Increased number of hypothalamic [³H](+)-amphetamine binding sites in genetically obese (ob/ob) mice

In genetically obese (ob/ob) mice the development of obesity was correlated with the binding of [³H](+)-amphetamine to the hypothalamus. In 39-day-old ob/ob mice, which had obtained a body weight > 150% of their lean littermates, hypothalamic [³H](+)-amphetamine binding had increased by approximately 60% above levels of their lean littermates. This increased number of hypothalamic [³H](+)-amphetamine binding sites appeared during the onset of obesity and then remained elevated following the most prominent weight gain. Since ob/ob mice are markedly hyperglycemic throughout their life, the increase in [³H](+)-amphetamine binding site density in the hypothalamus may be secondary to elevated blood glucose.