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At least 721 records · Page 40Linked to original sources
PubMed1982

The reproductive endocrine system in cystic fibrosis: 2. Changes in gonadotrophins and sex steroids following LHRH.

Hypothalamic-pituitary-gonadal function was assessed in forty-seven patients with cystic fibrosis (CF) by the 3-hr infusion of 100 microgram of synthetic gonadotrophin-releasing factor. LHRH and the results compared with a group of children being evaluated for short stature and delayed puberty ('controls'). Levels of gonadotrophins and sex steroids were measured prior to and during the infusion. In prepubertal boys, LH and FSH release evoked by LHRH was significantly greater (P less than 0.001) in 'control' subjects than in CF patients. In pubertal boys, LH and FSH release was also greater in 'controls' than in CF, though to a lesser degree (P less than 0.05). In pubertal girls, responses to LHRH were comparable for LH and slightly greater (P less than 0.05) in 'controls' for FSH. In the earliest pubertal groups of both sexes (male-Tanner genitalia stage 2; females-Tanner breast stage 2), LH secretion was similar in patients with CF and 'control' subjects. Significant increments of testosterone and oestradiol in pubertal CF patients do not occur until 6 h after the LHRH infusion begins, in contrast to a rise at 3 h in 'control' subjects. These data suggest that prepubertal boys with CF, who are the most impaired in height, weight and skeletal maturation, also have measurable abnormalities of LHRH-releasable gonadotrophin secretion. Despite continued impaired weight growth, pubertal patients do attain essentially normal gonadotrophin secretory responses to LHRH administration and are similar to subjects with constitutional delayed adolescent development in reproductive endocrine physiology.

Adolescent↗
PubMed1988

How the sauna affects the endocrine system.

The sauna induces changes in the secretion of hormones, some similar to changes induced in any other stress situation and others characteristic of exposure to the sauna. Noradrenaline is usually the only catecholamine raised by the sauna in people accustomed to it. The secretion of the antidiuretic hormone is increased and the renin-angiotensin-aldosterone system is activated. The concentrations of the growth hormone and prolactin, in particular, secreted from the anterior pituitary are increased in the circulation. The concentration of the immunoreactive beta-endorphin in blood may also increase which may reflect the feeling of pleasure or, on the other hand, discomfort induced by the sauna. The views on the effects of the sauna on the secretion of the ACTH and cortisol are partly contradictory, probably due to differing ways of taking the sauna bath. In Finnish sauna takers the concentration of cortisol in blood is not usually increased. The changes induced by the sauna in various hormone concentrations in the circulation are, however, normalized within a couple of hours after the heat stress.

Catecholamines↗
PubMed1987

Circadian time structure in the endocrine system of elderly subjects.

Six young, healthy males (mean age 27 +/- 0.8 years) and six healthy elderly men (mean age 75 +/- 2.0 years) underwent an evaluation of their circadian rhythms in cortisol, PRL, and TSH; oral body temperature and heart rate also were recorded. In the two groups no differences in the circadian patterns of cortisol, PRL, and body temperature were found. We consider it remarkable that the mesor of PRL values did not differ significantly between young and elderly subjects. A markedly advanced TSH acrophase was found in the elderly compared to the young controls. This change in acrophase could be important, because the hormone is known to be a marker of the function of the hypothalamus-hypophysis axis. In addition, an advance of the acrophase of the heart rate in the elderly compared to the younger age group was observed.

Adult↗
PubMed1978

[Circadian rhythms in the endocrine system (author's transl)].

In four sections, the contribution reviews data on 24-hour variations of cortisol, growth hormone, prolactine, testosterone, LH and FSH in the human plasma. 1) Experiments on isolated subjects show that the 24-h variation of cortisol is based on an endogenous circadian rhythm which can be independent from the rhythm of sleep and wakefulness. 2) The various pattern each of which has been described in good correspondence by several groups of authors, suggest a series of hormones with a strong circadian component (e.g. cortisol) to those with a weaker (testosterone) or even without a circadian component (FSH). 3) The sleep-wake-cycle influences the phase of hormone rhythms by various degrees; therefore, a uniform reference to sleep time seems preferable to a reference to local time in order to compare several rhythms. 4) The rhythms of cortisol and growth hormone as described in man agree satisfactorily with those in other vertebrate species.

Adrenal Cortex Hormones↗
PubMed1992

[The vitamin D endocrine system and bone tissue mineral metabolism in rats with adjuvant arthritis: the effect of 1,25-dihydroxyvitamin D3].

Adjuvant arthritis was induced in male rats by injecting bacillus Calmette-Guèrin in mineral oil in a hindpaw. A decrease in bone density, calcium and phosphorus content due to polyarthritis was found in the tibia of the noninjected hind leg. Arthritic rats demonstrated serum 1,25-dihydroxyvitamin D deficiency along with constant level of 25-hydroxyvitamin D. The disease caused a significant expression of 1,25-dihydroxyvitamin D3 receptors in lymphocytes. Arthritic rats were treated with 1,25-dihydroxyvitamin D3 (0.15 mg/kg/day orally) for 35 days. The treatment prevented the development of osteoporosis and a decrease of 1,25-dihydroxyvitamin D levels as well as reduced the expression of 1,25-dihydroxyvitamin D receptors in lymphocytes.

Animals↗
PubMed1988

Lack of endocrine systemic side effects after topical application of spironolactone in man.

In six healthy male volunteers, the percutaneous absorption of spironolactone was compared with placebo in a double-blind crossover study. The subjects were randomly given either a cream containing 5% spironolactone or placebo to be applied in a randomized sequential way to a well defined skin area equivalent to 55% of body area. During the 72 h following the application of the ointment, blood levels of canrenone, the major metabolite of spironolactone, have been determined. In order to estimate the systemic antiandrogenic effect of spironolactone, plasma levels of 17-alpha-Hydroxy progesterone (17 alpha-OH-P), Testosterone (pT) and non-conjugated 3 alpha-Androstanediol (3 alpha-diol, metabolite of the active androgen 5 alpha-Dihydrotestosterone or DHT) as well as salivary Testosterone (sT) which relate to the free and active plasma testosterone fraction have also been measured. Urinary levels of canrenone have been determined 48 hours after cream application. No changes in any levels of these hormones have been detected and plasma canrenone levels were undetectable during the 72 hours of topical treatment. Topically administered, spironolactone appears to have only a local skin impregnation.

17-alpha-Hydroxyprogesterone↗
PubMed1979

Development of Leydig cell tumors and onset of changes in the reproductive and endocrine systems of aging F344 rats.

The age-dependent onset of spontaneous testicular interstitial cell tumors was examined in F344 male rats. Light microscopy of testes established that nodular interstitial cell hyperplasia was evident in 3 of 5 12-month-old rats and in 5 of 5 rats at 15, 18, 21, and 24 months of age. Involution of the seminiferous epithelium was evident in all testes exhibiting extensive interstitial cell proliferation. Striking increments in serum prolactin and estradiol levels were noted with advancing age, whereas serum levels of follicle-stimulating hormone were unequivocally lower at 21 and 24 months than at 6 months of age. No measurable changes were detected in serum testosterone concentrations between 6 and 18 months of age, but marked increments in this androgen, without any measurable change in circulating luteinizing hormone titers, were apparent in 21- and 24-month-old rats. These findings point to a dynamic relationship between testicular interstitial cell tumorigenesis and age-related changes in the synthesis and/or secretion of gonadal and adenohypophyseal hormones.

Aging↗
PubMed1993

Brn-3.0: a POU-domain protein expressed in the sensory, immune, and endocrine systems that functions on elements distinct from known octamer motifs.

Characterization of Brn-3.0 and identification of a highly related member (Brn-3.1) of the class IV POU-domain family suggest potential roles of Brn-3.0 in the development of retinal ganglion cells and sensory neurons, as well as potential roles in the pituitary gland and the immune system. Brn-3.0 is expressed in the pituitary gland and in a corticotroph cell line. A functional DNA response element has been identified in the proopiomelanocortin promoter. In contrast to previously described mammalian POU-domain proteins, Brn-3.0 binds relatively ineffectively to known octamer DNA motifs, but instead binds with high affinity to a distinct set of DNA elements, functioning as a transcriptional activator. Brn-3.0, Brn-3.1, and the Drosophila tI-POU share an N-terminal region of homology, referred to as the "POU-IV box," which is similar to a conserved functional domain in the c-myc gene family.

Age Factors↗
PubMed1986

The role of condensed tannins in the nutritional value of Lotus pedunculatus for sheep. 5. Effects on the endocrine system and on adipose tissue metabolism.

1. Three experiments were conducted using Lotus pedunculatus containing high concentrations of condensed tannins (CT), and utilizing the principle that polyethylene glycol (PEG) application (molecular weight 3350) will irreversibly bind a portion of the CT and thus reduce the dietary reactive (i.e. non-PEG bound) CT concentration. Lotus diets containing 95, 45 and 14 g total reactive CT/kg dry matter (DM), induced by spraying with three PEG rates, were given to sheep at hourly intervals (600 g DM/d) for 21 d (Expt 1). In Expts 2 and 3, lambs grazed areas oversown with either lotus (89 g CT/kg DM) or clovers (Trifolium repens and Trifolium pratense; less than 1 g CT/kg DM) for 42 and 92 d respectively. In Expt 2 half the animals grazing each forage received oral PEG (75 g/d), whilst in Expt 3 half the lambs were sired by rams selected respectively for low or high levels of subcutaneous fat deposition. 2. Hormone concentrations in plasma (Expt 1 only) were determined by radioimmunoassay. Rates of [U-14C]-acetate and D-[U-14C]glucose incorporation and oxidation by subcutaneous and abdominal adipose tissue removed at slaughter, together with rate of glycerol release, were determined during in vitro incubation in all three experiments. 3. Plasma concentration of growth hormone was positively and linearly related to dietary reactive CT concentration, whilst 3,5,3'-triiodothyronine (T3) concentration tended to be negatively and linearly related to dietary reactive CT concentration. Diet CT concentration had no effect on plasma concentrations of the other hormones measured.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1976

The paraganglia, a persisting endocrine system in man.

The paraganglia have been traced in surgical samples of para-aortic and pelvic retroperitoneal tissues using the formal-dehyde-induced fluorescence method for catecholamines. Clusters of catecholamine-storing cells were found in all (12) patients studied. Microspectrofluorometric recordings showed high amounts of catecholamine in the well-vascularized cell groups. A large proportion of the paraganglia, which are most prominent during the fetal period, also persist during postnatal life.

Adult↗
PubMed1988

Enterochromaffin (EC-) cells of the mammalian gastro-entero-pancreatic (GEP) endocrine system: cellular source of pro-dynorphin-derived peptides.

It has long been disputed whether mammalian enterochromaffin (EC-) cells contain a peptide in addition to serotonin. Previous immunohistochemical studies have provided evidence for the presence of enkephalins in EC-cells. These findings, however, are equivocal. Therefore, the problem of opioid peptides in EC-cells has been re-examined in the gastro-intestinal mucosa of dog, guinea-pig and man. A battery of antisera against derivatives of pro-opiomelanocortin, pro-enkephalin and pro-dynorphin have been applied to semithin serial sections of the tissues, in combination with fluorescence histochemistry and serotonin immunocytochemistry. Our findings indicate that EC-cells of the investigated species contain pro-dynorphin-related peptides, i.e. dynorphin A and alpha-neo-endorphin, but no derivatives from pro-opiomelanocortin or pro-enkephalin. Since remarkable interspecies variations occur with respect to the number and staining characteristics of opioid immunoreactive EC-cells, it is concluded that pro-dynorphin shows specific routes of post-translational processing depending upon the species and the gastro-intestinal segment investigated. Future studies should focus on the mutual relationships between serotonin and dynorphins and on the physiological significance of these peptides in the gastrointestinal tract.

Adrenal Medulla↗
PubMed1984

Immunocytochemical localization of peptidergic cells in the neuro-endocrine system of the Colorado potato beetle, Leptinotarsa decemlineata, with antisera against vasopressin, vasotocin and oxytocin.

Antisera against vasopressin, vasotocin, oxytocin, neurophysin-1 and neurophysin-2 were used to investigate immunocytochemically the presence of neurons containing substances antigenically related to these peptides in the nervous system of the Colorado potato beetle. Ten different antisera were used, four against vasopressin, three against oxytocin and one against vasotocin, neurophysin-1, and neurophysin-2. Immunoreactivity was shown by all antisera except those against the neurophysins. The vasopressin antisera all gave different results. One antiserum revealed only a single neuron pair, whereas others revealed in addition one or two other different cell groups. The oxytocin antisera likewise revealed different neurons. The fixation procedure influenced the outcome of the immunocytochemical reaction. Immunoreactivity as revealed by vasopressin, vasotocin and oxytocin antisera is often co-localized in the same neurons; solid phase adsorptions showed that this is due to cross-reactivity of the antisera. Some of the immunoreactive neurons are identical to those recently described to contain a bovine pancreatic polypeptide/FMRFamide-like peptide. This co-localization is probably not due to a cross-reaction. These findings indicate the presence of several vasopressin-like and oxytocin-like substances which in the Colorado potato beetle all have a different degree of immunocytochemical resemblance to vasopressin and oxytocin.

Animals↗
PubMed1987

Calcium, vitamin D-endocrine system, and parathyroid hormone in black and white males.

The serum and urinary calcium, 25-hydroxyvitamin D (25OHD), 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), and parathyroid hormone (PTH) were studied in healthy black and white males living in Belgium, and the results were compared to data in blacks of similar age living in Zaïre. Dietary calcium and vitamin D were estimated in a sub-sample of blacks and whites examined in Belgium. Compared to whites (9.51 +/- 0.28 mg%) serum calcium was somewhat lower in blacks (9.26 +/- 0.27 mg% in Belgium; 9.19 +/- 0.48 mg% in Zaïre). The 24 hour urinary calcium excretion averaged 215.0 +/- 16.7 mg% in whites and was higher (P less than 0.05 or less) than in blacks (115 +/- 71 mg% in Belgium; 36 +/- 33 mg% in Zaïre). The serum 25OHD levels were similar in whites and blacks evaluated in Zaïre, both being higher (P less than 0.05 or less) than in blacks living in Belgium. In the latter blacks, an inverse correlation was observed between the 25OHD level and the duration of the stay in a temperate climate. Parathyroid hormone levels were slightly higher in blacks living in Belgium than in the other two groups of subjects. The serum levels of 1,25(OH)2D3 and human vitamin D-binding protein were similar in the three groups of subjects. Dietary calcium averaged 541 +/- 152 mg/day in blacks and was significantly (P less than 0.001) less than in whites (1,203 +/- 508 mg/day), whereas no significant difference was observed in dietary vitamin D intake between blacks and whites. It is concluded that calcium intake is low in blacks but stimulation of parathyroid hormone and 1,25(OH)2D3 required to achieve normocalcemia does not occur.

25-Hydroxyvitamin D 2↗
PubMed2002

Iodine species and the endocrine system: thyroid hormone levels in adult Danio rerio and developing Xenopus laevis.

Recently a new approach for the analysis of iodinated organic species in human serum has been developed using liquid chromatography-inductively coupled plasma-mass spectrometry (LC-ICP-MS). This method enables quantification of iodide, T4 and T3, as well as reverse T3 (rT3) and the synthetic precursors of TH, monoiodotyrosine (MIT), and diiodotyrosine (DIT) in a single injection. In this work, the LC-ICP-MS approach was used to analyze whole-body homogenates of adult male and female zebrafish (Danio rerio) and tadpoles of the African clawed frog (Xenopus laevis) at two different developmental stages (NF58 and 61) according to Nieuwkoop and Faber. The data demonstrate that the LC-ICP-MS method was successful at measuring I-, MIT, DIT, T4, T3, and rT3 in these two species. Furthermore, the method also detected five additional iodinated compounds which are currently unidentified.

Animals↗