Biorhythms of four serum proteins of the laboratory rat: IgG transferrin alpha 2-acute phase protein and a VLD lipoprotein.

Four serum proteins (IgG, alpha 2-macroglobulin or alpha 2-acute phase protein, transferrin and a VLD-lipoprotein) of the rat have been examined wit respect to quantitative alterations reflecting biorhythms. All four proteins show distinct biorhythms. VLDL and alpha 2-AP seem to undergo a common circadian rhythm whereas the circadian rhythms of IgG and transferrin are superimposed by an infradian and ultradian rhythm, respectively. The examined proteins are apparently regulated by different ways possibly dependent in each case on the biological function. By means of chronobiological investigations perhaps further functional characterization of serum proteins are possible and alterations of the biorhythm may give additional information for pharmacological or toxicological research.