406 THE DUCTLESS GLANDS 



not exerted through the pancreas, but part must be directly on 

 the liver. As we have previously seen (p. 162), adrenin has 

 a direct effect on the glycogen storage of the liver. 



We have then considerable evidence that the adrenal cortex 

 stimulates the growth of the gonads, and some little evidence 

 that adrenal hyperplasia induces overgrowth of the thymus. 

 The most usual theory as to the relation of the adrenal body to 

 the pancreas is that the former inhibits the latter. According 

 to some observers, this effect is not direct, but related to an 

 action on the vasoconstrictor nerves. 



D. Interrelationships involving the Organs of 

 Reproduction 



Action of the Reproductive Organs on the Pituitary Body 



Several authors report that pregnancy causes increased 

 activity of the pituitary gland. But it has been pointed out 

 that this may be simply a reaction to the changed metabolic 

 conditions obtaining during pregnancy. Castration in both 

 sexes is followed by hypertrophy of the anterior lobe of the 

 pituitary body. There seems to be a special overgrowth of the 

 eosinophile elements. 



Recent investigations lends support to the view that it is the 

 loss of the internally secreting elements of the testes (tlir 

 interstitial cells of Ley dig) which leads to hypertrophy of the 

 pituitary body. 



These observations indicate that the pituitary body is 

 normally held in check by the secretions of the reproductive 

 organs. When the inhibition is removed the pituitary shows 

 increased activity leading to overgrowth of different parts of 

 the body, as in acromegaly and after castration (Hoskins). 



Action of the Reproductive Organs on the Thymus 



The thymus normally persists till puberty, when the repro- 

 ductive organs grow. A priori, castration would tend to 

 prolong the period of persistence of the thymus. This has 

 been found experimentally to be the case. The work of 

 Calzolari, Henderson, and Goodall in this direction is referred 

 to in Chap. XIV. The sex glands then tend to exert a 

 depressant effect on the thymus. 





