Molecular analysis of hprt mutations induced by chromium picolinate in CHO AA8 cells

Virginia H. Coryell, Diane M Stearns

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

Chromium picolinate (CrPic) is a popular dietary supplement, marketed to the public for weight loss, bodybuilding, and control of blood sugar. Recommendations for long-term use at high dosages have led to questions regarding its safety. Previous studies have reported that CrPic can cause chromosomal aberrations and mutations. The purpose of the current work was to compare the mutagenicity of CrPic as a suspension in acetone versus a solution in DMSO, and to characterize the hprt mutations induced by CrPic in CHO AA8 cells. Treatments of 2% acetone or 2% DMSO alone produced no significant increase in 6-thioguanine (6-TG)-resistant mutants after 48 h exposures. Mutants resistant to 6-TG were generated by exposing cells for 48 h to 80 μg/cm2 CrPic in acetone or to 1.0 mM CrPic in DMSO. CrPic in acetone produced an average induced mutation frequency (MF) of 56 per 106 surviving cells relative to acetone solvent. CrPic in acetone was 3.5-fold more mutagenic than CrPic in DMSO, which produced an MF of 16.2. Characterization of 61 total mutations in 48 mutants generated from exposure to CrPic in acetone showed that base substitutions comprised 33% of the mutations, with transversions being predominant; deletions made up 62% of the mutations, with one-exon deletions predominating; and 1-4 bp insertions made up 5% of the characterized mutations. CrPic induced a statistically greater number of deletions and a statistically smaller number of base substitutions than have been measured in spontaneously generated mutants. These data confirm previous studies showing that CrPic is mutagenic, and support the contention that further study is needed to verify the safety of CrPic for human consumption.

Original languageEnglish (US)
Pages (from-to)114-123
Number of pages10
JournalMutation Research - Genetic Toxicology and Environmental Mutagenesis
Volume610
Issue number1-2
DOIs
StatePublished - Nov 7 2006

Fingerprint

CHO Cells
Mutation
Acetone
Dimethyl Sulfoxide
Thioguanine
Mutation Rate
picolinic acid
Safety
Dietary Supplements
Chromosome Aberrations
Blood Glucose
Weight Loss
Exons
Suspensions

Keywords

  • Chinese hamster ovary
  • Chromium picolinate
  • Genotoxicity
  • hprt
  • Mutational spectrum

ASJC Scopus subject areas

  • Health, Toxicology and Mutagenesis
  • Genetics

Cite this

Molecular analysis of hprt mutations induced by chromium picolinate in CHO AA8 cells. / Coryell, Virginia H.; Stearns, Diane M.

In: Mutation Research - Genetic Toxicology and Environmental Mutagenesis, Vol. 610, No. 1-2, 07.11.2006, p. 114-123.

Research output: Contribution to journalArticle

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AB - Chromium picolinate (CrPic) is a popular dietary supplement, marketed to the public for weight loss, bodybuilding, and control of blood sugar. Recommendations for long-term use at high dosages have led to questions regarding its safety. Previous studies have reported that CrPic can cause chromosomal aberrations and mutations. The purpose of the current work was to compare the mutagenicity of CrPic as a suspension in acetone versus a solution in DMSO, and to characterize the hprt mutations induced by CrPic in CHO AA8 cells. Treatments of 2% acetone or 2% DMSO alone produced no significant increase in 6-thioguanine (6-TG)-resistant mutants after 48 h exposures. Mutants resistant to 6-TG were generated by exposing cells for 48 h to 80 μg/cm2 CrPic in acetone or to 1.0 mM CrPic in DMSO. CrPic in acetone produced an average induced mutation frequency (MF) of 56 per 106 surviving cells relative to acetone solvent. CrPic in acetone was 3.5-fold more mutagenic than CrPic in DMSO, which produced an MF of 16.2. Characterization of 61 total mutations in 48 mutants generated from exposure to CrPic in acetone showed that base substitutions comprised 33% of the mutations, with transversions being predominant; deletions made up 62% of the mutations, with one-exon deletions predominating; and 1-4 bp insertions made up 5% of the characterized mutations. CrPic induced a statistically greater number of deletions and a statistically smaller number of base substitutions than have been measured in spontaneously generated mutants. These data confirm previous studies showing that CrPic is mutagenic, and support the contention that further study is needed to verify the safety of CrPic for human consumption.

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