Thyroid metabolism in the recessive sex-linked dwarf female chicken. 5. Effects of exogenous thyroid hormones on amino acid uptake by eggs.

The incorporation of L-methionine-3H(G) and L-lysine-4,5'3H(n) into egg albumen by dwarf and non-dwarf White Leghorn hens was studied together with the influence of exogenous triiodothyronine (T3) and tetraiodothyronine (T4) on those incorporation patterns. The results were influenced by the amino acid studied and by the strain of bird. The maximum uptake of methionine was a day 1 for the normal and at day 4 for the dwarf which suggested that the dwarf was storing methionine in the tissue first before incorporation into albumen. If the birds were given T3 the maximum for the normal was at day 1 and day 3 for the dwarfs. When T4 was given the maximum uptake was found at day 5 for normals, and at day 2 for dwarfs. In the dwarf, T4 administration essentially corrected the decreased rate uptake of methionine but markedly retarded its uptake by the normal birds. The results for lysine were quite different. The maximum uptake was on day 4 in control, day 3 for T3-treated and day 1 for T4-treated, normal birds. In dwarf birds, the maximum was at day 2 for the control and T4-treated, and day 4 for T3-treated groups. The data were interpreted to suggest strain differences in amino acid uptake patterns due to different rates of synthesis or composition of egg albumen and marked differences in response or recptor sites to thyroid hormones.