Decreased Response to Insulin in Adipose Tissue during Starvation: Effect of Hypophysectomy and Growth Hormone Administration

Fasting for twenty-four hours or longer reduced basal glucose oxidation and incorporation into lipid in rat adipose tissue. The “in vitro” effect of 50 and 100 μU./ml. insulin was also found to be significantly decreased. A ten-fold increase in insulin concentration increased glucose metabolism to levels comparable to those observed in tissues from fed rats. Hypophysectomy diminished markedly the difference in response to insulin between fed and fasted rats. Injection of 50 μgm. of growth hormone every twelve hours restored this difference. It is concluded that adipose tissue responsiveness to insulin is markedly reduced by fasting and that the hypophysis is implicated in this phenomenon. Growth hormone appears to be one of the factors that mediates this change in insulin response.