42 The Endocrine Organs 



sexual infantilism. In the adult animal (dog) Alquier and Theuveny found 

 diminished activity so far as production of spermatozoa is concerned, but 

 less distinct evidence of change in the ovary; although the animals 

 appeared to come on less completely in heat and to conceive with difficulty. 



With the Liver and Pancreas. — Other effects, of a more or less specific 

 character, are produced upon liver-glycogen. Krause and Cramer find that 

 in the cat and rat, fed with thyroid, glycogen disappears from the liver ; 

 but there is no glycosuria, the sugar having been conveyed to the tissues 

 and oxydised. Parhon has obtained a similar result with the rabbit. The 

 thyroid therefore produces mobilisation of carbohydrates. Thyroid feeding 

 also tends, as we have seen, to diminish the limit for the assimilation of 

 sugar. This may be due either to an increase in the secretion of adrenalin 

 or to a direct inhibitory effect on the internal secretion of the pancreas. 



After thyroidectomy the assimilation limit for sugar is markedly 

 raised ; and according to some observers adrenalin-glycosuria is greatly 

 diminished or fails to show itself. This statement, however, is contradicted 

 by Underhill. If the parathyroids are included in the removal, the assimila- 

 tion limit for sugar is lowered and adrenalin produces a stronger glycosuria 

 than in the normal animal. The influence of the thyroids and parathyroids 

 is therefore antagonistic in this as in some other respects. According 

 to Lorand, if a dog deprived of pancreas and exhibiting glycosuria is 

 thyroidectomised, the sugar disappears from the urine. Lorand further 

 states that extirpation of the pancreas has the effect of increasing the 

 amount of colloid in the thyroid vesicles, and that thyroidectomy causes a 

 marked increase in the amount of islet tissue in the pancreas. But both 

 these statements are difficult to accept on account of the differences which 

 are normally present, both in amount of colloid in the thyroid and in 

 number of islets in the pancreas. If substantiated, they would show a 

 direct correlation between the thyroid and the pancreas, the internal 

 secretion of the thyroid being restrained by that of the pancreas and the 

 internal secretion of the pancreas by that of the thyroid, so that when 

 either gland is extirpated, the internal secretion of the other either becomes 

 more active or increased in amount. 



With the Suprarenal Capsules. — There is an indirect way in which the 

 internal secretion of the pancreas can be influenced by thyroid secretion, 

 and that is by the effect which this produces upon the action of the 

 secretion of the suprarenal medulla. This effect appears, as Asher and 

 Flack have shown, to be in the direction of increase of excitability of those 

 tissues which are amenable to the action of adrenalin. On the other 

 hand, when the thyroid is extirpated the activity of the secretion of the 

 suprarenals is diminished. And the phenomena which are normally pro- 

 duced by sympathetic stimulation are similarly affected. Further, with 

 hyperthyrosis, such as occurs in intense thyroid feeding, most of the 

 symptoms are those of over-excitation of the sympathetic, and are similar 

 to those caused by adrenalin. There is, moreover, some evidence that the 



