556 



WILLY RUCH 



2. The antidiuretic activity of hypophyses and hypothalami from embryos and 

 postembryos has been estimated and the first appearance of neurosecretory 

 substance in the neurohypophysis has been determined histologically. 



3. At the moment of birth, Rattus and Meriones (Nidicolous) show an accelerated 

 development, or critical period, of the neurosecretory System, which manifests 

 itself in a rapid increase of antidiuretic hormone in hypophysis and hypo- 

 thalamus. Cavia and Acomys (Nidifugous) show the critical period during 

 embryonic life; Cavia after 48 days and Acomys after 29 days of gestation. 



4. In the hypophysis, neurosecretory substance can be detected for the first time 

 at birth in Rattus and Meriones, at the 42nd day of foetal development in 

 Cavia, and at the 30th day of foetal development in Acomys. 



5. The limited value of a histological évidence of first neurosecretion was dis- 

 cussed. 



6. The maturation of the neurosecretory System of our four rodents is compared 

 with the ripening of this System in some mammals, mentioned in literature, 

 in relation to both types of ontogeny. 



7. The présent opinion regarding the place of synthesis of both pituitary hor- 

 mones was used to discuss our estimation of antidiuretic hormone. There 

 is no disagreement between our expérimental results and the gênerai view 

 based on results obtained with quite différent methods. 



LITERATURVERZEICHNIS 



Acher, R. 1958. Etat naturel des principes ocytocique et vasopressique de la neurohypo- 

 physe, in 2. Int. Symp. iiber Neurosekretion Lund, 71 — 79, Springer, 

 Berlin. 



— 1966. Cheniistry of Neurophysiological Hormons, in The pituitary Gland vol. 3, 



Harris G. W., Donovan B. T. Ed., Butterworths, London. 



— J. Chauvet, G. Olivry. 1956 a. Sur l'existence éventuelle d'une hormone unique 



neurohypophysaire, I. Relations entre l'ocytocine, la vasopressine et la 

 protéine de van Dyke extraites de la neurohypophyse du bœuf. Biochim. 

 biophys. Acta 22: 421—27. 



— J. Chauvet, G. Olivry. 1956 b. Sur l'existence éventuelle d'une hormone unique 



neurohypophysaire, II. Variations des teneurs en activités ocytocique et 

 vasopressique de la neurohypophyse du rat au cours de la croissance et de 

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Adams, C. W. M. 1965. Neurohistochemistry, Elsevier, Amsterdam. 



Adolph, E. F. 1957. Ontogeny of physiological régulations in the rat. Quart. Rev. Biol. 32: 

 89—137. 



Amoroso, E. C., R. J. Harrison, L. Harrison-Matthews et al. 1958. Zitiert in: 

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