In confirmation of previous observations, lesions of the lateral preoptic area in rats abolished water ingestion during a 4-hr test following an intraperitoneal injection of hypertonic NaCl solution. However, it was observed that these animals increased their water intakes when tests were prolonged to 24 hr and drank almost exactly what they needed for osmoregulation. Furthermore, they increased their water intakes normally when NaCl was given in their diet, when NaCl was administered intravenously, or when they were water deprived and given preloads of isotonic saline to remove hypovolemia. These findings indicate that rats with lateral preoptic lesions do experience osmoregulatory thirst, and consequently, they raise new doubts about whether osmoreceptors located in the lateral preoptic area mediate thirst following the administration of osmotic loads.In 1971, Blass and Epstein reported that lesions of the lateral preoptic area (LPO) of rats abolished water ingestion during a 4-hr test following an ip injection of hypertonic NaCl solution. Intact rats, in contrast, drank rapidly following this treatment and consumed 10-15 ml within the first 2 hr of the test. The specificity of the behavioral impairment was suggested by the additional finding (Blass & Epstein, 1971) that rats with LPO lesions drank normally in response to the other major stimulus for thirst, hypovolemia. These and other findings have been used to support the widespread view that osmoreceptors, located in the LPO, mediate thirst when the effective osmolarity of extracellular fluid is elevated (see review by Blass, 1973).Blass and Epstein used an ip injection of This work was supported, in part, by grants from the National Institute of Mental Health (MH-20620 and MH-25140). It includes portions of a dissertation presented by the first author to the University of Pittsburgh in partial fulfillment of the requirements for the master's degree. The technical assistance of Jen-Shew Yen and the helpful comments of Neil Rowland regarding this project are gratefully acknowledged. This report was presented in preliminary form at the meeting of the Society for Neurosciences, Toronto, November 1976.Requests for reprints should be sent to

Studies were designed to assess the accuracy of urine glucose testing in a sample of juvenile diabetic subjects, and to determine the effects of a visual discrimination training procedure on the accuracy. In the first study, each of 81 juvenile-diabetic children was presented three prepared glucose solutions and asked to determine the glucose concentration using the 2-Drop Clinitest method. Results showed errors in 54.3% of the judgments, with greatest difficulty occurring with 1-g/dl concentrations. The majority of errors were false negatives. Study II involved similar testing accuracy on a sample of 10 nurses and 2 research technicians, before and after a visual discrimination training procedure. Results showed that the subjects were incorrect on 39% of the trials initially, with a reduction in the error rate to less than 19% after training.

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