Coexistence of intestinal trefoil factor (hITF) and oxytocin in magnocellular neurons in the human hypothalamus

Human intestinal trefoil factor hITF, a polypeptide of the P-domain family, was found to occur in hypothalamic neurons. With combined immunofluorescen ce and immunoperoxidase technique we investigated the coexistence of hITF w ith the neurohypophysial peptide oxytocin and the associated neurophysin I in sections of the human hypothalamus. In the supraoptic nucleus, 39.2% of magnocellular oxytocinergic perikarya show hITF immunoreactivity. A similar distribution was observed in perivascular hypothalamic oxytocinergic neuro ns, whereas in the paraventricular nucleus, 99% of the oxytocinergic neuron s show hITF coexpression. In the periventricular nucleus (PEV), single, sca ttered neurons with both immunoreactivities occur. Our findings indicate th at hITF and oxytocin are coexpressed in a portion of the magnocellular neur ons in the human hypothalamus, and that hITF is among the neurohypophysial peptides.