Prolonged effects of fasting-refeeding on rat adipose tissue lipoprotein lipase activity: influence of caloric restriction during refeeding.

We studied lipoprotein activity in white adipose tissue of male rats during a 3-day fast and up to 21 days of refeeding. Changes in LPL were considered in relation to concomitant changes in fat cell size. During fasting fat cell size decreased and LPL activity declined markedly (80%). With ad libitum refeeding LPL activity returned to control values by 3 or 5 days of refeeding, increased above control values (60-100%) by 10 days of refeeding and returned to control values by 20 days of refeeding. The normalization and overshoot of LPL activity preceded and accompanied increases in fat cell size, which occurred between days 5 and 10 of refeeding; LPL activity returned to control values Only after fat cell size also returned to control values. Mild food restriction (approximately 25%) during refeeding allowed LPL activity to return to control values but reduced the magnitude and duration of the overshoot. Severe food restriction (approximately 50%) during refeeding delayed the return of LPL activity to control values until day 20 of refeeding. These data support a role for LPL in restoration of adipocyte lipid stores during refeeding. Food restriction during refeeding influences LPL and may modulate the rate of lipid accumulation by adipocytes during refeeding.