The regulation of GH-dependent hormones and enzymes after feed restriction in dwarf and control chickens.
The principal objective of this study was to examine the GH-dependency of IGF-I and IGF-II changes in the chicken. To this end, the regulation of GH-dependent hormones and enzymes were studied in undernourished normal and dwarf chickens. The dwarf chickens examined exhibit a Laron-type dwarfism and have been shown to be GH receptor deficient. Thus, they provide an interesting model to determine the GH-dependency of IGF-I and IGF-II changes. Short (1 day) and long-term (7 days) feed restriction was imposed on growing normal and dwarf chickens to follow the subsequent endocrine changes. Since short-term feed restriction of dwarf chickens resulted in decreased plasma IGF-I, it appears that this is not a GH-dependent effect. However, with longer term undernutrition, IGF-I was not decreased in dwarf chickens. So, after a longer restriction period, the regulation of these factors appears to become more GH-dependent. IGF-II was not depressed at all by feed restriction in the dwarf chicken, suggesting a degree of GH-dependency.
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D002645:Chickens; D004392:Dwarfism / Q000235:genetics / Q000378:metabolism*; D005508:Food Deprivation; D005838:Genotype; D013006:Growth Hormone / Q000494:pharmacology*; D006706:Homeostasis; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D007453:Iodide Peroxidase / Q000378:metabolism*; D008862:Microsomes, Liver / Q000201:enzymology; D011986:Receptors, Somatotropin / Q000172:deficiency; D013963:Thyroid Hormones / Q000097:blood*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood