Experimental researches regarding the metabolic changes determined by the prolonged exposure to light or by keeping in darkness.

The authors conducted complex investigations in the domain of the intermediary metabolism under experimental conditions on 24 dogs grouped into three lots: lot A, twelve dogs, exposed for six months to the action of continuous light; lot B, six dogs, maintained in darkness; lot C, six dogs, maintained for the same period in the animal house, getting the same food as the other two lots, which are the control lot. We determined some biochemical, hematological, enzymatical parameters, before the beginning of the experiment, and after 24 hours, 48 hours, 7, 14 and 21 days, one, two, three, six months. Then the animals were sacrificed, and fragments from the aorta, coronary vessels, myocardium, brain, adrenals, pancreas and liver were examined both on the optical and on the electronic microscope and we analysed some fats from the vascular tissues. The net decrease of proteinemia with lot A was registered, concomitantly with a net decrease of serumalbumins, of the alpha 1-globulins and of the gamma-globulins, and with a rise of the alpha 2- and beta-globulins. The values of glycemia increased with lot A, and less with lot B. The thrombocytes decreased obviously with lot A, and less with lot B. GPT decreased with lot A, and GOT increased. The serum Zn decreased slowly with lot A, and more irregularly but more obviously with lot B. The serum Cu increased with lot A, and decreased with lot B. Alterations on the level of arterioles from the brain, aorta, myocardium and pancreas were evidenced, as well as electronmicroscopical alterations of the arteriolar walls and of the cellular organelles. The lipids from the brain, aorta and myocardium increased with both of the experimental lots and so did the cerebrosides, lecithins and the sphyngomyelin.