Independence of circulating insulin levels of the increased glucose turnover in shivering dogs

In dogs, selective insulin deficiency induced by simultaneous somatostatin and glucagon infusion does not alter the high rate of glucose utilization provoked by acute cold exposure. However, both in resting and in shivering dogs, lowering of plasma insulin decreases plasma glucose metabolic clearance significantly.     

Initiation of shivering in unanaesthetized dogs by local cooling within the vertebral canal

Zusammenfassung Bei unnarkotisierten Hunden konnte durch lokale Kühlung im Wirbelkanal bei indifferenter Umgebungstemperatur Kältezittern ausgelöst werden. Dieser an Tieren mit nicht beeinträchtigter Temperaturregulation erhobene Befund weist darauf hin, dass im Wirbelkanal temperaturempfindliche Strukturen lokalisiert sind, die an der Regelung der Wärmeproduktion mitbeteiligt sein können.     

Effects of anaesthesia and chronic catheterization on circulating levels of prostaglandins (PGE2 and PGF2a in dogs

Summary Chronic catheterization of aorta and inferior vena cava in dogs did not significantly affect circulating levels of prostaglandins (PGE₂ and PGF_2a ). Pentobarbital (30 mg/kg i.v.) anaesthesia produced a significant decrease in PGF_2a .This work was supported by INSERM (grant No. 76.5.183.5).We wish to thank Miss Laure Eloy and Mrs Annick Soubrier for their technical assistance.     

Effects of captivity on glucose tolerance in dogs

Captivity decreased tolerance to glucose and increased blood serotonin levels in 6 normal dogs investigated. Return to freedom brought normalization in the glucose tolerance test and reverted blood serotonin to control levels.     

Effect of ovariectomy on circulating calcitonin levels in the rat]

Ovariectomy in 3 month-old Rats is followed by a fall in plasma CT level and a decreased secretion of CT after a calcium load. These results show that ovarian hormones may play a role in the direct or indirect control of the secretion of CT in the adult female.     

Influence of sex on the urinary bilirubin excretion at increased free plasma haemoglobin levels in whole dogs and in isolated normothermic perfused dog kidneys

Résumé Si le taux sanguin en hémoglobine libre dépasse les 50 mg/100 ml, l'excrétion rénale de la bilirubine est fortement augmentée chez le chien, tandis qu'elle reste faible chez la chienne. Les mêmes résultats sont obtenues par perfusion de reins isolés avec du sang hépariné ou défibriné.     

Effect of insulin on the glucose uptake of protozoa.

Insulin stimulates the glucose uptake of Tetrahymena pyriformis. This shows the presence of insulin receptors in Tetrahymena, consequently receptors may be present in a level of phylogenesis, where the natural contact between the given hormone and the cell is unnecessary and impossible.     

The urinary excretion of bilirubin after increased plasma hemoglobin concentration in dogs

Résumé L'excrétion rénale de la bilirubine dans l'urine varie entre 0,1 et 0,8 mg par jour dans une série de 113 chiens normaux. Avec une concentration d'hémoglobine plasmatique libre, excédant 50 mg/100 ml, les auteurs ont remarqué une augmentation sensible de l'excrétion urinaire de la bilirubine, sans que les taux sanguin, de la bilirubine ni le clearance de la créatinine soient changés. Les résultats font supposer un métabolisme local de l'hémoglobine en bilirubine dans les reins.     

Tolerance to cold and glucose homeostasis in adrenal demedullated dogs

Summary The rise in O₂ consumption and in glucose turnover, induced by acute cold exposure is not suppressed by adrenal demedullation in dogs. However, both at neutral and cold ambient temperature, the mean plasma glucose concentrations are higher in normal (N) than in adrenal-demedullated dogs (ADMX). In the cold, the fall in rectal temperature is larger in ADMX than in N dogs.This work was supported by a grant from Université Claude Bernard (U.E.R. Lyon Nord and U.E.R. Biologie Humaine).The authors thank D. Rougier and G. Dallevet for their excellent technical assistance and A. Brillant for secreterial assistance.     

Some thoughts on the importance of insulin in the regulation of the blood glucose level

Insulin can influence rates of glucose utilization by muscle and possibly other tissues via both direct and indirect effects. It can control the rate of fatty acid mobilization from adipose tissue and the rate of fatty acid oxidation in muscle, and the latter inhibits glucose utilization and oxidation. Insulin may influence the levels of insulin-like growth factors I and II, both of which have effects on rates of glucose utilization by muscle. The intertissue cycle between glucose and lactate — the Cori cycle, which is influenced by insulin — may provide another novel mechanism for control of blood glucose. How far other anti-insulin hormones affect these processes is not clear.     

Effect of epinephrine upon irreversible disposal and recycling of glucose in dogs

Summary Irreversible utilization and recycling of glucose during epinephrine-induced hyperglycemia were studied in adrenal-demedullated dogs exposed to neutral or cold ambient temperature. Whatever the ambient temperature, most of the extra glucose mobilized by epinephrine is recycled rather than irreversibly utilized by the peripheral tissues.This work was supported by a grant from Université Claude Bernard (U.E.R. Lyon Nord and U.E.R. Biologie Humaine).J. Schellhorn was on leave from the University of Chile. The authors thank D. Rougier and G. Dallevet for their excellent technical assistance.