Immunohistological identification of neurophysin and neurophysin-like substances in different vertebrates

Using rabbit antisera to porcine neurophysin, the immunohistological unlabelled-antibody-peroxidase technique was applied to brains of man, rat, quail, pigeon, tortoise, frog, two cyprinid fishes, sturgeon and lamprey as well as to the urophysis of carp and the brain of the cockroach. In each of the investigated vertebrate speices the magnocellular neurosecretory system is immunoreactive, known to give a specific reaction for neurosecretory material by means of appropriate histological and histochemical methods, too. Moreover, in the rat brain we found immunoreactive material in neurons of the suprachiasmatic nucleus, in the parvocellular part of the paraventricular nucleus, in fibres of the external region of the median eminence and in neurosecretory exohypothalamic fibres. The subcommissural organ and Reissner's fibre as well as the urophysis of the fish spinal cord and neurosecretory cells of the insect brain are devoid of neurophysin or neurophysin-like substances.