CAROTENOIDS 



There were little, if any, seasonal variations in the carotenoids of 

 kidneys, skin, muscle, tongue, lungs, pancreas or eyes. The skin, liver, 

 and muscle contain considerable amounts in both sexes, but females 

 differ from males in mobilizing relatively enormous quantities of 

 carotenoids into the ovaries and mature eggs. The expulsion of the 

 ova represents a considerable loss of carotenoids to the female. 



The levels in male and female livers remained constant during 

 hibernation ; on spavv^ning there v^as a decrease which continued until 

 December. Gonads showed a marked seasonal variation which was 

 independent of dietary changes ; and the concentration in both testes 

 and ovaries dropped precipitately at spawning. During spawning 

 there was a very marked depletion of the carotenoids of female fat 

 bodies which indicates their significance in ovarian nutrition. Once 

 more there is a hint that carotenoids function in reproduction, and this 

 is enhanced by the fact that gonadal xanthophylls are unesterified. 



Table 39 

 Typical Values for the Carotenoid Content of various Frog Organs 



Ackerman, 3*^ who followed the seasonal variations in the liver of 

 R. esculenta, obtained results somewhat at variance with those of 

 Morton and Rosen. He found a fall in the liver carotenoids during 

 hibernation and a very sharp rise in the spring. 



Morton and Rosen noted a drop in the carotenoid content of both 

 male and female fat bodies during hibernation ; this indicates that 

 carotenoid metabolism continued during this period. Marked fluctua- 

 tions were recorded in the carotenes : xanthophylls ratio during deve- 



212 



