214 



METABOLIC HORMONES 



Cortical 

 hormones 

 in diuresis 

 and blood concentration 



Neurohypophysial 

 hormones 

 in ontidiuresis 

 end blood dilution 



ACTH 



NEUROSECRETION 



c 



Active transport 

 ^ Ion exchange 

 -► Diffusion 

 ^ Concentrating 

 mechgnisn\ 



Hormone favours process 

 'Hormone inhibits process 



Fig. 5-15. Diagrams to show the action of hormones on the kidney 

 tubules of a mammal, a. The cortical hormones, active in blood 

 concentration: aldosterone, increasing reabsorption of salts, and 

 HYDROCORTISONE, increasing water diuresis; obligatory endos- 

 mosis is then limited by the diffusion rate to about 80 % of com- 

 pletion. In the loop of Henle the urine still has *'free" water. 

 b. The neurohypophysial hormones, active in blood dilution: 



