Intercellular hormones

Abstract

The proliferation-promoting effect of products from damaged cells appears to be due to a variety of substances, among which are known growth factors and adenine nucleotides. Damaged-cell products caused increased growth of yeast when added to media well supplemented with biotin, panto-thenic acid, folic acid, thiamine, riboflavin, nicotinic acid, pyridoxine, choline, and amino-acids. Addition of adenosine triphosphate produced the same effect as addition of the damaged cell products. Adenosine triphosphate, muscle adenylic acid, and adenosine, but not yeast adenylic acid or yeast nucleic acid, increased the growth rate of yeast in synthetic media, with or without the addition of growth factor and amino-acid supplements. Certain adenine nucleotides act as growth factors. The metabolic effects of damaged-cell products were reproduced by a combination of known growth factors and adenosine triphosphate.