Anatomical mapping of the rat hypothalamus for calcitonin-induced anorexia

The primary physiological function of calcitonin, a peptide hormone secreted by the thyroid gland, is to modulate plasma calcium concentrations. Calcitonin also has several effects on the central nervous system including an inhibition of feeding behavior. In the present study synthetic salmon calcitonin (15 ng in 0.3 microliter) was found to produce a marked suppression of eating when infused in several hypothalamic areas. The greatest inhibition was produced by infusions into the paraventricular nucleus of the hypothalamus, the perifornical area and several areas on the floor of the hypothalamus. A less marked inhibition of eating was produced by infusions in the nucleus accumbens. Infusions in the olfactory tubercule, the ventrolateral hypothalamus, the medial forebrain bundle and the posterior nucleus of the hypothalamus had no effect. It is concluded that the anorectic effects of calcitonin on the central nervous system are mediated by several hypothalamic and extrahypothalamic sites.