Hypothalamic tuberoinfundibular dopaminergic (TIDA) neurons secrete dopamine, which inhibits pituitary prolactin

Hypothalamic tuberoinfundibular dopaminergic (TIDA) neurons secrete dopamine, which inhibits pituitary prolactin (PRL) secretion. and bromodeoxyuridine (BrdU) immunocytochemistry to detect BrdU incorporation. DF/df males and df/df treated with pGH experienced increased ( 0.01) weight gain compared with those treated with saline. DF/df had greater ( 0.01) TIDA neuron numbers than df/df, regardless of treatment. TIDA neuron number in pGH-treated df/df was greater ( 0.01) than in saline-treated df/df. Zona incerta and periventricular dopamine neurons were not affected by treatment or genotype. There was no effect of genotype or treatment on BrdU incorporation in the arcuate nucleus, median eminence, or periventricular region surrounding the third ventricle. Saline-treated df/df experienced decreased ( 0.05) dentate gyrus BrdU incorporation compared with saline-treated DF/df. In the lateral ventricle, pGH-treated males had greater BrdU immunoreactivity than pGH-treated females. The results show an effect of pGH on TIDA neuron development, although this effect is less potent than that of PRL, and likely GH-induced preservation of TIDA neurons rather than generation of new order PU-H71 TIDA neurons via neurogenesis. The tuberoinfundibular dopaminergic (TIDA) neurons are located in the arcuate nucleus (ARC) of the hypothalamus and extend to the external median eminence (ME). These neurons synapse on the pituitary portal vessels in which they release dopamine (DA), which inhibits prolactin (PRL) secretion (reviewed in1). Ames ((22,23). However, and DF/mice used in experimental procedures. Fertility was induced in dwarf males beginning at 6C8 wk of order PU-H71 age through treatment with order PU-H71 D/L-T4 (2 g ip; Sigma, St. Louis, MO) three times a week, followed by renal capsule pituitary grafts from DF/donors at 9 wk of age. Pituitary graft transplant surgeries were performed on isoflurane-anesthetized mice. Donors, which included DF/males and females aged 2C12 months, were anesthetized with a rompin, acepromazine, ketamaine cocktail and decapitated for pituitary gland removal. Whole single glands were placed under the kidney capsule of recipient animals. Recipients were observed continuously and body temperature was maintained until recovery from anesthesia. The colony was maintained under controlled temperature (22 2 C) and lighting (lights on from 0600 to 1800 h), with food and water available and littermates were initiated at 3 d of age. Animals were injected with saline (0.03 m NaHCO3/0.15 order PU-H71 m NaCl) or 50 g porcine (p) GH daily (National Hormone and Pituitary Program, National Institute of Diabetes and Digestive and Kidney Diseases, Torrance, CA). The biopotency of pGH was 1.8 IU/mg in terms of International Standard for bovine GH. Litters treated with saline served as controls. For the first 5 treatment days, solutions were administered sc due to solution leakage out of the intraperitoneal space at this age. Thereafter treatment solutions were administered into the intraperitoneal space. All mice were treated with BrdU (50 g/g, ip; Sigma) Rabbit Polyclonal to C1QC at 21, 31, 39, and 42 d of age and euthanized by perfusion at 45 d of age. Nine animals were used in each experimental group. Tissue preparation and induction of catecholamine (CA) fluorescence Mice were weighed and anesthetized with rompin, acepromazine, ketamaine cocktail (0.05 ml per 25 g body weight). Anesthesia was followed by transcardial perfusion with 0.9% NaCl and 4% paraformaldehyde-0.5% glutaraldehyde (faglu) fixative (32). Brains were postfixed overnight at 4 C, and ice crystal formation was prevented using a 30% sucrose-faglu solution. Brains were sectioned coronally at 30 m using a sliding microtome (Riechert, now Leica, Heidelberg, Germany) once saturated with sucrose-faglu. Brain sections were divided into six serial sets, each representative of the entire brain, and postfixed overnight. Sections were stored in cryoprotectant antifreeze (33) at ?20 C, except for those used for induction of CA fluorescence. Every sixth section was mounted out of faglu and examined for fixative-induced CA fluorescence using narrow-band excitation wavelengths (395C415 nm) and a violet barrier filter (460 nm) on a Nikon E800 microscope equipped for fluorescence epiillumination (Nikon, Tokyo, Japan). Immunocytochemistry (ICC) for BrdU or TH Tissue sections were pretreated with 0.1% hydrogen peroxide to inhibit endogenous peroxidase activity and 1% aqueous sodium borohydride to reduce glutaraldehyde-fixed linkages and allow antibody access..