CONTROL OF CELL MULTIPLICATION - PREPARATION AND IMMUNOLOGICAL COMPARISON OF INHIBITORY FACTORS IN HOMOGENATE AND PERFUSATE OF ADULT RAT-LIVER

  • 1 January 1978
    • journal article
    • research article
    • Vol. 28  (3) , 169-175
Abstract
The control of organ cell multiplication by a negative feed-back mechanism implies that factors of the inhibitory mechanism are present in the blood and are produced by the target organ itself. The inhibitors present in the cytosol of adult rat liver and in efferent fluid from an isolated perfused organ were examined. These 2 materials yielded predominantly protein molecules having in common a MW of approximately 80,000 daltons and an isoelectric point between pH 8-9. They inhibit both the multiplication of LF hepatoma cells in vitro and the DNA synthesis in the remnant liver following partial hepatectomy in rats. The inhibitors were compared immunologically. When antibodies against the cytosol inhibitor were tested with the Ouchterlony technique against either the original antigen or the inhibitory fraction isolated from the perfusion effluent, a common precipitation line appeared. The inhibitory activity of both the cytosol and the perfusate was neutralized by prior incubation with anti-cytosol antibodies. These results, which strongly suggest a common inhibitor in the cytosol and the perfusate, strongly support the hypothesis of a feed-back mechanism for the control of liver cell proliferation.

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