of the siigarflies; whether this is due to the intracelhilar proteinase activity 

 of the ingested meat, or to that of the gut inself, could not be decided. 



Let us now return to the normal controls with mature ovaries. In contrast 

 to the normal controls with developing eggs these flies have a low proteinase 

 activity, the average value being 2-1 as compared with 13-6. 



The guts of these controls contained less meat than those of the flies with 

 developing ovaries. But in spite of containing some meat, the proteinase acti- 

 vity of the guts луеге not higher than that of completely empty guts from 

 starved females. 



Furthermore the values of the flies \vith ripe eggs were of the same order 

 as those of flies — m. n. с Thus it seems as if the m. n. с of flies with ripe 

 eggs either produce or release less hormone than those of flies with developing 

 ovaries. This points in the direction that there is a cycle in the function of the 

 m. n. c, and it is possible that this cycle is governed by the developmental 

 stage of the ovaries. 



The results of this series of experiments mainly corroborate and amplify 

 those of the series which has been published recently. But the higher values 

 obtained in the second series reveal a significant difference between the protein- 

 ase activity of flies — m. n. с and that of sugarflies. Also the difference in 

 proteinase activity between females \vith developing ovaries and those with 

 ripe eggs is more clearly seen than in the first series. 



The production of proteinase by the intestinal cells can be regarded as the 

 protein synthesis of these cells, and therefore the result of this investigation 

 seems to support the working hypothesis that the hormone from the m. n. с 

 in some way influences protein metabohsm and especially protein synthesis. 



As yet it is obscure, how the effect of the neurohormone on the production 

 of intestinal proteinase is brought about. It might be a specific effect on some 

 step in the synthesis of the proteinase, but it could just as well be an unspecific 

 effect. 



LITERATURE 



Charnev J. and Tomarelli R. M., 1947, J. biol. Chem., 171: 501—505. 

 Day M. F. and Powning R. F., 1949, Aust. J. sei. Res., B, 2: 175. 

 Johansson A. S., 1958, Nijtt Mag. Zool., 7: 1 — 132. 

 Dupont-Raabe M., 1952, \-irch. Zool. exp. gén., 89: 128—138. 

 — 1954, РиЬЫ, Staz. Zool. Napoli, 24 suppl.: 63—66. 



Navar K. K., 1958, Zweites Internationales Symposimn über Neurosekretion, Lund. 

 ^ 102—104. 



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