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At least 379 records · Page 21Linked to original sources
PubMed1995

Modulation of the activity of human 17 alpha-hydroxylase-17,20-lyase (CYP17) by cytochrome b5: endocrinological and mechanistic implications.

Using NADPH-cytochrome P-450 reductase as electron donor the homogeneous pig 17 alpha-hydroxylase-17,20-lyase (CYP17) was shown to catalyse the conversion of delta 5, as well as delta 4, steroids (pregnenolone and progesterone respectively) predominantly into the corresponding 17 alpha-hydroxylated products. The latter were then cleaved by the lyase (desmolase) activity of the enzyme into androgens. Cytochrome b5 stimulated both these activities, but its most noticeable effect was on the formation of delta 16-steroids, which compulsorily required the presence of cytochrome b5. These results on the pig enzyme confirm the original findings [Nakajin, Takahashi, Shinoda and Hall (1985) Biochem. Biophys. Res. Commun. 132, 708-713]. The human CYP17 expressed in Escherichia coli [Imai, Globerman, Gertner, Kagawa and Waterman (1993) J. Biol. Chem. 268, 19681-19689] was also purified to homogeneity and was found to catalyse the hydroxylation of pregnenolone and progesterone without requiring cytochrome b5. Like the pig CYP17, the human CYP17 also catalysed the cytochrome b5-dependent direct cleavage of pregnenolone into the delta 5,16-steroid, but unlike it the human enzyme did not cleave progesterone at all. 17 alpha-Hydroxypregnenolone was, however, cleaved into the corresponding androgen but only in the presence of cytochrome b5. 17 alpha-Hydroxyprogesterone was a poor substrate for the human CYP17; although it was converted into androstenedione in the presence of cytochrome b5 its K(m) was 5 times higher and Vmax. 2.6 times lower than those for the hydroxylation of progesterone. The endocrinological and mechanistic implications of these results are discussed.

Adrenal Cortex Hormones↗
PubMed1999

Laparoscopic adrenalectomy for phaeochromocytoma: endocrinological and surgical aspects of a new therapeutic approach.

OBJECTIVES: To evaluate the results of laparoscopic resection of phaeochromocytoma with a focus on pre- and intra-operative endocrinological and pharmacological aspects. DESIGN: Retrospective study based on review of case notes and intraoperative anaesthetic records. PATIENTS: Eight patients (four men, four women) aged 13 to 70 (median: 45) years with symptomatic phaeochromocytoma (two patients with MEN IIa syndrome) diagnosed 6-36 months before adrenalectomy in four patients and just before operation in the four remaining patients. All patients presented with hypertension. MEASUREMENTS: Pre- and postoperative blood pressure (BP) was assessed using a sphygmomanometer, intraoperative measurements being obtained by intra-arterial line. Adrenaline (A), noradrenaline (NA), metadrenaline (metA), normetadrenaline (normetA) and vanillylmandelic acid (VMA) were measured in 24-h urine samples. Adrenal imagery consisted in all patients of abdominal computed tomography and [131I] metaiodobenzylguanidine (MIBG) scintigraphy, and in 2 patients, adrenal magnetic resonance imaging and octreotide scintigraphy. Determination of plasma volume was performed by isotopic method. RESULTS: Median (range) preoperative systolic and diastolic BP was 140 (130-240) and 90 (80-150) mm Hg, respectively. Predominant catecholamine secretion consisted of A in four patients (A pattern) and of NA (NA pattern) in the other four. Tumours smaller than 30 mm usually secreted A while larger ones secreted NA. Pre- and intra-operative BP control was straightforward in all but two patients with preferential NA secretion. The median number of systolic and diastolic BP peaks were higher in patients with NA pattern (n = 6, range: 3-9) than in those with A pattern (n = 1.5, range: 1-6). Total duration of pneumoperitoneum ranged from 120 to 240 (median: 195) min. Intra- and post-operative complications included intra-abdominal bleeding, laparoscopically controlled (in one case), and upper pole kidney ischaemia in another. Postoperative hospital stay ranged from 4 to 11 days. All patients were asymptomatic postoperatively and pharmacologically controlled hypertension persisted in two of them. CONCLUSIONS: Laparoscopic adrenalectomy is a safe and efficient technique to remove phaeochromocytoma in terms of intra- and postoperative morbidity, with a low complication rate. Pre- and intra-operative pharmacological blood pressure control is as effective as in conventional adrenalectomy, with greater instability in noradrenaline secreting tumours.

Adolescent↗
PubMed2002

The endocrinology of pre-eclampsia.

Pre-eclampsia is a pregnancy specific syndrome that is a principal cause of maternal morbidity and mortality, accounting for almost 15% of pregnancy associated deaths, and is one of the major causes of iatrogenic prematurity among new born babies. The mild form of pre-eclampsia most commonly presents with the features of maternal hypertension and proteinuria, but can swiftly and unpredictably become severe with numerous multisystem complications involving the maternal liver, kidneys, lungs, blood and platelet coagulation and nervous systems. The diverse symptoms of pre-eclampsia have made it a difficult disease not only to define, but also to identify a causative agent for the symptoms. This review examines the complex endocrinological mechanisms believed to be responsible for the extensive complications of pre-eclampsia from the role of placental and endothelial dysfunction, to the causes of the oxidative stress and the ensuing general inflammation. It also highlights current endocrine findings that exhibit the potential for clinical application, as either potential markers or novel therapeutic targets, with the aim of either preventing or altering the course of this life-threatening disease of pregnancy.

Biomarkers↗
PubMed1999

Endocrinologically active retroperitoneal ganglioneuroma with positive iodine-131-metaiodobenzylguanidine scintigraphy.

BACKGROUND: A case of retroperitoneal ganglioneuroma incidentally found by ultrasonography in a 56-year old woman is presented. METHODS/RESULTS: Computed tomography revealed a solid round tumor 6 cm in diameter on the upper pole of the right kidney. Iodine-131-metaiodobenzylguanidine weakly accumulated in the tumor 24 and 48 h after the injection. Her serum catecholamines were within normal limits apart from slightly elevated norepinephrine at one of the two examinations. During the operation her serum epinephrine and dopamine levels were elevated to about 50 and 800 times higher than pre-operative values, respectively. CONCLUSION: This case is a rare ganglioneuroma in an adult patient that is endocrinologically active.

3-Iodobenzylguanidine↗
PubMed2001

[Endocrinologic aspects of habitual abortion].

Disorders of the luteoplacental progesterone shift in the first and second trimester lead to a insufficient progesterone secretion, thus constituting an important cause of early and late abortions. The endocrinological disorders caused by ovarian malfunction normally occur between the 5th and 10th weeks of pregnancy. We can distinguish early and late disorders of the corpus luteum graviditatis from a relative luteal deficiency owing to ovarian hyperstimulation. The delayed shift, however, is caused by trophoblast disorders and disturbances of placentation, thus leading to low blood levels of progesterone. Progesterone replacement therapy for the duration of insufficiency leads to significantly reduced rates of abortion. An increase in the rate of malformations is not to be expected.

Abortion, Habitual↗
PubMed2006

[The new role for endoscopic ultrasound in endocrinology: imaging of the adrenals and the endocrine pancreas].

Endoscopic ultrasound imaging of the adrenals and the endocrine pancreas enriches the diagnostic repertoire and improves the clinical opportunities of endocrinology. Its resolution enables detection of tumors as small as 2-3 mm. Endoscopic ultrasound imaging is especially relevant in the diagnosis of insulinomas and primary hyperaldosteronism, because it has direct consequences in planning a diagnostic and therapeutic strategy.

Adrenal Gland Diseases↗
PubMed1987

[The single hormone hypothesis. An instructive episode in the history of ovarian endocrinology].

In the mid-twenties of the present century renowned scientists held the opinion that only one female sex hormone is secreted by the ovary. A survey is given how this hypothesis arose, for which reasons it was favoured and why it had to be given up. The importance of the Allen-Doisy test (1923) and the Corner-Allen test (1929) and of the publications by these authors is stressed. Finally, it is shown that Thomas S. Kuhn's theory, explaining how scientific advance is promoted by changing a paradigm, is also applicable to this phase of research in ovarian endocrinology as well.

Animals↗
PubMed1983

[Aspects of an interplay between endocrinological and metabolic factors during birth].

The well-known rise of the levels of glucose, lactate, pyruvate, non-esterified free fatty acids (NFFA), glycerol, and ketone bodies during labour cannot be explained only by metabolic pathways. The simultaneous measurement of insulin, cortisol, hGH, and prolactin shows a striking change in secretion, especially of cortisol, after the first half of labour. It is assumed that cortisol plays an important part in the intrapartal metabolic conversions. The correlation cortisol/glucose becomes significant. There is no evidence of the known catabolic effect of cortisol under the conditions of labour, but these is evidence of a reduction of peripheral glucose utilisation. The role of cortisol for the intrapartal metabolic changes is discussed under the aspect of labour progress. The outlines of a very ingenious but also complex interplay between endocrinological and metabolic factors emerge which may provide useful tools for therapeutic use.

Fatty Acids, Nonesterified↗
PubMed1984

[Gynecological and endocrinological studies of thalidomide-damaged girls].

Gynaecological examinations were done for the first time in 32 girls, between age 13 and age 18 damaged by thalidomide. 11 of the girls had primary amenorrhoea at the time of examination. 9 of these cases showed genital malformations. 7 cases showed aplasia of the uterus. A rudimentary uterus and a hypo-plastic uterus were found in one patient each. In 8 girls these changes were combined with abnormalities of the vagina, 3 cases had vaginal aplasia. 4 cases had a blind vaginal sac. 1 case had a urogenital sinus. Two patients had primary amenorrhoea without genital malformations. In the girls who had started menstrual periods none of the 21 cases showed genital malformations. Supplementary endocrinological investigations were done to answer the question whether functional disturbances were caused by thalidomide in addition to organic changes. The development of puberty can be diagnosed from secondary sexual markers. Our patients had almost all advanced puberty with more mammary development than pubic development. The menarche between age 11 and age 16 showed no deviation from the normal in our patients. 11 girls had regular cycles. The hormonal vaginal cytology in 28 patients showed no sign of deficient estrogen. Neuro-endocrine maturation is responsible for the development of puberty. The basal secretions of FSH and LH increase. The dynamic functional test with LHRH shows the LH reserve of the pituitary which rises in a typical pattern. 14 patients had a LHRH test and nine of these showed a mature LH reserve corresponding to the index R2.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗
PubMed1989

Endocrinological disorders in shunted hydrocephalus.

Endocrinological findings were identified in 60% of 90 shunted patients with an isolated hydrocephalus, namely dwarfism in one third and abnormal proportions, obesity, sexual precocity and various combinations in 9-15%. Different causes of these findings were observed. But none of the cases had a malfunction of the shunt at the time of this study.

Cerebrospinal Fluid Shunts↗
PubMed1994

[Symptoms and endocrinologic features of catecholamine-secreting tumors. Results in 106 consecutive patients].

The clinical and endocrinological features in 106 patients (40 men, 66 women, mean age 48 +/- 14.3 years) treated between 1973 and 1993 for proven catecholamine-secreting tumours (phaeochromocytoma: n = 88, paraganglioma: n = 10, adrenal medullary hyperplasia: n = 8) were analysed. The most frequent symptoms were palpitations (68%), severe sweating (53%) and headache (42%). 10% of patients were symptom-free. 58% of patients had consistently raised blood pressure, and 20% of patients suffered paroxysmal blood pressure crises. However, 22% of patients did not have hypertension. Raised urinary catecholamines were found in more than 95% of cases; MIBG (metaiodobenzylguanidine) scintigrams were abnormal in more than 85% of cases. Patients with catecholamine-secreting tumours do not always have "classical" features. The high sensitivity of properly performed catecholamine measurement on plasma and urine has made dangerous stimulation and suppression tests obsolete.

Adolescent↗
PubMed1996

Metabolic and endocrine changes induced by chronic heat exposure in broiler chickens: biological and endocrinological variables.

The present study was designed to investigate the effect of chronic heat exposure (32 degrees constant) on plasma metabolites and hormone concentrations in broiler chickens. At 2 and 4 weeks of age, fifty-four male Shaver broiler chickens were allocated to one of three treatments: 22 degrees, ad lib. feeding (22AL), 32 degrees, ad lib. feeding (32AL) and 22 degrees, pair-feeding with the 32AL group (22PF). Ambient temperature was kept constant at either 22 or 32 degrees for 2 weeks. Plasma glucose, triacylglycerols, phospholipids, non-esterified fatty acids (NEFA), individual amino acids, uric acid, insulin, triiodothyronine (T3), thyroxine, corticosterone were determined. Sensitivity to exogenous insulin was also measured at 7 weeks of age. At 4 and 6 weeks of age, i.e. after 2 weeks at high ambient temperature, fasted 32AL chickens displayed similar concentrations of glucose and triacylglycerols to those of 22AL birds. When fed, 32AL chickens exhibited higher plasma levels of glucose and decreased concentrations of NEFA and amino acids. Feed restriction resulted in intermediate values. Concentrations of all plasma free amino acids were decreased under heat exposure except for aspartic acid, glutamic acid and phenylalanine. At 6 weeks of age, plasma T3 was reduced irrespective of the nutritional state, while plasma corticosterone concentrations were increased in 32AL birds compared with 22AL birds. Heat exposure did not change plasma insulin concentration in either fasted or fed chickens. The 32AL chickens displayed significantly reduced sensitivity to exogenous insulin when fasted, but an enhanced response to insulin when fed, compared with both 22 degrees groups. Such endocrinological changes could stimulate lipid accumulation through increased de novo lipogenesis, reduced lipolysis and enhanced amino acid catabolism under chronic heat exposure.

Amino Acids↗
PubMedDate not supplied

Epidemiological study of endocrinological effects of carbon disulfide.

One hundred seventeen viscose rayon workers exposed to carbon disulfide, and 66 workers who were not exposed to any toxic agent in the working environment, underwent an endocrinological examination that included determination of thyroxine, luteinizing hormone, follicle-stimulating hormone, prolactin, and testosterone in serum by radioimmunoassay methods. In the viscose rayon factory, the working conditions had not changed subsequent to 1932. Personal monitoring performed in 17 jobs showed that carbon disulfide exposures varied from 4 to 112 mg/m3. A carbon disulfide cumulative exposure index was calculated for each individual. Univariate analysis of the hormone levels versus exposure showed significantly lower levels of prolactin in the exposed versus nonexposed subjects (p = .01). After adjustment for age, alcohol, smoking, body mass index, and stress level, the carbon disulfide cumulative exposure index was not associated with any of the hormones. This discrepancy from previous studies may result from differences in exposure, in selection of the population, or in confounding biases.

Adult↗
PubMed2004

First trimester endocrinology: consequences for diagnosis and treatment of pregnancy failure.

First-trimester endocrinology is determined on the one hand by corpus luteum progesterone and estradiol biosynthesis and secretion and on the other hand by the time of onset and extent of progesterone and estradiol secretion by the placenta. This dual interplay is dominated by the corpus luteum placental shift, where a relative progesterone and estradiol deficiency can develop and may lead to early as well as late abortion. Measurements of serum progesterone and estradiol are mandatory in order to reveal such deficiencies and to treat them effectively with 17 alpha-hydroxyprogesterone caproate in combination with estradiol valerate or with progestins such as dydrogesterone.

17-alpha-Hydroxyprogesterone↗
PubMed2000

Endocrinology teaching rounds: primary amenorrhea in a 17-year-old woman.

This endocrinology teaching rounds documents the evaluation of a 17.7-year-old woman with primary amenorrhea. The normal timing of developmental milestones for young women from adrenarche and pubarche through pubertal maturation and growth is reviewed, as are etiologies for amenorrhea. The differential diagnosis of the problem is developed from the patient's initial visit to diagnosis and treatment. The highlights of the management of this young woman after a diagnosis of craniopharyngioma are also discussed. This clinical case emphasizes the importance of understanding normal developmental landmarks and of detecting aberrant physiology-associated amenorrhea even when screening laboratory tests appear normal so that defects in normal development can be addressed earlier in life.

Adolescent↗
PubMed1989

Hemodynamic and endocrinological effects of a new selective alpha 1-blocking agent, terazosin, in patients with essential hypertension. Results of long-term treatment.

Thirteen patients with essential hypertension were treated with an alpha 1-adrenoceptor antagonist, terazosin (1 to 4 mg/day) for 12 months. To assess the mechanism of its antihypertensive effect, the hemodynamic and endocrinological responses to terazosin were determined before, 3, and 12 months after the administration of terazosin. Blood pressure significantly decreased within 2 weeks after the start of terazosin and its effect was sustained throughout the 12 month period. Pulse rate did not change except slight increase in the third month. The hemodynamic studies revealed that total peripheral resistance significantly decreased and cardiac output slightly increased, indicating that the antihypertensive effect of terazosin is mainly produced by its vasodilation. Blood volume and plasma volume did not change. Although plasma renin activity remained the same, plasma aldosterone significantly decreased in response to terazosin. Plasma noradrenaline increased in the third month, but returned to the baseline level in the twelfth month. Thus, terazosin monotherapy lowered blood pressure throughout one year without drug tolerance including volume expansion and/or accentuation of renin-angiotensin-aldosterone system or sympathetic function.

Adrenergic alpha-Antagonists↗
PubMedDate not supplied

Recent developments in endocrinology and paracrinology of blastocyst implantation in the primate.

It is becoming increasingly evident that growth factors and cytokines play crucial roles in the process of blastocyst implantation. Endometrial differentiation and secretions, embryo development and secretions, and embryo-endometrium interaction leading to implantation require continuous and synchronous dialogue between these two compartments involving endocrine and paracrine regulators. In this review, a model of the endocrinology and paracrinology of blastocyst implantation in the primate is described.

Animals↗
PubMed1990

Short-term use of buserelin in combination with human menopausal gonadotrophins for ovarian stimulation for in-vitro fertilization in endocrinologically normal women.

Ten endocrinologically normal women were injected subcutaneously with 500 micrograms D-Ser(TBU)6-EA10-LHRH (buserelin) on days 3,4 and 5 after the start of the menses. Two types of response were observed. Five women (group A) responded promptly and had a mean number of 13.4 oocytes retreived after 11.4 days of stimulation. In the second group (B), two to three times more HMG was needed to obtain a mean number of 7.3 oocytes after 17.2 days of stimulation. The response upon stimulation could be predicted by the serum gonadotrophin output on days 4 and 5 of the cycle. One woman from group B had a premature LH rise on day 16 and luteinization; her cycle was abandoned. In the four other patients of group B, serum and urinary LH concentrations showed that pituitary gonadotrophin secretion had recovered before the ovulatory stimulus, without signs of premature luteinization. Two women in each group became pregnant, one of whom aborted. This short-term GnRH agonist treatment could be an alternative method for ovarian stimulation, although it did not totally prevent the occurrence of an endogenous LH surge.

Adult↗