Daily pattern of pituitary glutamine, glutamate, and aspartate content disrupted by cadmium exposure.

ABSTRACT

Cadmium is a neurotoxic heavy metal and is considered endocrine disruptor. In this work, we investigate the effects of cadmium on the 24 h changes of aspartate, glutamate, and glutamine content in the pituitary. Adult male Sprague-Dawley rats were treated with 25 or 50 mg/l of cadmium chloride (CdCl(2)) in the drinking water for 30 days. Metal exposure with the lowest dose induced the disappearance of the nocturnal peak of anterior pituitary amino acid content, and the appearance of a peak of glutamine concentration during the resting phase of the photoperiod. After exposure to 50 mg/l of CdCl(2), the peaks of anterior pituitary amino acid content at 1200 and 0000 h disappeared, and two minimal values at these same hours and a peak at 0800 h appeared. In the posterior pituitary, cadmium treatment with the lowest dose induced the appearance of a peak of aspartate and glutamate concentration at 1200 h, and the disappearance of the peak of glutamine content at 1600 h. After exposure to 50 mg/l of CdCl(2) aspartate and glutamate daily pattern presented two maximal values between 0000 and 0400 h, and the metal abolished glutamine daily pattern. These results suggest that cadmium disrupted aspartate, glutamate, and glutamine daily pattern in the pituitary.