Evidence for the co-expression of oxytocin and vasopressin messenger ribonucleic acids in magnocellular neurosecretory cells: simultaneous demonstration of two neurohypophysin messenger ribonucleic acids by hybridization histochemistry.

A novel enzyme-labelled oligonucleotide probe specific for oxytocin messenger ribonucleic acid (mRNA) and a radiolabelled oligonucleotide probe specific for vasopressin mRNA were used together to visualize both oxytocin and vasopressin mRNA's in hypothalamus sections from salt loaded (2% saline) rats. The results demonstrate that the majority of magnocellular neurons contain only oxytocin or vasopressin mRNA, however a small number of neurons, 1% to 2%, contained both oxytocin and vasopressin transcripts.