TEMPORAL CHANGES IN OVARIAN ORNITHINE DECARBOXYLASE AND CYCLIC AMP IN IMMATURE RATS STIMULATED BY EXOGENOUS OR ENDOGENOUS GONADOTROPHINS

1977 ◽  
Vol 73 (3) ◽  
pp. 463-471 ◽  
Author(s):  
D. C. JOHNSON ◽  
TATSURO SASHIDA
Keyword(s):  
Enzyme Activity ◽  
Cyclic Amp ◽  
Ornithine Decarboxylase ◽  
Actinomycin D ◽  
Control Level ◽  
Decarboxylase Activity ◽  
Immature Rats ◽  
Lh Rh ◽  
Lh Releasing Hormone ◽  
Pregnant Mare Serum Gonadotrophin

SUMMARY Pregnant mare serum gonadotrophin given intravenously to immature rats caused a maximal (×70) increase in ornithine decarboxylase activity (ODC) at 3 h; enzyme activity declined to about ten times the control level by 9 h and a second rise began after about 20 h. Anti-PMSG given 30 min after PMSG reduced the peak response by 70%. Actinomycin D, or cycloheximide, completely prevented an increase in ODC when given with PMSG, but only cycloheximide lowered the enzyme activity when given 18 h later. Ovine FSH plus LH also produced a peak in ODC at 3 h but the activity decreased quickly and by 9 h it was at the control level. Secretion of endogenous FSH and LH, induced by hourly injections of LH releasing hormone (LH-RH) increased ODC to the same extent as did the exogenous hormones; ODC was still higher than in the controls 4 h after the last dose of LH-RH. Increased endogenous levels of FSH and LH did not consistently raise ovarian cyclic AMP content and the increases found were much less than those obtained after injection of PMSG or FSH + LH. The results indicate that increased ODC is induced and maintained by the continual presence of gonadotrophin. The dependence of increased ODC upon increased cyclic AMP cannot be unequivocally determined because of important differences in the timing of the responses and the difficulty in determining biologically significant changes in cyclic AMP.

Ornithine decarboxylase in rat small intestine: stimulation with food or insulin

1976 ◽  
Vol 231 (5) ◽  
pp. 1557-1561 ◽  
Author(s):  
DV Maudsley ◽  
J Leif ◽  
Y Kobayashi
Keyword(s):  
Enzyme Activity ◽  
Small Intestine ◽  
Ornithine Decarboxylase ◽  
Diamine Oxidase ◽  
Actinomycin D ◽  
Histidine Decarboxylase ◽  
Decarboxylase Activity ◽  
Adenosylmethionine Decarboxylase ◽  
Diamine Oxidase Activity ◽  
Similarities And Differences

Ornithine decarboxylase in the small intestine of starved rats was stimulated 3- to 10-fold by refeeding or administration of insulin. A peak is observed 3-5 h following treatment after which the enzyme activity rapidly declines. The rise in ornithine decarboxylase is reduced by actinomycin D or cycloheximide. The increase in enzyme activity occurs mainly in the duodenum and jejunum with less than a twofold change being observed in the ileum. A small (twofold) increase in S-adenosylmethionine decarboxylase activity in the small intestine was observed after food, but there was no change in diamine oxidase activity. Whereas pentagastrin and metiamide administration markedly stimulated histidine decarbosylase in the gastric mucosa, no consistent effect of these agents on ornithine decarboxylase in the small intestine was observed. The similarities and differences between histidine decarboxylase and ornithine decarboxylase are discussed.

STIMULATION BY β2-ADRENERGIC RECEPTORS OF THE PRODUCTION OF CYCLIC AMP AND PROGESTERONE IN RAT OVARIAN TISSUE

1980 ◽  
Vol 87 (1) ◽  
pp. 123-129 ◽  
Author(s):  
ALBERT RATNER ◽  
G. K. WEISS ◽  
CAROLYN R. SANBORN
Keyword(s):  
Cyclic Amp ◽  
Adrenergic Receptors ◽  
Ovarian Tissue ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Adrenergic Stimulation ◽  
Immature Rats ◽  
Luteal Tissue ◽  
Pregnant Mare Serum Gonadotrophin ◽  
Stimulation Of

Ovarian tissue from immature rats treated with pregnant mare serum gonadotrophin (PMSG) or PMSG and human chorionic gonadotrophin was incubated in Medium 199. Stimulation of the formation of cyclic AMP in follicular and luteal tissue by terbutaline (10−5 mol/l), a selective β2-agonist, was blocked by butoxamine (10−5 mol/l), a selective β2-antagonist, whereas practolol (10−5 mol/l), a selective β1-antagonist, was ineffective. Propranolol (10−5 mol/l), a non-selective β-antagonist, butoxamine nor practolol affected the increase in cyclic AMP promoted by the addition of 1 μg LH. Stimulation of the production of progesterone in both follicular and luteal tissue by terbutaline was blocked by butoxamine, but not by practolol. These findings indicated that β-adrenergic stimulation of ovarian cyclic AMP and progesterone is mediated by β2-adrenergic receptors.

scholarly journals Studies on sex-organ development. Oestrogenic effect on ornithine decarboxylase activity in the differentiating Müllerian ducts and other organs of the chick embryo

1978 ◽  
Vol 176 (1) ◽  
pp. 143-149 ◽  
Author(s):  
C S Teng ◽  
C T Teng
Keyword(s):  
Enzyme Activity ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Mullerian Duct ◽  
Stages Of Development ◽  
Müllerian Duct ◽  
Mullerian Ducts ◽  
The Right ◽  
The Brain

The activity of ornithine decarboxylase in the differentiating left and right Müllerian ducts was assayed and compared with that in other embryonic organs, i.e. the liver and the brain throughout the stages of development. In general the enzyme activity was high in the early stages and decreased extensively in the late stages of development. Specifically, in the left and righ Müllerian ducts, the enzyme activity was high from day 8 to day 9 of incubation. In the right duct the enzyme activity started to decline on day 9 and then continuously decreased to an almost undetectable value on day 18 of incubation. In the left duct the enzyme activity also decreased slightly from day 9 to day 12; however, it increased from day 13 to day 15 and finally decreased to a constant value from day 18 until hatching. The alteration in enzyme activity in the Müllerian duct as assayed in vitro during development is not due to the effect of the size of the endogenous ornithine pool. When the enzyme activity was subjected to oestrogen stimulation, an increase of 5–10-fold for the left duct and of 5–3-fold for the right duct was observed during the course of development. No such stimulation was observed with the treatment of progesterone. Testosterone consistently caused a 25–30% inhibition of the enzyme activity in the Müllerian duct. Oestrogen slightly stimulated the enzyme activity in the developing liver but inhibited that of the brain. The concentration of the three polyamines measured in the Müllerian duct corresponds to the activity of the enzyme determined.

scholarly journals The effects of 24R,25-dihydroxycholecalciferol and of 1 α,25-dihydroxycholecalciferol on ornithine decarboxylase activity and on DNA synthesis in the epiphysis and diaphysis of rat bone and in the duodenum

1983 ◽  
Vol 214 (2) ◽  
pp. 293-298 ◽  
Author(s):  
D Sömjen ◽  
I Binderman ◽  
Y Weisman
Keyword(s):  
Vitamin D ◽  
Enzyme Activity ◽  
Ornithine Decarboxylase ◽  
Thymidine Incorporation ◽  
Single Injection ◽  
Fold Increase ◽  
Decarboxylase Activity ◽  
Long Bones ◽  
Vitamin D Metabolites ◽  
Ornithine Decarboxylase Activity

The effect of cholecalciferol metabolites on ornithine decarboxylase activity and on DNA synthesis in developing long bones was investigated in vitamin D-depleted rats. In the epiphysis there was a 6.4-fold increase in ornithine decarboxylase activity 5 h after a single injection of 24R,25-dihydroxycholecalciferol but not of 24S,25-dihydroxycholecalciferol or other vitamin D metabolites. In comparison, in the diaphysis and duodenum, 1 alpha,25-dihydroxycholecalciferol, but not other vitamin D metabolites, caused a 3-3.5-fold increase in the enzyme activity. The enzyme activity in the tissues examined attained a maximal value at 5 h after the injection of the metabolites. The activity of ornithine decarboxylase in the epiphysial region increased dose-dependently as the result of a single injection of 24R,25-dihydroxycholecalciferol and attained a maximal value at a dose between 30 and 3000 ng. In addition, administration of 24R,25-dihydroxycholecalciferol, but not 24S,25-dihydroxycholecalciferol or other metabolites, caused within 24 h a 1.7-2.0-fold increase in [3H]thymidine incorporation into DNA of the epiphyses of tibial bones. In comparison, 1 alpha,25-dihydroxycholecalciferol caused a 1.5-fold increase in [3H]thymidine incorporation into DNA of the diaphyses and of the duodenum. The present data indicate that 24R,25-dihydroxycholecalciferol is involved in the regulation of epiphyseal growth, whereas 1 alpha,25,dihydroxycholecalciferol stimulates the proliferation of cells in the diaphysis of long bones and in the intestinal mucosa.

scholarly journals Ornithine decarboxylase activity in chick duodenum induced by 1 α, 25-dihydroxycholecalciferol

1981 ◽  
Vol 195 (3) ◽  
pp. 685-690 ◽  
Author(s):  
T Shinki ◽  
N Takahashi ◽  
C Miyaura ◽  
K Samejima ◽  
Y Nishii ◽  
...  
Keyword(s):  
Vitamin D ◽  
Enzyme Activity ◽  
Ornithine Decarboxylase ◽  
Calcium Absorption ◽  
Duodenal Mucosa ◽  
Decarboxylase Activity ◽  
Absorption Mechanism ◽  
Deficient Diet ◽  
Ornithine Decarboxylase Activity ◽  
Hormone Administration

The effect of cholecalciferol and its metabolites on ornithine decarboxylase activity was investigated in the duodenal mucosa of vitamin D-deficient chicks. The duodenal ornithine decarboxylase activity decreased in animals fed a vitamin D-deficient diet and its retarded activity was increased dose-dependently by a single injection of cholecalciferol. Among various metabolites of cholecalciferol tested, 1 alpha, 25-dihydroxycholecalciferol [ 1 alpha, 25 (OH)2D3] was the most potent stimulator. Stimulation of the enzyme activity was detected as early as 2h after intravenous administration of 1 alpha, 25 (OH)2D3 and a maximal value was attained at 6 h. The maximal value was 27 times higher than the control. In addition, treatment with 1 alpha 25 (OH)2D3 affected the duodenal content of polyamines. The content of putrescine increased to a value of three times that of the control 6 h after the hormone administration. The spermidine content did not change appreciably. The enhancement of duodenal ornithine decarboxylase activity by 1 alpha, 25 (OH)2D3 occurred in parallel with the enhancement of calcium absorption, which was first detected 3 h after the hormone administration. The enhancement appeared to be tissue-specific. It was observed in every intestinal segment, but was highest in the duodenum. Enzyme activity in other tissues was not influenced appreciably by 1 alpha, 25 (OH)2D3. These results clearly indicate that the duodenal biosynthesis of polyamines is regulated by 1 alpha, 25 (OH)2D3, suggesting the possibility that duodenal ornithine decarboxylase may be involved in the calcium absorption mechanism.

scholarly journals Diamine-induced inhibition of liver ornithine decarboxylase

1979 ◽  
Vol 177 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Arja Kallio ◽  
Monica Löfman ◽  
Hannu Pösö ◽  
Juhani Jänne
Keyword(s):  
Enzyme Activity ◽  
Ornithine Decarboxylase ◽  
Enzyme Inhibitor ◽  
Decarboxylase Activity ◽  
Enzyme Protein ◽  
Intracellular Degradation ◽  
Ornithine Decarboxylase Activity ◽  
Normal Rat

Re!peated injections of 1,3-diaminopropane, a potent inhibitor of mammalian ornithine decarboxylase, induced protein-synthesis-dependent formation of macromolecular inhibitors or ‘antienzymes’ [Heller, Fong & Canellakis (1976) Proc. Natl. Acad. Sci. U.S.A.73, 1858–1862] to ornithine decarboxylase in normal rat liver. Addition of the macromolecular inhibitors, produced in response to repeated injections of diaminopropane, to active ornithine decarboxylase in vitro resulted in a profound loss of the enzyme activity, which, however, could be partly recovered after passage of the enzyme–inhibitor mixture through a Sephadex G-75 columin in the presence of 0.4m-NaCl. This treatment also resulted in the appearance of free inhibitor. In contrast with the separation of the enzyme and inhibitory activity after combination in vitro, it was not possible to re-activate, by using identical conditions of molecular sieving, any inhibited ornithine decarboxylase from cytosol fractions obtained from animals injected with diaminopropane. However, the idea that injection of various diamines, also in vivo, induces acute formation of macromolecular inhibitors, which reversibly combine with the enzyme, was supported by the finding that the ornithine decarboxylase activity remaining after diaminopropane injection appeared to be more stable to increased ionic strength than the enzyme activity obtained from somatotropin-treated rats. Incubation of the inhibitory cytosol fractions with antiserum to ornithine decarboxylase did not completely abolish the inhibitory action of either the cytosolic inhibitor or the antibody. A single injection of diaminopropane produced an extremely rapid decay of liver ornithine decarboxylase activity (half-life about 12min), which was comparable with, or swifter than, that induced by cycloheximide. However, although after cycloheximide treatment the amount of immunotitrable ornithine decarboxylase decreased only slightly more slowly than the enzyme activity, diaminopropane injection did not decrease the amount of the immunoreactive protein, but, on the contrary, invariably caused a marked increase in the apparent amount of antigen, after some lag period. The diamine-induced increase in the amount of the immunoreactive enzyme protein could be totally prevented by a simultaneous injection of cycloheximide. These results are in accord with the hypothesis that various diamines may result in rapid formation of macromolecular inhibitors to ornithine decarboxylase in vivo, which, after combination with the enzyme, abolish the catalytic activity but at the same time prevent the intracellular degradation of the enzyme protein.

Growth hormone inhibition of lipogenesis in sheep adipose tissue: requirement for gene transcription and polyamines

1994 ◽  
Vol 142 (2) ◽  
pp. 235-243 ◽  
Author(s):  
C A Borland ◽  
M C Barber ◽  
M T Travers ◽  
R G Vernon
Keyword(s):  
Growth Hormone ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Ornithine Decarboxylase ◽  
Gene Transcription ◽  
Actinomycin D ◽  
Total Activity ◽  
Decarboxylase Activity ◽  
Polyamine Biosynthesis

Abstract The chronic inhibitory effect of growth hormone (GH) on lipogenesis in sheep adipose tissue explants was investigated in an in vitro tissue culture system. In the absence of other hormones, GH caused a decrease in the rate of lipogenesis after 6 h of culture. In contrast, when lipogenesis was stimulated by the presence of insulin plus dexamethasone, GH again decreased lipogenesis but after a lag of at least 12 h. Actinomycin D, an inhibitor of gene transcription, prevented the effect of GH on lipogenesis in both the absence and presence of insulin plus dexamethasone. Actinomycin D added to tissue previously incubated for 6 h in the presence of GH alone prevented further decline in lipogenesis over the next 5 h, suggesting that transcription of a short-lived mediator protein is required for the GH effect to occur. An increase in ornithine decarboxylase activity was detected in explants exposed to GH, reaching a peak after 12 h incubation; this was prevented by actinomycin D. Methylglyoxal bis-(guanylhydrazone), an inhibitor of polyamine biosynthesis, partially alleviated the effect of GH on lipogenesis; this was reversed by addition of spermidine. However, spermidine did not reverse the effects of actinomycin D, implicating a short-lived protein in addition to ornithine decarboxylase in the action of GH. In the absence of other hormones GH had no effect on either the expressed (initial) or total activity of acetyl-CoA carboxylase, but GH prevented the increase in both expressed and total activities of the enzyme induced by insulin plus dexamethasone. Varying lipolysis and fatty acid accumulation in adipose tissue by addition of adenosine deaminase plus indomethacin or bovine serum albumin to the culture medium had no effect on lipogenesis and these agents partly alleviated GH inhibition of lipogenesis. No effect of GH was found on the amount of glycerol released by cultured tissue. GH also had no effect on fatty acid esterification. Thus the chronic inhibitory effects of GH on lipogenesis involve a protein with a very short half-life. The effect also requires polyamines but does not appear to involve changes in fatty acid concentrations in the cell. In addition GH appears to inhibit lipogenesis and to antagonise insulin-stimulation of lipogenesis by different mechanisms. Journal of Endocrinology (1994) 142, 235–243

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