The present study examines the involvement of cAMP in the transduction of the short-term effect of gonadotropin-releasing hormone (GnRH) on gonadotropin release in the teleost fish, tilapia. A 5 min pulse of dibutyryl cyclic AMP (dbcAMP; 0.03-3 mM) or forskolin (0.1-10 microM) resulted in dose-dependent surges in tilapia gonadotropin (taGTH) secretion from the perifused pituitary. The initial i...

In the present study, we examined the ability of adenosine 3',5'-cyclic monophosphate (cAMP) to reduce elevated levels of cytosolic Ca2+ concentration ([Ca2+]i) in pancreatic β-cells. [Ca2+]iand reduced pyridine nucleotide, NAD(P)H, were measured in rat single β-cells by fura 2 and autofluorescence microfluorometry. Sustained [Ca2+]ielevation, induced by high KCl (25 mM) at a basal glucose conc...

Cyclooxygenase 2 (COX-2) inhibitors and translocator protein 18 kDa (TSPO) drug ligands have been shown to have stimulatory effects on steroid production. Given that their mechanisms of action differ, we hypothesized that a combination treatment of both TSPO drug ligands and COX-2 inhibitors might have additive or synergistic effects on steroid production in the Leydig cell. We tested the effec...

BACKGROUND The present study was designed to examine the effect of chronic treatment with rosiglitazone - thiazolidinedione used in the treatment of type 2 diabetes mellitus for its insulin sensitizing effects - on the Leydig cell steroidogenic capacity and expression of the steroidogenic acute regulatory protein (StAR) and cholesterol side-chain cleavage enzyme (P450scc) in normal adult rats. ...

Multiple signal transduction pathways mediating gonadotropin-induced testosterone and 17β-estradiol (E(2)) production were identified in carp ovarian theca and granulosa cells in short-term co-incubation. Inhibitors of voltage-sensitive calcium channels (VSCCs) and calmodulin attenuated human chorionic gonadotropin (HCG)-induced steroid production, whereas modulators of adenylate cyclase and pr...

Monocyte chemotactic protein-1 (MCP-1), a specific chemoattractant for monocytes, has been thought to play an important role in the recruitment and accumulation of monocytes within the glomerulus seen in glomerular diseases. This study examined the role of tumor necrosis factor (TNF)-alpha-mediated cellular signal transduction pathways on mesangial cell MCP-1 gene expression and monocyte migrat...

We have tested the ability of various compounds to raise intracellular cyclic AMP (cAMP) levels and, either alone or in combination with retinoic acid (RA), to promote differentiation of two "RA-resistant" sublines of LA-N-5 human neuroblastoma cells, designated LA-N-5HP and LA-N-5R9. Direct activation of adenylate cyclase by forskolin and cholera toxin increased intracellular cAMP levels over ...

Yaekura, Kazuro, and Toshihiko Yada. [Ca]i-reducing action of cAMP in rat pancreatic b-cells: involvement of thapsigargin-sensitive stores. Am. J. Physiol. 274 (Cell Physiol. 43): C513–C521, 1998.—In the present study, we examined the ability of adenosine 38,58-cyclic monophosphate (cAMP) to reduce elevated levels of cytosolic Ca21 concentration ([Ca]i) in pancreatic b-cells. [Ca]i and reduced ...

High levels of the neuron-specific protein kinase C substrate, B-50 (= GAP43), are present in neurites and growth cones during neuronal development and regeneration. This suggests a hitherto nonelucidated role of this protein in neurite outgrowth. Comparable high levels of B-50 arise in the pheochromocytoma PC12 cell line during neurite formation. To get insight in the putative growth-associate...