SUMMARY1. Bile secretion was studied in anaesthetized rabbits from whom hepatic bile was collected by cannulation of the common bile duct.2. The flow and composition of bile formed by rabbits anaesthetized with urethane differed significantly from that formed by rabbits anaesthetized with pentobarbitone sodium.3. The i.P. injection of a hypertonic solution of sucrose (3 M) decreased bile flow and produced changes in the ionic composition of bile and of plasma.4. The infusion of sodium taurodeoxycholate (1.5-20 ,umole/min I.v.) gave higher rates of bile flow than did equimolar infusions of sodium taurocholate, and unlike taurocholate, increased the bicarbonate concentration of bile.5. Acetazolamide (10-100 mg/kg) increased the concentration of bicarbonate both in bile and in plasma, and had little effect on bile flow.6. The infusion of bromsulphthalein (5 mg/kg I.v.) decreased the excretion of bicarbonate into bile, and was associated with the formation of a hypotonic bile.7. The implications of these results in relation to the mechanisms of bile secretion are discussed.

Sodium fluoroacetate (1080) is a highly toxic metabolic poison that has the potential because of its lack of defined color, odor, and taste and its high water solubility to be intentionally or unintentionally ingested through food adulteration. Although the mechanism of action for 1080 has been known since the 1950s, no known antidote exists. In an effort to better understand the cardiopulmonary impacts of 1080, we utilized whole-body plethysmography and telemeterized Sprague-Dawley rats which allowed for the real-time measurement of respiratory and cardiac parameters following exposure using a non-invasive assisted-drinking method. Overall, the animals showed marked depression of respiratory parameters over the course of 24 h post-exposure and the development of hemorrhage in the lung tissue. Tidal volume was reduced by 30% in males and 60% in females at 24 h post-exposure, and respiratory frequency was significantly depressed as well. In telemeterized female rats, we observed severe cardiac abnormalities, highlighted by a 50% reduction in heart rate, 75% reduction in systolic blood pressure, and a 3.5-fold lengthening of the QRS interval over the course of 24 h. We also observed a reduction in core body temperature of nearly 15°C. Our study was able to describe the severe and pronounced effects of sodium fluoroacetate poisoning on cardiopulmonary function, the results of which indicate that both tissue specific and systemic deficits contribute to the toxicological progression of 1080 intoxication ABOUT THE AUTHOR Bryan J. McCranor is a research biochemist at the US Army Medical Research Institute of Chemical Defense where he is a principal investigator with the Inhalation Toxicology Team. Overall, his research focuses on the development of novel prophylactic, therapeutic and medical countermeasure treatments for exposure to chemical threat agents and toxic industrial compounds. His work centers on the identification of toxicological characteristics of toxic chemicals, investigation of potential novel therapeutic targets, and advancement of medical countermeasures.

The roles of selenium (Se) and glutathione peroxidase in reproductive function are poorly understood, but it is possible that they may be important for normal reproduction in the male. In rats fed a Se-deficient diet, the testes accumulated and retained more 75Se than did other tissues 1 week after injection Burk, Brown, Seely & Scaief, 1972). Autoradiographic studies of spermatozoa recovered from rat epididymides have shown that 75Se is associated with the midpiece of the spermatozoon. Gould (1970) (Li, 1975

SUMMARY1. The biliary effects of sodium taurodeoxycholate and sodium taurocholate were investigated in anaesthetized dogs and rats, and in the isolated perfused rat liver.2. Both bile salts had similar qualitative and quantitative effects on the flow and composition of bile in the dog.3. In the rat, the bile salts had similar effects on the ionic composition of bile, but differed in that bile flow was not always directly related to the rate of bile salt secretion in bile, in the experiments with sodium taurodeoxycholate.4. Sodium taurodeoxycholate is hydroxylated to form sodium taurocholate by the liver of the rat but not by that of the dog. 5. The biliary effects of sodium taurodeoxycholate in the rat and in the dog are contrasted with its effects in the rabbit, and the differences between the three species are discussed.

Subdiabetogenic doses of alloxan injected into the hepatic portal vein of rats abolished glucagon-induced inhibition of feeding (glucagon satiety) both in daytime tests using a palatable food and in nighttime tests using their standard pelleted diet. In contrast, inhibition of food intake by cholecystokinin and epinephrine and stimulation of feeding by 2-deoxy-D-glucose were not impaired by alloxan. Alloxan-induced deficits in glucagon satiety did not appear to result from generalized hepatocellular necrosis, because satiety deficits outlasted histological signs of toxicity and because furosemide, which produced a similar degree of hepatotoxicity, did not impair glucagon satiety. In addition, alloxan's effects were not associated with impaired glycogen storage or mobilization. Recovery of glucagon satiety occurred in some animals but not until 3-6 mo after alloxan. The degree of recovery was inversely related to alloxan dose. Our results indicate that, when administered into the hepatic portal vein, alloxan may be a relatively specific toxin for cells involved in the mediation of glucagon satiety. The specificity of the deficit and the time course of recovery suggest that the alloxan-sensitive cells may be hepatic vagal neurons.