Differences in the retinol circulating complex between healthy male and female infants.

The concentration of the three components of the retinol circulating complex demonstrates in healthy male infants, but not in females, a transient elevation culminating at 5-6 months after birth. This trimolecular peak is significantly less elevated in bilateral cryptorchid babies. The rise of the retinol related parameters seems directly induced by the testosterone hypersecretion previously described in male infants at 2-3 months. The delay in the liver response in terms of retinol secretion appears to depend on a temporary functional immaturity and/or a transitory depression of the hepatic protein-synthesizing machinery. The surge of the retinol circulating complex could play a crucial role in the O-mannosylation of several glycoproteins involved in male sexual differentiation.