bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serum 3'-monoiodothyronine levels in normal subjects and in patients with thyroid and non-thyroid disease
Authors: Kirkegaard C. , Faber J. , Cohn D. , Kølendorf K. , Thomsen H. Francis , Lumholtz I. B. , Siersbæk-Nielsen K. , Friis Th. 
Published: December 2008

Abstract.
Serum 3'-monoiodothyronine (3'-T1) levels were estimated by means of a specific radioimmunoassay (RIA) preceded by an ethanol extraction. The recovery of 3'-T1 was in mean (± sem) 110 ± 9%, and the lower detection limit was 23 pmol/l. Serum levels of 3'-T1 in 34 euthyroid healthy subjects were (median (range)) 55 pmol/l (<23-168 pmol/l), in 13 hyperthyroid patients 133 pmol/l (70-265 pmol/l) (P < 0.01) and in 13 hypothyroid patients <23 pmol/l (<23-68 pmol/l) (P <0.01). In 11 patients with chronic renal failure serum 3'-T1 levels were highly increased 285 pmol/l (115-1538 pmol/l) (P < 0.01) and correlated inversely to creatinine clearance (R = −0.68, P < 0.05). In patients with liver cirrhosis serum 3'-T1 levels were unaffected, whereas in 19 patients with endogenous depression studied before and after recovery from the depression serum levels decreased from 70 pmol/l (< 23-248 pmol/l) to 30 pmol/l (<23-95 pmol/l (P < 0.01). Administration of propranolol 40 mg b. i. d. for 2 weeks did not affect serum 3'-T1 levels. The study shows that 3'-T1 is present in serum from euthyroid man and varies with thyroid function. Further, it is suggested that 3'-T1 in contrast to other iodothyronines primarily is eliminated by the kidneys.
Effect of cycloheximide on iodothyronine formation in vitro
Authors: Inoue K. , Okamura K. , Shiroozu A. , Nakashima T. , Yoshinari M. 
Published: December 2008

Abstract.
The unique inhibitory effect of cycloheximide (CH) on the coupling of iodotyrosines was examined in vitro. Rat thyroid lobes were incubated for 8 h under our improved condition. In the presence of 10−4-10−3 m CH, the per cent uptake of 131I decreased, proportionate synthesis of [131I]MIT increased slightly, and that of [131I]T4 or [131I]T3 decreased markedly. The incorporation of medium 127I into T4 or T3 during the 8 h incubation period decreased markedly, but was fairly constant into MIT and only slightly decreased into DIT. Thus the inhibitory effect of CH seemed more prominent on iodothyronine formation than on iodotyrosine formation in this in vitro system. Inhibition of formation of newly labelled iodothyronines seemed to occur almost in parallel with the inhibition of [3H]amino acid incorporation into the thyroidal soluble protein. However, the coupling of iodotyrosines prelabelled in the absence of CH did not seem to be affected by CH. The presence of 10−4 m CH induced the Wolff-Chaikoff effect at a lower iodide concentration than that which occurred in the absence of CH, suggesting that CH sensitized the Wolff-Chaikoff effect. However, the organification of 127I and T4 synthesis were markedly reduced in the presence of CH even before the apparent Wolff-Chaikoff effect was initiated. These results give further support to our contention that prethyroglobulin is more important for organification of iodide than pre-existing thyroglobulin. We conclude that CH reduces coupling efficiency indirectly, probably by inhibiting the formation of prethyroglobulin with a favourable structure for coupling.
Enhanced release of T3 and rT3 compared to T4 from thyroglobulin during autolysis of dog thyroid homogenate
Authors: Laurberg Peter 
Published: December 2008

Abstract.
Previous studies on the secretion of thyroxine (T4), 3,5,3'-triiodothyronine (T3), and 3,3',5'-triiodothyronine (rT3) from perfused dog thyroids have indicated that a differential rate of secretion of various iodothyronines may take place.
The aim of the present study was to evaluate whether the proteolysis of thyroglobulin taking place during secretion could be involved in this phenomenon. Homogenate from the same dog thyroid was incubated either at pH 3.6 for 18 h without added protease or with pronase at pH 8.4 for 18 h. Iodothyronines were measured radioimmunologically in ethanol extracts of the hydrolysates. No significant deiodination of T4 to T3 and rT3 took place during incubation. During acid autolysis 17.5 ± 3.5% (mean ± SE, n = 5) of the T4 found after pronase hydrolysis was liberated, while 31.6 ± 4.8% of the T3 and 21.2 ± 4.2% of the rT3 were liberated (both values were significantly higher than that found for T4). Since iodothyronines in thyroglobulin are released nearly quantitatively during pronase hydrolysis, the results indicate that thyroid proteases acting at acid pH, liberates T3 and rT3 more easily than T4 from thyroglobulin.
This could be the mechanism behind the relatively high secretion of T3 and rT3 observed during acceleration of secretion from perfused thyroid lobes, and the relatively high secretion of T4 observed during deceleration of secretion.
Prostaglandins PGE and PGF in human ovarian follicles: endogenous contents and in vitro formation by theca and granulosa cells
Authors: Patwardhan Vasant V. , Lanthier André 
Published: December 2008

Abstract.
The possible role of prostaglandins of the PGE and PGF series in the follicular compartment of human ovaries or the capacity of that tissue to form them is not well defined. In the present experiment we have examined 1) the endogenous concentrations of PGE and PGF in follicles of human ovaries at various stages of the menstrual cycle, 2) the capacity of separated theca and granulosa to form PGE and PGF in vitro in the presence of substrate arachidonic acid and 3) the possible modulation of that capacity by previous in vitro exposure to hCG (10 IU) alone or in combination with hMG (5 IU). PGE and PGF were determined by radioimmunoassay.
Follicles from all stages of the cycle were found to contain measurable amounts of PGE (0.10–3.75 ng/follicle) and PGF (0.13–1.11 ng/follicle). These compounds were localized more in the theca than the granulosa cells. On a per follicle basis theca showed more capacity to form PGE and PGF in vitro than the corresponding granulosa cells. However, exposure to gonadotrophins stimulated PGE and PGF formation in the granulosa cells and not in the theca.
The presence of PGE and PGF in the follicles indicates a physiological role for these compounds in that tissue. Although thecal tissue showed a greater intrinsic capacity to form PGE and PGF, the contribution of granulosa cells may be more important under acute gonadotrophin stimulation.
Steroid responsiveness of the human cell line NHIK 3025
Authors: Østgaard Kjetill , Wibe Einar , Eik-Nes Kristen B. 
Published: December 2008

Abstract.
The human cell line NHIK 3025, derived from a carcinoma of the uterine cervix, contains a glucocorticoid and an androgen receptor. The effect of various natural and synthetic steroid hormones and antihormones on growth rate of these cells was therefore investigated.
Cells grown in Eagle's MEM with 10% foetal calf serum exhibited reduced growth when cultured with dexamethasone due to prolongation of the cell cycle. Glucocorticoid anti-inducers like progesterone had no significant effect on cell growth.
Methyltrienolone (R 1881) or 5α-dihydrotestosterone did not affect cell proliferation. The reported shortening of the cell cycle by testosterone is probably not directly connected with activation of the androgen receptor present, but possibly dependent on metabolic conversion of testosterone to the more potent growth stimulator 4-androstene-3β, 17β-diol.
The effect of several anti-androgens was also studied. The non-steroidal anti-androgens flutamide and SCH 16483 had no significant effect on cell proliferation. It was, however, found that a number of steroid antiandrogens, including R2956, stimulated cell growth. A significant stimulatory effect by R2956 was seen within the first cell generation, 4-androstene-3β,17β-diol had to be present during 2 days, and testosterone for even longer times before a similar effect on cell growth could be obtained.
Effect of short-term bromocriptine treatment on amniotic fluid prolactin concentration in the first half of pregnancy
Authors: Lehtovirta P. , Ranta T. 
Published: December 2008

Abstract.
The effect of short-term bromocriptine treatment on amniotic fluid and maternal prolactin concentrations was studied in 9 pregnant women in the first half of pregnancy. Bromocriptine suppressed the maternal serum prolactin level, but had no effect on the amniotic fluid level. Since both foetal and maternal prolactin secretion are suppressed by bromocriptine our results suggest that amniotic fluid prolactin is produced by extrapituitary tissues, which do not contain dopamine receptors.
Specific enzyme immunoassay for human chorionic gonadotrophin
Authors: Sekiya Tatsuhiro , Furuhashi Yoshihito , Goto Setsuko , Kaseki Shigeaki , Tomoda Yutaka , Kato Kanefusa 
Published: December 2008

Abstract.
A sandwich-type enzyme immunoassay system specific for human chorionic gonadotrophin (hCG) was prepared with the antibody Fab'-β-D-galactosidase complex and the antibody F(ab')2-immobilized silicone rubber solid phase by using a purified antibody to β subunit of hCG (hCGβ).
The assay system cross-reacted less than 4% with human luteinizing hormone (hLH) and human follicular stimulating hormone (hFSH), and proved to be highly sensitive with hCG measurable at levels as low as 0.3 mIU per assay tube.
Using 50 μl of serum sample, 6–600 mIU/ml of hCG in serum could be determined specifically with the same degree of precision as in radioimmunoassay but without sample interference with the assay.
The coefficients of variation within-run and between-run were 8.6–8.9%, and 4.9– 10.7%, respectively.
Values obtained with the enzyme immunoassay correlated well with those of radioimmunoassay ([unk] = 0.98, slope = 0.94, y-intercept = 10.2 mIU/ml for 75 serum samples).
Results of the immunoassay of hCG levels in serial samples of serum from healthy women and patients with choriocarcinoma show that this method is useful in the clinical diagnosis of trophoblastic disease.
Persistence of progesterone secretion after foetal death induced by vasopressin in rabbits
Authors: Wilks John W. 
Published: December 2008

Abstract.
Synthetic lysine-vasopressin (2 IU/kg body weight) terminated pregnancy in the rabbit when administered im on day 20, but not when administered on days 8 through 11 of gestation. Rabbits treated with vasopressin on day 20 delivered necrotic foetuses at the expected time of parturition (13/19 animals, day 32), aborted (3/19), or resorbed their foetuses (3/19). Uterine bleeding was noted in 68% of rabbits 5 days after vasopressin treatment on day 20 of pregnancy. Plasma concentrations of progesterone in vasopressin and saline treated rabbits were identical throughout pregnancy. Placental engorgement by erythrocytes was associated with foetal death in rabbits 1 h after vasopressin treatment on day 28 of gestation. Although vasopressin administration during the last third of gestation is detrimental to foetal life in the rabbit, the continuing normal secretion of progesterone indicates that the placentas remain viable. Available evidence suggests that foetal death results from ischaemia caused by placental vascular congestion and stasis following vasopressin administration.
Effect of rifampicin on the biosynthesis of testosterone in rat testis
Authors: Nocke-Finck Lieselotte , Breuer H. 
Published: December 2008

Abstract.
Male Wistar rats were treated with rifampicin (10 mg/kg) daily for 5 days. After 6 days, the rats were killed and the testes homogenised in tris buffer. The microsomal fractions were incubated with [4-14C]4-progesterone, [4-14C]17-hydroxyprogesterone or [4-14C]-androstene-3,17-dione, respectively, and a NADPH generating system. In rifampicin-treated animals, less [4-14C]progesterone was recovered after incubation with testicular microsomes than in controls. There was no significant difference in the formation of 17-hydroxyprogesterone between rifampicin-treated animals and the controls; however, a significant increase was found in the androstenedione fraction (+ 83%) and the testosterone fraction (+ 48%) under the influence of rifampicin. When [4-14C]17-hydroxyprogesterone or [4-14C]4-androstene-3,17-dione were incubated, no differences in the metabolic pattern were observed between treated and untreated rats. These findings suggest that rifampicin stimulates the activity of 17α-hydroxylase in the microsomal fraction of rat testes, thus leading to an increased formation of testosterone and androstenedione; in contrast, the 17,20-lyase and 17β-hydroxysteroid-dehydrogenase remain unaffected by rifampicin.
Multiple forms of growth hormone: detection in medium from cultured pituitary adenoma explants
Authors: Talamantes F. , Lopez J. , Lewis U. J. , Wilson C. B. 
Published: December 2008

Abstract.
Three pituitary adenomas obtained from patients with acromegaly were maintained in organ explant culture for a period of 12 days in a defined culture medium. Lyophilized culture medium from each was then examined by electrophoresis to determine which forms of growth hormone were secreted by the explants. All three explants secreted principally the major form of growth hormone. One adenoma however secreted unusually large amounts of two slowly migrating forms which were in low concentration in the GH-containing granules of normal pituitaries. On the other hand the adenoma produced a much lower amount of a 20,000-dalton variant than was seen in normal pituitary glands. The other two adenomas did not secrete the relatively large amounts of the slowly migrating forms although the quantity of the 20,000-dalton form was less than the amount seen in the normal pituitary. There was no evidence of proteolytic alteration of the growth hormone during the culturing process.
In companion experiments with rat pituitary glands the growth hormone did not undergo proteolytic degradation in the gland left in situ for 96 h at 5°C.
Effect of oestrogen on the responsiveness of the pituitary gland to LRH: the role of corpora lutea
Authors: Koiter T. R. , Pols-Valkhof N. , Schuiling G. A. 
Published: December 2008

Abstract.
The hypothesis that corpora lutea (CL) secrete substances which prevent oestrogens from influencing the state of responsiveness of the pituitary gland to LRH (RESP) was tested in rats rendered persistently oestrous (PO) by exposure to permanent illumination. In these rats ovulation and hence the presence of a single set of CL, was induced by exogenous gonadotrophin, hCG. The RESP of the animals was judged on 3 parameters based on the surge-like LH-secretory responses which were induced by 21-h long constant rate LRH infusions (104 ng/LRH/h). These 3 parameters were: a) the maximal height (MH) of the responses; b) the 'area under the curve' (AUC) of the LH values; and c) the constant β (or alternatively the t½) which characterizes the rate of decrease of the plasma LH concentrations after 2 h of infusion.
Four experiments were performed, all with PO rats: 1) rats were injected with either oestradiol benzoate (OeB; 3 μg sc) or oil on day 0 (the day treatments were started was always denoted as day 0); 2) rats were treated similarly, but they also received an ovulatory dose of hCG (50 IU/100 g b.w. ip) on day 0; 3) rats were injected with hCG on day 0 and with OeB or oil on day 3; and 4) rats were injected with hCG on days 0 and 4, on which latter day they also received OeB or oil. In all 4 experiments the LRH infusions were started 21 h after administration of OeB or oil. Blood samples for LH determinations were taken at times apparent from 'Results and Discussion'.
It is observed that: 1) after administration of OeB the MH and thereby the AUC increased significantly but the β of the LH-secretory responses was unchanged; 2) after administration of an ovulatory dose of hCG the LH-secretory responses changed also; of these responses, however, the β had decreased and the AUC had increased, whilst the MH remained unchanged; 3) when given together, OeB and hCG exhibited their effect simultaneously: the two effects are additive; 4) in the presence of 3-day old CL OeB is ineffective; and 5) in the presence of 4-day old CL neither OeB nor hCG is able to affect the RESP.
It is concluded: 1) OeB and 'hCG' probably influence a different substrate of the LH-release mechanism; and 2) that these results confirm the hypothesis that CL secrete substances which prevent oestrogen from affecting the RESP for at least 4 days.
If this hypothesis is extended to the cyclic rat, CL, arisen after the previous ovulation, may still be of importance on the day of the next pro-oestrus by exerting a significant influence on the RESP.
The renal kallikrein-kinin system in Brattleboro rats with hereditary hypothalamic diabetes insipidus
Authors: Bonner G. , Rascher W. , Speck G. , Marin-Grez M. , Gross F. 
Published: December 2008

Abstract.
The activity of the renal kallikrein-kinin system was investigated in male Brattleboro rats homozygous for hypothalamic diabetes insipidus (DI); LongEvans rats (LE) were taken as controls. In the rats with DI, urinary kallikrein excretion was lower (P < 0.05) than in the LE rats. However, when related to total renal mass or to body weight, there was no difference between the two strains. Kallikrein activity in the renal cortex was similar in the Brattleboro and the LE rats.
Antidiuretic hormone (vasopressin tannate) in a dose of 100 mU given once daily for 3 days had no effect on urinary kallikrein excretion in either of the strains. Water deprivation for 24 h resulted, also in both strains, in a similar reduction in urinary kallikrein excretion.
The renal kallikrein-kinin system of LE rats and that of DI rats does not principally differ in basic activity, nor in response to the administration of vasopressin, nor to water deprivation.
Effect of thiol blocking agents on the binding of T3 and T4 in rat liver nuclear extract
Authors: Knopp J. , Brtko J. 
Published: December 2008

Abstract.
Liver nuclei bind thyroid hormones (T3 and T4) with different binding affinities. In our studies it was estimated that the apparent association constant (Ka) in the liver nuclei for T3 was 8.8 × 1010 l mol−1 and for T4 was 4.1 × 109 l mol−1. We have found that the binding sites for T4 are also saturated by an excess of unlabelled T4 and that saturation was dependent on the purification step of liver binding proteins. In liver nuclear extracts with 0.4 mol l−1 KCl the specific binding of T3 and T4 was blocked with a typical -SH blocking agent N-ethylmaleinimide (NEM) and by new types of -SH blocking agents such as p-bromphenylisothiocyanate (p-BPI) and 2,3 dicyano-1,4-dithio-9,10 antrachinone (Delan). NEM and p-BPI increased the non-specific binding of T4 and completely abolished specific binding. All these agents blocked the specific binding of T3. These results demonstrate that T3 and T4 binding sites in the liver nuclei may not be altogether identical and that the different effects of -SH blocking agents on the binding of T3 and T4 is probably associated with the structural configuration of these drugs.
In vitro oestrogen synthesis by bovine placenta during pregnancy and induced parturition
Authors: Evans G. , Wagner W. C. 
Published: December 2008

Abstract.
Foetal (cotyledon) placental tissue was collected from 7 pregnant cows and from 9 cows immediately after delivery of the foetus during parturition induced by luteal removal at 250 or 270 days of gestation. These tissues were incubated with [3H]androstenedione (A), [3H]17α-hydroxyprogesterone (17αHP), or [3H]-pregnenolone (P5) to examine potential oestrogen precursors in the mid to late pregnant cow. Percentage conversion to unconjugated and conjugated oestrone (Oe1) and oestradiol (Oe2) was measured for each tissue with the various substrates. Unconjugated oestrogens predominated over conjugated (P < 0.001), and Oe1 over Oe2 (P < 0.001) in all incubations. There was no difference in conversion of A between pre- and postpartum foetal tissues. There was a significant elevation in conversion of P5 in post-partum foetal tissue (P < 0.05). These data demonstrate a) placental aromatase activity does not appear to increase as pregnancy progresses towards parturition, b) the bovine placenta is able to convert C21 steroids to oestrogens, and c) induction of enzymes for converting pregnenolone or related substrates to oestrogens may be involved in the pre-partum rise in oestrogen levels.
Pituitary function in idiopathic haemochromatosis: hormonal study in 36 male patients
Authors: Charbonnel B. , Chupin M. , Le Grand A. , Guillon J. 
Published: December 2008

Abstract.
Thirty-six male patients with idiopathic haemochromatosis were subjected to measurements of basal plasma values of testosterone, LH and FSH and to an LRH test. Nineteen were also subjected to basal plasma determinations of T3, T4, cortisol, TSH and prolactin and to a TRH test. In 11 cases GH values were measured before, during and after an arginine infusion.
Seventeen patients were found to have low levels of testosterone, LH and FSH, and no gonadotrophin responses to LRH. Seventeen others had normal levels of these three hormones, with normal responses to LRH. The two remaining patients had normal testosterone values but very increased gonadotrophin values: a fact which remains unexplained.
Basal levels of prolactin, GH, T3, T4, and TSH were normal: cortisol levels were either normal or increased in cases of poorly controlled diabetes. Prolactin responses to TRH were always normal. TSH responses to TRH were impaired in 2 cases, and GH responses to arginine in 3 cases.
Considering that other factors may be involved in the few impairments found in TSH and GH stimulations, it is concluded that the only indisputable pituitary insufficiency in about half of the cases of idiopathic haemochromatosis is gonadotrophic.
Action of cortisol introduced into the supraoptic nucleus, on vasopressin release and antidiuresis during hypertonic saline infusion in conscious rhesus monkeys
Authors: Streeten David H. P. , Souma Micki , Ross Gilbert S. , Miller Myron , Lewis Rosemary 
Published: December 2008

Abstract.
In human subjects cortisol raises the osmotic threshold for vasopressin release. The presumption that this results from a direct inhibitory action of cortisol on osmotically stimulated vasopressin release has been tested in conscious rhesus monkeys. Preparatory surgical procedures included chronic bladder catheterization, placement of cannulae in the right atrium, the left jugular vein and the stomach and stereotaxic insertion of metal cannulae in both supraoptic nuclei. The osmotic threshold for vasopressin release was defined as the plasma osmolality at the beginning of the 3 min urine sample in which free water clearance first fell by > 2 sd below the mean control level, in response to 5% saline infusion during constant hydration. Compared with control substances (0.9% saline solution or 11-deoxycortisol crystals), cortisol solution or crystals introduced into both supraoptic nuclei significantly lowered the plasma osmolality during the water-induced pre-saline diuresis, so that a larger amount of 5% NaCl infusion was required to reach the osmotic threshold. Thus, cortisol introduced into the supraoptic nuclei prolonged the duration of 5% saline infusion needed to reach the osmotic threshold, and raised the increment in plasma osmolality needed to reach the threshold but cortisol did not significantly raise the absolute level of the threshold.