Type 1 and 2 isoenzymes of cAMP-dependent protein kinase in Leydig cell steroidogenesis. 1991

R W Hipkin, and W H Moger
Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada.

This study examined the functional significance of the type 1 (T1) and type 2 (T2) cAMP-dependent protein kinase (PK-A) isoenzymes in androgen production by mouse Leydig cells. Leydig cells were exposed to cAMP analogues selective for either of the two cAMP binding sites on the regulatory subunits of each PK-A isoenzyme. As the two binding sites have been shown to exhibit positive cooperativity, coexposure to the appropriate combination of analogues will synergistically increase androgen production if either T1 or T2 PK-A is present and functional in the cell. We found that both PK-A isoenzymes are present and functionally active, though the T1 kinase predominates. Coexposure to the cAMP analogues and cAMP or luteinizing hormone also synergistically increased androgen production via both isoenzymes while forskolin acted only via the T1 isoenzyme, suggesting that forskolin may instigate cellular events in addition to cAMP synthesis.

UI MeSH Term Description Entries
D007527 Isoenzymes Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics. Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
D007985 Leydig Cells Steroid-producing cells in the interstitial tissue of the TESTIS. They are under the regulation of PITUITARY HORMONES; LUTEINIZING HORMONE; or interstitial cell-stimulating hormone. TESTOSTERONE is the major androgen (ANDROGENS) produced. Interstitial Cells, Testicular,Leydig Cell,Testicular Interstitial Cell,Testicular Interstitial Cells,Cell, Leydig,Cell, Testicular Interstitial,Cells, Leydig,Cells, Testicular Interstitial,Interstitial Cell, Testicular
D007986 Luteinizing Hormone A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Luteinizing hormone regulates steroid production by the interstitial cells of the TESTIS and the OVARY. The preovulatory LUTEINIZING HORMONE surge in females induces OVULATION, and subsequent LUTEINIZATION of the follicle. LUTEINIZING HORMONE consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH and FSH), but the beta subunit is unique and confers its biological specificity. ICSH (Interstitial Cell Stimulating Hormone),Interstitial Cell-Stimulating Hormone,LH (Luteinizing Hormone),Lutropin,Luteoziman,Luteozyman,Hormone, Interstitial Cell-Stimulating,Hormone, Luteinizing,Interstitial Cell Stimulating Hormone
D008297 Male Males
D010726 Phosphodiesterase Inhibitors Compounds which inhibit or antagonize the biosynthesis or actions of phosphodiesterases. Phosphodiesterase Antagonists,Phosphodiesterase Inhibitor,Phosphoric Diester Hydrolase Inhibitors,Antiphosphodiesterases,Inhibitor, Phosphodiesterase
D011494 Protein Kinases A family of enzymes that catalyze the conversion of ATP and a protein to ADP and a phosphoprotein. Protein Kinase,Kinase, Protein,Kinases, Protein
D000242 Cyclic AMP An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH. Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
D000728 Androgens Compounds that interact with ANDROGEN RECEPTORS in target tissues to bring about the effects similar to those of TESTOSTERONE. Depending on the target tissues, androgenic effects can be on SEX DIFFERENTIATION; male reproductive organs, SPERMATOGENESIS; secondary male SEX CHARACTERISTICS; LIBIDO; development of muscle mass, strength, and power. Androgen,Androgen Receptor Agonist,Androgen Effect,Androgen Effects,Androgen Receptor Agonists,Androgenic Agents,Androgenic Compounds,Agents, Androgenic,Agonist, Androgen Receptor,Agonists, Androgen Receptor,Compounds, Androgenic,Effect, Androgen,Effects, Androgen,Receptor Agonist, Androgen,Receptor Agonists, Androgen
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D051379 Mice The common name for the genus Mus. Mice, House,Mus,Mus musculus,Mice, Laboratory,Mouse,Mouse, House,Mouse, Laboratory,Mouse, Swiss,Mus domesticus,Mus musculus domesticus,Swiss Mice,House Mice,House Mouse,Laboratory Mice,Laboratory Mouse,Mice, Swiss,Swiss Mouse,domesticus, Mus musculus

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