[Effect of oxidized indoles on monoamine oxidase activity in the rat brain mitochondria].

There is increasing evidence, that oxidized indoles, isatin, 5-hydroxyoxindole, 2-oxindole, play important regulatory functions in the brain. Isatin and 5-hydroxyoxindole share some common regulatory properties in cell cultures (Cane et al., 2000, BBRC, 276, 379), however, their effects on brain mitochondrial monoamine oxidases, a potential target for their action, have not been compared yet.

Stimulatory effect of gonadotropin-releasing hormone (GnRH) on in vitro prolactin secretion and presence of GnRH specific receptors in a subset of human prolactinomas.

The purpose of this study was to determine whether gonadotropin-releasing hormone (GnRH) may exert a direct action on human prolactinomas. On a series of 17 adenomas, we studied the effect of GnRH on the in vitro prolactin (PRL) secretion of dispersed and perifused cells of 10 cases and the [125I]GnRH agonist binding on frozen sections of three out of the adenomas studied in perifusion and on the membrane preparations of seven other cases. Two 20-min pulses of GnRH (10(-7) mol/l) stimulated the in vitro PRL secretion of three adenomas out of 10 (increase of 200, 444 and 205%, respectively, above basal levels).

Characterization and distribution of receptors for gonadotropin-releasing hormone in the rat hippocampus.

Distribution and properties of receptors for gonadotropin-releasing hormone (GnRH) were analyzed in the brain of adult male rats. Binding of the iodinated GnRH agonist Des-Gly10-(D-Ala6)-GnRH ethylamide was studied in hippocampus and anterior pituitary using three convergent approaches: quantitative autoradiography on frozen tissue, binding to fresh slices, and binding to crude membrane preparations. In all cases, binding was specific, saturable, and time, pH, and temperature dependent.