DISCUSSION 



Although the initial studies on the loqgerhead turtles failed 

 to opacify the urinary tract, they did show nearly complete 

 absorption of contrast material from the neck and moderate 

 absorption from the hind limb at 1 hr. We believed this to be an 

 important finding when considering the need to attain the highest 

 possible blood levels of therapeutic agents in turtles that are 

 known to have or are suspected to have serious or life threaten- 

 ing systemic or localized disease amenable to drug therapy. 

 Traditional parenteral drug administration in sea turtles is 

 often done bv injection into the hind limb area. Results in the 

 present study indicated that subcutaneous injection in the dorsal 

 neck is perhaps more desirable in order to attain maximal thera- 

 peutic effects. 



Vascular access in these animals is quite limited, and 

 repeated subcutaneous or intramuscular injections become 

 necessary. The absorption of drugs from either of these sites 

 depends on several factors. Vascularity, blood flow, solubility, 

 and concentration all have important roles in drug absorption 

 (Fingle and Woodbury, 1975). Sodium diatrizoate is hypertonic 

 and highly soluble in water. Both of these factors lend them- 

 selves to its rapid absorption. These factors, of course, are 

 constant when the same drug and drug concentration are used at 

 different injection sites. The vascular supply to the area and 

 the blood flow then become predominant factors. In turtles that 

 died for various reasons, at the Galveston Laboratory, we 

 observed at necropsv a denser vascular network in the neck than 

 in the limbs. We believe this directly accounts for the observed 

 difference in absorption demonstrated in this studv. In Tables 2 



