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EFFECT OF ADRENERGIC BLOCKADE ON GLUCOSE AND FATTY-ACID MOBILISATION IN MAN
316 EFFECT OF COMPOUND
38,174
ON CARDIAC RESPONSE TO EXERCISE IN
2
SUBJECTS
EFFECT OF ADRENERGIC BLOCKADE ON GLUCOSE AND FATTY-ACID MOBILISATION IN MAN T. R. E. PILKINGTON M.D. Lond., M.R.C.P. SENIOR LECTURER
R. D. LOWE M.D. Cantab., M.R.C.P. MEDICAL RESEARCH COUNCIL FELLOW
B. F. ROBINSON M.B. Lond., The pulse is slowed, but there is no material change in the cardiac output. Exertional increase in stroke volume is clearly not inhibited.
M.R.C.P.
LECTURER IN MEDICINE
From the Medical Unit, St.
greatly changed, and it is clear that the normal exertional increase in stroke volume was not inhibited. The method used was, however, not sufficiently accurate to determine whether the fall in pulse-rate was fully compensated by an increase in stroke-volume, or whether cardiac output was somewhat reduced. Further studies are in hand to elucidate this point.
not
Discussion
Our
results, which confirm those of Black and Stephenson (1962), show that in man, as in animals, compound 38,174 is an effective antagonist of the beta action of catecholamines. It appears to have no effect on the alpha action, nor to have important direct circulatory activity. The ability to decrease the tachycardia of exercise shows that it can block stimulation by adrenergic nerves as well
by infused amines. The inhibition of adrenaline hyperpnoea is of some physiological interest, since its as
mechanism is still uncertain. Of the other effects, diarrhoea may be due to loss of adrenergic inhibition, comparable to that produced by guanethidine; the mechanism of the remainder is unknown, but a direct action on the central nervous system
EILEEN TITTERINGTON B.Sc. RESEARCH ASSISTANT
George’s Hospital, London, S.W.1
INJECTION of adrenaline raises blood-levels of free fatty acids and glucose (Cannon et al. 1924, Dole 1956, Gordon and Chetkes 1956), but it is not known whether these effects are mediated by a orB receptors (Ahlquist 1948) or by some other mechanism. Investigation of this a and with P blocking agents has given specific problem equivocal results. Schotz and Page (1960) reported that the a-blocking agents, phentolamine and phenoxybenzamine, inhibited the adrenaline-induced release of fatty acids from. isolated rat adipose tissue. However, in the intact dog Mayer et al. (1961) showed that after administration of the B-blocking agent, dichloroisoprenaline (D.C.I.), adrenaline caused less rise of fatty acids and of glucose; this result is difficult to interpret because D.c.1. itself raised the fatty-acid level. A naphthol referred
analogue of isoprenaline (compound 38,174, to as nethalide) has been shown to be a specific {3-receptor adrenergic-blocking agent (Black and Stephenson 1962, Dornhorst and Robinson 1962), and we have therefore used this drug and phenoxybenzamine to study the mechanism of the rise of plasma fatty acids and glucose produced by adrenaline.
now
likely. ability of the drug to increase exercise tolerance in our patients with ischaemic heart-disease is encouraging, and a controlled clinical trial in angina of effort is at present under way at University College Hospital and this hospital. Reduction of adrenergic cardiac stimulation clearly produces no disability in normal subjects. There is, however, reason to think that in circulatory failure the maintenance of cardiac output may critically depend on neurogenic drive, and in such circumstances great caution will be needed in the use of this and similar drugs. seems
The
Summary It has been confirmed in man that 2-isopropylamino-l(2-naphthyl) ethanol hydrochloride (nethalide) is a potent beta-receptor adrenergic-blocking agent. The circulatory and respiratory effect of moderate doses of infused isoprenaline were entirely prevented by tolerable doses of the drug. In normal subjects, and in patients with ischaemic heart-disease, the heart-rate was often slowed by the drug at rest, and always on exercise. Exercise tolerance was increased in some patients with
angina. We would like to thank Mr. W. Brough for technical assistance and Dr. R. D. Lowe for his help with some of the experiments. Compound 38,174 (’ Alderlin ’) was supplied by the Pharmaceuticals Division of Imperial Chemical Industries, Ltd. REFERENCES
Black, J. W., Stephenson, J. S. (1962) Lancet, ii, 311. Dornhorst, A. C., Herxheimer, A. (1958) ibid. ii, 723. Pilkington, T. R. E., Lowe, R. D., Robinson, B. F., Titterington, E. (1962) ibid. ii, 316.
Fig.
1-Effect of intravenous adrenaline on plasma-free fatty acids: after compound 38,174; C, after phenoxybenzamine.
A, control; B,
317
Methods Five healthy men (aged 19-40) were studied. Each subject fasted overnight and rested in the laboratory for 30 minutes before the start of the experiment, which lasted for 90 minutes; saline was infused for 30 minutes at 1 ml. per minute followed by 30 minutes’ infusion of adrenaline (5 (ig. per minute in 4 subjects, 10 tg. per minute in the 5th) and a final 30 minutes’ infusion of saline. All infusions were given from a constant-rate injection apparatus into a forearm vein. Blood samples were taken every 15 minutes from the opposite arm, through skin anssthetised with lignocaine. After the control experiment each subject took compound 38,174 orally for at least 5 days, reaching a final dose of 400-600 mg. daily, and 300 mg. was taken on the morning of the second experiment. In 3 subjects the experiment was again repeated after oral administration of phenoxybenzamine for 5-6 days, reaching a dose of 50-60 mg. daily; the completeness of the a-adrenergic blockade was assessed by infusing noradrenaline (0-05 (j<.g. per minute) into the brachial artery and measuring forearm blood-flow by mercury strain-gauge
plethysmography. Plasma-free fatty acids were estimated by the method of Shafrir and Steinberg (1960) and glucose ’by a modification of the glucose oxidase method of Middleton and Griffith (1957) using a mixture of enzyme, chromogen, and buffer (Boehringer
TC-M-1/15982). Results 1 shows the effect of adrenaline on plasma fatty acids. The normal rise is abolished by compound 38,174 but is unaffected by phenoxybenzamine. In all 3 subjects who took phenoxybenzamine there resulted an effective a blockade, judged clinically by a reduction of over 60% in the constrictor effect of noradrenaline on forearm blood-flow. Fig. 2 shows the effect of adrenaline on blood-glucose concentration. Neither phenoxybenzamine nor compound 38,174 has a conspicuous effect on the rise due to adrenaline, though compound 38,174 slightly raised the
Fig.
and phenoxybenzamine caused moderate increase and delay of the peak level. These results suggest that in man the effect of adrenaline upon fatty acid mobilisation is mediated by the (3-receptors. The action of adrenaline on glucose mobilisation does not seem to be mediated by either a orreceptors.
fasting plasma-glucose, a
Summary The effect of adrenaline infusions upon blood-glucose and free fatty acid concentrations has been studied in man.
The rise of free fatty acids in response to adrenaline is abolished by compound 38,174 (nethalide), a p-adrenergicblocking agent, but not by phenoxybenzamine, an (x-blocking agent. The response of glucose is abolished by neither drug. We are indebted to Dr. T. L. Dormandy for the plasma-glucose estimations, and to Imperial Chemical Industries, Ltd., for supplies of compound 38,174. REFERENCES
Ahlquist, R. P. (1948) Amer. J. Physiol. 153, 586. Black, J. W., Stephenson, J. S. (1962) Lancet, ii, 311. Cannon, W. B., McIver, M. A., Bliss, S. W. (1924) Amer. J. Physiol. 69, 46. Dole, V. P. (1956) J. clin. Invest. 35, 150. Dornhorst, A. C., Robinson, B. F. (1962) Lancet, ii, 314. Gordon, R. S., Cherkes, A. (1956) J. clin. Invest. 35, 206. Mayer, S., Moran, N. C., Fain, J. (1961) J. Pharm. exp. Therap. 134, 18. Middleton, J. E., Griffith, W. J. (1957) Brit. med. J. ii, 1525. Schotz, M. C., Page, I. H. (1960) J. Lipid Res. 1, 466. Shafrir, E., Steinberg, D. (1960) J. clin. Invest. 39, 310.
RECOGNITION OF TRANSFORMED SMALL LYMPHOCYTES BY COMBINED CHROMOSOMAL AND ISOTOPIC LABELS K. A. PORTER M.D., D.Sc. Lond. SENIOR LECTURER IN PATHOLOGY IN THE UNIVERSITY OF LONDON
M.D.
E. H. COOPER D. Phil. Oxon., M.R.C.P.
Lond.,
WATSON-SMITH RESEARCH FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS OF LONDON
From St.
Mary’s Hospital Medical School, London, W.1 AUTORADIOGRAPHIC evidence, based on the fate of cells labelled with tritiated thymidine, strongly suggests that in certain special circumstances some small lymphocytes can transform into large cells with pyroninophilic cytoplasm, and then proliferate. Suitable conditions exist when parental small lymphocytes are injected into Fl hybrids (Gowans et al. 1961), and when adult allogeneic * small lymphocytes are introduced into newborn rats (Porter and Cooper 1962) or lethally irradiated rabbits (Porter et al. 1962). But the correctness of this interpretation depends upon the assumption that re-utilisation of labelled material is insignificant. Recently this assumption has been challenged (Baserga and Kisieleski 1962), the inference being that the large cells may not be transformed small lymphocytes but may simply be host cells which have become labelled by the incorporation of tritiated deoxyribonucleic acid liberated from destroyed donor cells. If it could be clearly established that the isotopically labelled large pyroninophilic cells are of donor origin, these difficulties of interpretation would be resolved. In the experiments to be described here, small lymphocytes labelled with tritiated thymidine were transfused from adult male rats to newly born female rats of a different strain. Use was then made of the certainty with which the Y chromosome can be identified in this species (Tjio and Levan 1956) to demonstrate, by autoradiographs of cell Fig. 2-Effect of intravenous adrenaline on blood-glucose: A, control; B, after compound 38,174 ; C, after phenoxybenzamine.
*’ Allogeneic=genetically different; isogenic= genetically (Gorer et al. 1961).
similar
38,174
ON CARDIAC RESPONSE TO EXERCISE IN
2
SUBJECTS
EFFECT OF ADRENERGIC BLOCKADE ON GLUCOSE AND FATTY-ACID MOBILISATION IN MAN T. R. E. PILKINGTON M.D. Lond., M.R.C.P. SENIOR LECTURER
R. D. LOWE M.D. Cantab., M.R.C.P. MEDICAL RESEARCH COUNCIL FELLOW
B. F. ROBINSON M.B. Lond., The pulse is slowed, but there is no material change in the cardiac output. Exertional increase in stroke volume is clearly not inhibited.
M.R.C.P.
LECTURER IN MEDICINE
From the Medical Unit, St.
greatly changed, and it is clear that the normal exertional increase in stroke volume was not inhibited. The method used was, however, not sufficiently accurate to determine whether the fall in pulse-rate was fully compensated by an increase in stroke-volume, or whether cardiac output was somewhat reduced. Further studies are in hand to elucidate this point.
not
Discussion
Our
results, which confirm those of Black and Stephenson (1962), show that in man, as in animals, compound 38,174 is an effective antagonist of the beta action of catecholamines. It appears to have no effect on the alpha action, nor to have important direct circulatory activity. The ability to decrease the tachycardia of exercise shows that it can block stimulation by adrenergic nerves as well
by infused amines. The inhibition of adrenaline hyperpnoea is of some physiological interest, since its as
mechanism is still uncertain. Of the other effects, diarrhoea may be due to loss of adrenergic inhibition, comparable to that produced by guanethidine; the mechanism of the remainder is unknown, but a direct action on the central nervous system
EILEEN TITTERINGTON B.Sc. RESEARCH ASSISTANT
George’s Hospital, London, S.W.1
INJECTION of adrenaline raises blood-levels of free fatty acids and glucose (Cannon et al. 1924, Dole 1956, Gordon and Chetkes 1956), but it is not known whether these effects are mediated by a orB receptors (Ahlquist 1948) or by some other mechanism. Investigation of this a and with P blocking agents has given specific problem equivocal results. Schotz and Page (1960) reported that the a-blocking agents, phentolamine and phenoxybenzamine, inhibited the adrenaline-induced release of fatty acids from. isolated rat adipose tissue. However, in the intact dog Mayer et al. (1961) showed that after administration of the B-blocking agent, dichloroisoprenaline (D.C.I.), adrenaline caused less rise of fatty acids and of glucose; this result is difficult to interpret because D.c.1. itself raised the fatty-acid level. A naphthol referred
analogue of isoprenaline (compound 38,174, to as nethalide) has been shown to be a specific {3-receptor adrenergic-blocking agent (Black and Stephenson 1962, Dornhorst and Robinson 1962), and we have therefore used this drug and phenoxybenzamine to study the mechanism of the rise of plasma fatty acids and glucose produced by adrenaline.
now
likely. ability of the drug to increase exercise tolerance in our patients with ischaemic heart-disease is encouraging, and a controlled clinical trial in angina of effort is at present under way at University College Hospital and this hospital. Reduction of adrenergic cardiac stimulation clearly produces no disability in normal subjects. There is, however, reason to think that in circulatory failure the maintenance of cardiac output may critically depend on neurogenic drive, and in such circumstances great caution will be needed in the use of this and similar drugs. seems
The
Summary It has been confirmed in man that 2-isopropylamino-l(2-naphthyl) ethanol hydrochloride (nethalide) is a potent beta-receptor adrenergic-blocking agent. The circulatory and respiratory effect of moderate doses of infused isoprenaline were entirely prevented by tolerable doses of the drug. In normal subjects, and in patients with ischaemic heart-disease, the heart-rate was often slowed by the drug at rest, and always on exercise. Exercise tolerance was increased in some patients with
angina. We would like to thank Mr. W. Brough for technical assistance and Dr. R. D. Lowe for his help with some of the experiments. Compound 38,174 (’ Alderlin ’) was supplied by the Pharmaceuticals Division of Imperial Chemical Industries, Ltd. REFERENCES
Black, J. W., Stephenson, J. S. (1962) Lancet, ii, 311. Dornhorst, A. C., Herxheimer, A. (1958) ibid. ii, 723. Pilkington, T. R. E., Lowe, R. D., Robinson, B. F., Titterington, E. (1962) ibid. ii, 316.
Fig.
1-Effect of intravenous adrenaline on plasma-free fatty acids: after compound 38,174; C, after phenoxybenzamine.
A, control; B,
317
Methods Five healthy men (aged 19-40) were studied. Each subject fasted overnight and rested in the laboratory for 30 minutes before the start of the experiment, which lasted for 90 minutes; saline was infused for 30 minutes at 1 ml. per minute followed by 30 minutes’ infusion of adrenaline (5 (ig. per minute in 4 subjects, 10 tg. per minute in the 5th) and a final 30 minutes’ infusion of saline. All infusions were given from a constant-rate injection apparatus into a forearm vein. Blood samples were taken every 15 minutes from the opposite arm, through skin anssthetised with lignocaine. After the control experiment each subject took compound 38,174 orally for at least 5 days, reaching a final dose of 400-600 mg. daily, and 300 mg. was taken on the morning of the second experiment. In 3 subjects the experiment was again repeated after oral administration of phenoxybenzamine for 5-6 days, reaching a dose of 50-60 mg. daily; the completeness of the a-adrenergic blockade was assessed by infusing noradrenaline (0-05 (j<.g. per minute) into the brachial artery and measuring forearm blood-flow by mercury strain-gauge
plethysmography. Plasma-free fatty acids were estimated by the method of Shafrir and Steinberg (1960) and glucose ’by a modification of the glucose oxidase method of Middleton and Griffith (1957) using a mixture of enzyme, chromogen, and buffer (Boehringer
TC-M-1/15982). Results 1 shows the effect of adrenaline on plasma fatty acids. The normal rise is abolished by compound 38,174 but is unaffected by phenoxybenzamine. In all 3 subjects who took phenoxybenzamine there resulted an effective a blockade, judged clinically by a reduction of over 60% in the constrictor effect of noradrenaline on forearm blood-flow. Fig. 2 shows the effect of adrenaline on blood-glucose concentration. Neither phenoxybenzamine nor compound 38,174 has a conspicuous effect on the rise due to adrenaline, though compound 38,174 slightly raised the
Fig.
and phenoxybenzamine caused moderate increase and delay of the peak level. These results suggest that in man the effect of adrenaline upon fatty acid mobilisation is mediated by the (3-receptors. The action of adrenaline on glucose mobilisation does not seem to be mediated by either a orreceptors.
fasting plasma-glucose, a
Summary The effect of adrenaline infusions upon blood-glucose and free fatty acid concentrations has been studied in man.
The rise of free fatty acids in response to adrenaline is abolished by compound 38,174 (nethalide), a p-adrenergicblocking agent, but not by phenoxybenzamine, an (x-blocking agent. The response of glucose is abolished by neither drug. We are indebted to Dr. T. L. Dormandy for the plasma-glucose estimations, and to Imperial Chemical Industries, Ltd., for supplies of compound 38,174. REFERENCES
Ahlquist, R. P. (1948) Amer. J. Physiol. 153, 586. Black, J. W., Stephenson, J. S. (1962) Lancet, ii, 311. Cannon, W. B., McIver, M. A., Bliss, S. W. (1924) Amer. J. Physiol. 69, 46. Dole, V. P. (1956) J. clin. Invest. 35, 150. Dornhorst, A. C., Robinson, B. F. (1962) Lancet, ii, 314. Gordon, R. S., Cherkes, A. (1956) J. clin. Invest. 35, 206. Mayer, S., Moran, N. C., Fain, J. (1961) J. Pharm. exp. Therap. 134, 18. Middleton, J. E., Griffith, W. J. (1957) Brit. med. J. ii, 1525. Schotz, M. C., Page, I. H. (1960) J. Lipid Res. 1, 466. Shafrir, E., Steinberg, D. (1960) J. clin. Invest. 39, 310.
RECOGNITION OF TRANSFORMED SMALL LYMPHOCYTES BY COMBINED CHROMOSOMAL AND ISOTOPIC LABELS K. A. PORTER M.D., D.Sc. Lond. SENIOR LECTURER IN PATHOLOGY IN THE UNIVERSITY OF LONDON
M.D.
E. H. COOPER D. Phil. Oxon., M.R.C.P.
Lond.,
WATSON-SMITH RESEARCH FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS OF LONDON
From St.
Mary’s Hospital Medical School, London, W.1 AUTORADIOGRAPHIC evidence, based on the fate of cells labelled with tritiated thymidine, strongly suggests that in certain special circumstances some small lymphocytes can transform into large cells with pyroninophilic cytoplasm, and then proliferate. Suitable conditions exist when parental small lymphocytes are injected into Fl hybrids (Gowans et al. 1961), and when adult allogeneic * small lymphocytes are introduced into newborn rats (Porter and Cooper 1962) or lethally irradiated rabbits (Porter et al. 1962). But the correctness of this interpretation depends upon the assumption that re-utilisation of labelled material is insignificant. Recently this assumption has been challenged (Baserga and Kisieleski 1962), the inference being that the large cells may not be transformed small lymphocytes but may simply be host cells which have become labelled by the incorporation of tritiated deoxyribonucleic acid liberated from destroyed donor cells. If it could be clearly established that the isotopically labelled large pyroninophilic cells are of donor origin, these difficulties of interpretation would be resolved. In the experiments to be described here, small lymphocytes labelled with tritiated thymidine were transfused from adult male rats to newly born female rats of a different strain. Use was then made of the certainty with which the Y chromosome can be identified in this species (Tjio and Levan 1956) to demonstrate, by autoradiographs of cell Fig. 2-Effect of intravenous adrenaline on blood-glucose: A, control; B, after compound 38,174 ; C, after phenoxybenzamine.
*’ Allogeneic=genetically different; isogenic= genetically (Gorer et al. 1961).
similar