Properties of particulate and detergent-solubilized adenylate cyclase of rat testis. Effects of follitropin stimulation. 1978

H Abou-Issa, and L E Reichert

Basal, fluoride and follitropin stimulated activities of adenylate cyclase have been studied in the testes of immature rats. The enzyme was maximally activated (about twice the basal activity) by low concentrations of follitropin, with an apparent Km of about 9 . 10(-10) M. Both Mg2+ and Mn2+ activate the enzyme but the apparent Ka for Mg2+ is about 10 times that for Mn2+. However, the apparent Km values for MgATP2- and MnATP2- are nearly the same (1.4 . 10(-4) M) and the cation activation of the enzyme is mainly through an increase in V. Ca2+ inhibited all expressions of testicular adenylate cyclase activity. Follitropin and fluoride stimulated adenylate cyclase activity at all Mg2+ concentrations but did not significantly affect the apparent Ka for Mg2+ or the Km for the substrate (MgATP2-). The stimulatory effect of the hormone or fluoride is mainly through an increase in V. Testicular adenylate cyclase could be solubilized with Triton X-100 or Lubrol-PX. The detergent-solubilized enzyme exhibited Km for substrate and Ka values for divalent cations similar to those of the membrane-bound enzyme and remained responsive to stimulation by fluoride. The stimulatory effect of follitropin, however, was lost. Responsiveness to follitropin was also lost by membrane-bound adenylate cyclase after treatment with phospholipase, although the fluoride effect was unchanged. These results reflect the essential role of lipids in the regulation of the follitropin-specific response.

UI MeSH Term Description Entries
D008274 Magnesium A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D008297 Male Males
D008345 Manganese A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)
D008566 Membranes Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures. Membrane Tissue,Membrane,Membrane Tissues,Tissue, Membrane,Tissues, Membrane
D003902 Detergents Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties. Cleansing Agents,Detergent Pods,Laundry Detergent Pods,Laundry Pods,Syndet,Synthetic Detergent,Agent, Cleansing,Agents, Cleansing,Cleansing Agent,Detergent,Detergent Pod,Detergent Pod, Laundry,Detergent Pods, Laundry,Detergent, Synthetic,Detergents, Synthetic,Laundry Detergent Pod,Laundry Pod,Pod, Detergent,Pod, Laundry,Pod, Laundry Detergent,Pods, Detergent,Pods, Laundry,Pods, Laundry Detergent,Synthetic Detergents
D004789 Enzyme Activation Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme. Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D005459 Fluorides Inorganic salts of hydrofluoric acid, HF, in which the fluorine atom is in the -1 oxidation state. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) Sodium and stannous salts are commonly used in dentifrices. Fluoride
D005640 Follicle Stimulating Hormone A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Follicle-stimulating hormone stimulates GAMETOGENESIS and the supporting cells such as the ovarian GRANULOSA CELLS, the testicular SERTOLI CELLS, and LEYDIG CELLS. FSH 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. FSH (Follicle Stimulating Hormone),Follicle-Stimulating Hormone,Follitropin
D000255 Adenosine Triphosphate An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter. ATP,Adenosine Triphosphate, Calcium Salt,Adenosine Triphosphate, Chromium Salt,Adenosine Triphosphate, Magnesium Salt,Adenosine Triphosphate, Manganese Salt,Adenylpyrophosphate,CaATP,CrATP,Manganese Adenosine Triphosphate,MgATP,MnATP,ATP-MgCl2,Adenosine Triphosphate, Chromium Ammonium Salt,Adenosine Triphosphate, Magnesium Chloride,Atriphos,Chromium Adenosine Triphosphate,Cr(H2O)4 ATP,Magnesium Adenosine Triphosphate,Striadyne,ATP MgCl2
D000262 Adenylyl Cyclases Enzymes of the lyase class that catalyze the formation of CYCLIC AMP and pyrophosphate from ATP. Adenyl Cyclase,Adenylate Cyclase,3',5'-cyclic AMP Synthetase,Adenylyl Cyclase,3',5' cyclic AMP Synthetase,AMP Synthetase, 3',5'-cyclic,Cyclase, Adenyl,Cyclase, Adenylate,Cyclase, Adenylyl,Cyclases, Adenylyl,Synthetase, 3',5'-cyclic AMP

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