The glycogenolytic response to stimulation of the splanchnic nerves in adrenalectomized calves

Edwards, A V; Silver, M.

doi:10.1113/jphysiol.1970.sp009269

Cited by 67 publications

(41 citation statements)

References 22 publications

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“…Several studies showed that plasma glucose concentrations increased immediately after birth, without nutrient intake [68,101]. The rise of glucose concentration in the blood is a result of postnatal glycogenolysis that is associated with an increase in sympathetic efferent activity [102]. Sympathetic activity at birth also increases by as much as six fold, and the plasma free fatty acid concentration in the lamb rises within 2 h of birth [103].…”

Section: Carbohydrate Metabolism and Energy Homeostasismentioning

confidence: 99%

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Endocrine And Metabolic Adaptations Of Calves To Extra-Uterine Life

Kirovski

2015

Acta Veterinaria

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The transition from intra-to extra-uterine life is one of the greatest physiological challenges that occur in the life of animals. Immediately after birth, newborn calves have to adapt to new environmental and feeding conditions. Namely, at birth a break of the thermal balance occurs, since calves abruptly pass from a 38.8°C temperature in utero to an environmental temperature that is generally lower than 20°C. Additionally, at birth, the energy intake shifts from a continuous parenteral supply of nutrients (mainly glucose) to discontinuous colostrum and milk intake with lactose and fat as the main energy sources. Therefore, the most important issues related to metabolic changes during the transition from intra-to extra-uterine life are related to maintaining the homoeothermic conditions and control of energy metabolism. Those metabolic adaptations are under control of the endocrine system that is relatively mature at birth, but still requires morphological and functional changes after birth. Key hormones whose concentrations are signifi cantly changed around birth and are involved in an adequate adaptation of calves to extra-uterine life are those related to stress at birth (cortisol and cathecholamines), glucoregulatory processes (insulin and glucagon), thermogenesis (thyroid hormones) and growth (IGF axis).

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Section: Carbohydrate Metabolism and Energy Homeostasismentioning

confidence: 99%

“…Glycogen stores are rapidly mobilized and broken down in the starved calf [102]. Glucose is used for thermogenesis and for physical activity.…”

Section: Brown Adipose Tissue Metabolism and Thermogenesismentioning

confidence: 99%

Endocrine And Metabolic Adaptations Of Calves To Extra-Uterine Life

Kirovski

2015

Acta Veterinaria

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“…Niijima (16) demonstrated that intravenous injection of glucose increased the efferent ®ring rate in the hepatic branch of the vagus nerve in rats, and that the ®ring rate was directly related to the arterial blood glucose concentration over a range of physiologic concentrations (3.3±25.0 mmol/l). On the other hand, sympathetic stimulation was shown to activate glycogen phosphorylase and glucose-6-phosphatase (G-6-Pase) in rabbits (17) and to deplete hepatic glycogen reserves and increase net hepatic glucose output in calves (18). In 18 h fasted conscious dogs, infusion of somatostatin, 4-fold basal insulin, basal glucagon, and glucose to increase arterial glucose concentrations to 9±11 mmol/l was associated with a 38% reduction in hepatic norepinephrine spillover (19).…”

Section: Autoregulation In Response To Hyperglycemiamentioning

confidence: 99%

Autoregulation of hepatic glucose production

Moore

Connolly

Cherrington

1998

European Journal of Endocrinology

104

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In vitro evidence indicates that the liver responds directly to changes in circulating glucose concentrations with reciprocal changes in glucose production and that this autoregulation plays a role in maintenance of normoglycemia. Under in vivo conditions it is dif®cult to separate the effects of glucose on neural regulation mediated by the central nervous system from its direct effect on the liver. Nevertheless, it is clear that nonhormonal mechanisms can cause signi®cant changes in net hepatic glucose balance. In response to hyperglycemia, net hepatic glucose output can be decreased by as much as 60±90% by nonhormonal mechanisms. Under conditions in which hepatic glycogen stores are high (i.e. the overnight-fasted state), a decrease in the glycogenolytic rate and an increase in the rate of glucose cycling within the liver appear to be the explanation for the decrease in hepatic glucose output seen in response to hyperglycemia. During more prolonged fasting, when glycogen levels are reduced, a decrease in gluconeogenesis may occur as a part of the nonhormonal response to hyperglycemia.A substantial role for hepatic autoregulation in the response to insulin-induced hypoglycemia is most clearly evident in severe hypoglycemia (#2.8 mmol/l). The nonhormonal response to hypoglycemia apparently involves enhancement of both gluconeogenesis and glycogenolysis and is capable of supplying enough glucose to meet at least half of the requirement of the brain. The nonhormonal response can include neural signaling, as well as autoregulation. However, even in the absence of the ability to secrete counterregulatory hormones (glucocorticoids, catecholamines, and glucagon), dogs with denervated livers (to interrupt neural pathways between the liver and brain) were able to respond to hypoglycemia with increases in net hepatic glucose output. Thus, even though the endocrine system provides the primary response to changes in glycemia, autoregulation plays an important adjunctive role. European Journal of Endocrinology 138 240±248

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“…Thus, although experiments in which the peripheral ends of both splanchnic nerves are stimulated maximally for prolonged periods serve to demonstrate the occurrence of glycogenolysis in the liver in response to sympathetic stimulation in adrenalectomized animals, they do not necessarily provide a useful indication of the sensitivity of the underlying mechanism. The hyperglycaemic response to stimulation of the peripheral ends of either the left or the right splanchnic nerve has therefore been examined in greater detail in the adult cat and dog since the response in the calf had been shown to change with age during the first few weeks after birth (Edwards & Silver, 1970).…”

Section: Responses To Stimulation Of Both Splanchnic Nervesmentioning

confidence: 99%

The glycogenolytic response to stimulation of the splanchnic nerves in adrenalectomized calves, sheep, dogs, cats and pigs

Edwards¹

1971

The Journal of Physiology

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SUMMARY1. The effects of stimulation of the peripheral ends of one or both splanchnic nerves have been investigated in calves, sheep, dogs, cats and pigs after removal of both adrenal glands.2. Stimulation of both splanchnic nerves produced comparable hyperglycaemic and glycogenolytic effects in sheep, dogs and cats; the mean liver glycogen concentration was reduced by between 7 0 and 10O5 mg/g, five min after stimulation was discontinued, at which time the mean plasma glucose concentration had risen by between 126 and 137 mg/100 ml.3. In five 3-5 week-old calves which were tested under identical conditions the mean liver glycogen concentration was reduced by 13.3 + 1.9 mg/g and the plasma glucose concentration raised by 216 + 1-9 mg/100 ml., 5 min after stimulation was terminated.4. In pigs, stimulation of both splanchnic nerves invariably produced a rise in the plasma glucose concentration, even when the concentration of glycogen in the liver was less than 5 mg/g before stimulation. The response was, nevertheless, considerably smaller in these animals than in any of the other species investigated.5. Splanchnic nerve stimulation also caused a rise in mean aortic blood pressure and blood haematocrit during the period of stimulation; changes of approximately the same order of magnitude were encountered in all five species.6. Dogs were found to resemble calves in that the hyperglycaemic response to stimulation of a single splanchnic nerve did not differ significantly from that obtained when both were stimulated simultaneously; furthermore, either nerve was found to be equally effective.7. In cats the change in plasma glucose concentration in response to stimulation of a single splanchnic nerve was always less than that which occurred in response to bilateral stimulation although comparable changes in blood haematocrit occurred in both groups of animals.8. It is concluded that stimulation of the splanchnic nerves causes break-down of glycogen in the livers of various unrelated species of adult animals but that the magnitude of the hyperglyeaemic response in the young calf provides further evidence of the importance of the sympathetic system in the control of metabolism in the young animal.

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The glycogenolytic response to stimulation of the splanchnic nerves in adrenalectomized calves

Cited by 67 publications

References 22 publications

Endocrine And Metabolic Adaptations Of Calves To Extra-Uterine Life

Endocrine And Metabolic Adaptations Of Calves To Extra-Uterine Life

Autoregulation of hepatic glucose production

The glycogenolytic response to stimulation of the splanchnic nerves in adrenalectomized calves, sheep, dogs, cats and pigs

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