Jack Russell

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We have recently determined that high calcium concentrations, in parallel with their suppressive effects on parathyroid hormone (PTH) secretion, reversibly and specifically decrease preproPTH mRNA in cultured bovine parathyroid cells. In order to determine whether vitamin D metabolites also regulate the content of preproPTH mRNA, we tested their effects on(More)
The parathyroid gland responds to decreases in levels of extracellular calcium by increasing the secretion of both PTH and chromogranin-A (CGA) in approximately equal molar ratios. Because CGA has been suggested to be a precursor for biologically active peptides, we used primary cultures of bovine parathyroid cells to examine the effects of various peptides(More)
Regulation of prepro-PTH and vitamin D receptor (VDR) mRNAs in the parathyroid glands was studied in chickens in vivo. The birds were raised to 21 days of age on a vitamin D-deficient diet with 1% calcium and 0.65% phosphorous. At the end of this period, the chicks exhibited marked hypocalcemia and enlarged parathyroid glands. In three separate trials, the(More)
Naltrexone methylbromide and naloxone methylbromide, quaternary derivatives of naltrexone and naloxone respectively, are assumed to act peripherally. Both compounds reversed the intestinal stimulating effect of morphine in the dog. Naltrexone methylbromide 5 mg/kg s.c. blocked morphine-induced intestinal spike potentials for 50 min while intravenous doses(More)
To determine whether 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] regulates PTH secretion, we have tested its effects in both short term incubations (30-120 min) and long term primary cell cultures (24-96 h) of bovine parathyroid cells. In short term incubations, 10(-11)-10(-7) M 1,25-(OH)2D3 had no consistent effect on PTH secretion. In primary cultures of(More)
Corticotropin releasing hormone (CRH) is a 41-residue hypothalamic neuropeptide that has been shown to have potent behavioral effects in animals and has been implicated in clinical disorders in man. This review focuses on those aspects of the behavioral effects of CRH related to food-associated behaviors. The effects of CRH on food intake are compared with(More)
Previous studies have shown that 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] decreases levels of mRNA for prepro-PTH as well as PTH secretion after chronic exposure (24-48 h) of parathyroid cells in tissue culture. We have now extended these studies to determine the effects of the vitamin D3 metabolite on parathyroid secretory protein (PSP) gene expression.(More)
Chromogranin A (CGA), which is cosecreted from the parathyroid gland with PTH in response to low extracellular calcium, can be processed to amino-terminal peptides that, in turn, inhibit PTH secretion. The synthetic peptide KCIVEVISDTLSKPSPMPVSKECFE [CGA-(16-40)] is active in inhibiting secretion from freshly isolated or cultured bovine parathyroid cells.(More)
Isotopic markers were developed to allow measurement of the gastric emptying times of homogeneous and nonhomogeneous gel meals. Meals containing the dietary fibers psyllium and guar gum presented as homogeneous, viscous gels while meals containing the synthetic polymer polycarbophil presented as discrete gel particle-water mixtures. Fiber meals were labeled(More)
Daunorubicin and doxorubicin, two commonly used anticancer agents, are produced by the soil bacterium Streptomyces peucetius. Self-resistance to these antibiotics in S. peucetius is conferred by the drrAB locus that codes for two proteins, DrrA and DrrB. DrrA is an ATP-binding protein. It belongs to the ABC family of transporters and shares sequence and(More)