[The influence of CCNU (lomustine) on the neurosecretion of hypothalamic nuclei and the neurohypophysis during early stages of extrauterine development of the rat].

Abstract

The hypothalamo-neurohypophyseal neurosecretory system was investigated in 8-, 15- and 30-day-old rats subjected to three intragastric doses of CCNU - 12.5 mg/kg b. wt. each on the 3rd, 5th and 7th day after birth. Neurosecretory neurons in the hypothalamus were visualized in the paraffin sections by the immunoenzyme (PAP) technique using antibodies against neurophysin and by Gomori chrome-hematoxylin staining. Accumulation of neurophysin was observed in these cells after treatment with CCNU. Karyometric measurements showed an increase of the mean nuclear cross-section area in PVN neurons in 8-day-old rats exposed to CCNU. In four experimental rats disseminated intracerebral hemorrhagic foci were present. Plasma osmolality was far below the normal values on the 8th day, on the 15th day of life it shifted to hyperosmolality and returned to normal at the age of 30 days. Discussion of the results leads to the conclusion that the increase of the neurosecretory function observed in this experiment was secondary to vasogenic changes.