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 greater than 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.