Hydrocephalus-Induced Changes in the Endocrine Hypothalamus of the Hamster

Hydroceplanllus-induced changes in intracranial pressure (ICP), ventricular size, periventricular edema and erytlirocyte density(ED), median eminence thickness, and pituitary gland morphology were determined in adult female hamsters (Mesocricetus auratus). Hydrocephalus (HC) was induced by intracisternal injection of kaolin (0.03 ml, 50 mg/ml saline); controls did not receive kaolin. Animais were chronically cannulated and ICP measured periodically (Camino V 420). At selecied times control and treated animals were decapitated, brains removed with the pituitary gland attached and fixed by immersion in formalin. Coronal brain slices containing the paraventricular nuclei (PVN), supraoptic nuclei (SON), suprachiosmatic nuclei (SCN), subfornical organ (SFO) and median eminence (ME) were prepared using a rodent brain matrix slicer and ventricular arca was quantitated by morphometric analysis (Jandel Video Analysis System). Samples were collected from the cortex and periventricular white matter (containing the PVN, SON, and SCN) and the median eminence. The whole pituitary gland was also collected for determination of specific gravity by linear density column method. Erythrocyte Densiry was assessed by immersing hydrocephalic brain slices containing the select nuclei in Karnoviskys fixative on day 9 post HC induction, and in simerythrocytes stained for endogenous peroxidase by tretramethyl benzidine cylochemistry to facilitate visualization. Previous studies in our laboratory have establislied that HC can result in alterations in estrous cycle, water balance, food intake and growth. The result in part from decrease perfusion of the endocrine liypothalamus and pituitary gland, edema and pressure-induced changes in the median eminence structures.