Extra sugar during ether and nitrous oxide narcosis in fully phlorhizinized dogs. Sources of error in existing methods for the study of gluconeogenesis

Dogs were prepared by injecting subcutaneously I gram of phlorhizin suspended in olive oil once every twelve hours until the G: N ratio was constant, then every 24 hours.

It has been observed by Lusk 1 that fasting and phlorhizin alone do not remove all glycogen from the body. This was confirmed for dogs prepared in the manner described. Such animals were narcotized with ether, nitrous oxide and other narcotics. Narcosis with ether and nitrous oxide was always followed by a large increase of the glycosuria with a rise in the G: N ratio. When ether and chloroform were used, there was as a rule, a fall in the output of nitrogen and acetone bodies and a fall in sugar following the initial rise, but with nitrous oxide the rise in sugar was unaccompanied by such changes. In one of the ether experiments also the fall in nitrogen was very slight and there was no lessening of the glycosuria following the initial increase.

An animal prepared in the usual way was given a cold bath for 20 minutes followed by 6 hours of moderate shivering. After this 1 mg. of epinephrine was given intravenously once every 6 hours.

At first there was a marked increase in the glycosuria, but ultimately the G : N ratio resumed the normal level and was little affected by epinephrine. Nitrous oxide narcosis was then induced as before. The extra sugar for :24 hours was now 1.8 g. as compared with a minimum of 7 g. in two previous experiments.

It is concluded that the “extra” sugar which is eliminated when phlorhizinized dogs are narcotized with ether and nitrous oxide has its origin in glycogen; that the increase in glycosuria incidental to narcosis is a phenomenon which can occur independently of any fall in nitrogen or decrease of the acetone body output.