494 V. BLOOD LIPIDS 



(J) Plasma Carotene and Vitamin A as Influenced by Parturition. Sut- 

 ton and co-workers 870 reported that, at or immediately after parturition, 

 the plasma carotenoid and vitamin A levels of cows drop sharply, to re- 

 cover slowly during the following fourteen to twenty-one days. Goodwin 

 and Wilson 871 confirmed these observations; however, these later workers 

 do not consider these changes significant for vitamin A and /8-carotene per 

 se, but state that they are probably only a reflection of the changes in the 

 concentration of blood constituents during this period. 



(g) The Effect of Hormones on Plasma Carotene and Vitamin A. Wil- 

 liamson 872 reported that the injection of large doses of estradiol benzoate 

 over a nineteen-day period into thyroidectomized rabbits was followed by a 

 significant decrease in plasma vitamin A. No change was noted when this 

 hormone was administered to normal rabbits. On the other hand, when 

 estrogen was given to immature pullets, it evoked an increase in serum 

 vitamin A. The increase in vitamin A was confined to the ester fraction. 873 

 The estrogen effect was not counteracted by progesterone, although the 

 latter hormone reduced the hypertrophy of the oviduct caused by estro- 

 gen. 873 Gardiner et al. 873 reported that testosterone did not affect serum 

 vitamin A, although it might significantly increase the level of /3-carotene 

 in the blood. However, on the other hand, Danish and Klopp 874 reported 

 that the concentration of vitamin A in the plasma of man increases as a 

 result of the administration of testosterone. 



Young and Wald 875 reported that the intravenous injection of adrenalin 

 into rabbits caused a mobilization of vitamin A in the blood. However, 

 Goodwin and Wilson 876 were unable to confirm this finding, in the case of 

 either the rabbit or the rat, so that there is some doubt as to whether or not 

 the effect actually occurs. 



On the other hand, 3-j3-acetoxy-17o:-hydroxyallopregnan-20-one, the 

 so-called "Compound L," which, according to Bodansky and Markardt, 877 

 was isolated from the adrenal gland by Reichstein, 878 has been found to 

 decrease the plasma vitamin A of male rats considerably. 877 Thus, Bodan- 

 sky and Markardt 877 observed that, when 15 to 30 mg. daily doses of Com- 

 pound L were injected into male rats four months of age, over a period of 



870 T. S. Sutton, H. E. Kaeser, and P. A. Soldner, /. Dairy Sci., 28, 933-939 (1945). 



871 T. W. Goodwin and A. A. Wilson, Biochem. J., 49, 499-503 ( 1951 ). 



872 M. B. Williamson, Proc. Soc. Exptl. Biol. Med., 66, 621-623 (1947). 



873 V. E. Gardiner, W. E. Phillips, W. A. Maw, and R. H. Common, Nature, 170, 

 80-81 (1952). 



874 A. Danish and C. T. Klopp, Cancer Research, 10, 211 (1950). 



875 G. Young and G. Wald, Am. J. Physiol, 181, 210-215 (1940). 



878 T. W. Goodwin and A. A. Wilson, Biochem. J., 45, 370-372 (1949). 

 577 0. Bodansky and B. Markardt, J. Biol. Chem., 190, 83-93 (1951). 



