Growth hormone, glucocorticoid and thyroxine response to duration, intensity and wavelength of light in prepubertal bulls.

@article{Leining1980GrowthHG,
  title={Growth hormone, glucocorticoid and thyroxine response to duration, intensity and wavelength of light in prepubertal bulls.},
  author={K B Leining and H. A. Tucker and J S Kesner},
  journal={Journal of animal science},
  year={1980},
  volume={51 4},
  pages={932-42}
}
Effects of duration, intensity and wavelength of light on growth hormone (GH), glucocorticoids, thyrotropin (TSH) and thyroxine (T4) concentrations in serum were determined in prepubertal bulls maintained at 18 to 22 C and 60 tp 70% relative humidity. Mean GH was 8.3 +/- .8, 9.5 +/- 2.2 and 13.8 +/- 2.2 ng/ml (P greater than .10) during 6 weeks of exposure to 8 hr of light: 16 hr of dark (8L:16D), 16L:8D and 20L:4D, respectively. However, concentrations of GH were more variable (P less than .01… CONTINUE READING