Response of Triiodothyronine-dependent enzyme activities to Insulin Like Growth

PELLIZAS CLAUDIA G, COLEONI ALDO H, CABANILLAS ANA M, MASINI-REPISO ANA M, COSTAMAGNA MARÍA E

EUROPEAN JOURNAL OF ENDOCRINOLOGY

Alden Press Limited

Lugar: Oxford, Great Britain; Año: 1996 vol. 134 p. 215 - 215

0804-4643

font size="2"> Triiodothyronine (T3) is involved in the regulation of the growth hormone-insulin-like growth factor I (GH-IGF-I) axis. In this study we investigated the effect of GH and IGF-I on the metabolic response of T3 in target tissues by evaluating the activity of two T3-dependent liver enzymes: mitochondrial alpha-glycerophosphate dehydrogenase (alpha-GPD) and cytosolic malic enzyme (ME) in rat hepatocytes in primary culture. Growth hormone (35 nmol/l) as well as IGF-I (0.5 mumol/l) reduced alpha-GPD and ME activities (p < 0.01) compared to the control group. Timecourse studies indicated that IGF-I (1.5 mumol/l) significantly decreased alpha-GPD and ME activities (P < 0.01) after 24 h, whereas the effect of GH (35 nmol/l) was recorded only after 36 h (p < 0.01). This delayed effect of GH compared to IGF-I suggested the possibility that the effect of GH could be mediated by IGF-I synthesis. To test this hypothesis, the effect of GH