bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leucine assimilation in patients with diabetes mellitus
Authors: Bratusch-Marrain P. , Ferenci P. , Waldhäusl W. 
Published: December 2008

Abstract.
To estimate leucine metabolism in patients with absolute or relative insulin deficiency, elimination of an iv leucine load (50 mg/kg) was determined in 5 insulin-dependent diabetics, in obese (n = 5) as well as in ideal weight maturity onset diabetics (n = 5). Following leucine administration a marked rise of plasma insulin levels in obese diabetics, but lack of insulin response in insulin-dependent diabetics was observed compared to healthy controls (n = 6). Elimination half-life of leucine was similar in controls (34 ± 5 min), in obese (40 ± 4 min) and in ideal weight maturity onset diabetics (37 ± 2 min), but significantly prolonged in insulin-dependent diabetics (60 ± 3 min; P < 0.01). Thus in obese diabetics elevated plasma insulin levels and near normal elimination half-life of leucine suggest peripheral insulin resistance regarding leucine assimilation. In insulin-dependent diabetics, however, it appears that insulin deficiency is associated not only with elevated plasma leucine levels, but also with delayed elimination by peripheral tissues following administration of this amino acid.
Effects of phenylbutazone on thyroid iodine metabolism in vitro
Authors: Targovnik Héctor M. , Gluzman Bernardo E. , Coleoni Aldo H. , Niepomniszcze Hugo 
Published: December 2008

Abstract.
Several alterations of thyroid function parameters have been reported in patients treated with phenylbutazone and we have studied the effect of this drug on the intrathyroidal iodine metabolism. An inhibition of the iodide transport expressed in terms of T/M ratios was observed in bovine thyroid slices incubated with high phenylbutazone concentrations. 10−3m produced 72% inhibition whereas lower concentrations showed no significant difference as compared with controls.
Iodotyrosine synthesis was affected by 10−4m and 10−5m phenylbutazone. Formation of iodothyronine synthesis was markedly affected between 10−4m and 10−7m phenylbutazone concentrations. Thyroid peroxidase activity was measured by tyrosine-iodinase, triiodide and guaiacol assays. Soluble, pseudosolubilized and crude peroxidase preparations from bovine glands, as well as the soluble enzyme from human thyroids, have shown inhibition of tyrosine-iodinase activity when incubated with phenylbutazone in concentrations ranging from 10−3m to 10−8m, with a Ki of 4 × 10−6m for bovine thyroid peroxidase and of 6 × 10−6m for human soluble peroxidase. Formation of triiodide was affected between 10−3m and 10−8m phenylbutazone concentrations. Guaiacol peroxidation was scarcely affected by the action of the drug.
We have concluded that phenylbutazone affects the intrathyroidal iodine metabolism through the inhibition of thyroid peroxidase in concentrations which are usually present in the sera of patients treated with this drug.
Effects of D-mannoheptulose on blood glucose and alloxan sensitivity in mice
Authors: Boquist Lennart 
Published: December 2008

Abstract.
D-mannoheptulose (MH) administration induced a decreased serum insulin concentration in fed and starved mice, and a transient hyperglycaemia in fed mice, but not in starved ones. The liver glycogen concentration was decreased in starved controls and in fed mice treated with MH. Differences in the capacity for rapid hepatic glycogenolysis may have contributed to the different blood glucose responses in fed and starved mice. The hyperglycaemia in fed mice was unaffected by pre-treatment with L-leucine, or p-hydroxymercuribenzoate (PMB), but was abolished by pre-treatment with tolbutamide, and by post-treatment with insulin. Treatment of fed mice with MH before alloxan caused a marked "initial" hyperglycaemia but no second hyperglycaemia, and thus no development of alloxan diabetes. In starved mice injected with MH before alloxan there was an inhibition of the initial hyperglycaemia, but occurrence of a "second" hyperglycaemia, suggesting an absence of protection against the development of alloxan diabetes. The data show that alloxan diabetes may develop in the absence of an "initial" hyperglycaemia and a triphase blood glucose response. The hyperglycaemic action of MH in fed mice is believed to underlie the protection against alloxan toxicity.
Effects of arginine vasotocin, oxytocin, and arginine vasopressin on steroid-induced surges of luteinizing hormone and prolactin in ovariectomized rats
Authors: Salisbury Ronald L. , Krieg Richard J. , Seibel Hugo R. 
Published: December 2008

Abstract.
Several studies have indicated that arginine vasotocin (AVT), a nonapeptide closely related to vasopressin (ADH) and oxytocin (OT), may act as a pineal antigonadotrophic factor. The present studies were designed to investigate the effects of AVT on the luteinizing hormone (LH) and prolactin (Prl) release induced by sequential steroid priming of ovariectomized (OVX). rats. Sprague-Dawley rats were used 6–8 weeks post-OVX. After implantation of an intra-atrial bleeding catheter, animals were primed with 5 μg of oestradiol benzoate (EB) at 08.00 h on the next morning. Forty-eight hours later 1.5 mg of progesterone (P) was injected and animals were divided into groups which received either saline, AVT (1 of 4 doses), ADH, or OT. The saline or peptides were infused via the intra-atrial catheter at 10.00, 11.00, 12.00, and 13.00 h. Hourly blood sampling was performed at 11.00–18.00 h, and at 21.00 h. The 11.00, 12.00, and 13.00 h samples were taken 10 min after saline or peptide infusion. LH and Prl responses to the peptide infusions could be divided into pre-surge and surge effects. AVT caused a slight, but significant elevation of the normally low levels of LH and Prl which occurred before the onset of their surges. Only the highest dose of AVT (1.0 μg) blocked the LH surge. ADH, however, was capable of stimulating LH and Prl release during the pre-surge period and of inhibiting the LH surge. AVT at a dose of 0.5 or 1.0 μg specifically blocked the onset of the Prl surge, causing Prl to drop to its lowest level at 14.00 h - the time at which Prl levels were maximal in saline-treated animals. After this initial inhibition, however, Prl levels rebounded to show a delayed surge. OT infusion, on the other hand, caused a significant augmentation of the Prl surge. These data indicate that AVT may specifically block the onset of the Prl surge seen after sequential steroid priming of OVX rats, while OT may facilitate the Prl surge.
Some observations concerning the role of progesterone in the control of ovulation
Authors: Schuiling G. A. , Pols-Valkhof N. , Zürcher A. F. 
Published: December 2008

Abstract.
Pre-ovulatory LH-surges in 4-day cyclic rats (4d-r) were postponed 1, 4, or 8 days by treatment with progesterone (P), or 1 day by treatment with pentobarbitone just prior to the onset of the 'critical period' on pro-oestrus. P-delayed LH-surges tend to become higher with increasing duration of the preceding anovulatory period: 1 day-delayed surges were as high as 5d-r surges (i.e. about twice as high as spontaneous 4d-r surges); 8 days-delayed surges were significantly higher. Compared with 4d-r surges the time of onset and zenith of P-delayed surges is significantly advanced.
The 1 day-pentobarbitone-delayed surges too were as high as 5d-r surges, but still timed as 4d-r surges. On no 'artificial' pro-oestrus day did the responsiveness of the pituitary differ from the 'normal' pro-oestrus responsiveness.
It is concluded that P influences the timing but not the height of pre-ovulatory LH-surges.
Prolongation of the effects of gonadotrophins and prostaglandin E2 on ovarian cyclic AMP formation by inhibitors of protein synthesis
Authors: Bergh Christina , Ahrén Kurt 
Published: December 2008

Abstract.
The effects of LH, FSH and PGE2 on the accumulation of cyclic AMP by isolated whole ovaries from 23–24 day-old rats were studied in time-course experiments in presence and absence of two inhibitors of protein synthesis, puromycin and cycloheximide. In absence of these inhibitors ovarian cyclic AMP levels reached peak levels within 30 min for all three stimulators and returned towards pre-stimulation levels within 2–4 h. When puromycin (500 μg/ml) or cycloheximide (5 μg/ml) was present together with LH, FSH or PGE2, respectively, ovarian cyclic AMP levels did not decrease after the initial peak but remained high for the entire incubation period (4–5 h). The release of cyclic AMP to the incubation medium was also much higher when puromcyin or cycloheximide was present, illustrating that the effect of puromycin and cycloheximide was not caused by an inhibition of the cyclic AMP release. The effects of puromycin and cycloheximide were, in principle, the same when a phosphodiesterase inhibitor, 3-isobutyl-l-methylxanthine, was present. The results indicate either that there are, in the ovary, proteins with very rapid turn-over, necessary for the mechanism leading to refractoriness of the cyclic AMP system, or that the gonadotrophins and PGF2 as an early effect stimulate the production of a specific protein necessary for the development of refractoriness.
Large molecular species of chorionic gonadotrophin from human placental tissues: biosynthesis and physico-chemical properties
Authors: Maruo Takeshi , Segal Sheldon J. , Koide S. S. 
Published: December 2008

Abstract.
Human placental tissues in the first trimester of pregnancy were maintained in organ culture and incubated with [3H]proline for 90 min at 37°C. The tissues were homogenized with a protease inhibitor in the buffered medium and separated into subcellular components. A large molecular protein which reacted with antiserum to hCG hCGα and hCGβ, and with the receptor membranes obtained from bovine corpus luteum, was detected in the microsomal component and post-microsomal supernatant fraction. This protein was purified by chromatography on Sephadex G-100, Sepharose-6B and DEAE-Sephadex A-50. The large molecular species of hCG contained high radioactivity and was immunoprecipitated with all three antisera. The purified large molecular hCG was analyzed by electrophoresis on sodium dodecyl sulphate (SDS) polyacrylamide gel. Its molecular weight was estimated to be 90000 daltons. When the large molecular hCG was treated with 8 m urea and mercaptoethanol in the presence of SDS, a major portion of the material dissociated into immunoreactive α and β subunits of rather high molecular weights compared to standard hCG subunits. Under similar conditions standard hCG dissociates completely into its subunits. The present results suggest that the large molecular species of hCG might be a complex composed of larger forms of α and β subunits. This complex might be an intermediary component in the biosynthetic pathway of hCG or a product of posttranslational modification.
Stromal 5α-reductase activity is elevated in benign prostatic hyperplasia
Authors: Wilkin R. P. , Bruchovsky N. , Shnitka T. K. , Rennie P. S. , Comeau T. L. 
Published: December 2008

Abstract.
The activities of 5α-reductase and 3α(β)-hydroxysteroid dehydrogenase were assayed in homogenates of stroma and epithelium obtained from 3 normal, 9 hyperplastic and 2 carcinomatous human prostates. Irrespective of the normal or abnormal condition of the prostate, the localization of 5α-reductase was predominantly in stroma whereas the reductive and oxidative activities of 3α(β)-hydroxysteroid dehydrogenase were more evenly divided between stroma and epithelium. Furthermore, the mean specific activity of 5α-reductase in hyperplastic stroma at 84.6 ± 13.1 (± sem) pmol 30 min−1 mg protein−1 was almost 3 times greater (Student's t-test, P < 0.05) than the corresponding value in normal stroma, 31.6 ± 7.2 pmol mg protein−1 30 min−1. We conclude that the stroma is the primary site of conversion of testosterone to dihydrotestosterone in the human prostate owing to the prevalence in stroma of 5α-reductase, and that benign prostatic hyperplasia is characterized by an increased amount of stromal 5α-reductase activity.
Consecutive administration of synthetic LRH in the evaluation of gonadotrophin reserve in children
Authors: Tomita Masako 
Published: December 2008

Abstract.
Initial injection of synthetic luteinizing hormone releasing hormone (LRH) into 40 children elicited no response in LH and follicle stimulating hormone (FSH) in 15 patients with pituitary dwarfism, one with Kallmann's syndrome and in 3 anorexia nervosa patients. These patients were further treated with LRH for periods of either 3 or 14 days and the second LRH test showed an increase in LH and/or FSH in 67% of the patients with pituitary dwarfism, in the Kallmann's syndrome and in all of the anorexia nervosa patients. This result suggested that while pituitary gonadotrophs did not respond at the first LRH test because of the chronic absence of stimulation, consecutive LRH therapy, however, restored the ability to secrete LH and FSH and indicated that the pituitary was not the site of the primary lesion in these patients. The LRH test following consecutive administration of LRH may be valuable in determining whether the lesion is located in the hypothalamus or the pituitary.
Pituitary Cushing's disease without adenoma
Authors: Schnall Adrian M. , Kovacs Kalman , Brodkey Jerald S. , Pearson Olof H. 
Published: December 2008

Abstract.
Recent reports of patients with Cushing's disease who have been explored via the transsphenoidal route indicate that the great majority has pituitary adenomas. We report a patient with biochemically documented pituitary-based hypercortisolism who had a clinical and biochemical remission following hypophysectomy. Serial sections of the pituitary tissue removed showed hyperplasia of corticotroph cells but no adenoma. Hypophysectomy was complete as documented by serum levels of FSH, LH, TSH, prolactin, hGH and ACTH at the lower limits of the respective assays, with no response to appropriate stimuli. This case demonstrates that a minority of patients with Cushing's disease has corticotroph cell hyperplasia without a pituitary adenoma.
Effect of nutrition on growth and somatomedin A levels in the rat
Authors: Takano Kazue , Hizuka Naomi , Shizume Kazuo , Hasumi Yoko , Tsushima Toshio 
Published: December 2008

Abstract.
Serum somatomedin A was significantly reduced after 3 days of fasting in rats with a mean decrease of 23.6 ± 2.4% (N = 18) of initial values. Re-feeding for one day produced a definite increase in somatomedin A, with a rise in body weight.
When re-fed isocalorically for 21 days with diets of different quality, a low protein diet led to smaller increases in both seum somatomedin A and body weight in comparison to those of control-, high-protein- and high fat-diets (P < 0.001). There is a positive correlation between the increase in body weight and serum somatomedin A levels (N = 70, r = 0.71, P< 0.001). The effect of growth hormone on somatomedin generation was abolished in hypophysectomized rats fed with low-protein diet.
Our study suggests that protein in the diet is important for the generation of somatomedin A, which is necessary for normal growth.
Circadian variations of the response of plasma prolactin to brief exposure to ether in the male rat
Authors: Mattheij John A. M. , Swarts Hans J. M. 
Published: December 2008

Abstract.
Male adult rats, supplied with an indwelling chronic intrajugular cannula, were exposed to ether for 1 min at various times of the day. Blood samples were taken before and at regular intervals during 1 h following the ether exposure. Basal plasma prolactin showed a circadian variation. The highest level occurred at 1.00 h, and the lowest values were measured at 10.00 and 13.00 h, while a significant increase was observed at 16.00 h compared to the level at 10.00 and 13.00 h. At all times of the day studied exposure for 1 min to ether increased plasma prolactin for at least 30 min and the magnitude of this response to ether varied with the time of day. At 1.00 h the greatest response was observed, while at 10.00 and 13.00 h the most moderate response was measured. The data indicate that there is either a circadian rhythm in basal prolactin, which may cause a significant circadian variation in the magnitude of the stress response, or there is over the 24 h period a significant variation in stress-sensitivity of the hormone, which may contribute to the circadian variation of'basal' prolactin.
Parathyroid response to EDTA in hypoparathyroidism and in tetany
Authors: Burckhardt P. , Tscholl-Ducommun J. , Ruedi B. 
Published: December 2008

Abstract.
The parathyroid response to an EDTA infusion was measured in 11 patients with hypoparathyroidism and 22 patients with normocalcaemic tetany, and compared to that of normal controls and of 23 patients with primary hyperparathyroidism. Despite comparable basal PTH values, the patients with hypoparathyroidism and the normocalcaemic patients, with tetany following thyroid surgery, responded less than normals to EDTA, while normocalcaemic patients with tetany due to psychogenic hyperventilation responded more than normals. In hypoparathyroidism, mainly three types of results were observed: no response (total hypoparathyroidism), diminished or delayed response (partial hypoparathyroidism), and discrepant results using different antisera in cases of idiopathic hypoparathyroidism, suggesting the secretion of immunologically abnormal PTH. In tetany due to psychogenic hyperventilation, parathyroid hyperreactivity might be explained by repeated stimulation through respiratory alkalosis. Although the EDTA test rarely improved the diagnostic accuracy of basal PTH measurements in primary hyperparathyroidism, it was useful for differentiating between latent hypoparathyroidism and tetany due to psychogenic hyperventilation, both presenting with normal plasma calcium.
Studies of the human testis. XIV. Properties of C17-C20 lyase
Authors: Hosaka Masahiko , Oshima Hiroyuki , Troen Philip 
Published: December 2008

Abstract.
The properties of C17-C20 lyase in the human testis were investigated using a microsome fraction in the presence of NADPH. Michaelis constants (Km) of the enzyme were 1.7 × 10−5 m for 17α-hydroxyprogesterone and 5.9 × 10−7 m for 17α-hydroxypregnenolone. Km of the lyase for NADPH were determined as 6.3 × 10 −6 m in the presence of either 17α-hydroxyprogesterone or 17α-hydroxypregnenolone. In both instances, the maximum velocity (Vmax) of the lyase for 17α-hydroxyprogesterone was approximately two times higher than that for 17α-hydroxypregnenolone. Optimal pH and temperature of the enzyme for both 17α-hydroxyprogesterone and 17α-hydroxypregnenolone were 7.7 and 40°C, respectively. Each steroid substrate inhibited competitively the lyase activity for the other with inhibition constants (Ki) of 1.9 × 10−5 m for 17α-hydroxyprogesterone and 6.0 × 10−7 m for 17α-hydroprogesterone and 20α-dihydropregnenolone showed non-competitive inhibition of the lyase for either 17α-hydroxyprogesterone or 17α-hydroxypregnenolone. In contrast, testosterone inhibited the enzyme activity for 17α-hydroxyprogesterone competitively, but revealed typical uncompetitive inhibition of the lyase for 17α-hydroxypregnenolone. Similarly, the inhibition of the lyase by 5-androstenediol was competitive for 17α-hydroxyprogesterone and of the mixed type for 17α-hydroxypregnenolone. Furthermore, oestradiol-17β was found to be a competitive inhibitor of the lyase for 17α-hydroxyprogesterone, while it showed almost no inhibition of the enzyme for 17α-hydroxypregnenolone. The monosulphate steroids examined showed significant inhibition of the lyase for 17α-hydroxyprogesterone, but not for 17α-hydroxypregnenolone. From these results, it appears most likely that there are two different active sites for lyase, one for 17α-hydroxyprogesterone and the other for 17α-hydroxypregnenolone, although both sites show very similar properties.
17-ketosteroid reductase deficiency — plasma steroids and incubation studies with testicular tissue
Authors: Schnakenburg K. v. , Bidlingmaier F. , Engelhardt D. , Butenandt O. , Unterburger P. , Knorr D. 
Published: December 2008

Abstract.
The patient, diagnosed as a case of testicular feminisation in infancy, was examined at the age of 15 years because of severe symptoms of virilising puberty with poor breast development. Plasma steroid analyses revealed a 10-fold elevated androstenedione concentration (A: 1562 ng/100 ml). Testosterone (T: 266 ng/100 ml) was in the male pubertal range. Thus the A/T-ratio was far above normal. The oestrone/oestradiol ratio was also elevated (Oe1/Oe2: 10.2/2.2 ng/100 ml). A, T, Oe1 and Oe2 could not be suppressed by dexamethasone, but reacted promptly to fluoxymesterone (A: 781 ng/100 ml). hCG caused a further increase of the A/T-ratio (2220/246 ng/100 ml); ACTH did not alter the A-concentration. These findings together with simular investigations after gonadectomy suggest that the failure to convert A to T and Oe1 to Oe2 is essentially located in the testes. In vitro incubations of testicular tissue showed reduced 17-ketosteroid reductase activity in tissue slices and in the subcellular fractions microsomes and cytosole. This form of male pseudohermaphroditism can easily be detected already in infancy, if steroid analyses and stimulation tests are performed. In case of female sex assignment patients should be submitted to early orchidectomy in order to avoid virilisation in puberty.
Age-dependent variations in serum 1,25-dihydroxyvitamin D in childhood
Authors: Lund Bjarne , Clausen Niels , Lund Birger , Andersen Else , Sørensen Ole H. 
Published: December 2008

Abstract.
Circulating 1,25-dihydroxyvitamin D (1,25-(OH)2D) was measured in 87 children aged 3 months to 15 years, and in 11 adolescents 16–19 years of age. A positive correlation to growth velocity was observed, indicating that the biologically active vitamin D metabolite is an important physiological factor in the regulation of growth and development of the skeleton.
Post-encephalitic hypothalamic-pituitary insufficiency
Authors: Kupari Markku , Pelkonen Risto , Valtonen Ville 
Published: December 2008

Abstract.
Pituitary function was investigated in 3 patients who developed hypothalamic-pituitary insufficiency after viral meningoencephalitis. In 2 patients the causative agents were probably Influenza-A- and Herpes simplex virus whereas in the third patient it was not identified. The pattern of hormonal deficiencies indicated that all the central regulatory areas - hypothalamus, pituitary stalk and pituitary gland - may be injured after viral meningoencephalitis. Usually, the hormonal deficiency is permanent but it can also be transient.
Glucose tolerance, growth hormone and somatomedin levels in osteosarcoma patients
Authors: Adamson U. , Broström L.-Å. , Efendić S. , Hall K. 
Published: December 2008

Abstract.
Intravenous glucose tolerance, insulin response to glucose, the sensitivity of the periphery to insulin as well as growth hormone and somatomedin levels were determined in osteosarcoma patients and control subjects matched by age, sex, weight and length. The insulin response to glucose and the peripheral sensitivity to insulin were evaluated by using the individual blood glucose and plasma insulin curves for parameter identification in a mathematical model. The mean glucose tolerance was significantly decreased in the patients, most likely due to decreased peripheral insulin sensitivity. Plasma growth hormone levels were normal in all patients which was also the case with somatomedin levels determined by both radioreceptor- and radioimmunoassay.