Abstract
Hypothalamic neurosecretion in the dog was observed in the early period of post-natal development with the following results.
The earliest sign of production of secretory material was observed as a kind of nuclear secretion, and the widely known cytoplasmic secretory activity was found to follow the initial activity of the nucleus.
Nuclear secretion was learned to be characteristic to juvenile cells with enlarged nuclei.
Occurrence of nuclear secretion, initiation and development of cytoplasmic neurosecretion showed marked disagreement in the cellular activity between the supraoptic and the paraventricular nuclei in the course of post-natal growth of the dog, which suggests possible functional discrepancy of the nuclei from each other.
