Mercury localization in mouse kidney over time: autoradiography versus silver staining
Several methods of silver staining have been employed to localize mercury in tissue, under the assumption that the techniques represent total Hg, but recent reports have suggested that these stains are specific for a limited fraction of the Hg present in some samples. Magos et al. hypothesized that the stains actually vary with inorganic mercury content. The purpose of the present study was to compare localization by radiolabeling to localization by one silver stain, the photoemulsion histochemical technique, in tissues prepared to contain a range of levels of total Hg and a range of levels of inorganic Hg. Mice dosed with 8 mg Hg/kg as MeHg were killed 24 hr, 1 week, or 2 weeks after exposure, to allow a decrease in total Hg and an increase in the proportion of demethylated Hg over time. Mice dosed with 4 mg Hg/kg as HgCl/sub 2/ provided samples in which all the Hg present was in the inorganic form. Atomic absorption of kidneys of mice dosed with MeHg showed that total Hg fell from 55 micrograms/g to 39 to 25 over 2 weeks, while the inorganic fraction climbed from about 2 to 27 to 35%. Grain counts from autoradiographs of /sup 203/Hg-labeled sections correlated with total Hg content at +0.88, but silver staining was correlated with inorganic Hg content, appearing only at late termination times in MeHg-exposed animals, but soon after dosing in mice exposed to inorganic Hg. The photoemulsion histochemical technique revealed a substance strictly localized in the proximal tubules, while autoradiographs and grain counts showed total Hg to be present throughout the kidney tissue. These results support the contention that silver stains are selective for inorganic Hg.
- Research Organization:
- Univ. of Rochester, NY (USA)
- OSTI ID:
- 5400715
- Journal Information:
- Toxicol. Appl. Pharmacol.; (United States), Vol. 92:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
MERCURY
BIOLOGICAL LOCALIZATION
METABOLISM
ABSORPTION SPECTRA
AUTORADIOGRAPHY
HISTOLOGICAL TECHNIQUES
KIDNEYS
MICE
SILVER
STAINS
ANIMALS
BODY
ELEMENTS
MAMMALS
METALS
ORGANS
RODENTS
SPECTRA
TRANSITION ELEMENTS
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology
550501 - Metabolism- Tracer Techniques