scholarly journals Role of histone kinases as mediators of corticotropin-induced steroidogenesis*

1976 ◽  
Vol 160 (1) ◽  
pp. 1-9 ◽  
Author(s):  
W R Moyle ◽  
G J MacDonald ◽  
J E Garfink
Keyword(s):  
Cyclic Amp ◽  
Kinase Activity ◽  
Protein Kinase Activity ◽  
Dibutyryl Cyclic Amp ◽  
Cyclic Amp Accumulation ◽  
Calf Thymus ◽  
High Doses ◽  
Histone Kinase ◽  
Very High

In an attempt to determine the role of protein (histone) kinases as mediators of corticotropin-induced corticosterone formation, the ability of homogenates, prepared from adrenals treated with various doses of corticotropin to catalyse the phosphorylation of calf thymus histones was measured. Although corticotropin promoted an increase in histone kinase activity, much more of the hormone was required to induce this response than to stimulate steroidogenesis maximally. In addition, a derivative, nitrophenylsulphenyl-corticotropin, which inhibits the stimulatory effect of corticotropin on cyclic AMP accumulation, stimulated corticosterone synthesis without altering histone kinase activity. Very high doses of nitrophenylsulphenyl-corticotropin were capable of stimulating histone kinase activity. In contrast, when dibutyryl cyclic AMP was used to stimulate steroidogenesis under the same conditions, any dose of the nucleotide which increased adrenal corticosteroid content also increased histone kinase activity. Assuming that histones serve as useful substrates for measurement of total adrenal protein kinase activity, the role of protein kinases as mediators of steroidogenesis is not supported by these studies.

scholarly journals Receptor-mediated gonadotropin action in the ovary. Regulatory role of cyclic nucleotide phosphodiesterase(s) in intracellular adenosine 3′:5′-cyclic monophosphate turnover and gonadotropin-stimulated progesterone production by rat ovarian cells

1979 ◽  
Vol 180 (1) ◽  
pp. 201-211 ◽  
Author(s):  
Salman Azhar ◽  
K. M. Jairam Menon
Keyword(s):  
Cyclic Amp ◽  
Kinase Activity ◽  
Phosphodiesterase Inhibitors ◽  
Protein Kinase Activity ◽  
Dibutyryl Cyclic Amp ◽  
Steroid Production ◽  
Progesterone Production ◽  
Ovarian Cells ◽  
Cyclic Amp Accumulation

The regulatory role of cyclic nucleotide phosphodiesterase(s) and cyclic AMP metabolism in relation to progesterone production by gonadotropins has been studied in isolated rat ovarian cells. Low concentrations of choriogonadotropin (0.4–5ng/ml) increased steroid production without any detectable increase in cyclic AMP, when experiments were carried out in the absence of phosphodiesterase inhibitors. The concentration of choriogonadotropin (10ng/ml) that stimulated progesterone synthesis maximally resulted in a minimal increase in cyclic AMP accumulation and choriogonadotropin binding. Choriogonadotropin at a concentration of 10ng/ml and higher, however, significantly stimulated protein kinase activity and reached a maximum between 250 and 1000ng of hormone/ml. Higher concentrations (50–2500ng/ml) of choriogonadotropin caused an increase in endogenous cyclic AMP, and this increase preceded the increase in steroid synthesis. Analysis of dose–response relationships of gonadotropin-stimulated cyclic AMP accumulation, progesterone production and protein kinase activity revealed a correlation between these responses over a wide concentration range when experiments were performed in the presence of 3-isobutyl-1-methylxanthine. The phosphodiesterase inhibitors papaverine, theophylline and 3-isobutyl-1-methylxanthine each stimulated steroid production in a dose-dependent manner. Incubation of ovarian cells with dibutyryl cyclic AMP or 8-bromo cyclic AMP mimicked the steroidogenic action of gonadotropins and this effect was dependent on both incubation time and nucleotide concentration. Maximum stimulation was obtained with 2mm-dibutyryl cyclic AMP and 8-bromo cyclic AMP, and this increase was close to that produced by a maximally stimulating dose of choriogonadotropin. Other 8-substituted derivatives such as 8-hydroxy cyclic AMP and 8-isopropylthio cyclic AMP, which were less susceptible to phosphodiesterase action, also effectively stimulated steroidogenesis. The uptake and metabolism of cyclic [3H]AMP in ovarian cells was also studied in relation to steroidogenesis. When ovarian cells were incubated for 2h in the presence of increasing concentrations of cyclic [3H]AMP, the radioactivity associated with the cells increased almost linearly up to 250μm-cyclic [3H]AMP concentration in the incubation medium. The 3H label in the cellular extract was recovered mainly in the forms ATP, ADP, AMP, adenosine and inosine, with cyclic AMP accounting for less than 1% of the total tissue radioactivity. Incubation of cyclic AMP in vitro with ovarian cells resulted in a rapid breakdown of the nucleotide in the medium. The degradation products in the medium have been identified as AMP, adenosine and inosine. The rapid degradation of cyclic AMP by phosphodiesterase(s) makes it difficult to correlate changes in cyclic AMP concentrations with steroidogenesis. These observations thus provide an explanation for the previously observed lack of cyclic AMP accumulation under conditions in which low doses of choriogonadotropin stimulated steroidogenesis without any detectable changes in cyclic AMP accumulation.

scholarly journals Protein kinase activity in commercially available crystalline yeast alcohol dehydrogenase

1973 ◽  
Vol 131 (2) ◽  
pp. 271-274 ◽  
Author(s):  
B. E. Kemp ◽  
M. Froscio ◽  
A. W. Murray
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Alcohol Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Kinase Activity ◽  
Protein Kinase Activity ◽  
Density Centrifugation ◽  
Yeast Alcohol Dehydrogenase ◽  
Alcohol Dehydrogenase Activity ◽  
Calf Thymus

Commercially available crystalline yeast alcohol dehydrogenase contained protein kinase activity. Casein and phosvitin were readily phosphorylated, but whole calf thymus histone was not. The protein kinase activity was inhibited by KCl, was not stimulated by cyclic AMP and could be separated from the alcohol dehydrogenase activity by sucrose density centrifugation.

scholarly journals Changes in histone phosphorylation and associated early metabolic events in pig lymphocyte cultures transformed by phytohaemagglutinin or 6-N,2′-O-dibutyryladenosine 3′:5′-cyclic monophosphate

1971 ◽  
Vol 124 (1) ◽  
pp. 241-248 ◽  
Author(s):  
M E. Cross ◽  
M G. Ord
Keyword(s):  
Cyclic Amp ◽  
Kinase Activity ◽  
Specific Radioactivity ◽  
Dibutyryl Cyclic Amp ◽  
Kinase Activation ◽  
Cyclic Monophosphate ◽  
Lymphocyte Cultures ◽  
Histone Kinase ◽  
Rna And Dna ◽  
Phosphate Groups

1. Pig lymphocytes were transformed by dibutyryl cyclic AMP (6-N,2′-O-dibutyryladenosine 3′:5′-cyclic monophosphate) at concentrations of 0.01–0.1μm. The pattern of incorporation of label from [5-3H]uridine and [6-3H]thymidine into RNA and DNA respectively was identical with that obtained with unpurified phytohaemagglutinin. 2. Chlorpromazine (0.1μm) prevented the stimulation of [5-3H]uridine incorporation into RNA by phytohaemagglutinin, but only slightly lowered the lymphocyte response to dibutyryl cyclic AMP. 3. An increase in the size and specific radioactivity of the intracellular Pi pool was found immediately after stimulation by both phytohaemagglutinin and dibutyryl cyclic AMP. This was followed after some 30min by a rise in the specific radioactivity and concentration of ATP. 4. There was an immediate increase in the specific radioactivity of phosphate groups of histones; by about 45min after stimulation only the histones remaining after extraction of histone fraction F1 continued to incorporate 32P from [32P]Pi. 5. Histone kinase activity increased in the first 30min after stimulation; subsequently histone F1 kinase activity decreased, but activity with the other histones as substrate continued to increase for a further 30min. Kinase activation was effected by cyclic AMP (adenosine 3′:5′-cyclic monophosphate). 6. Histone phosphatase activity behaved similarly to that of the kinase.

scholarly journals Evidence for Ecto-Protein Kinase Activity That Phosphorylates Kemptide in a Cyclic AMP-dependent Mode

1989 ◽  
Vol 264 (24) ◽  
pp. 14549-14555 ◽  
Author(s):  
D Kübler ◽  
W Pyerin ◽  
O Bill ◽  
A Hotz ◽  
J Sonka ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Kinase Activity ◽  
Protein Kinase Activity

Regulation of protein kinase by vasopressin in renal medulla in situ

1977 ◽  
Vol 232 (1) ◽  
pp. F50-F57
Author(s):  
T. P. Dousa ◽  
L. D. Barnes
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Kinase Activity ◽  
Kinase Inhibitor ◽  
Renal Medulla ◽  
Protein Kinase Activity ◽  
Kinase Activation ◽  
Heat Stable ◽  
Protein Kinase Activation ◽  
Heat Stable Protein

Results of this study demonstrate that vasopressin activates protein kinase in intact renal medullary cells as detected by measurement of the (-cyclic AMP/+cyclic AMP) protein kinase activity ratios in freshly prepared tissue extracts (40,000 X g supernates) from bovine renal medullary slices. The activation of protein kinase was specific for vasopressin since parathyroid hormone, histamine, angiotensin II, or the inactive analog of vasopressin did not activate protein kinase. There was a direct correlation between the extent of protein kinase activation and the elevation in tissue levels of cyclic AMP elicited by increasing doses of vasopressin or with an increase in incubation time. The elevation of tissue cyclic AMP level and maximum activation of protein kinase reached maximum level at a vasopressin concentration of about 2 X 10(-9) M. Incubation of slices with vasopressin caused a dose-dependent decrease in the cyclic AMP-dependent protein kinase activity in the 40,000 X g supernate of homogenate from the renal medullary slices. This effect of vasopressin was specific for protein kinase since activity of lactate dehydrogenase or a specific [3H]colchicine-binding activity was not affected, and the decrease in the protein kinase was not due to the accumulation of a heat-stable protein kinase inhibitor. There was an increase in protein kinase was not due to the accumulation of a heat-stable protein kinase inhibitor. There was an increase in protein kinase activity extracted from 40,000 X g pellets of homogenate prepared from slices exposed to vasopressin. Results thus provide evidence that cyclic AMP-mediated protein kinase activation in the intact cells is an integral part of cellular response of the mammalian renal medulla to vasopressin.

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