raised serum PRL level in a dose-dependent manner with ED50 of 3.7 mg.kg-1 (95% confidence limits, 2.6-4.3 mg.kg-1) and PRL maximal level of 448 +/- 64 micrograms.L-1. Pergolide 2 mg.kg-1 i.p. caused a decrease (P < 0.01 vs saline) of PRL level, which was partially attenuated by SPD of 5 mg.kg-1 and completely abolished by 10 mg.kg-1.
CONCLUSIONS: SPD is a dopamine D2 receptor antagonist.
Keywords:
METHODS: After i.p. administration of dopamine receptor agonist, antagonist, or SPD, the serum PRL levels were determined by radioimmunoassay.
RESULTS: SPD (24 mg.kg-1, i.p.) caused a rapid rise in serum PRL level, lasting more than 1 h. SPD 0.2-40 mg.kg-1 raised serum PRL level in a dose-dependent manner with ED50 of 3.7 mg.kg-1 (95% confidence limits, 2.6-4.3 mg.kg-1) and PRL maximal level of 448 +/- 64 micrograms.L-1. Pergolide 2 mg.kg-1 i.p. caused a decrease (P < 0.01 vs saline) of PRL level, which was partially attenuated by SPD of 5 mg.kg-1 and completely abolished by 10 mg.kg-1.
CONCLUSIONS: SPD is a dopamine D2 receptor antagonist.