PI3K-dependent actions of insulin and IGF-I on seminiferous tubules from immature rats. 2013

Gustavo Monteiro Escott, and Ana Paula Jacobus, and Eloísa Silveira Loss
Laboratório de Endocrinologia Experimental e Eletrofisiologia, Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite 500, sala 212, Porto Alegre, Rio Grande do Sul, Brazil, 90050-170.

There is clear evidence that insulin and insulin-like growth factor I (IGF-I) are crucial for the normal metabolism and development of Sertoli cells. However, the mechanisms of insulin regulatory signaling remain unknown in these cells, especially during the immature period. The aim of this study was to investigate the electrophysiological effects of insulin and the effects of insulin and IGF-I on calcium uptake, amino acid, and glucose transport in whole seminiferous tubules from 12-day-old rats, as well as the involvement of PI3K/Akt signaling pathway in these effects. Insulin produces a depolarizing effect on the membrane potential of Sertoli cells in seminiferous tubules within 180 s. This effect was nullified by verapamil, an L-type voltage-dependent calcium channel blocker, therefore demonstrating a calcium-dependent depolarizing effect. Both insulin and IGF-I stimulate calcium uptake, amino acid, and glucose transport in whole testes from 12-day-old rats. These stimulatory effects of insulin and IGF-I on calcium uptake and amino acid and glucose transport on testicular tissue were nullified by wortmannin, which demonstrates the involvement of the PI3K/Akt signaling pathway in these hormonal effects.

UI MeSH Term Description Entries
D007328 Insulin A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1). Iletin,Insulin A Chain,Insulin B Chain,Insulin, Regular,Novolin,Sodium Insulin,Soluble Insulin,Chain, Insulin B,Insulin, Sodium,Insulin, Soluble,Regular Insulin
D007334 Insulin-Like Growth Factor I A well-characterized basic peptide believed to be secreted by the liver and to circulate in the blood. It has growth-regulating, insulin-like, and mitogenic activities. This growth factor has a major, but not absolute, dependence on GROWTH HORMONE. It is believed to be mainly active in adults in contrast to INSULIN-LIKE GROWTH FACTOR II, which is a major fetal growth factor. IGF-I,Somatomedin C,IGF-1,IGF-I-SmC,Insulin Like Growth Factor I,Insulin-Like Somatomedin Peptide I,Insulin Like Somatomedin Peptide I
D008297 Male Males
D008564 Membrane Potentials The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization). Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D002118 Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002121 Calcium Channel Blockers A class of drugs that act by selective inhibition of calcium influx through cellular membranes. Calcium Antagonists, Exogenous,Calcium Blockaders, Exogenous,Calcium Channel Antagonist,Calcium Channel Blocker,Calcium Channel Blocking Drug,Calcium Inhibitors, Exogenous,Channel Blockers, Calcium,Exogenous Calcium Blockader,Exogenous Calcium Inhibitor,Calcium Channel Antagonists,Calcium Channel Blocking Drugs,Exogenous Calcium Antagonists,Exogenous Calcium Blockaders,Exogenous Calcium Inhibitors,Antagonist, Calcium Channel,Antagonists, Calcium Channel,Antagonists, Exogenous Calcium,Blockader, Exogenous Calcium,Blocker, Calcium Channel,Blockers, Calcium Channel,Calcium Blockader, Exogenous,Calcium Inhibitor, Exogenous,Channel Antagonist, Calcium,Channel Blocker, Calcium,Inhibitor, Exogenous Calcium
D005947 Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Dextrose,Anhydrous Dextrose,D-Glucose,Glucose Monohydrate,Glucose, (DL)-Isomer,Glucose, (alpha-D)-Isomer,Glucose, (beta-D)-Isomer,D Glucose,Dextrose, Anhydrous,Monohydrate, Glucose
D000077191 Wortmannin An androstadiene metabolite produced by the fungi PENICILLIUM funiculosum that inhibits PHOSPHATIDYLINOSITOL-3-KINASES and alloantigen-specific activation of T-LYMPHOCYTES in human tumor cell lines. It is widely used in CELL BIOLOGY research and has broad therapeutic potential. MS 54,MS-54,MS54
D000081082 Phosphoinositide-3 Kinase Inhibitors Agents that inhibit PHOSPHOINOSITIDE-3 KINASE activity. Phosphoinositide-3 Kinase Inhibitor,Inhibitor, Phosphoinositide-3 Kinase,Inhibitors, Phosphoinositide-3 Kinase,Kinase Inhibitor, Phosphoinositide-3,Kinase Inhibitors, Phosphoinositide-3,Phosphoinositide 3 Kinase Inhibitor,Phosphoinositide 3 Kinase Inhibitors
D000596 Amino Acids Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins. Amino Acid,Acid, Amino,Acids, Amino

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