The use of isolated radiation in experiments with the rat. III. Effects of darkness, visible, and infra red radiation on three succeeding generations of rats. Reproduction
Luce, C.ausen, E.M.; Brown, E.F.
Jour Nutrition 18(6): 551-562
1939
Document Number: 297199
Continuing the studies made on growth and storage of vit. A in rats kept under controlled conditions of light, reproduction was studied in the same animals. The age of opening of the vagina and the onset of estrus was delayed when rats were bred in complete darkness. Radiation in the visible was found to promote maturity at an earlier age than normal for rats kept under exptl. conditions. Infra-red radiation gave an intermediate result. Radiation in the visible, and to a lesser extent in the infra-red, promoted the normal survival of young born. Equal energy equivalents in the near and far infra-red regions were used in these expts. 1/3 of this energy in the visible region was sufficient to give the results reported.