title: Parallel effects of insulin-like growth factor-II and insulin on glucose metabolism of developing mouse embryonic limb buds in culture.
abstract: The present study was undertaken to evaluate the functional significance of the previously observed increase in the level of IGF-II receptors despite the loss of growth promoting activity of IGF-II in differentiated limb buds in organ culture. In the present study IGF-II and insulin at similar concentration (0.1-1 microgram/ml) stimulated the glucose uptake by the tissue and incorporation into glycogen (approximately 2 and 4 times control) and stimulated the activity of glycogen synthase (approximately 2 times control) of the limb buds irrespective of the differentiation stage of the tissues. IGF-I had little or no effect. None of the hormones (IGF-I, II or insulin) had any effect on the CO2 production by the limb buds. These results suggest a regulatory role of IGF-II, complementary or overlapping with insulin, in glucose metabolism of the developing limb buds. The absence of the effects of both IGF-II and insulin on CO2 production by the tissue, however, indicate that the IGF-II and insulin regulation of glucose metabolism of the limb buds is predominantly on glycogen synthesis.
mesh_terms: D000818:Animals; D004622:Embryo, Mammalian / Q000187:drug effects / Q000378:metabolism*; D005121:Extremities / Q000196:embryology; D005947:Glucose / Q000378:metabolism*; D006006:Glycogen Synthase / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000494:pharmacology*; D007700:Kinetics; D051379:Mice; D009924:Organ Culture Techniques; D013002:Somatomedins / Q000494:pharmacology*
chemical_list: D007328:Insulin; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D006006:Glycogen Synthase; D005947:Glucose