Biomedical subjects
Publications and source records attributed to C Fourlon.
The effect of stress from cold and noise on rats fed with DDT in a sufficient dose of retinol is to increase growth and induce cytochrome P450 in the liver, but to a lesser extent than in control group kept in normal environment conditions.
In various regions of France (particularly in the North-East) potatoes have remained an important source of vitamin C. We measured by a specific method [7], the loss of ascorbic acid in the Bintje species of potatoes (grown in Pas-de-Calais) due to storage and different cooking procedures. Storage for 3 months in the dark at +12 degrees C decreases the ascorbic acid level by about 50%, storage for 6-8 months by about 66%. Cooking of peeled potatoes (in water, vapor or as French fries) causes an additional loss of vitamin C of roughly 40-45% whereas unpeeled potatoes loose only about 7% by cooking. When cooked potatoes are kept warm, on a hot plate, for an hour the loss of ascorbic acid amounts up to 70%. Thus three major factors determine the spontaneous destruction of ascorbic acid in potatoes, i.e. the length and conditions of storage (aging), the way of cooking and warming up. Potatoes, even when consumed in considerable quantities, can only supply part of the French recommended Daily Allowance [8] particularly from January through June.
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During two experiments hens are fed with diet supplemented with or without 10 ppm of Bacitracin or 0,5 ppm of Flavomycin. Both increase retinol transfer from diet to yolk. Differences are not always significant. They are concerning almost a more important percentage of eggs whose yolks contain between 500 and more than 700 IU of vitamin A (66,6 p. 100 for Bacitracin supplement; 80,9 p. 100 for Flavomycin supplement and 45 p. 100 for control). Each additive increases hepatic storage and serum level of retinol but not significantly. Transfer of vitamin A from diet to yolk is between 12,1 p. 100 and 24,0 p. 100 regarding individual variations. There is no influence from the strain. Warren or Dekalb, used.
During detoxication processes of DDT, there is, in the Rat, interference between vitamins A and E (D.1.alpha-tocopherol acetate). Vitamin E spares retinal and has a slighter but significant influence on P 450 cytochrome induction. These results are discussed.
Consumption of vitamin A and cytochrome P 450 by pregnant Rat is more important than in non pregnant and ovariectomised Rat. Estradiol implant in ovariectomised female has some, but slighter, influence only on retinol. These physiological situations have no action on the hepatic levels of tocopherols (total and alpha). These results are discussed.
There are significant differences between castrated and non castrated male Rats in regard to vitamine A hepatic storage and plasma level. Cytochrom P 450 levels are the same in both groups. Those results are discussed.
Phenobarbital administration to the Cat an animal hypersensitive to the actions of many toxic substances or to physiological compounds such as hormones, does not produce cytochrome P 450 induction. Consequently, hepatic storage of retinol remains unchanged. The specific and original characteristics of the Cat in this field are underlined by these results.
A 5 P. 100 level of protein from casein in a diet does not allow vitamin A to modify significantly induction of cytochrome P 450 on the Rat receiving or not receiving DDT. When the protein increases to a 15 p. 100 level, the induction is better providing vitamin A is to be given. If protein and vitamin A are necessary for cytochrom P 450 induction, an increase of protein level remains inefficient without vitamin A.
A relation vitamin A - vitamin D3 exists in diet for growing rats. When this decreases from 5 (microgram A - IU D3) or 15 (IU A - IU D3) to 1,25 (microgram/IU) or 3,75 (IU/IU) growth, calcemia are increasing but vitamin A hepatic storage is decreasing. In other words for a same quantity of retinol, cholecalciferol's level in diet determines hepatic stores of vitamin A. General aspect of this question is discussed.
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