Effects of trichloroethylene and perchloroethylene on wild rodents at Edwards Air Force Base, California, USA.

Effects of inhalation of volatilized trichloroethylene (TCE) or perchloroethylene (PCE) were assessed based on the health and population size of wild, burrowing mammals at Edwards Air Force Base (CA, USA). Organic soil-vapor concentrations were measured at three sites with aquifer contamination of TCE or PCE of 5.5 to 77 mg/L and at two uncontaminated reference sites. Population estimates of kangaroo rats (Dipodomys merriami and D. panamintinus) as well as hematology, blood chemistry, and histopathology of kangaroo rats and deer mice (Peromyscus maniculatus) were compared between contaminated and uncontaminated populations. Maximum soil-gas concentrations associated with groundwater contamination were less than 1.5 microl/L of TCE and 0.07 microl/L of PCE. Population estimates of kangaroo rats were similar at contaminated and reference sites. Hematology, blood chemistry, and histopathology of kangaroo rats and deer mice indicated no evidence of health effects caused by exposure. Trichloroethylene or PCE in groundwater and in related soil gas did not appear to reduce the size of small mammal populations or impair the health of individuals.

Regulation of plasma antidiuretic hormone in the dehydrated kangaroo rat (Dipodomys spectabilis M.).

A sensitive and specific radioimmunoassay was used to measure plasma antidiuretic hormone (plasma arginine vasopressin, PAVP) concentrations in a conscious desert-adapted mammal, the banner-tailed kangaroo rat (Dipodomys spectabilis; 131 +/- 2.3 g body mass), during normal hydration and in response to progressive dehydration. Simultaneous measurements of PAVP and plasma osmolality (POSM) in these experiments permitted determination of the hypothalamo-neurohypophyseal system-osmoreceptor set point and sensitivity to extracellular hyperosmolality during dehydration. In normally hydrated kangaroo rats, acclimated to room temperature (20-24 degrees) and fed a dry grain diet, POSM and PAVP averaged 308.6 +/- 0.7 mosmol/kg H2O and 6.0 +/- 0.7 pg/ml (2.2 +/- 0.2 microU/ml), respectively (means +/- SE). In separate groups of animals subjected to 48, 96, 144, or 192 hr of dehydration, POSM and PAVP increased in a parallel linear manner with time to maxima of 329.7 +/- 2.4 mosmol/kg H2O and 68.8 +/- 4.4 pg/ml (24.9 +/- 1.6 microU/ml), respectively, at 192 hr of dehydration. Thus, a highly correlated and significant relationship between POSM and PAVP (r2 = 0.941, P less than 0.001) exists in dehydrated kangaroo rats, quantitatively defined by the linear regression equation PAVP (pg/ml) = 2.99 (POSM - 306.4), with an apparent osmotic threshold for AVP release at a POSM of 306.4 mosmol/kg H2O.(ABSTRACT TRUNCATED AT 250 WORDS)