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oai:recercat.cat:2445/1542372025-12-05T09:33:51Zcom_2072_1057col_2072_478781col_2072_478799col_2072_478861col_2072_478917

Developmental regulation of GLUT-1 (Erytroid/HepG2) and GLUT-4 (Muscle/Fat) glucose transporter expression in rat heart, skeletal muscle, and brown adipose tissue Santalucía Albi, Tomàs Camps Camprubí, Marta Castelló, Anna Muñoz Moruno, Purificación Nuel, A. Testar, Xavier Palacín Prieto, Manuel Zorzano Olarte, Antonio Teixit adipós Monosacàrids RNA Adipose tissues Monosaccharides RNA The expression of GLUT-1 (erythroid/Hep G2) and GLUT-4 (muscle/fat) glucose transporters was assessed during development in rat heart, skeletal muscle, and brown adipose tissue. GLUT-4 protein expression was detectable in fetal heart by day 21 of pregnancy; it increased progressively after birth. attaining levels close to those of adults at day 15 post natal.'In contrast, GLUT-4 messenger RNA (mRNA)was already present in hearts from 17 day-old fetuses. GLUT-4 mRNA stayed low during early postnatal life in heart and brown adipose tissue and only increased after day 10 post natal. The expression pattern for GLUT-4 protein in skeletal muscle during development was comparable to that observed in heart. In contrast to heart and skeletal muscle, GLUT-4 protein in brown adipose tissue was detected in high levels (30% of adult) during late fetal life. During fetal life, GLUT-l presented a very high expression level in brown adipose tissue, heart, and skeletal muscle. Soon after birth, GLUT-1 protein diminished progressively, attaining adult levels at day 10 in heart and skeletal muscle. GLUT-1 mRNA levels in heart followed a similar pattern to the GLUT- 1 protein, being very high during fetal life and decreasing early in post natal life. GLUT-1 protein showed a complex pattern in brown adipose tissue: fetal levels were high, decreased after birth, and increased subsequently in post natal life, reaching a peak by day 9. Progesterone-induced postmaturity protected against the decrease in GLUT-1 protein associated with post natal life in skeletal muscle and brown adipose tissue. However, GLUT-4 induction was not blocked by postmaturity in any of the tissues subjected to study. These results indicate that: 1) during fetal and early post natal life, GLUT-1 is a predominant glucose transporter isotype expressed in heart, skeletal muscle, and brown adipose tissue; 2) during early post natal life there is a generalized GLUT-1 repression; 3) during development, there is a close correlation between protein and mRNA levels for GLUT-l, and therefore regulation at a pretranslational level plays a major regulatory role; 4) the onset of GLUT-4 protein induction occurs between days 20-21 of fetal life; based on data obtained in rat heart and brown adipose tissue, there is a dissociation during development between mRNA and protein levels for GLUT-4, suggesting modifications at translational or posttranslational steps; and 5) postmaturity blocks the decrease in GLUT-l expression but not the induction of GLUT-4. observed soon after birth. All these findings suggest that GLUT-1 repression and GLUT-4 induction are mediated by different mechanisms. 2020-03-27T11:22:37Z 2020-03-27T11:22:37Z 1992-02-01 2020-03-27T11:22:37Z info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 0013-7227 https://hdl.handle.net/2445/154237 061562 1370797 eng Reproducció del document publicat a: https://doi.org/10.1210/endo.130.2.1370797 Endocrinology, 1992, vol. 130, num. 2, p. 837-846 https://doi.org/10.1210/endo.130.2.1370797 (c) Association for the Study of Internal Secretions, 1992 info:eu-repo/semantics/openAccess 10 p. application/pdf Association for the Study of Internal Secretions Articles publicats en revistes (Infermeria Fonamental i Clínica)