226 



METABOLIC HORMONES 



maintained in frogs, but it is probable that hydrocortisone may 

 act here as in mammals. The removal of such hormones by 

 adrenalectomy in Rana temporaria (but not in R. pipiens) is followed 

 by oedema, or an excessive accumulation of water in the tissues ; 

 but the effect of injecting cortical extracts has not yet been shown 

 (Chester Jones, \9Sla), 



Intact 

 ia) 



Intact Isolated skin 



Fig. 5-20. Increase in rate of water uptake following dehydration or 



injection of neurohypophysial extract (frog ADH); a. and h. in 



intact Rana pipiens^ with the cloaca ligatured to prevent loss by 



excretion; c. in isolated frog's skin (from Sawyer, 1956). 



Teleostei. Although freshwater teleost fish are in much the 

 same osmotic relation to the environment as Amphibia, the scales 

 usually make the skin more waterproof, and water only enters the 

 tissues through the gut and gills. Diuresis by the kidneys seems 

 therefore to be the main means of water control, and there is some 

 evidence that the cortical cells of the anterior interrenal body 

 (§2.311) may be concerned; but the situation is different in 

 species adapted to different normal environments. In FunduluSy 

 the cortical cells remain inactive when the fish are in sea water, 



