bluuebunny/crossref_metadata_2025_split huggingface dataset:
Failure to secrete immunoreactive insulin by rats fed a low protein diet
Authors: Levine Leonora S. , Wright P. G. , Marcus Fanny 
Published: December 2008

Abstract.
Rats fed a 6% protein diet for 14 weeks showed a normal glucose tolerance but failed to release immunoreactive insulin (IRI), following iv glucose. Furthermore the isolated perfused pancreas of the rats fed the 6% protein diet secreted eleven times less IRI than the isolated pancreas prepared from the rats reared on an 18% protein diet when both were subjected to the same glucose challenge. This difference occurred despite the fact that the total IRI content of the pancreas' was not significantly different between the two groups. In the protein-malnourished rats it is suggested that the normal glucose tolerance response, despite the failure to release a concommitant amount of IRI, may indicate increased sensitivity to IRI or may be due to the secretion in these animals of a biologically active insulin, which shows no immunological cross-reactivity with pancreatic insulin. Alternately there may be increased peripheral glucose utilisation in the low protein rats.
Evidence for cleavage of [26-14C]cholesterol side-chain by human foetal membranes in vitro
Authors: Gunasegaram R. , Loganath A. , Peh K. L. , Ng S. C. , Karim S. M. M. , Ratnam S. S. 
Published: December 2008

Abstract.
With a view to establish the hitherto undescribed role of cholesterol in foetal-membranous steroidogenesis, homogenates of term chorion pars reflexa and amnion pars reflexa and pars placentaris collected from 6 women after spontaneous labour at term (38 to 41 weeks gestation) were incubated with [26-14C]cholesterol. Using reverse-isotope dilution analysis, [14C]isocaproic acid was isolated and characterized. This conversion constitutes strong evidence that C-20, 22-desmolase activity, normally present in the adrenal, gonadal and placental tissues, is present in the homogenates of both membranes. The efficiency of the enzymic conversion suggests that the chorion possesses a more active desmolase system compared to that of the amnion.
Serum non-protein bound percentage and distribution of the progestin ST-1435: no effect of ST-1435 treatment on plasma SHBG and CBG binding capacities
Authors: Lähteenmäki Pertti L. A. , Hammond Geoffrey L. , Luukkainen Tapani 
Published: December 2008

Abstract.
The non-protein bound percentage of ST-1435 was measured by centrifugal ultrafiltration-dialysis in undiluted female serum at 37°C. It was found that as much as 13% of ST-1435 in serum is not bound to proteins. The results also show that the affinities of SHBG and CBG of ST-1435 are very low and that SHBG and CBG do not bind ST-1435 under physiological conditions in serum. We suggest that ST-1435 is bound mainly to serum albumin, and that the binding to that accounts for more than 87% of total serum ST-1435 concentrations. During the treatment period of 3 months, no change in SHBG or CBG binding levels was observed when ST-1435 was administered parenterally.
The lack of any interaction between ST-1435 and high affinity serum steroid binding proteins, and the very high percentage of non-protein bound ST-1435 in serum, probably explain its extremely high biological potency at the hypothalamic-pituitary level, when compared for example with d-norgestrel. For the same reason, practically all the ST-1435 in hepatic portal blood is probably taken-up and very rapidly metabolised by the liver. This may explain why oral administration of ST-1435 results in low and inadequate plasma concentrations for contraceptive purposes, while alternative parenteral routes of administration result in relatively much higher serum concentrations of the steroid. Finally, because ST-1435 does not bind to SHBG and CBG under physiological conditions, and does not change plasma SHBG and CBG binding capacities, ST-1435 treatment will not indirectly alter the amounts of endogeneous sex steroid hormones or their distribution in plasma. Therefore, side effects such as acne or hirsutism are unlikely to develop as a result of sustained administration of this potent progestin.
Regulation of immunity in rats by lactogenic and growth hormones
Authors: Nagy Eva , Berczi Istvan , Friesen Henry G. 
Published: December 2008

Abstract.
Antibody formation to sheep red blood cells and the development of contact dermatitis in response to dinitrochlorobenzene are impaired in hypophysectomized (Hypo-X) rats. Rat prolactin, rat growth hormone, bovine prolactin, bovine growth hormone, human placental lactogen and human growth hormone all restored the immunological competence of Hypo-X animals. The possible mechanism of action of these hormones on immune reactions is discussed.
Effects of oestradiol benzoate on the pituitary-thyroid axis of male and female rats
Authors: Boado Rubén , Ulloa Edgardo , Zaninovich Angel A. 
Published: December 2008

Abstract.
In the present work the effects of oestradiol benzoate (EB) on pituitary and plasma concentrations of TSH, plasma T4 and T3, and thyroidal activity of male and female rats have been studied. Wistar rats weighing between 150 to 200 g were injected sc with varying doses of EB in corn oil for 9 or 30 days. The animals were exsanguinated by cardiac puncture and the hypophyses removed and individually homogenized at 4°C in 200 μl PBS buffer. Pituitary and plasma TSH were measured by radioimmunoassay. Thyroidal activity was evaluated by a 4 h 131I uptake and by 48 h thyroidal release plasma slopes derived form the ratio PB[125I] (from thyroidal secretion) to PB[131I] (from exogenous [131I]T4). In both male and female rats the 10 and 25 μg doses of EB produced a significant decrease in pituitary TSH content; this effect was more pronounced when the 25 μg dose was given over 30 days. Plasma T4 decreased significantly; plasma T3 was moderately elevated in all groups (NS) and significantly increased in female rats treated with 25 μg EB (P < 0.01). It is concluded that EB induced a marked depression of intrapituitary TSH, probably due to a decrease in synthesis, without affecting the release of TSH into the circulation. Moreover, EB accelerated peripheral T4 kinetics and thyroid gland activity, albeit to a moderate degree.
Lack of refractoriness to stimulation with long acting thyroid stimulator of thyroid hormone synthesis and thyroid hormone secretion in mice in vivo
Authors: Ikeda Hitoshi , Nagataki Shigenobu 
Published: December 2008

Abstract.
The present study was undertaken to examine whether long acting thyroid stimulator (LATS) induces refractoriness of thyroid hormone synthesis and thyroid hormone secretion to the stimulator in vivo. Male DDY mice fed with a low iodine diet and given 5 μg/ml of triiodothyronine (T3) in drinking water ad libitum for 4 days were injected with 0.25 ml of LATS positive serum (1000%/0.25 ml in the McKenzie bioassay) ip every 24 h for 9 days. Groups of 5 mice were sacrificed before and 1, 3, 5, 7 and 9 days after the first injection of LATS for the determinations of serum thyroxine (T4) concentrations, the 1 h thyroid 131I uptake and thyroid weight. Control mice were injected with LATS negative pooled normal sera. Serum T4 concentrations elevated significantly 24 h after the 3rd injection of LATS and remained elevated until the end of the experiment. One hour thyroid 131I uptake elevated about 3-fold 24 h after the first injection of LATS. It further increased 24 h after the 3rd injection of LATS to 10-fold of the value for control animals and stayed elevated at this same level for the remainder of the study.
These results indicate that stimulating effects of LATS on thyroid hormone synthesis assessed by thyroid 131I uptake and thyroid hormone secretion assessed by serum T4 concentrations were not diminished by the prior administration of the stimulator. These findings suggest that LATS does not induce refractoriness of either thyroid hormone synthesis or thyroid hormone secretion to the stimulator in mice in vivo.
Thyroxine and triiodothyronine levels in Snell mice
Authors: van Buul-Offers Sylvia , Hackeng W. H. L. , Schopman W. 
Published: December 2008

Abstract.
Since no data are available concerning thyroid hormone levels in Snell dwarf mice from birth on, a cross-sectional study was performed of l-thyroxine (T4) and l-triiodothyronine (T3) levels in blood or serum as a function of age of several litters, starting at birth. In normal Snell mice T4 levels in blood and serum are changing with age. T4 increases during the first 2 weeks of age and declines thereafter, until adult levels of about 50 nmol/l are reached at 21 days of age. Serum T3 values are in the range of 2–3 nmol/l. They do not show such an age-related pattern.
From birth on in each litter there was a clear separation between animals with low T4 levels in blood and the others. This separation was possible at all subsequent days until 9 days of age, when dwarfs can be recognized by eye. Above that age the low T4 values were associated with dwarfism. This suggests that dwarfs are hypothyroid already at birth.
Serum T3 in dwarfs falls below the normal range only after 4 weeks of age, resulting in a lower T4/T3 ratio than normal.
The half life time of exogenous T4 in serum of dwarfs is in the range of 13–18 h and not different from normal. For T3t½ is 9.5–11.1 h.
Dwarf mice become euthyroid by treatment with 0.1 μg T4 per day. 1 μg T4 was needed to reach a physiological level of T3. These data suggest that the peripheral conversion of T4 to T3 is slower in dwarfs than in normals. Treatment with hGH, prolactin, glucagon, insulin, testosterone and oestradiol had no influence on serum T4.
As expected TSH was stimulatory.
Similar results were obtained for serum T3, with the exception of prolactin which caused slightly increased levels of serum T3.
Plasma cortisol variations induced in the stallion by mating
Authors: Tamanini C. , Giordano N. , Chiesa F. , Seren E. 
Published: December 2008

Abstract.
Plasma cortisol variations have been determined by radioimmunoassay in 5 stallions during mating and in 2 teasers during oestrous female exposure. In all the animals, cortisol plasma levels consistently increase (71.1 ng/ml vs 44.0 and 63.0 ng/ml vs 35.1, in the stallions and in the teasers, respectively) 7–30 min after female exposure; 120 min after exposure, cortisol concentrations are again low.
Plasma levels of 17-OH-progesterone and testosterone in patients with varicoceles
Authors: Andò S. , Giacchetto C. , Colpi G. , Panno M. L. , Beraldi E. , Lombardi A. , Sposato G. 
Published: December 2008

Abstract.
In order to study Leydig cell function in patients with varicoceles, we determined plasma levels of the most important testicular steroids, 17-OH-progesterone (17-OH-P) and testosterone (T) in the basal condition and after hCG stimulation.
There was a significant inverse linear correlation between age, plasma testosterone, and 17-OH-P (n = 65, r = 0.316, P = 0.01, n = 48, r = 0.532, P = 0.01). This was in contrast to the absence of such correlations in normal men in the same age range.
Following hCG stimulation in 16 patients the 17-OH-P/T ratio was significantly increased with respect to normal controls. No correlation was been observed between sperm count and age in varicocele patients. Analysis of variance of 17-OH-P plasma levels between the patients with a sperm count less than 10 million/ml and that of more than 10 million/ml did not reveal any significant difference.
These results suggest that the deleterious effects of varicocele on seminiferous tubules and Leydig cells are unrelated. Moreover the increased 17-OH-P/T ratio after hCG stimulation suggests that some enzymatic impairment involving the last steps of testosterone biosynthesis exists in patients with varicoceles. This is evident in middle aged varicocele patients with a premature decrease of plasma levels of testosterone.
Unchanged biochemical indices of bone turnover despite fluctuations in 1,25-dihydroxyvitamin D during the menstrual cycle
Authors: Tjellesen Lone , Christiansen Claus , Hummer Lotte , Larsen Niels-Erik 
Published: December 2008

Abstract.
To examine the effect of endogenous oestrogens on calcium metabolism during the menstrual cycle, fasting blood and urinary samples were obtained every day throughout the menstrual cycle in 5 young women.
Bone turnover was estimated by serum alkaline phosphatase and fasting urinary excretions of hydroxyproline and calcium. Serum levels of oestradiol (E2), oestrone (E1), and androstenedione (A) showed the well known cyclic fluctuations, the serum 1,25-dihydroxyvitamin D (1,25(OH)2D) nearly doubled from the early follicular phase to the time of ovulation, although 25-hydroxyvitamin D (25OHD) and 24,25-dihydroxyvitamin D (24,25(OH)2D) were almost unchanged. No correlation between the rise in the serum 1,25(OH)2D level and the measured parameters of calcium metabolism was observed.
In view of these findings, the 1,25(OH)2D3 serum concentration measured in women with functioning ovaries can only be interpreted in the context of the menstrual cycle. The published normal range in women for the metabolite may also require reinterpretation.
Parallel insulin-like actions of human growth hormone and its part sequence hGH 7–13
Authors: Armstrong John McD. , Bornstein Joseph , Bromley Janet O. , Macaulay S. Lance , Ng Frank M. 
Published: December 2008

Abstract.
The insulin-like effects of human growth hormone and the synthetic part sequence, Nα-acetyl-hGH 7–13, on glycogen synthase and phosphorylase have been compared in an in vivo system using 16–18-day-old rats. Both the hormone and its part sequences had similar effects, increasing muscle glycogen synthase a activity and decreasing liver phosphorylase a activity, without affecting phosphorylase activity in muscle or synthase activity in liver. Insulin had similar effects, but also increased liver synthase a activity. The effects of all three substances could be abolished by prior treatment of the animals with anti-insulin serum, showing that the effects of growth hormone and its part sequences were insulin-dependent. Both growth hormone and the synthetic peptide increased the binding of insulin to liver plasma membrane. It is concluded that the insulin-like activity of human growth hormone is associated with a region containing residues 7 to 13 of the hormone molecule, and that this activity is insulin-dependent. It is suggested that both growth hormone and the synthetic peptide produce insulin-like activity by enhancing the binding of circulating insulin to its receptor.
Preclinical hyperthyroidism - a graded condition
Authors: Gemsenjäger E. , Girard J. 
Published: December 2008

Abstract.
In 65 consecutive surgical patients with multinodular goitre and with preclinical hyperthyroidism (TRH-resistant suppression of TSH in the presence of normal circulating thyroid hormones) the individual values of the FT4-index (FT4-I) and FT3-index (FT3-I) showed a wide range form low normal to high normal with mean values not differing from those in TRH-responsive goitre patients and from controls.
Thirty-five patients underwent repeated pre-operative TRH tests: 11 (group A) were TRH-unresponsive on one occasion, and TRH-responsive at another time. Fifteen (group B) were TRH-unresponsive on two occasions. Nine patients (group C) were preclinically hyperthyroid on one occasion and had supranormal individual thyroid hormone concentrations at another time. In multinodular goitre patients with preclinical hyperthyroidism a significant T3 increase was observed after oral TRH. In spite of a TRH-resistant suppressoin of TSH small amounts of TSH are thus still secreted. The degree of TSH suppression may be the result of a varying degree and pattern of continued, fluctuating or elapsed increase in thyroid hormone supply. The T3 response to oral TRH depends not only on the degree of TSH suppression, but also subtlely on the thyroidal reserve: in euthyroid TRH-TSH negative goitre patients a decrease of the TSH-regulated follicular mass by goitre resection abolished the pre-operatively significant T3 response to TRH during the post-operative phase of transient TSH deficiency.
Lipid fractions in primary hyperparathyroidism before and after surgical cure
Authors: Vaziri N. D. , Wellikson L. , Gwinup G. , Byrne C. 
Published: December 2008

Abstract.
A number of previous studies has suggested that PTH may possess a hyperlipimic property. We determined various lipid fractions in 24 patients with primary hyperparathyroidism before and 1–3 months after surgical cure. The mean values for serum total cholesterol, triglycerides. LDL-Chol, VLDL-Chol and HDL-Chol did not change significantly with definitive correction of hyperparathyroidism. The mean values for all lipid fractions were comparable to those of the age and sex-matched normal control group except for HDL-Chol which was significantly lower in the hyperparathyroid group both before and after definitive cure of hyperparathyroidism. Only one patient with combined elevation of serum triglycerides and cholesterol exhibited normalization of the lipid levels after surgery. Two other patients with hypertriglyceridaemia failed to show any reduction in their triglyceride levels after correction of their hyperparathyroidism. Our data suggest that long-standing elevation of PTH to the extent seen in primary hyperparathyroidism and in the absence of predisposing conditions does not increase serum lipids in human.
Discrimination between intact and mid-C-regional PTH using selective radioimmunoassay systems
Authors: Jüppner H. , Rosenblatt M. , Segre G. V. , Hesch R.-D. 
Published: December 2008

Abstract.
Two 125I-labelled hormone preparations (synthetic 44–68(Tyr)hPTH bearing a tyrosin at position No. 44 and 1–84 bPTH) were used to characterize antiserum G III for PTH radioimmunoassay. PTH fragments were used for displacement of either tracer and included 1–34 hPTH, 28–48 bPTH, 25–48 bPTH, 28–54 hPTH, 32–43 hPTH, 42–55(Tyr)hPTH (tyrosin at position No. 42), 1–65 bPTH fragments and intact 1–84 hPTH. Standard curves of the 44–68 hPTH, 1–65 bPTH and the 1–84 hPTH run in parallel to each other independent of the tracer used for the assay. When using the 44–68(Tyr)hPTH tracer, half-maximal displacement (1/2 max) was achieved at 24 pg/tube for 44–68 hPTH, 450 pg/tube for 1–65 bPTH and at 1300 pg/tube for 1–84 hPTH. When carrying out the assay with the 1–84 bPTH tracer, the values for 1/2 max were 11.5 pg/tube for 44–68 hPTH, 135 pg/tube for 1–65 bPTH and 370 pg/tube for 1–84 hPTH. Gel filtration of plasma and peritoneal dialysate from one patient with terminal renal insufficiency and secondary hyperparathyroidism indicate that due to the high affinity of the antibody for the mid-C-regional hPTH, this assay system is appropriate for the discrimination of intact PTH and large mid-C-regional fragments, that include most of the 44–68 hPTH sequence.
Effects of triiodothyronine and nutritional status on nuclear non-histone proteins of the rat liver
Authors: Juge-Aubry Cristiana E. , Bachmann Kurt , Burger Albert G. 
Published: December 2008

Abstract.
In the hepatic nucleus of the rat at least 2 nuclear globulin bands, identified by SDS polyacrylamide gel electrophoresis, are known to be influenced by thyroid hormones. In the present article a quantitation of these bands was obtained by scanning techniques. The effects of T3 were studied in male thyroidectomized (Tx) and intact rats. After sacrifice the hepatic nuclear globulins were prepared according to published methods.
In Tx rats substituted with a single dose of 50 μg or during one week 2 μg T3 the t band decreased from 5.3% to 2.7% of the total nuclear globulin content which represent a complete normalisation.
The n band did not show this rapid response to T3 as 2 μg given for one week only partially restored this band (Tx 1.4%,Tx + T32.2%).
However during starvation of intact rats only the n band was slightly influenced by T3 as 2 μg of T3 partially prevented the decrease of this band seen in untreated euthyroid starving rats. The increase of the t band in starvation was not affected by T3.
In conclusion: the n and t bands are controlled by several factors, two of which are T3 and nutrition. The control of the t band seems to be dominated by the nutritional status of the animal. T3 seems to keep some activity on the n band, even in starved rats.
The effects of long-term normalization of sodium balance on linear growth in disorders with aldosterone deficiency
Authors: Kuhnle Ursula , Rösler Ariel , Pareira Judith A. , Gunzcler Peter , Levine Lenore S. , New Maria I. 
Published: December 2008

Abstract.
The effect of normalization of sodium balance was evaluated in children with aldosterone deficiency of several etiologies. In salt-losing congenital adrenal hyperplasia (CAH), treatment with a mineralocorticoid in doses that normalized plasma renin activity (PRA) induced a marked increase in linear growth. Serum 17-hydroxyprogesterone (17-OHP) and androgens fell further when adequate sodium balance was achieved, allowing in some cases a reduction in glucocorticoid replacement dose. Together with PRA measurement they were the most sensitive indicators of adequate mineralocorticoid and glucocorticoid replacement therapy. In 2 teenage children with aldosterone deficiency due to Addison's and autoimmune polyglandular disease similar improvement in growth as well as onset of puberty occurred when sodium balance was normalized by increased mineralocorticoid therapy. These studies show that adequate sodium balance is essential for normal growth and pubertal development.
Kinetics of the iodide trapping mechanism in normal and pathological human thyroid slices
Authors: Gluzman Bernardo Ernesto , Niepomniszcze Hugo 
Published: December 2008

Abstract. Kinetics of the iodide trapping mechanism in thyroid slices was studied in human and animal tissues. Slices were incubated with several medium iodide concentrations, ranging from 5 × 10−6 m to 2 × 10−4 m, in order to calculate in the steady state the following kinetic parameters of the iodide transport: Km, maximal capacity (C) and diffusion factor (D).
Results indicated that the Km was similar in magnitude (10−5 m) in all cases where trapping activity was present, while maximal capacity (C) values showed significant differences between those pathologies in which trapping activity was hyperstimulated (dishormonogenetic goitre, Graves' disease, toxic adenoma) and those where thyroid tissues presented focal or total alterations on its structure (non-toxic nodular goitre, Hashimoto's thyroiditis, thyroid cancer) or where thyroid tissues were not sufficiently stimulated by TSH (extranodular tissue of toxic adenoma). 'Warm' nodules were not significantly different from normal human thyroid. These results suggest that the scattered trapping values observed in the different thyroid pathologies correspond to quantitative differences between them rather than to qualitative alterations in the thyroid iodide pump.