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L Peyrin

Publications and source records attributed to L Peyrin.

At least 91 records · Page 5Linked to original sources
PubMed1980

[Primary postural hypotension. Physiopathological study of 8 cases (author's transl)].

Physiological tests showed that both branches of the baroreflex arc-vagal cardiomoderator and, predominantly, sympathetic vasoconstrictor--were affected. There was no rise in serum and urinary noradrenaline levels in standing position, and adrenaline concentrations were rarely increased under induced hypoglycaemia. Dopamine beta-hydroxylase activity and reactivity of the renin-angiotensin-aldosterone system remained normal in most cases. Physiopathologically, the two clinical forms described (i.e. with and without central nervous symptoms) cannot be differentiated.

Aged↗
PubMed1980

Sex differences in the sympatho-adrenal response to isometric exercise.

The effects on heart rate, blood pressure, and plasma catecholamines (epinephrine, norepinephrine, dopamine) of sustained isometric contraction (SIC) were studied in six women and nine men. Each subject held a tension equivalent to 30% of maximal handgrip strength until exhaustion. There were no significant differences between women and men in the duration of handgrip. Rise of heart rate and blood pressure were similar for women and men. Considering the absolute plasma levels of each catecholamine, no sex differences was observed at rest and at any time during SIC, except for epinephrine whose concentration was higher in men at first min of SIC. On the other hand, women and men exhibited different adrenergic patterns in response to SIC: in the first min of exercise the plasma level of the three catecholamines increased in men whereas for women plasma catecholamines levels were essentially unaffected. Thus, epinephrine seems to play a minor role in the regulation of heart rate and blood pressure during SIC for women. Another interesting result of our study is that SIC is able to induce an increase in dopamine plasma level for women as well as for men.

Adult↗
PubMed1980

Sex differences in the adrenergic response to hypoglycemic stress in human.

We have found different patterns of adrenergic response to insulin-induced hypoglycemia in men and women. The differences involve the readiness of adrenergic reactivity, the magnitude of the responses, and the nature of secreted amines. In men, a strong and transient discharge of epinephrine (E) is observed in plasma, corresponding to a great increase in the urinary level of this amine in the 2 h period following insulin. In women, the adrenergic response is delayed and consists of moderately increased amounts of E and norepinephrine (NE) which persist in plasma for a longer period. From the correlations observed between urinary amount and the increase of plasmatic catecholamines after 30, 45, and 60 min, it may be assumed that urinary data may reflect the cumulative plasma levels of catecholamines in the corresponding period, but not the precise pattern of plasmatic changes. Our findings show that the differences in adrenergic behavior previously observed in men and women under the effect of psychological stress, may also be induced by a metabolic stimulus such a insulin hypoglycemia; however, women, but not men, exhibit a mild release of NE under this metabolic stress.

Adult↗
PubMed1980

Dietary induced changes in catecholamine metabolites in rat urine.

The influence of dietary conditions on the excretion of catecholamine metabolites has been investigated in rats. Four groups of rats were nourished over several days, with the usual cereal rat chow (A) or a synthetic complete food (B) or 15% milk (C) or 12% sucrose solution (D). Interference from cereal-rich diet was observed on most metabolites: dopamine (DA), 3-O-methyldopamine (3-MT), 3,4-dihydroxyphenylacetic acid (DOPAC), norepinephrine (NE) and epinephrine (E). The cereal-induced interference was the highest for conjugated DA metabolites. Sucrose diet suppressed the chemical dietary interferences on DA metabolites but induced sympathetic hyperactivity, together with sustained changes in lipid metabolism, as previously observed in sucrose overfeeding. Milk diet induced too catecholamine release but did not reduce dietary interference on DA and 3-MT. From these results, we conclude that the synthetic cereal-free meal B is convenient in studies including most catecholamine metabolites, except for conjugated DOPAC. In the latter case, sucrose diet proofs more appropriate, provided it is used over a short period.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1980

Neonatal pattern of adrenergic metabolites in urine of small for gestational age and preterm infants.

Catecholamines (DA, NE, E), methoxyamines (MT, NMN, MN), DOPA and DOPAC were studied in urine of term small for gestational age infants (SGA) and preterm with appropriate birthweights for gestational age (PT) during the first ten days of life. Results were compared to values obtained for full term infants (FT). As a whole no deficit in urine catecholamines was observed in either group of SGA and PT neonates suggesting that capacities to synthesize catecholamines are already developed at birth. Furthermore, in SGA infants, adrenergic function seems to be enhanced during the first four days of life; however, SGA infants with low blood glucose levels excreted amounts of epinephrine similar to those of FT neonates, but much lower than those obtained in normoglycemic SGA neonates. These data suggest that enhanced release of catecholamines is required in SGA infants to maintain the glycemic homeostasis. In premature infants, the adrenergic pattern was highly altered only in younger preterm neonates (31 weeks of gestational age) who excreted more catecholamines than older preterm babies (33 to 36 weeks) or full term neonates; this catecholamine increase in urine of young preterm infants might be related to immaturity of storage vesicles and/or to thermoregulatory or respiratory events. On the other hand, a striking deficit in excretion of DOPAC was observed in small for gestational age infants and in young preterm neonates during the first ten days of life. DOPAC excretion was even lower in SGA than in young preterm neonates. These findings suggest that the maturation of dopaminergic neurons occurs late in gestational age and is greatly dependent on nutritional factors.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1980

Catecholamine-fuel interrelationships during exercise in fasting men.

Adrenergic response to exercise and the relationships between plasma catecholamines and blood energetic substrates were studied in sedentary men after 15 h of fasting. Subjects pedaled a bicycle ergometer until exhaustion at a work load approximating 80% maximal oxygen consumption. Working ability was diminished by the fast (P less than 0.025). Resting plasma norepinephrine level was increased by fasting. During exercise plasma epinephrine (E) and norepinephrine (NE) concentrations were more elevated in fasting subjects than in fed subjects. Plasma catecholamine (CA) levels in fasting men correlated with blood glucose, blood lactate, and plasma glycerol concentrations. There was no significative correlation between CA and plasma free fatty acid (FFA) levels. The increased adrenergic activity in fasting subjects correlated with reduced endurance time. This study emphasizes the role of CA release, probably combined with other hormonal factors, in the mobilization of energy substrates during submaximal exercise.

Adrenal Medulla↗
PubMed1980

Urinary excretion of catecholamines and metabolites in the Lyon strain of genetic hypertensive rats.

Urinary catecholamines (Norepinephrine : NE, Epinephrine : E) methoxylated amines (Metanephrine : MN, Normetanephrine : NMN) and 3-methoxy-4-hydroxyphenylglycol (MHPG) have been studied in the Lyon hypertensive strain of rats (LHS) and their normotensive controls (LNS) at three ages (5, 9 and 21 weeks) characteristic of the development of hypertension. In 5-week-old rats, increased excretion of E, MN, NMN and early elevation of the ratio E/E+NE were observed, thus suggesting a sympatho-adrenal hyperactivity, with accelerated maturation of E secretion. At adult age, the excretion of most adrenergic metabolites was similar in the two strains of rats. However, the data from adult LHS are difficult to interpret because of a potential renal impairment at this age. Furthermore, there was a positive correlation between systolic blood pressure and urinary catecholamines at 5 weeks and 9 weeks of age but not at 21 weeks. It is suggested that the early sympathoadrenal hyperactivity, which disappears with age, may be related to the onset of hypertension in the Lyon strain of hypertensive rats.

Adrenal Glands↗
PubMed1980

[Relation between dopamine and serotonin motor effects on isolated rat duodenum. Possible participation of an excitatory dopaminergic receptor].

The experimental facts presented here allow us to establish a relationship between DA motor effects on isolated rat duodenum, studied in a previous work, (excito-motor between 10(-9) M and 10(-5) M and inhibitor beyond 10(-5) M) and the functional aptitude of this duodenum to answer to 5-HT : 5-HT excito-motor effects are amplified by DA at concentrations less than or equal to 2.6 X 10(-6) M and on the contrary antagonized by DA at concentrations above 5 X 10(-6) M. On the other hand, DA excito-motor effects do not appear on 5-HT-desensitized duodenums. The study of 5-HT dose-response curves in the presence of different concentrations of DA suggests that the amplification of serotonergic effects observed with small DA concentrations can be possibly related to the additional effects of 5-HT on its own receptors and of DA on another receptor. The receptor involved in DA excito-motor action seems to be closely related to the 5-HT receptor since its effects are blocked by the same molecules (methylsergide, cyproheptadine) and since DA excito-motor action is no more evident on 5-HT-desensitized duodenums, but several arguments support the specificity of this receptor for DA (though it is not blocked by haloperidol). Some of its effects are in line with those of DA receptors made conspicuous in other territories and not blocked by haloperidol : central and human colon receptors. On the contrary, DA used at high concentrations (greater than or equal to 5 X 10(-6) M) seems to be able to occupy serotonergic sites, preventing 5-HT access to its receptors until its concentration is high enough to displace DA. From a functional point of view, this antagonistic effect of DA at high concentrations against 5-HT excito-motor effects could facilitate alpha- and beta-mediated inhibitory effects.

Acetylcholine↗
PubMed1979

[Adrenergic response to intense muscular activity in sedentary subjects as a function of emotivity and training].

Seven male sedentary human subjects were studied during intense muscular work (80% of maximal oxygen uptake) performed either for 15 min or until exhaustion (mean duration: 47 +/- 2 min). Plasma catecholamines were estimated before and after the experiment by means of an original fluorimetric assay. Epinephrine or norepinephrine were individually isolated from plasma and assayed in single extracts by a highly sensitive fluorimetric method. Epinephrine and norepinephrine levels as low as 15 ng per liter were detectable by this procedure in human plasma. The adrenergic pattern was found to be greatly different from one subject to another and related to emotivity: the effect of this factor was revealed by the predominance of epinephrine in plasma at rest or under exercise (ratio NA/A less than 1). In nonemotive subjects (ratio NA/A greater than 1 at rest) plasma epinephrine and norepinephrine increased progressively during exercise. Increments after exercise were higher for norepinephrine changes; however, the fact that epinephrine concentrations correlated significantly with norepinephrine suggests a simulataneous and coordinated stimulation of adrenal glands and orthosympathetic nervous system. In emotive subjects (ratio NA/A less than 1 at rest) the apprehension of muscular work promoted a difference in catecholamine responses: norepinephrine release was not affected by subject's anxiety, while epinephrine secretion, already elevated before the test, reached a high degree of magnitude in the first minutes of muscular work, remaining nearly constant until exhaustion. Physical training of nonemotive subjects, during 2 months with two intense exercises by a week, reduced strongly norepinephrine release after exhaustive muscular work. In the same conditions, the adrenal-medullary response was not significantly modified when compared with untrained subjects. Our results suggest that the adrenergic behaviour during exercise is a function of effort intensity to be supplied; catecholamines seem to be important factors in regulating body homeostasy during muscular work in man. In addition, emotive subjects exhibit amplified adrenal-medullary response, which may be related to psychological stimuli.

Anxiety↗
PubMed1979

The pattern of urinary catecholamines and their metabolites in Duchenne myopathy, in relation to disease evolution.

In this report we have tried to determine whether or not catecholamines are involved in the progressive muscular dystrophy. Catecholamines and their metabolites were studied in urines of children with Duchenne disease or other forms of myopathy (limb-girdle and facio-scapulo humeral myopathies). Catecholamine deaminated metabolites were normal in either form of myopathy; in contrast, Duchenne patients, contrarily to other children, eliminated excessive amounts of most amines (catecholamines and methoxylated amines) in relation to age and degree of disease evolution. Our results indicate that catecholamines are not the primary factors involved in the pathogenesis of Duchenne myopathy, but are rather secondary to some disease effects. It is suggested that the high excretion of catecholamines and their methoxylated amine metabolites observed in severely affected Duchenne boys might be related to thermoregulatory process or/and to alterations in some enzymatic systems.

Adolescent↗
PubMed1979

Age-related changes in catecholamine metabolites of human urine from birth to adulthood.

Catecholamines (dopamine [DA], norepinephrine [NE], epinephrine [E]), methoxyamines (3-methoxytyramine [MT], normetanephrine [NMN], metanephrine [MN]), DOPA, and acidic metabolites (3,4-dihydroxyphenylacetic acid [DOPAC], vanilmandelic acid [VMA]) were determined in human urines from one day of age to adulthood, in order to investigate sympatho-adrenal development during life. All adrenergic compounds are present in neonate urines on the first day of life, but their postnatal evolution is quite different according to the nature of metabolites. Daily E, MN and VMA amounts remain low until the 10th month of life; daily NE, MT and DOPA levels increase progressively, but, in contrast, NMN amounts are already high in the neonatal period and increase only beyond the fourth year of age. DA is at either age the predominant catecholamine but its elimination is relatively more important in the neonatal period.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1979

Metabolic adrenergic changes during submaximal exercise and in the recovery period in man.

The urinary excretion of dihydroxyphenylalanine (DOPA), catecholamines (CA) [dopamine (DA), norepinephrine (NE), and epinephrine (e)], their 3-O-methylated derivatives [3-O-methyldopamine (3-MT), normetanephrine (NMN), and metanephrine (MN)], and their deaminated metabolites [dihydroxyphenylacetic acid (DOPAC) and vanilmandelic acid (VMA)] was studied in six healthy men, at rest during short-term (15 min) or exhaustive submaximal exercise, and in the 2-h postexercise recovery period. During short-term exercise only NE and VMA excretions increased, whereas in postexercise period only DA output was enhanced. Exhaustive muscular work induced a rise in NE and E excretion during the test, and an increase in DA, NE, and NMN urinary levels during postexercise recovery, while the output of deaminated metabolites was unaltered. It is concluded that both release and synthesis of CA are stimulated by submaximal exercise, which induces, in addition to NE, a specific release of DA. A possible role of NE in lipid mobilization during recovery from exhaustive muscular work is evoked. The origin and role of released DA are also discussed.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1979

[Changes in blood levels of noradrenaline in man following short and long term exogenous infusion].

Norepinephrine (NE) was infused in four normal men in doses of 1.5, 6.0 and 9.0 microgram/min for 60 min. The rise in plasma NE was observed only after 5 min and steady state plasma NE and infusion rates. The calculated turnover time averaged 35 sec for 1.5 microgram/min infusion and 20 sec for both 6.0 and 9.0 microgram/min infusion experiments. These differences may be explained by adjustments occurring in inactivation processes in relation to infused doses. A basal endogenous overflow rate of 15 ng kg-1 min-1 was calculated for NE. In the month following NE infusion plasma concentrations decreased exponentially but remained above preinfusion values during about 10 days. The above results confirm the important role of inactivation mechanisms to remove NE from plasma and show that the amine taken up by sympathetic neurons may be released over a long period following the end of infusion.

Adult↗
PubMed1979

[Effects of precursors and metabolites of catecholamines on motricity of isolated rat duodenum. Particular reference to dopamine].

Studying the effects, on the isolated rat duodenum motricity, of ten compounds precursors or metabolites of catecholamines, the following results were obtained: The direct metabolites of epinephrine and norepinephrine (metanephrine, normetanephrine), are either ineffective at concentrations below 5 X 10(-6) M, or weakly inhibitory at higher concentrations. Such inhibitory effects are prevented by alpha- and beta-blockers. 3-methoxy, 4-hydroxyphenylglycol and vanylmandelic acid have no significant effect. The catecholamine precursor, dopamine, the related compounds DOPA, 3 methoxytyramine, and to a lesser extent, 3-O methyl DOPA and homovanillic acid, have excito-motor effects at concentrations ranging mainly from 10(-7) M to 10(-5) M. At higher concentrations, the same compounds frequently exhibit inhibitory effects. The excito-motor effects might be due to a serotoninergic mechanism, since they are suppressed by the serotoninergic blocking agents methysergide and cyproheptadine. Furthermore, in the case of DOPA, we were able to establish a relationship between the excito-motor effects and duodenal serotonin stores. As for the inhibitory effects, they may be prevented by using alpha and beta blocking agents. Dihydroxyphenylacetic acid has no effect on the isolated rat duodenum motricity. The fact that dopamine and related compounds may have excitomotor effects at some concentrations, correlated with some physiopathological observations in man and animal allows some considerations about the eventual role of dopamine on intestinal motricity.

Animals↗
PubMed1979

[Malignant pheochromocytoma].

The reported incidence of malignant pheochromocytoma varies from series to series. In this series 4 cases (7.2 p. 100) were observed out of a total of 55. In two cases the tumour progressed rapidly but in the other two cases, metastases were detected 3 to 12 years after the apparent cure of a histologically benign pheochromocytoma. The urinary levels of catecholamines and their metabolites gave no indication of the underlying malignancy. The diagnosis was only made from the clinical and radiological detection of metastases (2 hepatic, 2 bone). There is no satisfactory treatment and various therapeutic methods have to be used in succession; surgery for a single metastasis, radiotherapy and antiadrenergic agents to combat clinical manifestations. The natural history of this tumour is relatively long.

Adrenal Gland Neoplasms↗