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Biomedical subjects

L Hummer

Publications and source records attributed to L Hummer.

At least 55 records · Page 3Linked to original sources
PubMed1979

Plasma corticotropin and cortisol in patients with pituitary adenomas.

Plasma ACTH and cortisol were measured during insulin-induced hypoglycemia in 39 patients with a pituitary adenoma or after hypophysectomy and in 26 healthy persons. Adrenocortical insufficiency was defined as failure to increase plasma cortisol to at least 500 nmol/liter (18 microgram/dl) during hypoglycemia. No proper distinction was possible between patients with normal and impaired cortisol response to hypoglycemia on the basis of the ACTH results. When all 39 patients were compared to the 26 controls, the cortisol results differed significantly, but those of ACTH did not. These results demonstrate a limited value of ACTH measurements in secondary adrenocortical failure.

Adenoma↗
PubMed1978

Discrepancy between ACTH and cortisol responses to insulin induced hypoglycaemia.

The purpose of this study was to assess the normal relationship between plasma ACTH and cortisol during insulin induced hypoglycaemia. Twenty-six healthy persons were studied. Peak plasma concentration and the amounts of ACTH and cortisol secreted during hypoglycaemia were compared. There was no significant correlation between the ACTH and cortisol values. The ACTH responses varied significantly more than those of cortisol. This probably signifies an over-capacity of ACTH secretion in comparison to the secretory capacity of the adrenal cortex.

Adrenocorticotropic Hormone↗
PubMed1978

Influence of morphine anaesthesia on the endocrine-metabolic response to open-heart surgery.

Twelve patients scheduled for aortic valve replacement during extracorporal circulation were randomly allocated to either morphine anaesthesia or fluroxene anaesthesia. Morphine in a total dose of 4 mg/kg was administered before skin incision. At the start of extracorporal circulation all patients received 25 g glucose intravascularly. The endocrine-metabolic response to surgery, as expressed by changes in plasma ACTH, cortisol, insulin, growth hormone, cyclic adenosine-3',-5'-monophosphate (cyclic AMP), glucose, free fatty acids, blood b-hydroxybutyrate and cumulative nitrogen balance was measured before and during anaesthesia and surgery, and on the first five post-operative days. It was found that morphine anaesthesia blocked the increase in ACTH, cortisol, growth hormone, cyclic AMP, and glucose during surgery. However, after initiation of extracorporal circulation only ACTH, cortisol, and, to a lesser degree, the glucose and insulin response to glucose were lowered by morphine anaesthesia. From the first to the fifth days after operation no differences between the two groups could be demonstrated in any parameter. Cumulative nitrogen balance was similar in the two groups. It is concluded that morphine in large doses administered before skin incision inhibits the initial endocrine-metabolic response to open-heart surgery, but that the effect is short-lasting and without effect on overall postoperative protein catabolism.

Adolescent↗
PubMed1977

Thyroid and testicular hormone responses to graded and prolonged exercise in man.

Eight men were studied during graded (47, 77 and 100% of maximal oxygen uptake) and prolonged (76%) exhaustive treadmill running. Plasma catecholamine levels increased progressively with intensity and duration of exercise. Serum concentrations of thyroid-stimulating hormone (TSH) increased with increasing work loads and were 107 (58--243)% (P less than 0.001) above resting values after maximal work. Thyroxine, triiodothyronine and luteinizing hormone in serum never changed significantly. While a small increase in testosterone concentrations (13 [1--24]%) after maximal exercise probably could be explained by changes in plasma volume, a definite increase (31 [14--56]%) occurred after 40 min of prolonged exercise. During continued exercise testosterone concentrations then gradually declined. Testicular stimulation by the increased catecholamine concentrations possible contributed to the rise in testosterone concentrations, but no evidence was found for a direct catecholamine induced increase in the activity of the thyroid gland. The exercise induced increase in TSH levels possibly explians the increased thyroid hormone secretion rate, which previously has been found in individuals participating in physical training programs.

Adult↗
PubMed1977

Pituitary-thyroid responsiveness to thyrotropin-releasing hormone in preterm and small-for-gestational age newborns.

A dose of 40 microgram TRH was injected intravenously in 12 preterm (PT) and 15 small-for-gestational age (SGA) babies (with advanced gestational ages) between 5 and 167 hours after birth. Serum-thyrotropin (TSH) was measured prior to and 30 and 180 min after TRH; serum-thyroxine (T4) and serum-triiodothyronine (T3) were measured prior to and 180 min after TRH. The percentage increase in serum-TSH in PT and SGA babies was comparable to that of fullterm newborns. The serum-TSH 30 min after TRH in SGA newborns was significantly correlated to basal TSH values, such a correlation could not be shown in the preterms. One SGA and four PT babies had a repeat TRH-test performed later in infancy: In all but one PT with a gestational age of 27 weeks the TSH rise was lower than in the neonatal period. The thyroid hormone responses after TRH were similar in the two groups of babies. The percentage increase above basal levels were: Median serum-T3 increase about 46% and median serum-T4 increase about 14%. It is concluded that in low-birth-weight newborn babies the pituitary TSH response to exogenous TRH was like that detected in fullterm newborns and more pronounced that later in infancy. The effect of endogenous TSH as measured by thyroid hormone increases was of the same magnitude as observed in fullterms and in adults.

Female↗
PubMed1977

Serum immunoreactive corticotrophin and response to metyrapone in old age in man.

Attempts have been made to establish the level of immunoreactive corticotrophin (IR-ACTH) in serum in healthy subjects with partts were investigated and the clinical and biochemical condition s of selection specified. Serum IR-ACTH was determined by a radioimmunoassay procedure using an N-terminal antibody produced against the 1--24 sequence of the conrticotrophin molecule. The morning level of serum IR-ACTH was determined in 115 fasting healthy subjects, range less than 16--210 pg/ml, median 94 pg/ml (3rd International Standard preparation). The level was found to be unchanged within the age interval 20--94 years, irrespective of sex. Thy nycterohemeral variation of the IR-ACTH concentration in serum was studied in 11 sibjects. A rhythmic variation of the IR-ACTH level was not constantly found and age-related difference in the temporal pattern was not demonstrated. In 10 young and 10 elderly subjects a metyrapone test was carried out and the IR-ACTH response was determined. The rise in serum IR-ACTH concentration varied between 20 and 739 pg/ml. Any significant age-related difference in response was not found. The interpretation of the present results with respect to the decreased secretory activity of the glucocorticoid producing system in the aged is discussed. It was concluded that the findings in this study did not indicate a primary deficiency of the axis of the glucocorticoid producing system, neither at the pituitary level nor at the adrenocortical level, as a causal factor to the decreased glucocorticoid production in old age.

Adrenocorticotropic Hormone↗
PubMed1977

Effect of thyrotrophin releasing hormone (TRH) in patients with pituitary disorders.

The secretion and biological activity of thyroid stimulating hormone (TSH) were studied in 22 patients with a pituitary tumour (17 acromegalics and 5 patients with a chromophobe adenoma) and in 36 hypophysectomized patients (16 acromegalics and 20 with a chromophobe adenoma). Thyroid function was assessed by serum thyroxine (T4), serum triiodothyronine (T3), and thyroxine-binding globulin (TBG) concentration. Serum TSH was measured before and after injection of TSH releasing hormone (TRH), and in 19 hypophysectomized patients the T3 response after TRH was measured. In addition a TRH test was performed 1-2 weeks after surgery in 11 patients. The basal serum TSH did not differ from euthyroid control values in any of the groups and no late effect of hypophysectomy was observed. Subnormal peak TSH values were seen in 10 out of 37 euthyroid patients, whereas 9 out of 11 hypothyroid patients responded normally. Hypophysectomy caused an immediate but transient decrease in peak TSH in patients with a chromophobe adenoma only. The rise in serum T3 after TRH was significantly lower in hypophysectomized patients than in controls. An increase in TSH was followed by a T3 response in all patients except in 4 out of 8 euthyroid acromegalics. In patients operated on for a chromophobe adenoma the T3 response was correlated with serum T4, whereas this was not the case in acromegalics.

Acromegaly↗
PubMed1977

Lack of effect of prolactin inhibition by alpha-bromoergocriptine (CB 154) on plasma aldosterone in anephric and non-nephrectomized patients on regular haemodialysis.

To investigate whether a direct influence exists between the prolactin suppressive effect of alpha-bromoergocriptine (CB 154) and the aldosterone response to a potassium stimulation, the present study was performed in 7 anephric patients and in 7 non-nephrectomized patients, all on regular haemodialysis. The increase in the plasma potassium concentration between dialysis was used as a stimulus to the adrenals, and was correlated to the increase in the plasma aldosterone concentration (PAC). Plasma samples were obtained during a control period and during a corresponding period of treatment with bromocriptine. Despite a significant fall in the prolactin levels during the bromocriptine treatment, no differences in the aldosterone response to the increasing potassium concentration in the two periods were found neither in the anephric nor in the non-nephrectomized patients. It is concluded that depression of prolactin levels by the dopamine agonist (bromocriptine) has no influence on the ability of the adrenals to react with an increase in aldosterone secretion following potassium stimulation in dialysis patients with and without preserved renin-angiotensin system.

Adrenocorticotropic Hormone↗
PubMed1976

Immunoreactive corticotrophin reserve in old age in man during and after surgical stress.

Attempts have been made to establish whether the immunoreactive corticotrophin (IR-ACTH) reserve was impaired in old age during surgical stress and whether an exhaustion of the IR-ACTH reserve could be traced postoperatively. Recognition of the degenerative changes of the senescent adenohypophysis has made this investigation essential in an effort to analyze factors responsible for the high risk involved in surgery on the aged. In the study 18 young and 14 elderly patients were subjected to elective abdominal or thoracic surgery, and the IR-ACTH response was determined. No significant age-related difference in response to surgery was found. On the 5th day after operation an intravenous metyrapone test was carried out, and the IR-ACTH response in plasma determined. In the elderly, the IR-ACTH response to metyrapone was not found to be inferior to that in the young patients. It was concluded that the IR-ACTH reserve was unimpaired during surgery in old age and that exhaustion was not in evidence based on unimpaired IR-ACTH response during repeated stress in the postoperative period. Therefore, decreased ACTH reserve seems not to be a factor involved in the higher surgical risk in the elderly.

Adrenocorticotropic Hormone↗
PubMed1976

Thyrotropin response to thyrotropin-releasing hormone in fullterm, euthyroid and hypothyroid newborns.

The serum concentration of thyrotropin (TSH) and the TSH response following thyrotropin-releasing hormone (TRH) were studied in 16 euthyroid babies from 16 to 172 hours after birth and in 2 primary hypothyroid babies, 3 and 28 days of age. Serum-TSH was measured before an intravenous injection of 40 mug TRH and after 30 and 180 min. In the euthyroid babies increased basal levels of TSH were seen shortly after birth, followed by a pronounced decline. The extent of TSH increase after TRH could be correlated with the basal levels, and the relative increase was comparable to that which occurs in adults. In the hypothyroid babies very high basal levels of serum-TSH were seen, 125 and 400 muU/ml respectively, with no further increase following TRH stimulation. It was concluded that in euthyroid fullterm newborn, the relative response of serum-TSH to TRH was equal to that of adults, in spite of elevated thyroid hormone concentrations. In the hypothyroid newborn very high levels of serum-TSH were seen and a supplementary TRH-test seems without diagnostic value in congenital hypothyroidism.

Congenital Hypothyroidism↗
PubMed1976

Evolution of autonomy in idiopathic non-toxic goiter, evaluated by regional suppressibility of 99mTc-uptake and TSH response to TRH.

Seventeen euthyroid patients with non-toxic goiter were studied, 7 had diffuse goiters and 10 had nodular goiters. The TSH response to TRH and the 99mTc-uptake were measured before and after T3 suppression. The uptake, measured with a gamma camera, was calculated for the whole gland and for a maximum of 6 regions within the thyroid gland. The suppressibility of 99mTc-uptake (percent change of uptake) ranged from 0 to 95%, it was significantly greater in patients with diffuse than in those with nodular goiters, and was alike in nodular and internodular tissue. The patients with diffuse goiter were significantly younger than those with nodular goiter. Abolished TSH response to TRH was seen in 2 patients with negative T3 suppression tests. In another 2 patients impaired TSH response was associated with impaired suppressibility. In 13 patients with normal TRH tests, the suppression of uptake was normal in 8 and subnormal in 5. The results suggest that nodularity and functional autonomy may develop in non-toxic goiters. In some of these goiters the mass of autonomous tissue may be large enough to cause negative TRH tests, probably indicating hypersecretion of thyroid hormones, although not necessarily above the normal range.

Goiter↗
PubMed1975

Human serum thyrotrophin level and response to thyrotrophin-releasing hormone in the aged.

170 healthy volunteers were investigated, and the clinical and biochemical conditions of selection specified. The fasting morning level of serum thyrotrophin (TSH) was determined in all volunteers and found unchanged within the age interval 18-94 years, independent of sex. This is in disagreement with results obtained by other investigators who found an increase of TSH in old age. The implications of the criteria of selection are discussed. Nycterohemeral rhythm was studied in 16 persons. Rhythmic variation was an inconstant finding, and the pattern in the young could not be distinguished from that in the old. The TSH response to thyrotrophin-releasing hormone (TRH) was determined in 53 persons of various ages and found unrelated to age. Nonetheless, the lowest responses were observed in the aged, but the difference was not statistically significant. Possible physiological interpretations of an unaltered TSH secretion in spite of an age-related decrease in thyroid function are discussed.

11-Hydroxycorticosteroids↗