摘要:

Blood sugar levels and adrenal weights (where possible) were recorded, after a 24-h fast, in normal intact, adrenal-demedullated, and adrenalectomized rats kept at 4 °C for up to 130 days. These were compared with data from control rats kept at 21 °C. Hypoglycemia (relative to the control value) prevailed in both normal intact and, more profoundly, in adrenal-demedullated rats during the first 24 h of chilling but no deaths occurred. Adrenalectomized rats, whose blood sugar level at 21 °C was subnormal, at 4 °C soon showed extreme hypoglycemia and died. More prolonged chilling in normal intact rats resulted in hyperglycemia which lasted until after the 25th day. In contrast, in chilled adrenal-demedullated animals the blood sugar remained at the control level throughout this period. At the 50th day the blood sugar of normal intact animals fell to the control value and remained so thereafter. A similar fall in adrenal-demedullated rats resulted in hypoglycemia, but a rise to control values was recorded from the 75th day. Adrenocortical hypertrophy was generally more extensive in the demedullated animals than in the normal intact animals but was absent in both groups by the 130th day. We conclude that the adrenal medulla, besides helping to provide extra blood glucose during exposure to short-term chilling, is also responsible for the sustained hyperglycemia of rats chilled for prolonged periods and thus assists in their acclimation to long-term cold stress.

ISSN:0008-4212    

DOI:10.1139/y69-001

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

This study examines the effect of chlorpromazine on the hypermotility and hyperthermia induced by amphetamine in rats and correlates the effects observed with brain levels of the stimulant. Chlorpromazine antagonized these effects of amphetamine initially, and there was a dose–effect relationship in this antagonism. On the other hand, a combination of 7.2 mg/kg chlorpromazine and 8.5 mg/kgdl-amphetamine caused a delayed excitation and hyperthermia. The excitatory effect of this dose of amphetamine was prolonged by doses of chlorpromazine ranging from 1.9 to 7.2 mg/kg. Chlorpromazine modified the disposition of amphetamine as evidenced by considerably higher and more sustained brain levels of the stimulant in rats which received the combined treatment. The significance of these findings and the similarity of the interaction of chlorpromazine and imipramine with amphetamine are discussed.

ISSN:0008-4212    

DOI:10.1139/y69-002

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Immunofluorescence studies showed that, in the species investigated, antisera to growth, hormones localize only in the acidophils of the pituitary gland. Cross-reactions between antigens can be detected by use of this technique even when other methods have failed.

ISSN:0008-4212    

DOI:10.1139/y69-003

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Multiple antigenic sites on growth hormone were determined by the fluorescent-antibody method, with use of heterologous antigen and antisera for inhibition.

ISSN:0008-4212    

DOI:10.1139/y69-004

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Severe myocardial injury was produced in eight anesthetized dogs by the injection of microspheres into the coronary circulation. Cardiac output and renal blood flow were monitored continuously with electromagnetic flow probes around the ascending thoracic aorta and left renal artery respectively. Intravenous infusions of isoproterenol and of dopamine (0.01–0.64 and 0.4–32.0 μg/kg per minute respectively) produced an increase in the cardiac output. Renal blood flow increased with small doses of isoproterenol but tended to decrease with higher doses; in contrast, all doses of dopamine increased renal blood flow. Dopamine was more effective in raising the systemic arterial blood pressure, but also increased cardiac work. Occasional extrasystoles were induced at higher doses of both amines. In three unanesthetized dogs sensitized by prior ligation of a coronary artery, the largest doses of dopamine tested (24–64 μg/kg per minute) did not produce cardiac arrhythmias. However, when dopamine was given to anesthetized dogs during vagal-induced cardiac slowing (a condition conducive to the emergence of ventricular automaticity), arrhythmias were induced. These data suggest that dopamine can increase both cardiac output and renal blood flow after severe myocardial injury, and may be a rational agent in the treatment of cardiogenic shock. Its arrhythmogenic properties would not appear to restrict its use.

ISSN:0008-4212    

DOI:10.1139/y69-005

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

In conscious pancreatic-fistula dogs with low gastroenterostomies the interactions of pancreozymin (PZ) with methacholine were studied. Combinations of methacholine and PZ depressed amylase, lipase, and total protein secretion when doses were high, i.e. above 2 units/min PZ with 2 μg/min methacholine as background, and above 4 μg/min methacholine with 2 units/min PZ as background. Atropine depressed the enzyme response to Boots but not to Jorpes PZ. It did not alter the depression produced by high doses of PZ and methacholine in combination. These data are consistent with the view that the actions of PZ and methacholine on enzyme production are closely related.

ISSN:0008-4212    

DOI:10.1139/y69-006

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Diets of varying thrombogenic potencies were fed to rats for a period of 6 weeks. The thrombogenic potency of these diets was determined by the extent of the hepatic infarcts (consequent upon thrombosis in the hepatic vein) which occurred within 24 h after the injection ofS.typhosaendotoxin. Those groups of rats receiving the low thrombogenic diets were more suitable as controls for the animals on the high thrombogenic diets than were normal rats fed standard laboratory chow. The thrombogenic potency of the diets was inversely related to the ratio of [AMP][ATP]/[ADP]2found in the liver. A decrease in this ratio should favor platelet aggregation, and the results are thus in accord with the hypotheses implicating adenine nucleotides in thrombogenesis. The thrombogenic potency of the diets was directly related to the activity of liver phosphofructokinase. This increase in activity is probably linked to the disturbed adenine nucleotide metabolism. Oxidative phosphorylation mechanisms were investigated as possible causes for the changes in adenine nucleotides, but no important alteration in these reactions could be demonstrated. The exact mechanism by which the thrombogenic diets alter the adenine nucleotide ratio and the phosphofructokinase activity remains to be elucidated.Des rats ont été nourris pendant 6 semaines avec des régimes de forces thrombogènes variées. Cette capacité thrombogène est évaluée d'après la sévérité des infarcti hépatiques (provoqués par un thrombus dans la veine hépatique) que l'on trouve en dedans de 24 h après l'injection d'endotoxine deS.typhosa. Les groupes de rats sur régimes thrombogènes à force faible constituent de meilleurs groupes témoins que ne le sont des animaux, recevant un régime usuel. La force thrombogène de ces régimes est en relation inverse avec le rapport [AMP][ATP]/[ADP]2que l'on trouve dans le foie. Un abaissement de ce rapport devrait favoriser l'agrégation des plaquettes sanguines; les résultats obtenus supportent les hypothèses selon lesquelles les nucléotides d'adénine sont impliqués dans la thrombogénèse. L'activité de la phosphofructokinase est augmentée en relation directe avec la force thrombogène des régimes. Cette augmentation est probablement liée au métabolisme anormal des nucleotides d'adénine. Aucun changement n'a pu être décelé dans les mécanismes de phosphorylation oxydative, qui pourraient provoquer des altérations dans le métabolisme des nucléotides d'adénine. Le mécanisme exact par lequel les régimes thrombogènes agissent au niveau des nucléotides d'adénine et de la phosphofructokinase est inexpliqué.

ISSN:0008-4212    

DOI:10.1139/y69-007

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Ninety-day-old male and female rats of the Wistar strain were force-fed a liquefied diet twice daily for a 2-week experimental period. The amounts fed corresponded to ad libitum intakes of similar groups of animals fed the diet in the dry state. The animals were adjusted to the feeding technique for 1 week prior to the experimental period. At the end of the experimental period the carcasses of the force-fed animals and the ad libitum control groups were analyzed for fat, nitrogen, and moisture content. The frequency of feeding had no significant effect on percentage carcass fat, but lessened frequency of feeding was associated with a decrease in percentage carcass protein (N × 6.25) which was of slight significance. Subsequently, 35-day-old animals were treated similarly. In the younger animals the method of feeding had a significant effect on carcass fat, with an increase in fat content in the force-fed animals which was apparent in the males but was not of significance in the females. The increased fat deposition in the immature male animals was accompanied by a decreased weight gain. A significant decrease in percentage carcass protein was observed in the immature force-fed animals.

ISSN:0008-4212    

DOI:10.1139/y69-008

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Plasma renin activity, aortic tissue renin, and plasma renin substrate concentrations were measured simultaneously and sequentially in groups of rats after (1) bilateral nephrectomy, (2) water deprivation, and (3) bilateral adrenalectomy. Following nephrectomy, plasma renin activity and aortic tissue renin fell in parallel fashion to undetectable or very low levels after 18 h, whereas the substrate concentration in plasma increased markedly. Rats deprived of water for 3 days, but receiving Purina Chow, showed a significant increase in plasma renin activity and in aortic tissue renin and a marked decrease in plasma substrate concentration. Bilateral adrenalectomy resulted in a. very marked augmentation of plasma renin activity and of aortic tissue renin with a concomitant suppression of plasma substrate concentration. These findings suggest that arterial tissue renin reacts to the same stimuli which modify renin activity in plasma.

ISSN:0008-4212    

DOI:10.1139/y69-009

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The fluorescent histochemical technique of Falck for demonstrating catecholamines in sympathetic nerve fibers was modified for use in brown fat. In normal interscapular and mediastinal brown fat, the nerve fibers surrounded the arterial Mood vessels and all parenchymal cells. Both immunosympathectomy and surgical denervation gave an almost identical histological picture of massive loss of nerves from the blood vessels only. The parenchymal innervation remained intact. The blood vessels retained single isolated nerve fibers, which were relatively more numerous on the small vessels and which were connected with the parenchymal innervation. After sympathetic nerve fibers were depleted of catecholamines by treating the rat with reserpine, the parenchymal nerves reestablished catecholamine fluorescence at a faster rate than the blood vessel nerves. Intrinsic (tissue) ganglia in the brown fat were resistant to immunosympathectomy. These ganglia contained cells which were very brightly fluorescent. These results indicate that there are two anatomically, immunologically, and pharmacologically different nerve supplies to brown fat, one to the blood vessels and the other predominantly to the parenchyma. It was concluded that the parenchymal nerve supply is derived from the intrinsic ganglia via 'short' adrenergic neurons, and the blood vessel innervation is derived from the sympathetic chain via 'long' adrenergic neurons.

ISSN:0008-4212    

DOI:10.1139/y69-010

出版商:NRC Research Press    

年代:1969

数据来源: NRC