Sodium fluoride-induced changes in the hypothalamic neurosecretory system of the spotted owlet, Athene brama Temminck.

Administration of 10 or 20 mg of sodium fluoride (NaF) induced depletion of neurosecretory material (NSM) from the neurons of the supraoptic (SON) and paraventricular (PVN) nuclei in spotted owlet (Athene brama Temminck). The residual NSM in the perikarya was aranged in caplike paranuclear positions. The NSM in the hypothalamo-hypophysial tract, the zona externa of the anterior median eminence (ME) and in the neural lobe (NL) showed only a partial lossmthe effects of NaF administration on the HNS of the spotted owlet are similar to those induced by such stimulators of ADH secretion as hypertonic saline, morphine and formalin. Hence the histological changes induced by NaF administration in the HNS of the spotted owlet are presumably indicative of increased neurosecretory activity resulting in the augmented secretion of ADH. It is suggested that NaF, like other stressful agents, is a stimulator of ADH secretion.