The effects of 2 microtubular-disruptive drugs, colchicine and vinblastine, on the phytohaemagglutinin (PHA)-induced blast transformation and mitogenic stimulation of human lymphocytes were studied. Both drugs markedly inhibited cell growth and DNA synthesis and lowered the mitotic index. No microtubules were seen with the electron microscope in cells treated with PHA plus colchicine or vinblas...

When prepared by methods utilized in our laboratory, pure populations of Schwann cells in culture do not divide, but, after recombination with peripheral sensory neurons or their processes, proliferate rapidly (Wood and Bunge, 1975, Nature (Lond.) 256:661--664). In this paper, we demonstrate that a membrane fraction prepared from sensory ganglion neurites is also mitogenic for Schwann cells and...

Recent studies show that nonamidated gastrins (Gly-gastrin and progastrin) stimulate colonic proliferation. However, the role of nonamidated vs. amidated gastrins in colon carcinogenesis has not been defined. We measured intermediate markers of carcinogenesis in transgenic mice overexpressing either progastrin (hGAS) or amidated gastrin (INS-GAS) in response to azoxymethane (AOM). The hGAS mice...

Insulin-like growth factors (IGFs) are potent mitogens for FRTL5 rat thyroid follicular cells. IGFs also synergize the independent mitogenic effects of thyrotropin-stimulating hormone (TSH) and other agents that increase intracellular AMP concentration. We examined whether FRTL5 cells and M12 cells, a TSH-independent mutant cell line derived therefrom, secrete IGF that regulates the growth of r...