SECTION 9 



COLLAGEN AND HYDROXYPROLINE IN TOXICOLOGICAL 

 STUDIES WITH FISHES 



Foster L. Mayer and Paul M. Mehrle 



Chronic toxicity studies with fish are expensive, high-risk endeavors, 

 requiring from 10 months to one year to conduct. Such studies include 

 growth, reproduction, and survival of adults, and growth and survival of 

 the offspring. As a consequence, there has been much interest in the de- 

 velopment of alternative methodologies that provide similar information 

 with less expenditure of time and effort. Grant and Schoettger (1972) 

 stated that the monitoring in fish of biochemical factors that can be cor- 

 related with toxicant exposures and residues, provides a useful means of 

 anticipating the subtle, adverse impacts of organic contaminants on the 

 fish. To date, however, investigators have used biochemical measurements 

 alone in many studies to arrive at rather broad conclusions, without deter- 

 mining the ultimate effects on growth, reproduction, and survival (i.e., 

 whether the chemical changes observed were within the adaptive capacity of 

 the fish). Therefore, attempts were made to assess the possibility of 

 using biochemical factors as indicators or predictors of growth and devel- 

 opment in fish, thus decreasing the time required for chronic toxicity 

 determinations. Growth of fish is usually evaluated by measuring weight 

 and length; however, biochemical changes due to intoxication should occur 

 before reductions in growth. As potential indicators of growth and devel- 

 opment, backbone collagen and the hydroxyproline concentration in collagen 

 were selected, and these measurements were incorporated into basic studies 

 with toxaphene to provide information for the establishment of water qual- 

 ity criteria (Mayer at al., 1975, 1977; Mehrle and Mayer, 1975a, 1975b, 

 1976). 



RATIONALE FOR MONITORING HYDROXYPROLINE AND BACKBONE COLLAGEN 



Collagen is the major fibrous protein of all vertebrates and most of 

 the invertebrate phyla (Piez and Likens, 1958). Its most important func- 

 tion in vertebrates is to serve as the major component of the organic ma- 

 trix of connective tissues and bones. The collagen molecule is unique in 

 its amino acid content (Harrington and Hippel, 1963); the amino acids 

 hydroxyproline and proline combined make up about one-tenth and glycine 

 another third of the total amino acid composition in collagen. In animal 

 tissues, hydroxyproline is found only in the protein's collagen and elas- 

 tin. Since the total amount of elastin is very small in comparison with 



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