We have previously reported that endothelin-1 (ET-1) stimulates heat shock protein (HSP) 27 induction in osteoblast-like MC3T3-E1 cells and that p38 mitogen-activated protein (MAP) kinase acts at a point downstream from protein kinase C (PKC) in HSP27 induction. In the present study, we investigated the effect of the adenylyl cyclase-cAMP system on ET-1-stimulated induction of HSP27 in MC3T3-E1...

GATA-4, a transcription factor implicated in lineage determination, is expressed in both parietal and visceral endoderm of the early mouse embryo. In embryonic stem cell-derived embryoid bodies, GATA-4 mRNA is first detectable at 4-5 days of differentiation and is confined to visceral endoderm cells on the surface of the bodies. Previously we reported that targeted mutagenesis of the Gata4 gene...

Brown adipose tissue thermogenesis at the cost of energy is not only important for the development of obesity, but also possesses great promise in anti-obesity treatment. Uncoupling protein 1 (UCP1) expression has been reported to be under control of the intracellular deacetylase SIRT1. Here, we investigated the effect and mechanism of inflammation and sirtuin-1 (SIRT1) activation on the induct...

[Formula: see text]/NH3fluxes were used to probe apical Na-K-2Cl transport activity of macula densa (MD) cells from rabbit kidney. In the presence of 25 mM NaCl and 5 mM Ba2+, addition of 20 mM[Formula: see text] to the lumen produced a profound intracellular acidification, and ∼80% of the initial acidification rate was bumetanide sensitive. The[Formula: see text]-induced acidification rate was...

The mechanisms by which noradrenaline, lipolytic agents and long-chain fatty acids stimulate glucose transport were investigated in rat brown adipocytes. Glucose transport was evaluated with tracer D-[U-14C]glucose and cell respiration was measured polarographically. Noradrenaline increased basal oxygen consumption (8-10-fold) and glucose transport (4-5-fold) in a dose-dependent manner, with a ...

BACKGROUND Protein tyrosine phosphorylation (TP) of human sperm is related to sperm capacitation and zona pellucida (ZP) binding. The aim of this study was to determine whether the TP of capacitated sperm is a useful marker for the ability of sperm to bind to the ZP and undergo the ZP-induced acrosome reaction (AR). METHODS Semen samples were obtained from 115 subfertile men with sperm count ...

Cultured renal epithelial cells rapidly downregulate expression of the vasopressin-regulated water channel aquaporin-2 (AQP-2). Our aim was to define conditions that favor maintenance of AQP-2 expression in vitro without genetic manipulation. We show here that primary cultures of rat inner medullary collecting duct (IMCD) cells retain AQP-2 expression for at least 6 days when grown with dibutyr...

The water permeability of the renal collecting duct is regulated by the insertion of aquaporin-2 (AQP2) into the apical plasma membrane of epithelial (principal) cells. Using primary cultured epithelial cells from the inner medulla of rat kidney (IMCD cells), we show that osmolality and solute composition are potent regulators of AQP2 mRNA and protein synthesis, as well as the classical cAMP-de...

BACKGROUND The multixenobiotic resistance system (MXR) allows aquatic organisms to cope with their habitat despite high pollution levels by over-expressing membrane and intracellular transporters, including the P-glycoprotein (Pgp). In mammals transcription of the ABCB1 gene encoding Pgp is under cAMP/PKA-mediated regulation; whether this is true in mollusks is not fully clarified. METHODOLOG...

The effects of cadmium, endosulfan, and atrazine on corticosterone secretion and viability of adrenal cells of African clawed frog (Xenopus laevis) and bullfrog (Rana catesbeiana) were assessed in vitro using a new bioassay. The bioassay relies on stimulation with adrenocorticotropic hormone (ACTH), the endogenous secretagogue for corticosterone secretion, and with dibutyryl cyclic adenosine mo...