Effects of cyclosporine at the hypothalamic-pituitary axis in pituitary-grafted young female rats

Abstract

This work was designed to investigate the effects of cyclosporine on prolactin secretion by an ectopically grafted heterologous pituitary gland, and on the hypothalamic content of norepinephrine, dopamine and serotonin. The administration of cyclosporine prevented the augmentation in plasma prolactin levels which occurred following an ectopic graft of a litter-mate pituitary gland. In contrast, in sham-operated rats, cyclosporine increased prolactin levels on day 8 of treatment. Both pituitary grafting and cyclosporine treatment in sham-operated rats decreased hypothalamic norepinephrine content. In grafted rats, cyclosporine returned hypothalamic norepinephrine to normal. Hypothalamic serotonin content decreased 8 days after pituitary grafting but increased to the values of control animals after cyclosporine administration. Cyclosporine treatment for 2 and 8 days increased serotonin content in sham-operated animals. As expected, the hypothalamic dihydroxphenylacetic acid/dopamine index increased after pituitary grafting and administration of cyclosporine for 8 days resulted in a further increase. Cyclosporine administration for 2 days, however, decreased this index to the values observed in control animals while drug treatment of control rats for 8 days decreased the dihydroxyphenylacetic acid/dopamine index. In vitro release of prolactin from the ectopic gland was markedly decreased in animals treated with cyclosporine for 2 days and this effect was less evident in 8-day treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Superior Cervical Ganglionectomy Effects on Median Eminence and Anterior and Mediobasal Hypothalamic Taurine Content in Male Rats: Effects of Hyperprolactinemia

“…However, in pituitary-grafted animals the reduction was less pronounced thus indicating that, besides the surgery, prolactin modifies NE content in the brain areas studied as shown in previous work from the literature [28]. Acute surgery differentially modifies TAU content in the hypophysiotropic area of the hypothalamus and the median eminence, as was previously shown in the areas studied for dopamine and serotonin metabolisms [4] and for several neuropeptide contents, i.e.…”

Effect of Cyclosporine on Immune Responses in Submaxillary Lymph Nodes of Pituitary-Grafted Rats

“…In a previous study we reported the exis tence of an antagonistic interaction between prolactin and cyclosporine in hypothalamic monoamine metabolism [20], similar to that described in lymphocytes [18,19]. In order to further analyze the interrelations between high prolactin levels, cyclosporine and im mune responses, rats made hyperprolactin emic by an ectopic pituitary graft were em ployed.…”

“…Sensitivity was 0.045 ng/ml, using the r-prolactin-RP-3 reference preparation. All samples were mea sured in the same assay to avoid interassay variations [20].…”

Neural Substrates for Behaviorally Conditioned Immunosuppression in the Rat

“…(BBB) during acute administration (Fahr, 1993), direct effects on the hypothalamus and the pituitary have been reported (Stephanou et al, 1992;Esquifino et al, 1995;Wera et al, 1995;Chou and Fong, 1999;Ló pez-Calderó n et al, 1999). Thus, CsA might reach the CNS through those brain areas with a weak BBB, like circumventricular organs, subsequently signaling to forebrain structures (Fig.…”