STARVATION METABOLISM AND PLASMA CORTICOSTERONE WITH REFERENCE TO ACTIONS OF METOPIRONE AND PROPYLTHIOURACIL

The body weight of normally feeding rats increased during the night and decreased in the day (3-6%; similar changes were observed in liver (±12%)). These increases in weight occurred during the period of greatest intake of food and water. After 3 days of starvation, carcass and liver lost about 20 and 40%, respectively, of the initial weight. The fat bodies decreased by 50% in 2 days of starvation. There was no change in protein content of liver and carcass. Pretreatment with metopirone or propylthiouracil inhibited the loss of weight in carcass and liver by 70 and 20%, respectively. Thyroxine restored the normal weight loss in starved, metopirone-treated animals. Plasma corticosterone was measured at 12-hour intervals in normally feeding and starved rats. Removal of food at first abolished the diurnal rhythm, and there was a large increase in the steroid concentration. Pretreatment with metopirone prevented this rise in corticosterone. There was an increase in the activity of tyrosine-α-oxoglutarate transaminase in the liver of starved rats, and the activity of the enzyme fluctuated in line with the variations in plasma corticosterone. In contrast, the total activity of glutamate-pyruvate transaminase increased gradually during 3 days of starvation (fourfold increase). Liver glycogen had fallen to zero by the second day of starvation; it then increased, and by the third day it had reached a concentration which was about 35% of that in fed animals. Starvation resulted in an increase of 60-80% in the concentration of free tyrosine and phenylalanine in liver. After the first 24 hours the concentration of tyrosine fluctuated and was inversely related to the activity of tyrosine transaminase. © 1968.