title: Influence of triiodothyronine and growth hormone on growth of dwarf and normal chickens: interactions of hormones and genotype.
abstract: The effects of dietary triiodothyronine (T3), injections of a preparation of growth hormone (GH) (purified from chicken pituitary tissue) and their combination on growth were investigated in three lines of chickens. The three lines were the Cornell K strain (K) (a single Comb White Leghorn strain), the Cornell K strain hemizygous for the sex-linked dwarfing gene (SLD), and the Cornell K strain homozygous recessive for the autosomal dwarfing gene (ADW). A dietary T3 treatment by genotype interaction was observed. Dietary T3 (0.1 ppm) decreased growth in the K line, tended to decrease growth in the ADW line while it tended to increase growth in the SLD line. Chicken growth hormone (100 micrograms/kg body wt) alone did not affect growth in any of the lines studied. There was, however, a GH treatment by T3 treatment interaction. Chicken GH overcame the growth-depressing effects of T3 in the K and ADW lines while it tended to promote growth in T3 treated SLD birds. Dwarf (SLD) chickens had higher basal circulating GH concentrations, lower circulating immunoreactive somatomedin C concentrations, and lower circulating T3 concentrations than the K or ADW chickens.
mesh_terms: D000375:Aging; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002645:Chickens / Q000254:growth & development*; D004392:Dwarfism / Q000235:genetics / Q000503:physiopathology*; D005838:Genotype; D013006:Growth Hormone / Q000097:blood / Q000494:pharmacology*; D008297:Male; D013045:Species Specificity; D014284:Triiodothyronine / Q000097:blood / Q000494:pharmacology*
chemical_list: D014284:Triiodothyronine; D013006:Growth Hormone