摘要:

Rapidly accumulating evidence indicates that every hypothalamo-pituitary axis is influenced by both sleep (irrespective of the time of day when it occurs) and circadian rhythmicity (irrespective of the sleep or wake condition). Circadian effects seem to be exerted by a modulation of the amplitude of secretory pulses. Sleep may affect pulse frequency. Recent studies indicate that this complex temporal organization is not limited to pituitary and pituitary-dependent hormones but also underlies glucose regulation and insulin secretion.

ISSN:1663-2818    

DOI:10.1159/000181794

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

It has been suggested that subclinical signs of neuropathy appear earlier than microvascular complications of diabetes. To evaluate the occurrence of autonomic nervous system dysfunction in the early stage of childhood diabetes, subclinical signs of autonomic neuropathy (resting heart rate, hyperventilatory arrhythmia, standing/lying heart rate ratio, orthostatic decrease in blood pressure, and increase in blood pressure during sustained handgrip) were investigated in 54 children with type 1 diabetes divided into three groups: 14 recent-onset diabetics (3 weeks after the diagnosis), 20 diabetics in the remission phase, and 20 patients after the remission phase. 30 healthy age-matched children were used as control group. The mean resting heart rates of the diabetic groups in the remission phase and after the remission phase were significantly higher than those in the healthy control group (81.7 ± 5/min and 88.5 ± 6/min vs. 72.2 ± 8/min; p < 0.01). The hyperventilatory arrhythmia in the group of diabetic children after the remission phase in comparison with the control group was significantly decreased (29.1 ± 4/min vs. 22.7 ± 3/min; p < 0.01). In a few cases of the recent-onset diabetic group, the increase in resting heart rate, the decrease in hyperventilatory arrhythmia, and the standing/lying heart rate ratio proved to be significant. In the remission phase, the same parameters showed abnormal values in one third to one fifth of the children. In the diabetic group after the remission phase, these parameters were established as pathologic in one half to one fifth of the children, and in some cases, the orthostatic decrease in blood pressure and the increase in blood pressure during sustained handgrip were pathognomic as well. These results indicate that the initial, functional disturbances of the autonomic nervous system may appear early during the course of childhood diabetes and they emphasize the necessity to search for subclinical neuropathy in diabetic chil

ISSN:1663-2818    

DOI:10.1159/000181795

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Arginine-vasopressin (AVP) was measured by radioimmunoassay in extracted and unextracted urine using two different antisera. The specificity of the assay was confirmed by high-performance liquid chromatography. By the use of a high specific antiserum, AVP can reliably be measured in unextracted urine. Measurements with a less specific antiserum revealed higher concentrations, probably due to nonspecific binding. The extraction of AVP by the use of octadecasilyl-silica columns is unable to separate the intact hormone from substances interfering with the assay. The urinary AVP excretion in 34 normal children and adolescents ranged between 3.5 and 120 ng/m2/24 h with a mean of 39.1 ± 29.9 ng/m2/24 h

ISSN:1663-2818    

DOI:10.1159/000181796

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

α-Melanocyte-stimulating hormone (α-MSH) and adrenocorticotropin (ACTH) immunoreactivity (IR) was measured in the blood of 22 healthy women with normal ovulatory process in the early and late follicular (near to ovulation) phases and in the early luteal phase of the menstrual cycle. Plasma α-MSH IR ranged from undetectable values to 81.3 pg/ml, the highest levels being found in the late follicular phase (15.52 ± 4.16 pg/ml). In contrast, plasma ACTH IR was always detectable (range: 18.5–63.2 pg/ml), but its concentration did not differ significantly between the 3 phases of the menstrual cycle. High-pressure liquid chromatography fractionation of Sep pak C18-purified α-MSH IR revealed in all 3 phases the presence of 3 major peaks of α-MSH IR, coeluting with desacetyl-α-MSH, α-MSH and diacetyl-α-MSH, respectively. The most abundant peak always coeluted with authentic desacetyl-α-MSH, and the ratio between this deacetylated and the other 2 acetylated forms was similar in the 2 follicular phases (1:1.25 and 1:1.16 in the early and late phase, respectively), but significantly different in the luteal phase (1:0.48). The fluctuations in plasma concentration of the above MSH-related peptides suggest that different rates of α-MSH acetylation and release take place in the pituitary gland depending on the phase of the men

ISSN:1663-2818    

DOI:10.1159/000181797

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

To date, the effects of long-term growth hormone (GH)-releasing hormone [GHRH(1-29)-NH2] treatment on the plasma concentrations of somatostatin-like immunoreactivity (SLI) remain undefined. In the present study, the effect of GHRH(1-29)-NH2 therapy on plasma SLI levels has been studied in 11 non-GH-deficient children. The pattern of administration was 5 µg/kg body weight, given subcutaneously once every day. There was no significant change in plasma SLI levels after bolus injection of GHRH(1-29)-NH2 before and during GHRH(1_29)-NH2 therapy. However, plasma SLI rose in basal plasma and nocturnal sleep after 3 months of GHRH(1-29)-NH2 therapy and remained the same during 6 months of treatment with GHRH(1-29)-NH2. The reason for this finding is uncertain, but an increase in SLI release from the enteroinsular axis is a possible explanation. The association of our findings with the role of the circulating SLI on nutrient homeostasis and the effects of GHRH on growth velocity is discussed

ISSN:1663-2818    

DOI:10.1159/000181798

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Slowly growing X-ray-induced rat insulinomas and derived cell lines have been used as a model system for glucose-induced insulin release. During perfusions of tumors transplanted under the kidney capsule, the carbohydrates glucose and D-glyceraldehyde increased insulin secretion. These stimuli and the amino acids leucine and alanine also provoked insulin release in freshly isolated tumor cells. Under these conditions, glucose utilization had a Km of 4.6 mM and maximal velocity of 0.9 nmol/min/106 cells. A continuous cell line was established from such a preparation. In culture, glucose-induced insulin secretion was no longer detectable while responses to D-glyceraldehyde and amino acids were retained. Glucose metabolism in the cell line showed a decrease in Km to 0.7 mM glucose and an increased maximal velocity of 1.4 nmol/min/106 cells. Attempts to revert these alterations were undertaken using glucose-deficient culture medium to diminish glycolytic flux. Basal insulin release was lowered, while the growth pattern of the cells remained unchanged. Another approach involved the use of sodium butyrate which has been demonstrated to promote differentiation in other cell systems. Whereas sodium butyrate markedly increased cellular insulin content, the secretory responses were not improved. These results provide evidence that the loss of glucose-induced insulin secretion is paralleled by alterations in glucose metabolism.

ISSN:1663-2818    

DOI:10.1159/000181799

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

A 21-year-old goitrous hypothyroid Chinese woman had elevated serum iodotyrosines with a monoiodotyrosine level of 85.9 nmol/l (normal 0.49–0.89 nmol/l) and a diiodotyrosine level of 25.3 nmol/l (normal 0.023–0.53 nmol/l). She was amenorrheic with low luteinizing hormone and follicle-stimulating hormone levels at 5.8 and 2.8 U/l, respectively. The hypogonadotropic hypogonadism was due to an elevated prolactin level of 8.8 nmol/l. She also had a low potassium level of 3.2 mmol/l, and a high urinary aldosterone level of 158 nmol/day. The hyperprolactinemia, hypogonadotropic hypogonadism, hyperaldosteronism and hypokalemia subsided with the administration of bromocriptine 5 mg/day. However, bromocriptine accentuated the hyperiodotyrosinemia, and the patient remained hypothyroid. Levothyroxine therapy lowered the monoiodotyrosine and diiodotyrosine levels, ameliorated all her endocrinopathies, started her periods, and shrank the goiter. She probably had a deiodinase defect which permitted the discharge of accumulated iodotyrosines from the thyroid gland. Since iodotyrosines are tyrosine hydroxylase inhibitors, the hyperiodotyrosinemia causes dopamine synthesis inhibition, and induces the hyperprolactinemia and hyperaldosteron

ISSN:1663-2818    

DOI:10.1159/000181800

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:1663-2818    

DOI:10.1159/000181801

出版商:S. Karger AG    

年代:1990

数据来源: Karger