53 U. S. BUREAU OF FISHERIES 



PHARMACOLOGICAL STUDIES 



Because of the increasing importance of the role of some minerals 

 in the metabolism of man and his domestic animals, and because much 

 discussion had appeared in scientific and trade journals concerning the 

 effect of these minerals in human and animal nutrition as they natu- 

 rally occur in foods such as fishery products and as they occur in organic 

 form, it has become necessary for the Division to conduct investiga- 

 tions in this field. Accordingly, late in 1935, an assistant pharma- 

 cologist was appointed to our technological staflf; and his work thus 

 far has been in the pioneer development of a new applied science, 

 namely, that of the pharmacology of fishery products. Up to the 

 present, studies have been made of the metabolism of arsenic and 

 copper as they occur naturally in fish and shellfish. As a result of this 

 work, a report was published in the Journal of Nutrition, vol. 10, no. 3, 

 September 1935, entitled "Metabolism in the Rat of the Naturally 

 Occurring Arsenic of Shimp as Compared with Arsenic Trioxide", 

 by E. J. Coulson, assistant pharmacologist, United States Bureau of 

 Fisheries, and Dr. Roe E. Remington and Dr. Kenneth M. Lynch, 

 Medical College of the State of South Carolina, Charleston, S. C. 



Investigations of the characteristics of the organic arsenic compound 

 of slump, including actual feeding tests with both rats and with man, 

 have shown that this compound is very readily absorbed from the 

 gastrointestinal tract, but it is rapidly and almost completely elim- 

 inated by the kidneys. Control tests using inorganic arsenic in the 

 form of arsenic trioxide, indicate that this form of arsenic, on the other 

 hand, is absorbed and stored. 



The retention of the inorganic arsenic compound was as high as 80 

 percent during the initial period of feeding. A study of the chemical 

 characteristics of the arsenic compound of shrimp has shown that it is 

 a very stable compound in which the arsenic atom is not ionized. In 

 other words, the arsenic is not in an active state. Thus the arsenic 

 compound of shrimp closely resembles the organic arsenic derivatives 

 of the fatty series which are said to be so stable as to lack something 

 of 'the therapeutic activity shown by the more dynamic compounds 

 derived from the benzene series, such as atoxyl and salvarsan. The 

 arsenic compound from shimp is soluble in water and readily diffuses 

 through a collodion membrane. It is also soluble in ethyl alcohol 

 and methyl alcohol but insoluble in ether, acetone, and chloroform. 

 The stable, undissociated characteristic of the organic arsenic com- 

 pound of shrimp and its ready solubility in water, without doubt, ac- 

 count for the rapidity \\'ith which it is eliminated from the bodj''. 



Thus, there need be no fear of any cumulative toxicity resulting 

 from the organic arsenic as it occurs in shrimp. While the subject has 

 not yet been investigated, it would appear that similar results might 

 be expected from the organic arsenic of other fish and shellfish. 



Like studies on the effect of feeding organic copper in the form of 

 "c/)ppery green" oysters have yielded similar results. 



This new field of the pharmacology of fisherj'' products premises to 

 yield interesting and important results in future years and in one 

 aspect is closely related to the role of mineral elements in human and 

 animal nutrition. It is no longer safe to evaluate the relative metab- 

 olism or assimilability of the mineral content of foods by chemical 

 analyses alone. 



