| Popis: |
The hypothalamus was identified many years ago as an important site in the regulation of body weight (Hetherington and Ranson, 1940). Although the metabolic messenger(s) responsible for transmitting information regarding adipose energy stores to this site was unknown, numerous investigations suggested that a circulating product of adipose tissue was the agent involved. This unidentified entity was made more tangible in the late 1950s by classic parabiosis experiments, which surgically linked rodents bearing induced lesions of the ventromedial nucleus (Hervey, 1959) to intact controls. In these rats that featured conjoined circulatory systems, the lesioned animals rapidly became obese as a result of hyperphagia, while intact control animals lost body weight due to decreased food intake. Although these studies directly supported the prevailing theories of lipostasis, the identity of the putative “satiety factor” remained a mystery until quite recently. |
