AMINO ACID INCORPORATION BY LIVER MICROSOMES 235 



a decreased functional stability of the microsomal membranes, which 

 secondarily influences the activity of the attached particles, is a factor of 

 importance in this reduction of activity. 



The positive after-effects described have been observed in experiments 

 with just fertilized sea-urchin eggs, and with liver directly or indirectly 

 influenced by corticoids. In this case the activity of the cell-free incorpora- 

 tion systems becomes abnormally high in proportion to the amount of 

 RNP-particles present. There are some indications that these effects are 

 related to a facilitated release of labelled proteins from the particles. 



The possibility is considered that effects of this kind may reflect 

 simple intracellular regulation mechanisms, which to some extent may 

 continue to operate also when the gross structural organization of the 

 cells has been destroved. 



References 



1. Arrhenius, E., and Hultin, T., Exp. Cell Res. 22, 476 (1961). 



2. Bernhard, W., and Rouiller, C, J. biophvs. biochem. CytoL, Suppl. 2, 73 

 (1956). 



3. Ceriotti, G., J. biol. Chem. 214, 59 (1955). 



4. Cohn, P., Biochim. biophvs. Acta 33, 284 (1959). 



5. Decken, A. von der, and Hultin, T., E\p. Cell Res. 14, 88 (1958). 



6. Decken, A. von der, and Hultin, T., E.xp. Cell Res. 15, 254 (1958). 



7. Decken, A. von der, and Hultin, T., "Progress in Biophysics and Biophysical 

 Chemistry" (in press). 



8. Decken, A. von der, Low, H., and Hultin, T., Biochem. Z. 332, 503 (i960). 



9. Feigelson, P., Feigelson, M., and Greengard, O., " ist Internatl. Congr. 

 Endocrinology", Abstracts 823 (i960). 



10. Hanzon, V., Hermodsson, L. H., and Toschi, S.,jf. Ultrastriictiire Res. 3, 216 



(1959)- 



11. Hirsch, G. C, Noturzvissenschofteti 47, 25 (i960). 



12. Hultin, T., Arrhenius, E., Low, H., and Magee, P. N., Biochem. J. 76, 109 

 (i960). 



13. Hultin, T., Magee, P. N., and Arrhenius, E., "4th Internatl. Congr. Biochem", 

 Abstracts 185 (1958). 



14. Hultin, T., and Bergstrand, A., Developmental Biol. 2, 61 (i960). 



15. Kay, R. E., and Entenman, C, Proc. Soc. exp. Biol. 91, 143 (1956). 



16. Kemp, A., and Kits van Heijningen, A. J. M., Biochem. jf. 56, 646 (1954). 



17. Korner, A., Biochim. biophvs. Acta 35, 554 (i960). 



18. Krebs, H. A., and Henseleit, K., Hoppe-Seyl. Z. 210, 33 (1932). 



19. Low, H., Biochim. biophvs. Acta 32, i (1959). 



20. Lowe, C. U., Rand, R. N., and Venkataraman, P. R., Proc. Soc. exp. Biol. 98, 

 696 (1958). 



21. Mole, R. H., Brit.jf. exp. Path. 37, 528 (1956). 



22. Morgan, W. S., von der Decken, A., and Hultin, T., Exp. Cell Res. 20, 655 

 (i960). 



23. Palade, G. E.,y. biophvs. biochem. Cytol. i, 59 (1955). 



24. Rendi, R., Exp. Cell Res. 17, 585 (1959). 



