Effects of prolonged fasting on glucose-3H3 metabolism in rat
Piccardo, M.G.; Buono, A.; Marchetti, A.M.
Bollettino della Societa Italiana di Biologia Sperimentale 54(20): 2035-2037
1978
ISSN/ISBN: 0037-8771 PMID: 753297 Document Number: 127002
Using glucose-3-3H as a marker the effect of starving rats for 72 h was compared with that of withholding food for only 12 h. It was discovered incidentally that the rats that received no food for 72 h had lost 20% of their weight, and these animals showed a pronounced snesitivity to an i.p. injection of the anesthetic thiopental, since there was a 30% mortality among them. The anesthesia was preliminary to incannulation of the caudal vein for the infusion of the labeled glucose. The glycemia of the rats after 72 h fasting was radically reduced compared with the groups fasting only 12 h. The rates of production (gluconeogenesis) and utilization of glucose were only 1/2 those of the rats on the 12 h fasting regime. Rats on a 72 h fast derive their glucose only from gluconeogenesis, and the amount of glucose generated from muscular amino acids, lactate, pyruvate and glycerol from intermediate metabolism apparently were materially restricted under prolonged fasting.