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PubMedDate not supplied

Chronobiology of the endocrine system.

One-hundred and ninety-four children (11 +/- 1.5 years of age), 43 young adult subjects (21 +/- 2 years of age) and 149 elderly subjects studied in 278-24 hour profiles (77 +/- 8 years of age) were studied over one or several 24-hour spans. All subjects followed a diurnal activity pattern with rest during the night. Blood and urine were collected at 4-hour intervals over a 24-hour span (6 samples). The circadian rhythms of 22 endocrine parameters were explored in plasma and five in urine. In the children and the elderly subjects, the investigations extended over all four seasons allowing also the study of seasonal variations or circannual rhythms. The circadian rhythms were characterized by population mean cosinor for each group of subjects. The circannual rhythms were explored by single cosinor, by one and two way analysis of variance applied to the circadian means obtained during each season and by comparison of the circadian rhythm parameters obtained during the four seasons by the parameter test described by Bingham et al. Circadian rhythms were found in most and circannual rhythms in many parameters. The rhythm characteristics are presented as cosinor summaries and acrophase charts. Although there were certain differences in some rhythm parameters between the age groups, the elderly showed a remarkable maintenance of their circadian time structure. In the circannual frequency range, the elderly men showed more circannual periodicity as group phenomenon than the women. Many endocrine rhythms show high amplitude rhythms which have to be taken into account in the selection of the time for endocrine testing and in the interpretation of the results.

Adolescent↗
PubMed1989

Enhanced activity of the cardiac endocrine system during right ventricular hypertrophy.

In a model of pulmonary hypertension induced by a single injection of monocrotaline (MCT), we observed a time-dependent right ventricular hypertrophy, which became apparent in treated rats 21 days after administration of MCT and progressed through day 45. Associated with this right ventricular hypertrophy were time-dependent increases in ventricular levels of immunoreactive atrial natriuretic peptide (iANP). Forty-five days after MCT treatment, treated rats exhibited a 72-fold increase in right ventricular iANP levels and a 7-fold increase in left ventricular iANP levels. Hybridization analysis of total RNA extracted from cardiac tissue indicated that both atrial and ventricular ANP mRNA levels were elevated in treated rats. These data suggest that during pulmonary hypertension and cardiac hypertrophy the endocrine activity of the heart expands to include ventricular tissue. ANP binding site autoradiography revealed decreased binding site density in the kidney and hearts of treated rats at 49 days, consistent with the occurrence of desensitization/down-regulation. Enhanced ventricular ANP production may serve as a compensatory response to sustained elevation of pulmonary arterial pressure or may function as an autocrine/paracrine system regulating cardiac function. In either case, the effects of augmented ANP production may be subject to modulation by the status of ANP receptors in target organs and cells.

Animals↗
PubMedDate not supplied

[Ultrastructure of the liver and endocrine system in aging rats: effect of piracetam].

Lipogenic pigmentation is described in thyroid follicular, parathyroid, and pineal cells, as well as in adrenocortical macrophages. Piracetam activated pituitary prolactin cells and increased paracrystals in thyroid follicular cells; smooth endoplasmic reticulum was increased and glycogen content decreased in numerous hepatocytes randomly distributed over the lobule.

Adrenal Cortex↗
PubMed1995

[Lithium and its effects on the endocrine system, bones and peripheral nerves--a current review].

Controlled studies in 1990-1992 with Danish, Sardinian, and Hongkong-Chinese patients consistently revealed a prevalence of goiter of about 50% in lithium treated patients. This is far beyond the frequency generally assumed for Germany, the whole country still known to be an endemic goiter area. Hypothyroidism as a side effect of lithium occurs in a clearly different group of patients and is much less frequent, the overall incidence being not substantially different from the incidence in the general population. But the risk of becoming hypothyroid as well as hyperparathyroid during lithium prophylaxis is markedly higher in women over 45 years of age, who in the general population are also prone to both endocrine dysfunctions. Lithium is considered to have a provoking role. Lithium is known to be accumulated in the bone and an impact on bone metabolism was shown in animal studies. The data reviewed prohibit the use of lithium during lactation and enforce strict indication in children. In adults the effect of lithium on bone should be considered only in osteomalacia and severe osteoporosis. This review is illustrated by the case of a 60-year-old woman, who after 4 years of successful treatment with lithiumcarbonate because of schizoaffective psychosis, developed a syndrome of hypercalcemia. Exstirpation of a parathyroid adenoma rendered her normocalcemic. Moreover, a pre-existing diffuse goiter had grown to a large nodular goiter within the course of her 5-year treatment. As she finally became paraparetic, she was admitted to our rehabilitation center for the diseases of the spinal cord. Her paraparesis may have been caused not only by the lithium-induced primary HPT, but in part by lithium itself. There are a few reports on lithium causing peripheral neuropathy at toxic levels. A transient deterioration of a pre-existing neuropathy, as in our case study, may have happened at lithium serum levels not far beyond the upper limit of 0.8 mmol/l.

Adult↗
PubMed1990

Immunogenetic markers for autoimmune diseases of the endocrine system.

New immunogenetic markers are demonstrated for type 1 diabetes mellitus, Graves' disease and Hashimoto's thyroiditis. These markers are detected by restriction fragment length polymorphism (RFLP) analysis of HLA-D region genes and genes for the tumor necrosis factor alpha (TNF alpha). By analysing haplotypes transmitted to diabetic probands in families and comparing them with haplotypes that are only transmitted to healthy siblings it is shown that DQw8-DQB1 gene variation is important for susceptibility on DR4 haplotypes. Analysis of this DQw3 split in patients with Hashimoto's thyroiditis reveals that the other DQB1 gene variation, namely DQw7, displays the strongest association with Hashimoto's thyroiditis. This DQB1 variation has several implications for susceptibility and/or pathogenesis of both autoimmune endocrine diseases. Novel polymorphisms for TNF alpha are detected and it is shown that heterozygosity for TNF polymorphisms is significantly associated with type I diabetes and Graves' disease. Furthermore, DR4 haplotypes transmitted to diabetic probands possess significantly more the 10.5 Kb fragment in contrast to DR4 haplotypes transmitted only to healthy family members. This genetic polymorphism raises functional issues in susceptibility to autoimmune disease and can lead to a new explanation of the enigmatic HLA-association with a variety of diseases.

Diabetes Mellitus, Type 1↗
PubMed2002

Transglutamines and endocrine system (minireview).

Transglutaminases catalyze the posttranslation modification of proteins by catalyzing Ca2+ dependent acyl-transfer reaction resulting in the formation of new g-amide bonds between g-carboxamide groups of peptide-bound glutamine residues and various primary amines. Such glutamine residue serves as acyl-donor and the most common acyl-acceptors are e-amino groups of peptide-bound lysine residues or primary amino groups of some naturally occurring polyamines, like putrescine or spermidine. The active site of cysteine reacts first with the g-carboxamide group of glutamine residue to form the acyl-enzyme intermediate under the release of ammonia. In the second step, the complex reacts with a primary amine to form an isopeptide bond and liberate the reactivated enzyme. The presence of transglutaminases has been observed in various endocrine glands such as human pituitary, which was investigated by immunohistochemical methods using specific antibodies. A significant increase in the expression and activity of tissue transglutaminase was observed during involution of thymus. In the genital tract of the male rat two different forms of the enzyme transglutaminase could be identified and characterized. the presence of p53 and tissues transglutaminase gene expressions in human normal and pathologic adrenal tissues. The Ca2+-responsive enzyme transglutaminase, which catalyzes the cross-bridging of proteins, was found in pancreatic islet cells.

Animals↗
PubMed1978

[Endocrine system reaction in relation to the clinical manifestations of lung cancer].

Using radiobiochemical methods "in vitro" by means of determining hormone production in blood serum, the authors studied the functional state of the hypophysis, adrenal glands, the pancreas and thyroid in 51 patients with lung cancer: stage I--in 8 patients, II--in 7, III--in 23 and IV--in 13. Histological structure: adenocarcinoma--in 9, epidermoid cancer--in 29, undifferentiated cancer--in 5. The analysis indicated that the hormonal disbalance in the organism of lung cancer patients is not evidenced by secondary clinical manifestations of the disease (atelectasis, suppuration, etc), there being a number of general regularities in the response of the hypophysis, adrenal glands, the pancreas and thyroid depending on the stage. This dependence shows a sinusoidal pattern maximum pronounced in stage I. Some common regularities in the endocrinous response of the hypophysis and adrenal glands are observed in different histostructure of the tumor, the response increasing in the following sequence: adenocarcinoma, epidermoid, undifferentiated cancer.

Adenocarcinoma↗
PubMedDate not supplied

[The long-term sequelae of the effect of incorporated radioactive iodine on the endocrine system in an endemic locality-].

25-30 years after the 131J therapeutic dose intake the function of the thyroid gland was found to get impaired in 18% of those irradiated, with the diabetes mellitus incidence rate tending to be on the increase almost two-fold. 131J did not have apparent suppressive action on sexual glands and adrenals. In those persons having taken 131J, frequency of the thyroid gland neoplasia gets increased almost 6-fold as compared to general population.

Diabetes Mellitus↗
PubMed1983

Long-lasting impairment of immune and endocrine systems of offspring induced by injection of dexamethasone into pregnant mice.

Dexamethasone was injected daily (2.5 and 5 micrograms/day) into pregnant mice from the 8th gestational day until delivery, and their offspring were examined in terms of body weight, organ histopathology, immunological function, and serum hormone level. Two different postnatal patterns were observed among the treated offspring: one pattern showing a wasting appearance and death within 1 week, and the other showing retardation of growth without any wasting appearance. In the latter, the offspring showed an immunologically impaired antibody-forming capacity to T-cell-dependent antigen (SRBC) and cell-mediated cytolytic T-cell activity. Histologically, the lymphoid tissues, thyroid, and adrenals of these offspring are atrophied and their serum thyroxine (T4) levels were significantly reduced. These results suggest that intrauterine exposure of the fetus to dexamethasone can disrupt the normal development and function of endocrine and immune organs which can lead to early death or retardation of growth after birth.

Animals↗
PubMed1989

The calcium endocrine system.

The role of calcium as a modulator of a large number of physiological processes is well known. It is not surprising that the two principally in the understanding of its subcellular physiology and molecular biology. There is new knowledge on hepatocellular uptake of vitamin D. The subsequent hepatic conversion of vitamin D to 25 hydroxy vitamin D may indeed be under the feedback control of the active vitamin D, 1,25 dihydroxyvitamin D. Vitamin D now also appears to have many new and diverse functions some of which already have clinical application.

Calcium↗
PubMed1993

An integrated view of the role of the endocrine system in the genesis of the osteoporosis associated with aging.

Estrogen deficiency is the major determinant of increased bone resorption and bone loss occurring in early menopause (first 5-6 years). The increased bone resorption is probably caused by the release of immune system cytokines such as IL-1, IL-6 and TNF by osteoblasts, the biosynthesis of which is no longer suppressed by estrogen. PTH secretion, although decreased in early menopause, may also contribute to increased bone destruction because of the presence of cytokines such as IL-1 and TNF which increase the sensitivity of bone to the resorptive effects of PTH. For the same reasons, the bone-destructive effects of increased serum levels of PTH occurring in the late menopause may be exaggerated.

Aging↗
PubMedDate not supplied

[The mechanism of the effect of reserpine on endocrine system function].

The experiments in rabbits and guinea-pigs showed that the use of reserpine, 0.1 and 0.25 mg/kg body weight a day, led to a 2-2.8-fold increase in thyroid hormones and 25-45% enhancement in cortisol in the blood. At the same time cAMP concentrations increased by 87% and almost by 5 times in the thyroid and adrenals, respectively. The pancreas exhibited a 5-fold increase in cAMP, 2.5- and 2.3-fold decrease in insulin in rabbit peripheral blood and in the activity of pancreatic aldolase and dehydrogenases, respectively. Blood levels of glucose reduced by 15-17%.

Adrenal Cortex Hormones↗
PubMed1990

[Paraneoplastic syndromes--the endocrine system and the lungs].

By the term "paraneoplastic syndrome" is meant a constellation of symptoms and findings that can be traced back to a tumor, but which are not caused by local or metastatic mechanisms. Such paraneoplastic syndromes can suggest the diagnosis of a tumor, or serve to chart the course of known tumor disease. When the pathophysiology is known, the mediators (hormones) may replace the clinical syndrome as useful parameters. With respect to the pathobiology of tumors, an analysis of paraneoplastic syndromes would seem to be highly promising, and might possibly form the basis for the development of new therapeutic concepts.

Biomarkers, Tumor↗
PubMed2005

Changes in the neuromodulators of the diffuse endocrine system of the alimentary canal of farmed rainbow trout, Oncorhynchus mykiss (Walbaum), naturally infected with Eubothrium crassum (Cestoda).

A histopathological and immunohistochemical study on the intestines of 45 specimens of farmed rainbow trout, Oncorhynchus mykiss (Walbaum), from Loch Awe, Scotland, revealed a number of cellular deviations in individuals naturally infected with the pseudophyllidean cestode Eubothrium crassum (Bloch, 1779). Twenty-five individuals (55.5%) were infected with an average worm burden of 18.84 +/- 4.06 (mean +/- SE) cestodes per host (range, 2-80 worms; total 471 worms). The cestodes, measuring an average 8.23 +/- 1.10 cm (mean +/- SE; range, 5.3-13.0 cm) in length, were found attached by their scolices to the mucosal lining of the distal portion of the pyloric caeca. Within the caeca, the strobila evoked a mild catarrhal enteritis, namely an enhanced mucus production with epithelial cellular desquamation, a leucocytic infiltration of the lamina propria-submucosa and vacuolization of the intestinal epithelial cells. Eosinophilic granular cells of the stratum granulosum exhibited granular depletion, while within the catarrh, the presence of a high number of rodlet cells was noticed. Immunohistochemically, the occurrence of E. crassum caused a significant reduction in the number of bombesin-, gastrin-releasing peptide and glucagon-like immunoreactive endocrine cells, but an increase in the relative densities of endocrine cells containing cholecystokinin-8- and gastrin-like substances. There were, however, no significant differences in the number of endocrine cells that were immunoreactive to secretin, neuropeptide Y and peptide histidine-isoleucine antisera in the digestive tracts of either the infected or non-infected O. mykiss.

Animals↗
PubMed1993

Review of the biological effects of weightlessness on the human endocrine system.

Studies from space flights over the past two decades have demonstrated that there are basic physiological changes in humans during space flight. These changes include cephalad fluid shifts, loss of fluid and electrolytes, loss of muscle mass, space motion sickness, anemia, reduced immune response, and loss of calcium and mineralized bone. The cause of most of these manifestations is not known but the general approach has been to investigate systemic and hormonal changes. However, data from the 1973-1974 Skylabs, Spacelab 3 (SL-3), Spacelab D-I (SL-DI), and now the new SLS-1 missions support a more basic biological response to microgravity that may occur at the tissue, cellular, and molecular level. This report summarizes ground-based and SLS-1 experiments that examined the mechanism of loss of red blood cell mass in humans, the loss of bone mass and lowered osteoblast growth under space flight conditions, and loss of immune function in microgravity.

Anemia↗
PubMed1993

Effects of somatotropin treatment on growth performance, carcass traits, and the endocrine system in finishing beef heifers.

The objectives of this study were to investigate the effects of exogenous somatotropin on growth performance and carcass traits and on concentrations of somatotropin (ST), IGF-I, insulin, glucagon, free fatty acids (FFA), and glucose in plasma of finishing Simmental beef heifers. Three treatment groups, which included 12 heifers each, received a subcutaneous injection of a slowly released recombinant bovine somatotropin (rbST) at two doses (320 and 640 mg, respectively) or a placebo at 2-wk intervals. Treatments began at an average BW of 286 kg and continued until the animals were slaughtered at approximately 520 kg. Heifers had ad libitum access to corn silage and received 1.8 kg/d of concentrate. A before-feeding blood sample was collected from the jugular vein immediately before and 1 wk after each injection during treatment. Treatment tended to increase ADG and to reduce energy consumption per kilogram of gain, whereas feed and energy intake were not altered. Dressing percentage and conformation did not seem to be affected by treatment. Treatment led to a dose-dependent reduction of fat tissue in carcass as well as in kidney fat and to a simultaneous increase of lean tissue (P < .05). Furthermore, treatment caused moderate increases of ST in both treated groups, whereas IGF-I concentrations increased markedly soon after the beginning of the treatment. Insulin and FFA concentrations were elevated in treated groups compared with controls. Glucagon concentrations were not altered by treatment. Effects on growth performance and carcass characteristics are discussed in view of metabolic and endocrine changes.

Adipose Tissue↗
PubMed1998

The endocrine system: an overview.

A plethora of hormones regulate many of the body's functions, including growth and development, metabolism, electrolyte balances, and reproduction. Numerous glands throughout the body produce hormones. The hypothalamus produces several releasing and inhibiting hormones that act on the pituitary gland, stimulating the release of pituitary hormones. Of the pituitary hormones, several act on other glands located in various regions of the body, whereas other pituitary hormones directly affect their target organs. Other hormone-producing glands throughout the body include the adrenal glands, which primarily produce cortisol; the gonads (i.e., ovaries and testes), which produce sex hormones; the thyroid, which produces thyroid hormone; the parathyroid, which produces parathyroid hormone; and the pancreas, which produces insulin and glucagon. Many of these hormones are part of regulatory hormonal cascades involving a hypothalamic hormone, one or more pituitary hormones, and one or more target gland hormones.

Endocrine Glands↗