734 THE ENDOCRINE ORGANS, OR DUCTLESS GLANDS 



Suprarenal Extracts — Preparation 



Injection, particularly intravenous, of extract of the adrenal gland 

 has furnished us with most of the evidence upon which our knowledge 

 regarding the function of this organ depends. Such an extract is best 

 made by grinding the entire gland with fine sand in a mortar and then 

 extracting with a weak' (decinormal) solution of hydrochloric acid. The 

 extract may then he boiled, filtered through muslin and nearly neutral- 

 ized, preferably by means of sodium acetate. If kept in this acid reac- 

 tion, the active principle of the extract does not materially deteriorate 

 with time, but if it he neutralized or considerably diluted, destruction 

 due to oxidation occurs, as evidenced by a distinct browning of the 

 solution. The active principle of such extracts has keen isolated in a 

 crystalline form (Takamine and Abel). It has been given various names 

 (adrenalin, suprarenin, adrenin, etc.), but the tendency is definitely 

 towards the use of epinephrine. Chemically, epinephrine has been found 

 to be orthodioxyphenylethylolmethylamine. 



HO 



IIO<^ \ -*CH(OH) - CH 2 NHCH 3 . 



It will be noted that it is closely related to tyrosine (see page 604). It 

 is also closely related to a group of substances (amines) occurring in 

 putrid meat and to which the active principles of ergot belong. It 

 contains an asymmetric carbon atom (asterisked in formula), which 

 indicates that there must be three varieties of epinephrine, differing 

 from one another in the effect which they produce on the plane of 

 polarized light (i.e., a dextro- and a levo-rotatory and a racemic form). 



Epinephrine can be prepared by synthetic means, the first product of 

 this synthesis being the racemic salt, which can then be split by appro- 

 priate methods into dextro- and levo- varieties. The levo- variety ap- 

 pears to be identical in its pharmacological action with the natural product. 

 The dextro- variety on the other hand has only poorly developed physio- 

 logic activities (about seven per cent that of the levo- variety), while 

 the racemic variety comes in between the two in its action. A valuable 

 assay of the amount of epinephrine in tissue extracts can be made by 

 the method of Cannon, Folin and Denis, 62 in which an acid extract of 

 the gland is treated with phosphotungstic acid, and the blue color thereby 

 developed compared colorimetrically with a standard blue. 



Physiological Action 



The physiological effects of the intravenous injection of epinephrine are 

 markedly excitatory and slightly inhibitory in nature. We will consider 



