title: II - Insulin processing in mitochondria.
abstract: Our objective was to know how insulin is processing in mitochondria; if IDE is the only participant in mitochondrial insulin degradation and the role of insulin degradation on IDE accumulation in mitoplasts. Mitochondria and its fractions were isolated as described by Greenwalt. IDE was purified and detected in immunoblot with specific antibodies. High insulin degradation was obtained through addition to rat's diet of 25 g/rat of apple and 10 g/rat of hard-boiled eggs, 3 days a week. Mitochondrial insulin degradation was assayed with 5 % TCA, insulin antibody or Sephadex G50 chromatography. Degradation was also assayed 60 min at 37 °C in mitochondrial fractions (IMS and Mx) with diet or not and without IDE. Degradation in fractions precipitated with ammonium sulfates (60-80 %) were studied after mitochondrial insulin incubation (1 ng. insulin during 15 min, at 30 °C) or with addition of 2.5 mM ATP. Supplementary diet increased insulin degradation. High insulin did not increase mitoplasts accumulation and did not decrease mitochondrial degradation. High insulin and inhibition of degradation evidence insulin competition for a putative transport system. Mitochondrial incubation with insulin increased IDE in matrix as observed in immunoblot. ATP decreased degradation in Mx and increased it in IMS. Chromatography of IMS demonstrated an ATP-dependent protease that degraded insulin, similar to described by Sitte et al. Mitochondria participate in insulin degradation and the diet increased it. High insulin did not accomplish mitochondrial decrease of degradation or its accumulation in mitoplasts. Mitochondrial incubation with insulin increased IDE in matrix. ATP suggested being a regulator of mitochondrial insulin degradation.
authors: Endocrinology Research Center "Dr. Cesar Bergada" (CEDIE-CONICET), Endocrinology Division, Children Hospital. R. Gutierrez, Gallo 1330 (C1425), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina. mccamberos@cedie.org.ar.
authors: María Del Carmen
authors: MD
authors: Camberos
authors: Department Genetic and Evolution, School of Natural and Exact Sciences, University of Buenos Aires (UBA), Buenos Aires, Argentina.
authors: Adriana A
authors: AA
authors: Pérez
authors: Endocrinology Research Center "Dr. Cesar Bergada" (CEDIE-CONICET), Endocrinology Division, Children Hospital. R. Gutierrez, Gallo 1330 (C1425), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina.
authors: Gisel A
authors: GA
authors: Passicot
authors: Endocrinology Research Center "Dr. Cesar Bergada" (CEDIE-CONICET), Endocrinology Division, Children Hospital. R. Gutierrez, Gallo 1330 (C1425), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina.
authors: Lucía C
authors: LC
authors: Martucci
authors: Laboratory of Endocrinology and Metabolism, Department of Physiology and Pharmacology, University of Pernambuco, Recife, Pernambuco, Brazil.
authors: María I
authors: MI
authors: Wanderley
authors: Laboratory of Endocrinology and Metabolism, Department of Physiology and Pharmacology, University of Pernambuco, Recife, Pernambuco, Brazil.
authors: Daniel P
authors: DP
authors: Udrisar
authors: Endocrinology Research Center "Dr. Cesar Bergada" (CEDIE-CONICET), Endocrinology Division, Children Hospital. R. Gutierrez, Gallo 1330 (C1425), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina.
authors: Juan C
authors: JC
authors: Cresto
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D004035:Diet Therapy; D007328:Insulin / Q000378:metabolism* / Q000494:pharmacology; D007339:Insulysin / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D063306:Mitophagy / Q000187:drug effects; D051381:Rats
chemical_list: D007328:Insulin; D000255:Adenosine Triphosphate; D007339:Insulysin
keywords: ATP-dependent protease; Chromatography studies; IDE Insulin degradation; Mitochondrial fractions; Supplementary diet