Thyrotrophin and prostaglandin E2 increase calmodulin levels and cyclic AMP phosphodiesterase activity in cultured porcine thyroid cells

1988 ◽  
Vol 117 (1) ◽  
pp. 109-114 ◽  
Author(s):  
N. Takasu ◽  
T. Yamada ◽  
Y. Shimizu

ABSTRACT Thyrotrophin (TSH) and prostaglandin E2 (PGE2) increased cellular cyclic AMP (cAMP), calmodulin levels and cAMP phosphodiesterase activity in cultured porcine thyroid cells. Dibutyryl cAMP (dbcAMP), a stable analogue of cAMP, increased calmodulin levels and cAMP phosphodiesterase activity. These results indicate that TSH- and PGE2-stimulated increases in calmodulin are mediated by cAMP. This increased concentration of calmodulin in turn stimulates cAMP phosphodiesterase. Double reciprocal plots of cAMP hydrolysis yielded two apparent Michaelis constants (Km); the lower in the 1 μmol/l and the higher in the 10 μmol/l range. Thyrotrophin, PGE2 and dbcAMP increased the values of maximal velocity without changing the Km values. J. Endocr. (1988) 117, 109–114

1987 ◽  
Vol 7 (10) ◽  
pp. 3629-3636
Author(s):  
J Nikawa ◽  
P Sass ◽  
M Wigler

Saccharomyces cerevisiae contains two genes which encode cyclic AMP (cAMP) phosphodiesterase. We previously isolated and characterized PDE2, which encodes a high-affinity cAMP phosphodiesterase. We have now isolated the PDE1 gene of S. cerevisiae, which encodes a low-affinity cAMP phosphodiesterase. These two genes represent highly divergent branches in the evolution of phosphodiesterases. High-copy-number plasmids containing either PDE1 or PDE2 can reverse the growth arrest defects of yeast cells carrying the RAS2(Val-19) mutation. PDE1 and PDE2 appear to account for the aggregate cAMP phosphodiesterase activity of S. cerevisiae. Disruption of both PDE genes results in a phenotype which resembles that induced by the RAS2(Val-19) mutation. pde1- pde2- ras1- ras2- cells are viable.


2003 ◽  
Vol 17 (11) ◽  
pp. 1380-1391 ◽  
Author(s):  
Marie Georget ◽  
Philippe Mateo ◽  
Grégoire Vandecasteele ◽  
Larissa Lipskaia ◽  
Nicole Defer ◽  
...  

1988 ◽  
Vol 255 (2) ◽  
pp. H335-H342 ◽  
Author(s):  
M. Artman ◽  
P. A. Kithas ◽  
J. S. Wike ◽  
S. J. Strada

Inotropic response to four different types of pharmacological stimuli were compared in isolated right ventricular papillary muscles from newborn (24–48 h of age), immature (14–16 days), and adult (6–7 mo) rabbits. Forskolin, a direct activator of adenylate cyclase, produced a 12.5-fold increase in the maximal rate of tension development in the newborn group. The maximum response to isoproterenol was only 45% of the maximum forskolin response, suggesting incomplete physiological coupling of myocardial beta-adrenergic receptors to adenylate cyclase at birth. In contrast to the substantial inotropic response to agents that stimulate adenosine 3',5'-cyclic monophosphate (cAMP) generation (forskolin and isoproterenol), a selective inhibitor of cAMP hydrolysis (milrinone) was relatively ineffective in the newborn group. Sulmazole, a drug that enhances calcium sensitivity of the contractile proteins, produced its greatest inotropic effect in immature myocardium. Cytosolic high-affinity cAMP phosphodiesterase activity was partially purified from ventricular homogenates by anion-exchange chromatography. The kinetics of cAMP hydrolysis (Km and Vmax) and inhibitory potency of milrinone were comparable in each age group. Thus the age-related differences in inotropic responsiveness may not be attributable to postnatal changes in myocardial cytosolic high-affinity cAMP phosphodiesterase activity.


1983 ◽  
Vol 98 (3) ◽  
pp. 357-363 ◽  
Author(s):  
Nobuyuki Takasu ◽  
Kazunori Takahashi ◽  
Tatsuro Ishigami ◽  
Takashi Yamada ◽  
Seiya Sato

The human thyroid contained prostaglandin (PG) E2, PGF2α and 6-oxo-PGF1α, an end-metabolite of prostacyclin (PGI2), the 6-oxo-PGF1α content being the highest of these prostaglandins. Graves's thyroid contained a significantly higher amount of PGF2α and lower amounts of PGE2 and 6-oxo-PGF1α than the normal thyroid. Thyrotrophin acutely augmented the thyroid contents of PGE2, PGF2α and 6-oxo-PGF1α. The TSH-stimulated increases in PGE2 and 6-oxo-PGF1α were lower but the TSH-stimulated increase in PGF2α was significantly higher in Graves's thyroid than in the normal thyroid. Prostaglandin E2 and PGI2 stimulated human thyroid cyclic AMP synthesis, with the magnitudes of PGE2-and PGI2-stimulated increases in cyclic AMP being equal in normal and Graves's thyroid. Prostaglandin E2α did not stimulate cyclic AMP synthesis significantly. These results provide evidence that prostaglandins play important roles in thyroid physiology and the pathophysiology of Graves's disease.


1971 ◽  
Vol 49 (11) ◽  
pp. 999-1004 ◽  
Author(s):  
Ivo Polacek ◽  
Jean Bolan ◽  
Edwin E. Daniel

Theophylline, diazoxide, and papaverine in low concentrations relaxed the uterus with minimal or no elevation of cyclic AMP (cAMP) levels. In higher concentrations, theophylline relaxed the uterus and increased its cAMP levels, but imidazole reversed the increase in cAMP without causing recontraction. Imidazole and NaF caused uterine contractures but did not detectably decrease cAMP levels until several minutes after the onset of contractures. The uterine relaxations produced by theophylline and/or dibutyryl cAMP in amounts which increased uterine cAMP were not reversed by propranolol. These results eliminate the possibility that propranolol interfered with a relaxant action of cAMP. Along with previous data, these results also show that uterine contractile activity was not determined primarily by the general levels of cAMP and that phosphodiesterase activity in the uterus was insufficient to rapidly affect these cAMP levels. Also, substances like theophylline, diazoxide, and papaverine, postulated to inhibit phosphodiesterase activity, did not bring about their relaxant effects by this mechanism.


Genetics ◽  
1977 ◽  
Vol 85 (4) ◽  
pp. 623-628
Author(s):  
John A Kiger

ABSTRACT A study of Drosophila nullosomic for chromomere 3D4 shows that this region of the genome is necessary for male fertility, normal female fertility and normal oogenesis. Males nullosomic for 3D4 lack normal, motile sperm. Females nullosomic for this region exert a maternal influence on their progeny which results in a diversity of imaginal defects. The observation that chromomere 3D4 is the most probable locus for a chromosomal region which affects cAMP phosphodiesterase activity, and which may contain a structural gene for the enzyme, prompts the hypothesis that the diverse physiological effects caused by nullosomy for 3D4 are the result of an aberrant cAMP metabolism.


1991 ◽  
Vol 128 (2) ◽  
pp. 213-218 ◽  
Author(s):  
J. R. Bourke ◽  
S. Murdoch ◽  
S. W. Manley ◽  
T. Matainaho ◽  
G. J. Huxham ◽  
...  

ABSTRACT Thyrotrophin (4-256 μU/ml) promoted an increase in the rate of release of radioiodine from the organic iodine pool of cultured porcine thyroid cells in follicular formations. This action of TSH was antagonized by low concentrations of epidermal growth factor (EGF; 0·1–5 nmol/l). The maximal effect of EGF was reached by 0·5 nmol/l. EGF (0·5–5 nmol/l) also inhibited the stimulatory effect of 8-chloro cyclic AMP (0·06–1·0 nmol/l) on radioiodine turnover. Exposure of thyroid cultures to media with a calcium concentration of 17·7 μmol/l (1% of normal) resulted in a very marked increase in the rate of release of radioiodine. The effect of TSH in low-calcium media was to inhibit the increased release of radioiodine, and EGF (0·5 nmol/l) antagonized this inhibitory effect of TSH. The calcium ionophore, A23187, stimulated radioiodine release in a dose-dependent fashion, and EGF (1·7 nmol/l) inhibited this response. Fluid transport in thyroid monolayers was stimulated by prostaglandin E2 (PGE2; 1 μmol/l). EGF (5 nmol/l) also stimulated fluid transport, but antagonized the effect of PGE2 added subsequently. It was concluded that EGF exerted acute antagonistic effects on thyroid cell responses in vitro to cyclic AMP and agents promoting accumulation of cyclic AMP in time-frames too short for these inhibitory effects to be attributable to the dedifferentiative effect of the growth factor. Journal of Endocrinology (1991) 128, 213–218


1970 ◽  
Vol 120 (1) ◽  
pp. 187-193 ◽  
Author(s):  
E. G. Loten ◽  
J. G. T. Sneyd

1. 3′:5′-Cyclic nucleotide phosphodiesterase activity was measured in homogenates prepared from epididymal fat-pads and isolated fat-cells incubated in the absence and presence of insulin. 2. Homogenates of insulin-treated tissues showed an increase in phosphodiesterase activity compared with controls. No effect of insulin was observed when the hormone was added directly to homogenates. 3. There was kinetic evidence for the presence of two 3′:5′-cyclic nucleotide phosphodiesterases in adipose tissue. Insulin raised the maximal velocity of the low-Km enzyme and lowered the Km of the higher-Km enzyme. 4. It is suggested that the effect of insulin on adipose tissue phosphodiesterase accounts for the ability of this hormone to lower cyclic-AMP concentration in the tissue.


1988 ◽  
Vol 8 (1) ◽  
pp. 505-510 ◽  
Author(s):  
R B Wilson ◽  
K Tatchell

sra5 mutations in Saccharomyces cerevisiae were previously shown to suppress the inefficient growth of ras2 strains on nonfermentable carbon sources and to result in deficient low-Km cyclic AMP (cAMP) phosphodiesterase activity. We have cloned SRA5 by complementation. It maps to the right arm of chromosome XV, tightly linked to PRT1, and its sequence matches the sequence of PDE2, encoding the low-Km cAMP phosphodiesterase. Disruptions of SRA5 allowed ras1 ras2 strains to grow either on rich media supplemented with cAMP or on minimal media without exogenous cAMP. sra5 strains failed to survive prolonged nitrogen starvation in the presence of exogenous cAMP.


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