Early effects of total pancreatectomy on fat metabolism in the rat

Within 2 hours after ‘total’ pancreatectomy in fasting rats blood concentrations of glucose, ketone bodies and total lipids were significantly elevated. Blood ketone bodies and total lipids increased before the blood glucose reached diabetic levels. The increase in blood lipids was due largely to triglycerides and was accompanied by accumulation of fat in the liver and kidneys. When depleted of body fat prior to surgery, pancreatectomized rats did not develop ketosis, hyperlipemia or fatty liver and kidneys. Repeated injections of insulin started immediately after pancreatectomy prevented development of diabetes. When insulin was given for the first time 1 day after pancreatectomy, blood glucose, ketone bodies and fats were lowered to normal fasting levels within 3 hours; 2 days after pancreatectomy, blood glucose and fats were reduced to normal levels whereas the ketonemia, although somewhat decreased, remained high. The rapid changes in blood ketone bodies are interpreted as evidence of a direct insulin action on liver. The decreased insulin effect on ketonemia in rats deprived of insulin for 2 days may indicate development of hepatic resistance to insulin.

The relationship of hyperglycaemia to hyperlipaemia and ketonaemia in depancreatized baboons (Papio ursinus)

The influence of pancreatectomy on the blood sugar and on the serum lipids and ketone bodies has been examined in fifteen male baboons while receiving insulin as well as during periods of insulin deprivation. In insulin-treated baboons, a daily hyperglycaemia, alternating with periods of reduced blood-sugar concentration, was not associated with the development of a lipaemia. During insulin withdrawal, it was shown that (1) hyperlipaemia, cholesterolaemia, phospholipaemia and ketonaemia developed consistently in all baboons; (2) hyperglycaemia preceded lipaemia by 24–48 hr; (3) the triglycerides were the most sensitive fraction of the serum lipids, largely accounting for the initial lipaemia following insulin deprivation and showing the most rapid decline during the 24 hr following the re-administration of insulin; and (4) insulin exerted a transitory action on the blood sugar but a more prolonged one on the serum lipids. It is suggested that this differential action of insulin on the blood sugar and on the blood fats might assist in interpreting the seeming inconsistency between the severity of the diabetes and the observed levels of the blood fats in man.

No direct relationship could be established between the severity of the lipaemia or of the hyperglycaemia and the severity of the ketosis in insulin-deprived, depancreatized baboons. It is suggested that the wide variations in the levels of the serum lipids and of the ketone bodies following insulin withdrawal are indicative of subtle individual differences in the relative intensity of activity of the endocrine glands, particularly the adrenal cortex, the thyroid and the pituitary, in each baboon at any given moment.

Influence of insulin on protein metabolism and cardiac glycogen in Houssay animals

The urinary nitrogen excretion of hypophysectomized-depancreatized (Houssay) cats on constant diets was measured before and during the administration of insulin. Metabolic periods of 4–8 days were used. Nitrogen retention occurred in the absence of the anterior pituitary, when urinary glucose was reduced by 5 gm or more during insulin treatment. Otherwise, retention of nitrogen did not occur. Conventional calculation of the total utilization of glucose for these and control groups of animals suggest that the amount of change in glucose utilization and secondary hormonal effects exert more influence on protein metabolism than the actual amount of carbohydrate used. Restoration of hepatic tissue (protein) was grossly demonstrable. In animals lacking insulin, the anterior pituitary, or both, cardiac glycogen appeared to be significantly related to the level of blood glucose.

Pancreatectomy diabetes in the rat as influenced by strain, age and sex

Partial pancreatectomy was performed on young and adult rats of the Wistar and the Osborne-Mendel strains. All operations were done by the same operator to minimize effects of variation in technique. Observation of the resulting alterations in glucose metabolism revealed: a) strain difference. Osborne-Mendel animals were frequently made diabetic but Wistar animals never; b) sex difference. Males developed diabetes with four times the frequency of the females, a sex difference opposite to that found in alloxan diabetes production; c) age difference. Surgery in the immature animal was much more often successful in producing diabetes than it was in the adult.

Effects of small daily doses of growth hormone on nitrogen output in normal and depancreatized dogs

Storage of nitrogen was readily detected in normal bitches which received daily subcutaneous injections of 1.0 mg of purified growth hormone, and was very large after daily doses of 2.5–5.0 mg. In depancreatized bitches, receiving constant amounts of food and insulin, 2.5–5.0 mg daily doses of the same growth hormone preparations either failed to induce nitrogen storage, or caused nitrogen loss. Nitrogen storage was readily induced in depancreatized bitches by large single doses of purified growth hormone preparations, if the dose of insulin was adequately increased during the following days; a small daily dose of growth hormone, accompanied by an even greater increase in insulin dosage, was less effective. Failure to induce nitrogen storage in depancreatized animals with growth hormone alone occurred in experiments in which glucosuria was not increased; with growth hormone and additional insulin, nitrogen storage was induced despite a large increase in glucosuria. These findings suggest: that growth hormone and insulin are both involved in induction of nitrogen storage, that the function of growth hormone is not merely one of stimulating insulin output, and that the function of insulin in this connection is not purely one of counteracting the unfavorable effect of growth hormone on carbohydrate utilization.