The expression of 14 kDa group II phospholipase A2 [also referred to as secretory PLA2 (sPLA2)] is induced in rat glomerular mesangial cells by exposure to inflammatory cytokines and forskolin, a cAMP elevating agent. Previously we have shown that dexamethasone and transforming growth factor-beta 2 (TGF-beta 2) suppress sPLA2 protein synthesis and enzyme activity induced by cytokines and forsko...

Forskolin acts primarily by activating the enzyme adenylate cyclase, which results in increased cyclic adenosine monophosphate (cAMP) in cells. Cyclic AMP belongs to a class of substances known as "second messengers" and is one of the most important cell-regulating compounds. Among its many roles, cAMP activates numerous other enzymes involved in diverse cellular functions. Hormones and neurotr...

Increases in cAMP have been shown previously to enhance the strength of the granule cell to Purkinje cell synapse. We have examined the mechanisms underlying this enhancement in rat cerebellar brain slices. Elevation of cAMP levels by forskolin increased synaptic currents in a dose-dependent manner. Fluorometric calcium measurements revealed that forskolin did not affect presynaptic calcium inf...

The interaction of several inorganic ions (Mn2+, Ca2+, VO3-, and F-) with adenylate cyclase in the albino rabbit ciliary process particulate fraction was studied. Effects of these substances were determined on three activity states of the enzyme (basal, Gs-protein stimulated activity via isoproterenol activation of beta-adrenergic receptors, forskolin-activated catalytic unit) in the presence o...

The purpose of these experiments was to determine whether the activity of the voltage-dependent Ca2+ channel was modulated in the same manner in islets of the ob/ob mouse as in islets of homozygous lean mice of the same strain. The effect of agents that are known to alter the concentrations and movements of intracellular Ca2+ were investigated in relation to glucose-stimulated insulin secretion...

Forskolin, a plant diterpene, directly stimulates adenylate cyclase and also potentiates receptor-mediated stimulation of this enzyme by many stimulatory--but not inhibitory--agonists. We exploited the potentiating effect of forskolin to test the hypothesis that adenosine initiates coronary relaxation through activation of adenylate cyclase. In six open-chest dogs, intracoronary forskolin infus...

Exposure of bovine chromaffin cells in primary culture to 5 microM reserpine or 25 microM forskolin results in an increase in enkephalin peptide levels within 24-48 hr; 25 microM forskolin (or cholera toxin at 50 micrograms/ml) causes a 1.5- to 2-fold increase in enkephalin peptide levels, which is maximal after 48 hr of exposure and is totally blocked by addition of cycloheximide (0.5 microgra...

Emerging data suggest that nutritional status and body weight are related to reproductive function, and nutrient imbalances during pregnancy lead to changes in the expression of fetal genes. Recent studies show that the mTOR acts as a placental growth signalling sensor and its expression is down-regulated in intrauterine growth restriction. To date, very little is known about the expression of ...

Granulosa cell mitogenesis is critical for the development of normal ovarian follicles. FSH and other mitogenic stimuli play a crucial role in this process. We have shown that exposing granulosa cells to 5alpha-dihydrotestosterone (DHT) reduces forskolin-stimulated cyclin D2 mRNA expression, which leads to cell cycle arrest resulting in reduced cell proliferation. The present study investigated...

The human carcinoma-derived cell line Calu-6 has previously been demonstrated to endogenously express human renin (hREN) mRNA and to markedly increase steady-state hREN mRNA levels (100-fold after 24 hours) in response to analogues of cAMP and postreceptor activators of adenylyl cyclase such as forskolin. However, both transfection analysis using hREN promoter-reporter constructs and nuclear ru...