Proteins 43 



yield of the microsome fraction declines. Growth hormone restores 

 to normal the mitochondrial RNA and leads to an apparent shift of 

 RNA from the microsome fraction to the supernatant fraction, i.e. 

 to other portions of the cytoplasm. Untreated adrenalectomised rats 

 acquire more liver DNA but lose some of their mitochondria. All- 

 oxan diabetes in the rat increases the yield of supernatant liver 

 fraction at the cost of other components. Castration produces no 

 change in the liver fractions (Reid, 1956) . 



Oestrogens lead to doubling of the nuclear volume in the rat 

 uterine gland cells and tripling in volume of surface epithelial cell 

 nuclei. The DNA content per nucleus remains constant, the water 

 content per nucleus is slightly increased and there is a substantial 

 increase in total organic matter per nucleus. The non-histone pro- 

 tein fraction of the nucleus is mainly responsible for the nuclear 

 hypertrophy (Gelfand and Clemmons, 1955) . 



An increase of DNA has been recorded in the liver cells of pa- 

 tients dying as a consequence of a thyroid crisis after thyroidectomy 

 for Graves' disease, possibly the result of toxic action of thyroxin 

 (Majewski, 1956) . Although the meaning of these isolated facts is 

 far from clear, they point the way to further investigations that may 

 well throw much light on protein synthesis. 



MALNUTRITION 



Rats fed on low protein (6.4 per cent) , high carbohydrate diet, 

 comparable with that of the poor people in Jamaica, show great 

 reduction in N:DNA ratio of the liver and still more of muscle. 

 Re-feeding quickly leads to new formation of protein and DNA in 

 the liver at a rate about twice as speedy as during normal growth 

 (Mendes and Waterlow, 1958) . 



Kwashiorkor, a disease caused by protein deficiency, in the pres- 

 ence of excess dietary carbohydrate, is widely distributed over 

 Africa, West Indies, Ceylon. Children so affected show an enlarged 

 liver which is fatty and seriously depleted of protein. The average 

 loss of liver protein and RNA is 40 per cent in Jamaican cases. The 

 muscles lose more protein than the liver (Waterlow and Weiss, 

 1956) . 



