摘要:

SUMMARYCatecholamines and physical exercise are known to influence the metabolism of several minerals in man, but the effects on magnesium (Mg) have been scarcely investigated. In the present study, infusion of adrenaline (5 μg/min for 30 min followed by 10 μg/min for 30 minutes) significantly reduced the plasma Mg levels in healthy males. This effect was abolished by simultaneous infusion of propranolol. Noradrenaline had no such effect. In order to stimulate endogenous catecholamine release healthy males carried out physical exercise in four different ways: (1) ergometer bicycling at maximum load until exhaustion with and without oral beta‐blockade, (2) ergometer bicycling with stepwise increasing load until exhaustion, (3) isokinetic maximal exercise with one leg, with blood sampling both from the venous effluent of the exercising leg and the opposite resting arm and (4) long‐term (60 min) steady state ergometer bicycling at approximately 65% of estimated maximum capacity. During short‐term (less than 20 min) intense exercise (i.e. experiments 1–3) the plasma Mg concentrations were increased. This was probably due to a reduction of plasma volume and to an influx of Mg to the vascular pool. During long‐term steady state exercise (experiment 4) the Mg levels were not significantly affected but decreased during the first hour of recovery. These results suggest that both the beta‐adrenergic system and muscular activity by itself affect M

ISSN:0300-0664    

DOI:10.1111/j.1365-2265.1985.tb00217.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYWe have studied the relationship between mean pretreatment levels of serum prolactin and the presence of positive immunohistochemical staining for prolactin in the pituitary tumours of 55 patients. Pretreatment serum prolactin was significantly higher in patients with tumours showing many prolactin immunostaining cells than in those with none (P>0·001). When the pretreatment serum prolactin exceeded 6000 mU/1, the tumours contained over 90% of prolactin positive cells; one patient was an exception who had received longterm high dose bromocriptine therapy, and her tumour showed only occasional cells with positive staining. When the pretreatment serum prolactin level was under 2500 mU/1, a tumour was found which showed either no cells or fewer than 1% of cells which stained for prolactin. There was no significant difference in pretreatment serum prolactin levels between 11 patients with craniopharyn‐giomas and 34 patients with pituitary macroadenomas showing no prolactin immunostaining. Seventy‐one percent (32) of the 45 patients with craniophar‐yngiomas or tumours with negative immunostaining for prolactin, had raised pretreatment serum prolactin levels (above 360 mU/1) although this was usually only slightly elevated; the levels exceeded 2500 mU/1 in six (13%) of them (two craniopharyngiomas, four pituitary tumours) but in none did the levels exceed 6000 mU/1. Four of the 55 pituitary tumours showed occasional cells (less than 1%) that stained positively for growth hormone. In none of the patients with these tumours was there evidence of acromegaly or pathologically elevated circulating growth hormone

ISSN:0300-0664    

DOI:10.1111/j.1365-2265.1985.tb00218.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYFour recent reports describe a multisystem disorder in which ACTH insensitivity is associated with achalasia and alacrima. We report studies on a male patient with this rare triad. The patient had alacrima from birth; isolated glucocorticoid deficiency had been diagnosed at 3·5 years of age and achalasia at age 6. The possibility that this syndrome could be due to a parasympathetic degeneration has already been proposed; the cause of the glucocorticoid deficiency, however, remains unclear. Parasympathetic function in other areas was investigated to determine whether there might be a more generalized abnormality. Specific cardiac tests of parasympathetic function showed that parasympathetic input to the heart was affected in the patient, while the same tests in an Addisonian child were normal. We show, then, a hitherto undetected parasympathetic abnormality in a patient with this syndrome, suggesting a generalized disturbance of this system. On this basis we may hypothesize that the glucocorticoid failure may be a consequence of the loss of parasympathetic input to the adrenal gland, although this remains to be demonstrated experimentally

ISSN:0300-0664    

DOI:10.1111/j.1365-2265.1985.tb00219.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThe HLA‐A and ‐B antigen distribution in 132 Hong Kong Chinese patients with Graves’ disease, including 24 with thyrotoxic periodic paralysis, was compared with that in 110 controls. The HLA‐DR antigen distribution in 68 patients was compared with that in 47 controls. The prevalence of Bw46 was significantly increased in patients with Graves’ disease and with periodic paralysis. The prevalence of DRw9 was also slightly increased but not at a statistically significant level. The high prevalence of Bw46 related to patients with early age at onset whereas patients with later age at onset had a significantly increased prevalence of HLA B5. It is suggested that Graves’ disease in Chinese is due to two HLA‐associated mechanisms in which early‐onset disease is associated with Bw46 and late‐onse

ISSN:0300-0664    

DOI:10.1111/j.1365-2265.1985.tb00220.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThe disappearancein vitroof ACTH from whole human blood and plasma held at 22°C has been monitored using a dispersed adrenal cell bioassay and an unextracted radioimmunoassay. In three normal subjects after a metyrapone test and two patients with Addison's disease, endogenous bioactive ACTH levels were unchanged for at least 1 h in blood and 2 h in plasma. Moreover<50% of the bioactive plasma ACTH was still present in the plasma samples from the patients with Addison's disease after 24 h incubation at ambient temperatures. Human pituitary ACTH (1–39), spiked into plasma from dexamethasone suppressed subjects to give a concentration of 250 ng/1, was stable by bioassay for at least 2 h. No loss of biological activity was observed on subjecting plasma from a patient with Addison's disease or spiked plasma to two cycles of thawing at 37°C and freezing at — 70°C or thawing at 20°C and freezing at — 20°C. Some loss of bioactivity (20%) occurred on subjecting the patient's, but not ACTH‐spiked plasma to four cycles of thawing at 20°C/freezing at — 20°C. We conclude that bioactive ACTH (endogenous or exogenous) may be more stablein vitroin human blood and plasma than has been previously thought. If our studies can be confirmed in a larger series then it may be that conditions for handling blood specimens for ACTH assays coul

ISSN:0300-0664    

DOI:10.1111/j.1365-2265.1985.tb00221.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYResting growth hormone and prolactin levels and dynamic responses to bromocriptine and metoclopramide have been measured in epileptic patients before treatment, and compared with a matched group taking phenytoin alone. Mean resting levels of prolactin were higher in patients taking phenytoin (untreated patients 204 mU/1, phenytoin treated patients 302 mU/1), but dynamic responses to metoclopramide and bromocriptine were unaffected. Mean resting levels of growth hormone were also higher in patients taking phenytoin (untreated patients 1·4 mU/1, phenytoin treated patients 6·0 mU/1) and paradoxical suppression was seen following bromocriptine. Phenytoin is unlikely to have any major action on the D2receptor present on the lactotroph. The abnormalities in growth hormone may explain the well recognized effects of phenytoin on connective tissu

ISSN:0300-0664    

DOI:10.1111/j.1365-2265.1985.tb00222.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThe interaction between the stimulatory effects of hpGRF 1–44 and the inhibitory effects of somatostatin on GH release have been investigated in six normal male subjects receiving continuous 4 h infusions of these peptides alone and in combination. hpGRF 1–44 0·3 μg/kg/h alone produced a peak GH response of 27·0 ± 7·6 mU/1 (mean ± SEM). Somatostatin 1·0 μg/kg/h markedly inhibited the GH response to hpGRF 1–44 with mean levels>4·0 mU/1 during the infusion, though a rebound rise in GH levels to 26·1 ± 9·0 mU/1 was observed at the end of the infusion period. Somatostatin 0·2 μg/kg/h inhibited the GH response to hpGRF 1–44 to a lesser degree (peak GH during the infusion 11·7 ± 2·5 mU/1) and the rebound rise in GH levels (maximum 13·2 ± 4·3 mU/1) was less than that observed with high dose somatostatin. During somatostatin 1·0 μg/kg/h alone GH levels were suppressed>1·0 mU/1 followed by a rebound at the end of the infusion in only two subjects. These data demonstrate a dose‐dependent inhibition of hpGRF 1

ISSN:0300-0664    

DOI:10.1111/j.1365-2265.1985.tb00223.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYWe assessed the effects of ranitidine and cimetidine (histamine H2‐receptor antagonists) on the serum concentrations of parathyroid hormone (PTH) in 22 patients with end‐stage chronic renal failure. Treatment for 3 months induced a significant decrease in serum concentrations of PTH determined by radioimmunoassay directed at the mid portion of the PTH molecule. In contrast, significant increases were noted using an assay directed at the aminoterminal portion, whereas no change was noted with a carboxy‐terminal assay. No significant changes in serum calcium, phosphate and alkaline phosphatase were noted after treatment with either agent, but serum concentrations of osteocalcin increased significantly. We conclude the H2‐receptor antagonists do not favourably influence the natural history of hyperparathyroid bone disease in patients with end‐stage chronic rena

ISSN:0300-0664    

DOI:10.1111/j.1365-2265.1985.tb00224.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYIn a prospective study of the incidence of thyrotoxicosis sera from 216 thyrotoxic patients in seven English towns were assayed for TSH‐receptor antibodies. The incidence of antibody negative thyrotoxicosis correlated closely with the previous prevalence of endemic goitre in the towns (r= 0·9) indicating a high current incidence of toxic nodular goitre in previously goitrous towns. Antibody positive thyrotoxicosis, an indicator of Graves’ disease, showed no correlation with goitre although there was statistically significant geographical variation in incidence. The percentage of all thyrotoxic patients who were antibody positive varied between towns, from 35% to

ISSN:0300-0664    

DOI:10.1111/j.1365-2265.1985.tb00225.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYWe have studied the effects of the TRH related dipeptide histidyl‐proline diketopiperazine [cyclo (His‐Pro)] on basal and stimulated TSH and PRL secretion in normal volunteers, in patients with microprolactinomas and in patients with primary hypothyroidism. Cyclo (His‐Pro), 400 μg intravenously did not alter basal TSH or PRL levels in normal males and females and was also without effect upon the elevated basal TSH and PRL levels in patients with primary hypothyroidism and microprolactinomas respectively. The same dose of cyclo (His‐Pro) did not affect the TSH or PRL response to TRH (100 μg i.v.) in normal male volunteers. These data indicate that cyclo (His‐Pro) does not affect TSH and PRL secretion in man at this dosage. It is also unlikely that this molecule will be of any therapeutic benefit in states of hyperpro

ISSN:0300-0664    

DOI:10.1111/j.1365-2265.1985.tb00226.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY