Distribution of the C-terminal glycopeptide of the vasopressin prohormone in rat brain: An immunocytochemical study

The distribution of the C-terminal glycopeptide of the vasopressin prohormone was mapped in rat brain by an immunocytochemical method using antibodies to the sheep glycopeptide. The antibodies did not react with vasopressin, oxytocin or their related neurophysins. Stained neural perikarya were observed in the hypothalamus (suprachiasmatic, paraventricular, and supraoptic nuclei) and in the bed nucleus of the stria terminalis. Fibres were detected in the hypothalamus and in extrahypothalamic regions (the frontal cortex, the lateral septum, the bed nucleus of the stria terminalis, the medial nuclei of the thalamus, the lateral habenula, the amygdala, the mesencephalic central gray, the raphe nucleus of the solitary tract and the cervical spinal cord). The distribution of glycopeptide immunoreactive cells was generally similar in young rats (8 weeks old) to the distribution in older rats (13 weeks old) except in the bed nucleus of the stria terminalis where stained neurons were relatively sparse or absent in the younger animals. Similarly, in the young rats the density of fibres containing the glycopeptide was reduced in territories innervated by the bed nucleus. In both young and old rats the neuronal distribution of the glycopeptide was identical to the distribution of vasopressin, which suggests that the glycopeptide and vasopressin are co-transported from the sites of biosynthesis to the sites of release.