Starvation-induced changes in insulin binding to hypothalamic receptors in the rat

Publisher Website
Google Scholar
Abstract
To determine whether insulin binding to receptors in the CNS can be modified by changes in energy balance, hypothalami from 48 h food deprived and 14 day food restricted (8 or 4 g chow/day) rats were removed and insulin binding to partially purified membranes from both medial and lateral hypothalamic regions was studied. Hypothalamic insulin concentration was measured in similarly treated animals. Although hypothalamic insulin concentration did not vary, insulin binding to lateral receptors was significantly lower than that obtained from the medial region. After prolonged food restriction, binding to medial receptors was significantly reduced in comparison to controls, whereas binding in the lateral region remained unchanged; differences were most pronounced at near-physiological insulin concentrations. Changes in percent specific [125I]insulin binding were associated with corresponding changes in maximal insulin-binding capacity, the latter being inversely related to receptor affinity for this hormone. Insulin, acting via hypothalamic receptors, may serve as a metabolic feedback signal linking the periphery with central body weight regulatory mechanisms.