The formation of collagen fibrils under physiological conditions of ionic strength, pH and temperature was markedly affected by the presence of small amounts of bovine tendon glycoprotein. The absorbance of the gels at 400nm was decreased, and they took longer to form. Over the range of concentration tested, the negative specific absorbance, -AA,p., and the specific retardation, Rs,., both increased with the glycoprotein to collagen ratio.When added during the nucleation phase, glycoprotein was still able to exert its effect almost fully, and so must act to inhibit the later stages of fibril formation. Several pieces of evidence showed that glycoprotein acts via a weak binding to the collagen molecule. Electron microscopy established that fibrils formed in the presence of glycoprotein had a normal cross-striation pattern, but were significantly thinner than fibrils formed in control gels. The results suggest that glycoprotein could act in tissues to help regulate the diameter of collagen fibrils.

ExtractMaternal rats were underfed during pregnancy and lactation. At 7 days of age their offspring received one injection of sheep erythrocytes. The immune response (hemolytic plaque-forming cells in spleen and thymus) to this antigen showed a peak at 15 days of age in undernourished rats, 2 days later than in normal animals. However, the size of this response at its peak was, in the undernourished group, at least appropriate for body weight. Growth retardation during the fetal and suckling periods resulted also in an increased rate of uptake of 3 H-corticosterone into spleen and thymus in vivo. Speculation

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