Share This:
https://ntp.niehs.nih.gov/go/7259

Abstract for IMM87036 - Tertiary butylhydroquinone (TBQ) (CASRN 1948-33-0)

Abstract

The following abstract presents results of a study conducted by a contract laboratory for the National Toxicology Program (NTP). The findings have not been peer reviewed and were not evaluated in accordance with the levels of evidence criteria established by the NTP on March 2009 (see http://ntp.niehs.nih.gov/ntp/htdocs/levels/09-3566%20NTP-ITOX-R1.pdf). The findings and conclusions for this study should not be construed to represent the views of the NTP or the US Government.

Immunotoxicity of Tertiary butylhydroquinone (TBQ)
(CAS No. 1948-33-0)

Final Range-Finding Report in Female B6C3F1 Mice
NTP Study Number: IMM87036

Summary

Tertiary butylhydroquinone (TBQ) is a potent antioxidant which has a wide distribution in cosmetics and in the food supply. The available toxicology data indicates that TBQ has few toxicities at the maximum tolerated dose. There are no studies conducted on the potential immunotoxicity of TBQ. Hydroquinones have been shown to be myelotoxic; thus, the immune system may represent a possible target. As a result of the wide usage of TBQ, it was selected by the NTP for immunotoxicological assessment.

The doses selected for evaluation of the immune system as a target for toxicity were 25, 75 and 150 mg/kg. Higher doses of 200 mg/kg/day for 14 days had lethal actions in the B6C3F1 mouse; thus, the high dose used in the immunotoxicity evaluation is considered to be a maximum tolerated dose for 14 days of oral exposure.

TBQ at doses between 25 and 150 mg/kg administered for 14 days by gavage produced only slight alterations in two innate immune activities. There was a slight increase in the amount of the 3rd component of complement, a slight increase in FC mediated adherence and phagocytosis by peritoneal adherent cells, and a slight increase in natural killer cell activity. These increases in innate immune response may be a physiological response to TBQ. All other immune parameters assessed were unaffected. Host resistance to one bacterial challenge (Streptococcus pneumoniae) and the B16F10 pulmonary tumor challenge were not altered by TBQ exposure. In the basic toxicology studies, liver and spleen weight increased slightly, reticulocyte number increased, total number of the polymorphonuclear leukocytes decreased, and blood glucose increased slightly in mice treated with TBQ. From previous studies on fate and distribution, there is good reason to believe that TBQ was well absorbed and distributed to the immunocompetent cells and did not cause an adverse effect. The endpoints evaluated are shown is Tables ES-1, ES-2 and ES-3.

The studies were conducted at the Medical College of Virginia Immunotoxicology Laboratory under NTP Contract No. ES 55094. The in-life phase of the studies was conducted between 5 May 1987 and 15 December 1987. The animals were housed in the animal facility of the Strauss Building.

The study director was Albert E. Munson. Kimber L. White, Jr., Michael P. Holsapple, S. G. Bradley, J. Ann McCay, Helen H. Lysy, and Deborah L. Musgrove were the major participants in the studies.

To the best of our knowledge, no significant deviations occurred that affected the quality of the data and the ability to interpret the data with respect to the immunotoxicology of tertiary butylhydroquinone.

 

Table ES-1
SUMMARY TABLE FOR TOXICOLOGY STUDIES
Tertiary Butylhydroquinone

Parameter Results

Periodic Weights

No Effect

Gross Pathology

No Effect

Hispathology

No Effect

Organ Weights

Liver

Increased

Spleen

Increased

Lungs

No Effect

Thymus

No Effect

Kidney

No Effect

Brain

No Effect

Hematology

RBCs

No Effect

Retic's

Increased

Leukocytes

No Effect

Leukocyte Diff

 

    Lymphocytes

No Effect

    Neutrophils

Decreased

Serum Chemistries

SGPT

No Effect

Albumin

No Effect

BUN

No Effect

Glucose

Increased

Total Protein

No Effect

Bone Marrow

Cellularity

No Effect

DNA Synthesis

No Effect

Stem Cells

 

    CFU-GM

No Effect

    CFU-M

No Effect

 

Table ES-2
SUMMARY TABLE FOR IMMUNOLOGY STUDIES
Tertiary Butylhydroquinone

Parameter Results

T Cells

No Effect

B Cells

No Effect

IgM AFC to sRBC

No Effect

IgG AFC to sRBC

No Effect

DHR to KLH

No Effect

Mitogens - Con A

No Effect

        - PHA

No Effect

        - LPS

No Effect

        - Medium

No Effect

MLR

No Effect

 

 

NK Cell Activity

Increased

 

 

Serum Complement

 

CH50

No Effect

C3

Increased

Macrophage (RES)

No Effect

 

 

Macrophage (Peritoneal)

 

Cell #

No Effect

Differential

 

    Lymphocytes

No Effect

    Poly's

No Effect

    Monocytes

No Effect

Phagocytosis Cova

No Effect

Phagocytosis cRBC

Increased

Adherence of cRBC

Increased

 

Table ES-3
SUMMARY TABLE FOR HOST RESISTANCE STUDIES
Tertiary Butylhrodroquinone

Model Results

Streptococcus pneumoniae

No Effect

B16F10 Melanoma

No Effect


Return to Organ Systems Toxicity Abstracts