growth rates of the surviving catfish fry may not have been fully representa- 

 tive of the original populations. 



EFFECT OF ORGANOCHLORINE CONTAMINANTS ON COLLAGEN FORMATION 



Various reports have stated that vitamin C is involved in the hydroxyla- 

 tion of drugs and chemicals in the liver of mammals (Axelrod zt al., 1954; 

 Levin at al., 1960; Street zt al., 1971; Wagstaff and Street, 1971), and in 

 collagen formation by the hydroxylation of proline to hydroxyprol ine (Barnes, 

 1969; Barnes oX al. , 1970; Mussini dial.,; Peterkofsky, 1972) (Figure 1). 

 Since these two hydroxylation processes may compete for the available vitamin 

 C, an attempt to determine the effects of toxaphene on the distribution of 

 vitamin C in liver and bone in channel catfish was made (Mayer and Mehrle, 

 1977). Ten-month old fish was continuously exposed to 37 to 475 ng/1 of tox- 

 aphene, and to exaggerate the response, a diet low in vitamin C was fed to 

 all test fish. The diet contained 63 mg of vitamin C per kilogram of food, 

 rather than the recommended amount of 100 mg/Kg (National Academy of 

 Sciences, 1973). Vitamin C in liver and bone, and collagen in bone were 

 determined after 90 and 150 days of exposure. 



Within each time period, the vitamin C content of the liver remained 

 rather constant, regardless of the toxaphene exposure (Table 4). Vitamin 



TABLE 4. MEAN CONCENTRATIONS OF VITAMIN C (pg/g OF WET TISSUE) IN LIVER 

 AND BACKBONE AND COLLAGEN (mg/g OF DRIED BONE) IN THE BACKBONE OF 

 CHANNEL CATFISH FED A DIET LOW IN VITAMIN C, AFTER 90- AND 150-DAY 

 EXPOSURES TO DIFFERENT CONCENTRATIONS OF TOXAPHENE. 



Standard error. 

 *Significantly different from controls (P<0.05) 



97 



