These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Reversal by ascorbic acid of suppression by endogenous histamine of rat lymphocyte blastogenesis.
    Author: Oh C, Nakano K.
    Journal: J Nutr; 1988 May; 118(5):639-44. PubMed ID: 3367243.
    Abstract:
    Addition of concanavalin A (Con A) to a culture of spleen cells of ODS-od/od rats, which cannot synthesize ascorbic acid, increased the activity of histidine decarboxylase (HDC) in the culture, leading to accumulation of histamine (Hm) in the medium. Treatment of the culture with cimetidine, a type 2 Hm antagonist, enhanced Con A-dependent lymphocyte blastogenesis even in the absence of any exogenously added Hm. Addition of low doses of histaminase increased Con A-dependent lymphocyte transformation. At higher doses, it abrogated the reaction. At concentrations of more than 10(-10) M, exogenously added Hm suppressed the Con A-dependent uptake of [3H]thymidine by the lymphocytes, but it significantly augmented the response at 10(-14) M. The addition of ascorbic acid (10(-8)-10(-5) M) to the culture suppressed the Con A-mediated HDC induction and inhibited Hm biosynthesis. Concomitantly added ascorbic acid at the concentrations of 10(-8)-10(-4) M increased the uptake of [3H]thymidine dependent on Con A or phytohemagglutinin by the lymphocytes. These results suggest that mitogen-dependent lymphocyte blastogenesis is activated by Hm produced by the spleen cells per se. However, when culture was prolonged, high concentrations of Hm suppressed the reaction. Ascorbic acid enhances mitogen-dependent lymphocyte blastogenesis through inhibition of HDC induction, leading to attenuation of immunosuppressive Hm production by the spleen cells.
    [Abstract] [Full Text] [Related] [New Search]