Gonadotropins cross the vascular endothelial barrier to reach their target organs.
Hormone concentrations in blood are very low and fluctuate rapidly to give sharp biological
effects. Nonspecific transendothelial transport mechanisms are slow and markedly concentration
dependent. There is thus a need for specific transendothelial transport mechanisms
for these hormones. We will describe a specific transcytosis mechanism involving endothelial
lutropin/chorionic gonadotropin (LH/CG) receptors identical to those observed in the
target Leydig cells. A new role for the LH/CG receptor as a transcytotic carrier of
its ligands in endothelial cells is suggested.
LH/CG receptor - endothelial cells - receptor-mediated transcytosis - lutropin - protein
hormones
