RESUMO
The serum prolactin levels of eighteen normal rabbits are measured by using method of RIA. The values before drug treatment are taken as the control values of each group. Prolactin levels after 15, 30 and 45 minutes of i.v. Ranitidine treated group, when compared to its own control values, are not significantly raised whereas those levels after i.v. cimetidine are raised significantly in the paired t-test. Prolactin levels of i.v.cimetidine group , when compared with iv ranitidine group by unpaired t-test, are significantly raised [t = 2.737, 4.215 and 2.834 at 10,15, 45 minutes intervals respectively, at 10 degree of freedom, (p < 0.05)]. In the comparison between i.v. cimetidine and i.v. cimetidine pretreated with i.v. diphenhydramine groups (by unpaired t- test), presence of diphenhydramine HCl can cause statistically significant reduction at 30,45 minutes (at 10 degree of freedom. t- 2.666 and 2.440 respectively, (p < 0.05). The result shows that i.v.cimetidine can significantly liberate prolactin from the Ant. Pituitary, unlike i.v. ranitidine. Central H1 and H2 receptors contribute in prolactin secretion.