Danielle Gourdji

Learn More
The effects of thyrotropin-releasing hormone and 17 beta-estradiol on the electrical membrane properties of a prolactin-secretin pituitary cell line (GH3/B6) were studied with intracellular microelectrode recordings. Of the cells tested, 50 percent were excitable and displayed calcium-dependent action potentials when depolarized. When injected directly on(More)
The in vivo internalization of thyrotropin-releasing hormone (TRH) was studied by using a semiquantitative immunoelectron microscopic method. Pituitary glands of normal male rats intravenously injected with 100 ng TRH and sacrificed after 5-60 min were used. Ultrathin sections were obtained by cryoultramicrotomy of fixed pituitary glands. Pituitary cellular(More)
In the present report, we have investigated the role of DNA methylation on the binding and trans-acting properties of transcription factors involved in the regulation of the rat prolactin (rPRL) gene, specifically Pit-1. To this aim we took advantage of a model system composed of three GH3 rat pituitary tumor cell lines that greatly differed in the extent(More)
1. Regulation of pulsatile secretion of growth hormone (GH) relies on hypothalamic neuronal loops, major transmitters involved in their operation are growth hormone releasing hormone (GHRH) synthetized mostly in arcuate nucleus (ARC) neurons, and somatostatin (SRIH), synthetized both in hypothalamus periventricular (PVe) and ARC neurons. 2. Neurons(More)
Secretory activity of the anterior pituitary gland is regulated by the brain through stimulatory and inhibitory substances released from nerve endings in the median eminence of the hypothalamus and carried by the adenohypophysial portal blood system to their respective target cells. These hypothalamic influences are modulated by the feedback action of(More)
In the present study, we tested whether 17beta-estradiol (E2)-induced PRL sensitivity to somatostatin-14 (SRIF) involves selective up-regulation of discrete somatostatin receptor subtypes (ssts) in primary cultures of female rat pituitary cells. The efficacy of the endogenous peptide SRIF to inhibit GH and PRL secretion and cAMP accumulation was compared(More)
A cDNA membrane array displaying 1183 probes was used to detect hypothalamic and pituitary changes in gene expression accompanying ageing and age-associated pituitary macroadenomas. Four groups of male Sprague-Dawley rats (3-, 15-, 24-month-old and 24-month-old with prolactinoma) were compared in two independent hybridizations. cDNA array data were(More)
The lysosomotropic agent, chloroquine, has been used to investigate the implication of lysosomal activity and membrane traffic in TRH binding, TRH internalization and TRH-induced stimulation of prolactin secretion in a rat prolactin cell line (GH3/B6). Chloroquine by itself does not affect cell number, cell protein and basal prolactin secretion. It does not(More)
GH3/B6 rat prolactin cells were used to analyse at the cellular level the mechanisms by which 17 beta-estradiol (E2) regulates TRH responsiveness of prolactin cells. Before experiments, cells were grown for up to 7 days in 3 different media: normal medium (N) containing 15% horse serum and 2.5% fetal calf serum, CD medium prepared with charcoal-dextran(More)