INFLUENCE OF MESOXALATE AND VARIOUS HORMONES ON CARBOHYDRATE METABOLISM IN ISOLATED RAT DIAPHRAGM IN VITRO

SUMMARY 1. The effect of hypophysectomy, or of adrenalectomy, and injection of pituitary growth hormone (GH) or of cortisol, on the uptake of glucose and the incorporation of glycine into protein by isolated rat diaphragm, and the effect of the addition of insulin in vitro on these processes, has been studied. 2. Both hypophysectomy and adrenalectomy raised the uptake of glucose by isolated diaphragm, while treatment of the intact or of the hypophysectomized rat with GH, or of the intact or of the adrenalectomized rat with cortisol, depressed it. Although hypophysectomy and adrenalectomy did not influence the additional glucose uptake induced by 200 mu./ml. of insulin in vitro, both these operations enhanced the effect of 0·1–1·0 mu./ml. of insulin on glucose uptake by diaphragm in vitro. Treatment of the rat with GH or cortisol diminished the rise in glucose uptake of diaphragm induced by 0·1–1·0 mu./ml. insulin. 3. Hypophysectomy depressed, and administration of GH to the intact or hypophysectomized rat raised, the incorporation of glycine into protein of the isolated diaphragm, but neither of these operations altered the magnitude of the stimulation of incorporation induced by 1·0 mu./ml. insulin. 4. Adrenalectomy raised, and administration of cortisol to the intact or adrenalectomized rat depressed, the incorporation of glycine into protein of the isolated diaphragm; adrenalectomy enhanced, the injection of cortisol diminished, the effect of 1·0 mu./ml. insulin on these processes. 5. The possibility that GH directs insulin towards the stimulation of protein synthesis, in part by restraining the action of insulin on carbohydrate metabolism, is discussed.

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THE ADRENAL CORTEX AND EFFECTS OF ADRENALINE ON CARBOHYDRATE METABOLISM IN THE ISOLATED RAT DIAPHRAGM

Acta Endocrinologica ◽

10.1530/acta.0.0440090 ◽

1963 ◽

Vol 44 (1) ◽

pp. 90-100

Author(s):

P. R. Bouman ◽

W. Dermer

Keyword(s):

Glucose Uptake ◽

Carbohydrate Metabolism ◽

Glycogen Content ◽

Qualitative Change ◽

Glycogen Metabolism ◽

Synergistic Action ◽

Rat Diaphragm ◽

Glycogen Deposition ◽

Isolated Rat

ABSTRACT The in vitro effects of adrenaline on glycogen metabolism and glucose uptake were studied in diaphragms of intact, adrenalectomized and adrenodemedullated rats decapitated under »Nembutal« anaesthesia. Adrenalectomy and pretreatment of adrenalectomized rats with cortisol caused an increase in the net loss of glycogen induced by adrenaline. When glycogen deposition in the absence of adrenaline was also taken into account, the overall magnitude of the glycogenolytic response appeared to be unchanged. The apparent qualitative change in response induced by these procedures was attributed to increased initial glycogen values. In diaphragms of adrenalectomized and adrenodemedullated rats the response to adrenaline was identical, the initial glycogen content being the same in these preparations. None of the experimental procedures affected the variable inhibition of glucose uptake by adrenaline. These results do not favour the existence of a »permissive« or synergistic action of adrenocortical steroids with regard to the effects of adrenaline on peripheral carbohydrate metabolism.

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EFFECTS OF ADRENALINE ON CARBOHYDRATE METABOLISM IN THE ISOLATED DIAPHRAGM OF INTACT AND ADRENALECTOMIZED RATS AS INFLUENCED BY »NEMBUTAL« ANAESTHESIA

Acta Endocrinologica ◽

10.1530/acta.0.xxxv0541 ◽

1960 ◽

Vol XXXV (IV) ◽

pp. 541-550 ◽

Cited By ~ 7

Author(s):

P. R. Bouman ◽

W. Dermer

Keyword(s):

Glucose Uptake ◽

Carbohydrate Metabolism ◽

Glycogen Content ◽

Glycogen Metabolism ◽

Rat Diaphragm ◽

Simultaneous Inhibition ◽

Glycogen Deposition ◽

Isolated Rat ◽

Adrenalectomized Rats

ABSTRACT Hemidiaphragms of intact and adrenalectomized rats which had been killed by decapitation, were incubated for 1 hour at 37° C under aerobic conditions. Glucose uptake and glycogen deposition were determined. Addition of adrenaline in vitro (1 μg/ml) caused a substantial decrease in glucose uptake in both types of diaphragms, this decrease being equivalent to a simultaneous inhibition of glycogen deposition. »Nembutal« anaesthesia prior to decapitation was found to alter the response to adrenaline. This change was most clearly observed in diaphragms of adrenalectomized rats. Here, adrenaline mainly affected glycogen metabolism by way of glycogen degradation, whereas the overall magnitude of the response was not materially changed. However, glucose uptake appeared to be only slightly decreased by adrenaline under these conditions. The change in response to adrenaline was attributed to the higher initial glycogen content observed in diaphragms of nembutalized rats. It was suggested that prevention of an acute release of endogenous adrenergic substances, occurring after decapitation of unanaesthetized donor rats, may be the actual cause of this phenomenon. Attention was drawn to the significance of the initial glycogen content as an important factor in carbohydrate metabolism of the isolated rat diaphragm.

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Effect of a Prolonged Fast on the Apparent Galactose Uptake of the Isolated Rat Diaphragm in vitro

Nature ◽

10.1038/179967a0 ◽

1957 ◽

Vol 179 (4567) ◽

pp. 967-968

Author(s):

JEDDI HASAN

Keyword(s):

Rat Diaphragm ◽

Prolonged Fast ◽

Diaphragm In Vitro ◽

Isolated Rat

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SENSITIVITY OF THE RAT DIAPHRAGM TO GROWTH HORMONE.

Acta Endocrinologica ◽

10.1530/acta.0.0540645 ◽

1967 ◽

Vol 54 (4) ◽

pp. 645-662 ◽

Cited By ~ 8

Author(s):

Å. Hjalmarson ◽

K. Ahrén

Keyword(s):

Growth Hormone ◽

Inhibitory Effect ◽

Rat Diaphragm ◽

Intracellular Accumulation ◽

Slight Effect ◽

Kidney Capsule ◽

Muscle Tissues ◽

Hypophysectomized Rats ◽

Isolated Rat

ABSTRACT The effect of growth hormone (GH) in vitro on the rate of intracellular accumulation of the non-utilizable amino acid α-aminoisobutyric acid (AIB) was studied in the intact rat diaphragm preparation. Bovine or ovine GH (25 μg/ml incubation medium) markedly stimulated the accumulation of AIB-14C by diaphragms from hypophysectomized rats, while there was no or only a very slight effect on diaphragms from normal rats. In diaphragms from rats with the pituitary gland autotransplanted to the kidney capsule GH in vitro stimulated the accumulation of AIB-14C significantly more than in diaphragms from normal rats but significantly less than in diaphragms from hypophysectomized rats. Injections of GH intramuscularly for 4 days to hypophysectomized rats made the diaphragms from these rats less sensitive or completely insensitive to GH in vitro. These results indicate strongly that the relative insensitivity to GH in vitro of diaphragms from normal rats is due to the fact that the muscle tissues from these rats has been exposed to the endogenously secreted GH. The results show that GH can influence the accumulation of AIB-14C in the isolated rat diaphragm in two different ways giving an acute or »stimulatory« effect and a late or »inhibitory« effect, and that it seems to be a time-relationship between these two effects of the hormone.

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