Relations of the Suprarenals with Other Endocrine Organs 71 



secretion of adrenalin into the blood. The variety of these does not, 

 however, indicate specific relationship. On the other hand, the secretion 

 of the suprarenal medulla has an influence upon many diverse organs and 

 glands — including most of the other ductless glands ; this is probably due 

 to the fact that adrenalin activates sympathetic nerve-endings throughout 

 the body. 



With the Sexual Glands. — A direct relationship between the develop- 

 ment of the sexual glands and that of the suprarenals may be regarded as 

 well established, although the nature of the relationship — whether through 

 the nervous system or, as is more probable, through chemical agencies — is 

 not precisely known. The connexion appears to be more with the cortex 

 of the adrenals than with the medulla. During pregnancy the whole gland 

 undergoes enlargement : the cortex much more than the medulla. Whilst 

 hypertrophy of the cortex is stated to occur as the result of castration, various 

 observers have found that increase is also associated with sexual precocity. 

 Further, in diseased conditions resulting in hypoplasia of the adrenals, 

 changes in the testicles, especially in their interstitial cells, have been noted. 



Elliott and Tuckett do not admit any special connexion between the 

 suprarenals and the sexual glands. They associate the cortex more 

 particularly with the development of the muscular system. They also 

 point out that the lower the animal in the vertebrate, or at any rate 

 in the mammalian series, the greater is the relative development of 

 the cortex. 



With Externally Secreting Glands. — Injection of suprarenal extract 

 was found by Langley (in the cat) to produce an active secretion of all 

 the salivary and mucous glands of the mouth, gullet, and trachea. The 

 secretion is not arrested by small doses of atropine, and is similar to that 

 produced by sympathetic excitation. The lacrimal glands are also stimu- 

 lated to active secretion : and this is said to be the case also with the 

 gastric glands. 



With the Liver. — The secretion of bile is increased by adrenalin. But 

 the most noteworthy effect on this organ is upon its glycogenic function, 

 for the autacoid of suprarenal medulla even in small doses produces a rapid 

 conversion of the liver glycogen into sugar, which passes into the blood and 

 eventually into the urine. The effect is similar to that caused by Bernard's 

 sugar puncture of the medulla oblongata and by excitation of the splanchnics. 

 It will be remembered that after section of the splanchnics Bernard found 

 that puncture of the medulla oblongata fails to cause glycosuria. The 

 effects on the liver are probablv in large measure, if not entirely, due to 

 reflex or other excitation of cells in the nerve-centre. These give origin 

 to nerve-impulses travelling along sympathetic fibres to the suprarenals, 

 and thus cause the outpouring of an excess of adrenalin into the blood ; 

 this again excites the terminal apparatus of the sympathetic nerves in 

 the liver-cells. Kahn noticed that if one suprarenal is left, its medulla 

 shows indications of over-activity and far less adrenalin is stored within 



