In luteal cells, prostaglandin (PG)F2a mobilizes intracellular calcium concentration ([Ca]i), generates reactive oxygen species (ROS), depletes ascorbic acid (AA) levels, inhibits steroidogenesis, and ultimately induces cell death. We investigated the hypothesis that [Ca]i mobilization stimulates ROS, which results in depletion of cellular AA in rat luteal cells. We used a self-referencing AA-s...

Calcium salts of analogues of dipicolinic acid were substituted for calcium dipicolinate in tests of germination of spores of Bacillus megaferium ATCC 10778. Only 4Hpyran-2,6-dicarboxylic acid was as active as dipicolinic acid. 3-Methyldipicolinic acid and 4-methyl-4H-pyran-2, B-dicarboxylic acid were active but the germination proceeded less rapidly. In the presence of a threshold concentratio...

Both forskolin, the activator of adenylate cyclase, and 8-bromocyclic (cAMP) increase cytosolic calcium levels (measured using Quin 2) and adrenocorticotropin (ACTH) release from a tumor cell line of the mouse anterior pituitary (AtT-20/D16-16). Somatostatin (SRIF) blocks the ACTH release response to each secretagogue but only inhibits forskolin-stimulated calcium mobilization suggesting that S...

Gabapentin induces pancreatic acinar cell tumors in rats through unknown, yet apparently nongenotoxic mechanisms. The primary objective of this study was to determine whether gabapentin acts as a tumor promoter by stimulating acinar cell proliferation in rat pancreas. To this end, indices of pancreatic growth, including increased pancreatic weight, stimulation of acinar cell proliferation, and/...

In the testis the mesenchymally derived peritubular cells produce a paracrine factor, PModS, that mediates mesenchymal-epithelial interactions and modulates Sertoli cell functions essential for the process of spermatogenesis. PModS has a more dramatic effect on Sertoli cell differentiated functions in vitro than any regulatory agent previously shown to influence the cells, including FSH. The cu...

An FP prostaglandin (PG) receptor on the A7r5 rat aorta smooth muscle cell line has been characterized by assays of phosphoinositide (PI) turnover and intracellular calcium mobilization stimulated by structurally diverse PGs. In the PI turnover assay, cloprostenol was the most potent PG tested, with a potency (EC50) of 0.84 +/- 0.06 nM (mean +/- S.E.M., n = 34), and was a full agonist. Other kn...

Otopetrin 1 (OTOP1) is a multitransmembrane domain protein, which is essential for mineralization of otoconia, the calcium carbonate biominerals required for vestibular function, and the normal sensation of gravity. The mechanism driving mineralization of otoconia is poorly understood, but it has been proposed that supporting cells and a mechanism to maintain high concentrations of calcium are ...

Daily oral administration of 1,25-dihydroxycholecalciferol to vitamin D-deficient rats increases the rate of disappearance of [(3)H]1,25-dihydroxycholecalciferol and increases the rate of appearance of metabolites both less polar and more polar than 1,25-dihydroxycholecalciferol in the intestine, bone, liver, kidney, plasma, and muscle. Since 1,25-dihydroxycholecalciferol is believed to be the ...

Free intracellular calcium ([Ca2+]i), in addition to being an important second messenger, is a key regulator of many cellular processes including cell membrane potential, proliferation, and apoptosis. In many cases, the mobilization of [Ca2+]i is controlled by intracellular store activation and calcium influx. We have investigated the effect of several ion channel modulators, which have been us...

Previous studies have indicated that nitric oxide (NO) released from Kupffer cells modulates biological viability of cocultured hepatoma cells. This study was designed to evaluate the mechanisms by which Kupffer cells synthesize and release NO in reponse to cocultured hepatoma cells. Kupffer cells isolated from male Wistar rats were cocultured with rat hepatoma cell line, AH70 cells. The sum of...