BODY FAT REGULATION: IDENTIFICATION OF HUMORAL FACTORS

Project: Research project

Description

In 1953 Kennedy proposed the lipostatic theory for the control of body
weight by regulation of total body energy stores. A subsequent parabiosis
experiment implicated a blood borne factor in the feedback regulation of
energy balance suggested that development of obesity led to the production
of a circulating "satiety factor". The factor carried information on the
size of body fat stores to the hypothalamus which then controlled food
itake to correct energy balance. Recently we have reported a specific loss
of fat from parabiotic partners of obese rats, independently of a
significant change in food intake. This implies that, in a situation of
severe obesity, a humoral factor is released to inhibit further fat
deposition. Whether the loss of fat is secondary to development of insulin
resistance in adipocytes remains to be determined. However, this data may
be evidence for humoral agents that play a role in regulation of body fat
independently of long-term control of food intake. A series of experiments has been designed using animal models that are
either parabiotic partners of obese rats or are rats that are recovering
from food deprivation. In each situation adipocyte lipid metabolism and
sensitivity towards lipogenic and lipolytic agents will be examined. We
hope to determine whether body fat is regulated, in part, by changes in
sensitivity towards humoral factors that would promote either lipid
deposition or lipid mobilization. The responses of mature rats,
maintaining a stable body weight, will be compared with those of young rats
that are in a dynamic phase of growth. In addition we intend to use an in
vitro bioassay to partially purify the anti-lipogenic agent that is
produced by obese rats. The proposed experiments provide a novel approach for elucidating
mechanisms that may contribute towards the regulation of body fat content
at a "set-point".
StatusFinished
Effective start/end date4/1/863/31/88

Funding

  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health

Fingerprint

Adipose Tissue
Adipocytes
Obesity
Eating
Fats
Lipid Mobilization
Food Deprivation
Lipid Metabolism
Biological Assay
Hypothalamus
Animal Models
Body Weight
Growth

ASJC

  • Medicine(all)