Lack of Substantial Neuroendocrine Changes in Short-Term High Dose Cadmium treated Rats

A 35-day cadmium (Cd) 5 mg/kg/day treatment, by oral gavage did not modify adrenal cortex, Leydig cells, thyroid function or autacoid 5-hydroxytryptamine peripheral metabolism but it increased urinary catecholamine excretion and decreased hypothalamic 5-hydroxytryptamine levels. Remarkable Cd concentrations were found at the renal and adrenal level, thymus and spleen on a decreasing scale. Cd brain and testicular concentrations did not change, neither were their histological features appreciable modified. Renal tissue showed marked degenerative changes. The increase in catecholamine excretion may indicate an activation of chromaffin tissue and peripheral adrenergic neurotransmission. Hypothalamic 5-hydroxytryptamine changes focus attention on possible subtle changes of neurotransmitters of the median eminence area, involved in the pituitary control, with a blood-brain barrier more permeable than other areas of the brain.