339 IN VITRO EFFECTS OF TESTOSTERONE AND DIHYDROTESTOSTERONE ON CYCLIC AMP AND CYCLIC GMP LEVELS IN ISOLATED HUMAN CAVERNOUS ARTERIES AND CORPUS CAVERNOSUM

2007 ◽  
Vol 6 (2) ◽  
pp. 107
Author(s):  
E. Waldkirch ◽  
S. Ückert ◽  
C. Bruns ◽  
D. Schultheiss ◽  
M. Sohn ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Corpus Cavernosum ◽  
In Vitro Effects

In Vitro Effects of Ethanol on Rabbit Platelet Aggregation, Secretion of Granule Contents, and Cyclic AMP Levels in the Presence of Prostacyclin

1989 ◽  
Vol 61 (02) ◽  
pp. 254-258 ◽  
Author(s):  
Margaret L Rand ◽  
Peter L Gross ◽  
Donna M Jakowec ◽  
Marian A Packham ◽  
J Fraser Mustard
Keyword(s):  
Cyclic Amp ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Inhibitory Effects ◽  
Low Concentrations ◽  
Rabbit Platelets ◽  
High Concentrations ◽  
In Vitro Effects ◽  
Aggregation Of Platelets

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.

Effect of Cyclic AMP and Cyclic GMP on Thromboplastin (Factor III) Synthesis in Human Monocytes In Vitro

1983 ◽  
Vol 50 (04) ◽  
pp. 804-809 ◽  
Author(s):  
Torstein Lyberg
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Immune Complexes ◽  
Phosphodiesterase Inhibitors ◽  
Inhibitory Effect ◽  
Intracellular Camp ◽  
Human Monocytes ◽  
Purified Protein Derivative ◽  
A 23187

SummaryHuman monocytes in vitro respond to various agents (immune complexes, lectins, endotoxin, the divalent ionophore A 23187, 12-0-tetradecanoyl-phorbol 13-acetate [TPA], purified protein derivative [PPD] of Bacille Calmette-Guerin) with an increased synthesis of the protein component of thromboplastin. The effect of cyclic AMP and cyclic GMP on this response has been studied. Dibutyryl-cyclic AMP, prostaglandin E1 and the phosphodiesterase inhibitors 3-butyl-1-methyl-xanthine (MIX) and rac -4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (Ro 201724), separately and in combination have a pronounced inhibitory effect on the response to immune complexes and PPD, and a moderate effect on the response to endotoxin and lectins. The effect on TPA response and on the response to A 23187 was slight. Dibutyryl-cyclic GMP (1 mM) gave a slight inhibition of the TPA arid IC response, but had essentially no effect on the response to other inducers. The intracellular cAMP level increased when monocytes were incubated with IC, TPA or A 23187 followed by a decrease to basal levels within 1-2 hr, whereas lectin (PHA) and PPD did not induce such changes. The cAMP response to endotoxin varied. Stimulation with IC induced an increase in monocyte cGMP levels, whereas the other stimulants did not cause such changes.

Possible role of cyclic GMP in stimulus-secretion coupling by salt gland of the duck

1979 ◽  
Vol 237 (5) ◽  
pp. C200-C204 ◽  
Author(s):  
D. J. Stewart ◽  
J. Sax ◽  
R. Funk ◽  
A. K. Sen
Keyword(s):  
Cyclic Amp ◽  
Guanylate Cyclase ◽  
Cyclic Gmp ◽  
Salt Gland ◽  
Domestic Ducks ◽  
Stimulus Secretion Coupling ◽  
Stimulation Of

Stimulation of salt galnd secretion in domestic ducks in vivo increased the cyclic GMP concentration of the tissue, but had no effect on cyclic AMP levels. Methacholine, which is known to stimulate sodium transport by the glands both in vivo and in vitro, stimulated ouabain-sensitive respiration in salt gland slices. Cyclic GMP stimulated ouabain-sensitive respiration to the same extent as methacholine. Guanylate cyclase stimulators, hydroxylamine and sodium azide, also stimulated ouabain-sensitive respiration. The stimulation of ouabain-sensitive respiration by methacholine was blocked either by atropine or by removal of calcium from the incubation medium. The stimulation of ouabain-sensitive respiration by cyclic GMP still occurred in the absence of calcium. The above observations seem to indicate that cyclic GMP acts as a tertiary link in the process of stimulus-secretion coupling in the tissue.

Follicle-stimulating hormone-induced prostaglandin E formation in isolated rat ovarian theca

1983 ◽  
Vol 97 (1) ◽  
pp. 43-49 ◽  
Author(s):  
U. Zor ◽  
B. Strulovici ◽  
R. Braw ◽  
H. R. Lindner ◽  
A. Tsafriri
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Follicle Stimulating Hormone ◽  
Fold Increase ◽  
Prostaglandin E ◽  
Β Subunit ◽  
Biochemical Effects ◽  
Isolated Rat ◽  
Stimulating Hormone

The aim of this study was to search for direct biochemical effects of highly purified FSH on isolated ovarian follicular theca in vitro. Granulosa cells (GC; approximately 1 × 105 cells per follicle) were flushed from isolated follicles of pro-oestrous rats. The remaining theca layer and the isolated GC were incubated with highly purified ovine FSH. Prostaglandin E (PGE) accumulation was measured by radioimmunoassay. Follicle-stimulating hormone induced a 15-fold increase in PGE accumulation over the basal level in the follicular theca, the stimulated rate exceeding threefold that observed in the GC fraction derived from the same follicle. Follicle-stimulating hormone caused no significant increase in cyclic AMP level or steroidogenesis in the theca layer, but was active on these parameters in the GC. In contrast, LH increased the accumulation of cyclic AMP, progesterone and testosterone, as well as of PGE, in follicular theca. Exogenous 8-bromo cyclic AMP or cyclic GMP also stimulated PGE production in follicular theca or GC, but FSH was without any effect on the level of endogenous cyclic GMP in GC or follicular theca. Antibodies to FSH prevented the effect of FSH (but not that of LH) on PGE formation by follicular theca and GC, while antibodies to the β-subunit of LH blocked the effect of LH but not of FSH. We conclude that highly purified FSH has a stimulatory effect on PGE formation by the follicular theca.

Influence of dopamine on cyclic nucleotide enzymes in bovine retinal membrane fractions

1993 ◽  
Vol 10 (6) ◽  
pp. 991-996 ◽  
Author(s):  
Ari Sitaramayya ◽  
Lorraine Lombardi ◽  
Alexander Margulis
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Cyclic Nucleotide ◽  
D2 Receptors ◽  
D1 Receptors ◽  
Metabolizing Enzymes ◽  
D2 Agonist ◽  
Hydrolysis Of ◽  
Cyclic Amp Synthesis

AbstractDopamine is a major neurotransmitter and neuromodulator in vertebrate retina. Although its pharmacological and physiological actions are well understood, the biochemical mechanisms of its signal transduction are less clear. Acting via D1 receptors, dopamine was shown to increase cyclic AMP levels in intact retina and to activate adenylate cyclase in retinal homogenates. The action via activation of D2 receptors is controversial: it was reported to decrease cyclic AMP levels in intact retina but inhibition of cyclase could not be demonstrated in retinal homogenates; also it was reported to activate rod outer segment cyclic GMP phosphodiesterase in vitro but did not decrease cyclic GMP levels in aspartate-treated retinas. We made an attempt to fractionate bovine retinal membranes and to investigate the effects of dopamine, via Dl and D2 receptors, on the synthesis and hydrolysis of cyclic AMP and cyclic GMP. Activation of cyclic AMP synthesis was noted in all fractions, but no effects were evident on cyclic nucleotide hydrolysis or cyclic GMP synthesis in any fraction. Also, D2 agonist did not inhibit cyclic AMP synthesis. These observations suggest that D2 receptors may not be directly coupled to cyclic nucleotide metabolizing enzymes in bovine retina.

CYCLIC AMP AND CYCLIC GMP ACCUMULATION IN HAMSTER PRE-OVULATORY FOLLICLES STIMULATED WITH LH AND FSH

1978 ◽  
Vol 87 (1) ◽  
pp. 158-163 ◽  
Author(s):  
Anastasia Makris ◽  
Kenneth J. Ryan
Keyword(s):  
Cyclic Amp ◽  
Dose Response ◽  
Cyclic Gmp ◽  
Time Course ◽  
Hormone Action ◽  
Acute Response ◽  
Cyclic Amp Accumulation ◽  
Ovulatory Follicles ◽  
Higher Doses

ABSTRACT Cyclic AMP and cyclic GMP accumulation in hamster pre-ovulatory follicles was determined after in vitro stimulation by LH and FSH. Combined time course and dose response experiments determined that the acute response of the follicles (0–30 min) to LH and FSH was similar with respect to cyclic AMP accumulation. The pattern of cyclic GMP accumulation was, however, distinctly different in LH and FSH stimulated follicles. LH increased follicular cyclic GMP only at the lowest dose (0.005 IU/ml), while higher doses of LH had no effect. In contrast, FSH at all doses stimulated cyclic GMP accumulation. The different cyclic AMP to cyclic relationships generated in the follicles by LH and FSH may be determinants in specificity of hormone action in pre-ovulatory follicles.

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