Effect of streptozotocin-induced diabetes on phosphodiesterase activity in rat luteal cells
The present studies were carried out to characterize the cAMP- phosphodiesterase enzyme (PDE) in luteal cells recovered from pseudopregnant rats with streptozotocin-induced diabetes. A significant increase in the specific activity of the enzyme was detected in luteal cells from diabetic rats (Group...
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todo:paper_1040452X_v45_n1_p43_Stein2023-10-03T15:57:47Z Effect of streptozotocin-induced diabetes on phosphodiesterase activity in rat luteal cells Stein, P. Téllez-Iñón, M.T. Tesone, M. cAMP Corpus luteum Diabetes Insulin Ovary Phosphodiesterase phosphodiesterase animal cell article corpus luteum enzyme activity female female infertility insulin dependent diabetes mellitus luteal cell nonhuman priority journal progesterone synthesis rat 3',5'-Cyclic-Nucleotide Phosphodiesterase Animals Calmodulin Cell Fractionation Chromatography, Ion Exchange Diabetes Mellitus, Experimental Female Kinetics Ovary Pseudopregnancy Rats Rats, Sprague-Dawley Superovulation Animalia The present studies were carried out to characterize the cAMP- phosphodiesterase enzyme (PDE) in luteal cells recovered from pseudopregnant rats with streptozotocin-induced diabetes. A significant increase in the specific activity of the enzyme was detected in luteal cells from diabetic rats (Group D) with respect to control rats (Group C). This increase could not be prevented by insulin therapy (Group I). Luteal cells from Groups C and D rats responded in vitro to insulin by increasing their PDE activity (% of stimulus of specific activity: C = 75%, D = 110%). However, in cells isolated from Group I, the hormone caused an inhibition of PDE activity (% of inhibition of specific activity: 48%). When cytosolic fractions from Groups C, D, and I were submitted to ion exchange chromatography, two PDE activity peaks could be observed and the activity of the different fractions was increased in the presence of Ca2+ and calmodulin. Nevertheless, the Ca2+ -calmodulin effect was much lower in the extracts from Groups D and I than for controls. Kinetic studies of luteal PDE showed nonlinear Lineweaver-Burk graphs with two apparent ATP hydrolysis sites. Similar K(m) values were found for PDE from groups C, D, and I, whereas the V(max2) for the enzyme was higher in Groups D and I. The endogenous concentration of cAMP, measured by RIA, showed no significant differences among Groups C, D, and I. On the basis of these results, we conclude that the specific activity of PDE is significantly increased in luteal cells from streptozotocin-induced diabetic animals, which could explain the previously described reduction in LH- stimulated progesterone production by luteal cells in diabetic rats. Fil:Stein, P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Tesone, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_1040452X_v45_n1_p43_Stein |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
cAMP Corpus luteum Diabetes Insulin Ovary Phosphodiesterase phosphodiesterase animal cell article corpus luteum enzyme activity female female infertility insulin dependent diabetes mellitus luteal cell nonhuman priority journal progesterone synthesis rat 3',5'-Cyclic-Nucleotide Phosphodiesterase Animals Calmodulin Cell Fractionation Chromatography, Ion Exchange Diabetes Mellitus, Experimental Female Kinetics Ovary Pseudopregnancy Rats Rats, Sprague-Dawley Superovulation Animalia |
| spellingShingle |
cAMP Corpus luteum Diabetes Insulin Ovary Phosphodiesterase phosphodiesterase animal cell article corpus luteum enzyme activity female female infertility insulin dependent diabetes mellitus luteal cell nonhuman priority journal progesterone synthesis rat 3',5'-Cyclic-Nucleotide Phosphodiesterase Animals Calmodulin Cell Fractionation Chromatography, Ion Exchange Diabetes Mellitus, Experimental Female Kinetics Ovary Pseudopregnancy Rats Rats, Sprague-Dawley Superovulation Animalia Stein, P. Téllez-Iñón, M.T. Tesone, M. Effect of streptozotocin-induced diabetes on phosphodiesterase activity in rat luteal cells |
| topic_facet |
cAMP Corpus luteum Diabetes Insulin Ovary Phosphodiesterase phosphodiesterase animal cell article corpus luteum enzyme activity female female infertility insulin dependent diabetes mellitus luteal cell nonhuman priority journal progesterone synthesis rat 3',5'-Cyclic-Nucleotide Phosphodiesterase Animals Calmodulin Cell Fractionation Chromatography, Ion Exchange Diabetes Mellitus, Experimental Female Kinetics Ovary Pseudopregnancy Rats Rats, Sprague-Dawley Superovulation Animalia |
| description |
The present studies were carried out to characterize the cAMP- phosphodiesterase enzyme (PDE) in luteal cells recovered from pseudopregnant rats with streptozotocin-induced diabetes. A significant increase in the specific activity of the enzyme was detected in luteal cells from diabetic rats (Group D) with respect to control rats (Group C). This increase could not be prevented by insulin therapy (Group I). Luteal cells from Groups C and D rats responded in vitro to insulin by increasing their PDE activity (% of stimulus of specific activity: C = 75%, D = 110%). However, in cells isolated from Group I, the hormone caused an inhibition of PDE activity (% of inhibition of specific activity: 48%). When cytosolic fractions from Groups C, D, and I were submitted to ion exchange chromatography, two PDE activity peaks could be observed and the activity of the different fractions was increased in the presence of Ca2+ and calmodulin. Nevertheless, the Ca2+ -calmodulin effect was much lower in the extracts from Groups D and I than for controls. Kinetic studies of luteal PDE showed nonlinear Lineweaver-Burk graphs with two apparent ATP hydrolysis sites. Similar K(m) values were found for PDE from groups C, D, and I, whereas the V(max2) for the enzyme was higher in Groups D and I. The endogenous concentration of cAMP, measured by RIA, showed no significant differences among Groups C, D, and I. On the basis of these results, we conclude that the specific activity of PDE is significantly increased in luteal cells from streptozotocin-induced diabetic animals, which could explain the previously described reduction in LH- stimulated progesterone production by luteal cells in diabetic rats. |
| format |
JOUR |
| author |
Stein, P. Téllez-Iñón, M.T. Tesone, M. |
| author_facet |
Stein, P. Téllez-Iñón, M.T. Tesone, M. |
| author_sort |
Stein, P. |
| title |
Effect of streptozotocin-induced diabetes on phosphodiesterase activity in rat luteal cells |
| title_short |
Effect of streptozotocin-induced diabetes on phosphodiesterase activity in rat luteal cells |
| title_full |
Effect of streptozotocin-induced diabetes on phosphodiesterase activity in rat luteal cells |
| title_fullStr |
Effect of streptozotocin-induced diabetes on phosphodiesterase activity in rat luteal cells |
| title_full_unstemmed |
Effect of streptozotocin-induced diabetes on phosphodiesterase activity in rat luteal cells |
| title_sort |
effect of streptozotocin-induced diabetes on phosphodiesterase activity in rat luteal cells |
| url |
http://hdl.handle.net/20.500.12110/paper_1040452X_v45_n1_p43_Stein |
| work_keys_str_mv |
AT steinp effectofstreptozotocininduceddiabetesonphosphodiesteraseactivityinratlutealcells AT tellezinonmt effectofstreptozotocininduceddiabetesonphosphodiesteraseactivityinratlutealcells AT tesonem effectofstreptozotocininduceddiabetesonphosphodiesteraseactivityinratlutealcells |
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1807321808654827520 |