bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aldosterone escape to chronic ACTH administration in man
Authors: Gaillard Rolf C. , Riondel Anne M. , Favrod-Coune Charles A. , Vallotton Michel B. , Muller Alex F. 
Published: December 2008

Abstract. Prolonged ACTH administration produces a transient and self-limiting stimulation of aldosterone secretion which has been attributed to sodium retention, to inhibition of final enzymatic steps of aldosterone biosynthesis and/or to a morphological change of the glomerulosa cells.
This study was undertaken to determine the possible role of the renin-angiotensin system in mediating the aldosterone escape to repeated ACTH stimulation. We studied in normal male volunteers the effect of a 4 day ACTH administration on urinary aldosterone metabolite excretion (3 oxo-conjugate and tetrahydroaldosterone) during concomitant diuretic administration (spironolactone or triamterene). In addition the plasma aldosterone response to acute iv stimulation with ACTH before and during the corticotrophin-induced 'refractory state' was examined both on normal and on low sodium diet.
Spironolactone was unable to counteract the sodium retention induced by ACTH stimulation; aldosterone excretion showed the same transient increase as with ACTH alone while plasma renin activity remained low. Triamterene produced a negative sodium balance, a significantly more sustained increase in aldosterone excretion and an increase in plasma renin activity. In either situation the two metabolites of aldosterone showed the same pattern of excretion.
The plasma aldosterone response to acute iv ACTH stimulation was completely blocked during the corticotrophin-induced 'refractory state' on normal sodium intake, whereas on low sodium diet a clear-cut response was still obtained.
These data suggest that the transient effect of ACTH on aldosterone secretion is dependent on the state of activity of the renin-angiotensin system. When renin was stimulated by low sodium intake or sodium depletion, the aldosterone response to repeated ACTH administration was more sustained, and when renin was stimulated by low sodium intake, the aldosterone response to acute ACTH was maintained.
In conclusion we suggest that the renin-angiotensin system is able to delay but not to suppress the changes induced in the zona glomerulosa by prolonged ACTH stimulation.
Changes in ovarian oestrogens and in plasma gonadotrophins in female rabbits from birth to adulthood
Authors: de Turckheim M. , Berger M. , Jean-Faucher Ch. , Veyssière G. , Jean Cl. 
Published: December 2008

Abstract. Plasma oestrogens (E1, E2) and gonadotrophins, and ovarian oestrogens, were determined in female rabbits from birth to 6 months. Increases in ovarian weight followed a curvilinear pattern, with a phase of slow growth (from 1 to 60 days) preceding a phase of rapid growth (from 60 to 90 days). At birth, E2 was already quantifiable in ovaries; it remained at very low levels up to 50 days. Ovarian E2 content increased until 6 months with two sharp rises between 50 days (46 ± 4 pg/2 ovaries) and 60 days (365 ± 53 pg/2 ovaries) and between 80 days (326 ± 77 pg/2 ovaries) and 90 days (1118 ± 307 pg/2 ovaries). E1 appeared in ovaries at 50 days and then followed a pattern similar to that of E2. Oestrogens were never detected in plasma.
At birth FSH and LH levels were similar to those measured in adult females but from 10 days the secretion of both gonadotrophins showed a clear dissociation. LH concentrations varied little during the period studied (between 1077 ± 106 pg/ml to 2030 ± 466 pg/ml). Plasma FSH levels were considerably higher between 10 and 50 days than those measured thereafter, particularly in adulthood. The decline in FSH levels occurred simultaneously with the rise in ovarian oestrogens.
Early post-operative growth hormone levels predict the result of transsphenoidal tumour removal in acromegaly
Authors: Bynke Olof , Karlberg Bengt E. , Kågedal Bertil , Nilsson Ove R. 
Published: December 2008

Abstract. Serum human growth hormone (hGH) measurements were performed during transsphenoidal microsurgery for acromegaly and in the early period afterwards. There were 14 patients of which 2 were operated on twice. In 11 patients (2 patients at reoperation) the serum hGH concentration was normalized to less than 5 μg/l within 3 h after completion of surgery. On five occasions only partial restoration of the hGH values was obtained and additional treatment was given in 2 patients by successful re-operation.
The early post-operative hGH concentrations were consistent with the clinical evaluation of the patients and the hGH concentrations during follow-up for an average of 27 months. We conclude that early post-operative serum hGH measurement is of value for evaluation of the efficiency of the tumour removal and the need for further treatment.
Effects of hysterectomy and uterine extracts on growth hormone, somatomedin, prolactin, thyrotrophin and thyroid hormones in adult rats
Authors: Bíró J. , Ritzén E. M. , Hall K. , Eneroth P. 
Published: December 2008

Abstract. Plasma concentrations and anterior pituitary content of growth hormone (rGH), thyroid stimulating hormone (rTSH), and rat prolactin (rPrl) as well as the plasma concentrations of triiodothyronine (T3), thyroxine (T4) and somatomedin A (SM-A) have been determined in intact, castrated or hysterectomized adult rats with and without treatment with steroid-free, crude uterine extracts.
Hysterectomy caused a significant increase in the plasma GH but decrease in the plasma TSH concentrations. Injection of crude, steroid-free uterine extracts for 14 days had the following effects: decreased plasma GH concentration of intact rat and anterior pituitary GH content of both intact and castrated animals; increased plasma TSH and T3 concentrations above the ovariectomized control; decreased pituitary content of prolactin in castrated rats. The plasma levels of immunoreactive somatomedins A were negatively correlated to the plasma GH concentrations but positively correlated to the body weight.
It was concluded that the uterus is not only a target for different endocrine influences but contains biologically active, non-steroidal substances which have a complex effect on the endocrine system of adult, female rats.
Uptake of triiodothyronine into cultured human muscle cells
Authors: Bolhuis P. A. , van den Berg C. , Ponne N.J. , de Zwart H.J. D. , de Jong J. M. B. V. 
Published: December 2008

Abstract. The uptake of T3 was measured in cultured human muscle cells at 37°C and pH 7.4 in a medium containing albumin and glucose. The initial uptake increased linearly when the total T3 concentration was varied from 10−9 to 10−4 m. At prolonged incubation time the uptake decreased to virtually zero in about 30 min.
These data indicate a rapid passive transport mechanism of T3 and a fast equilibration of the cellular T3 with the surrounding medium. In agreement with these conclusions the efflux of T3 was rapid and the initial uptake was not altered by pre-incubation in a T3-containing medium.
Blastocyst attachment in the ovariectomized rat treated with an intrauterine injection of luteinizing hormone-releasing hormone (LRH)
Authors: Jones Robert C. 
Published: December 2008

Abstract. Pregnant rats were bilaterally ovariectomized on day 3 and the blastocyts were maintained in a state of delayed implantation by the daily sc injection of 4 mg progesterone from day 3 to 6. On the morning of day 6 the rats received an intrauterine injection of 1 mg LRH in the right horn. A second group of rats was treated as above and was additionally injected with 2 mg of indomethacin on day 5 and 1 mg on the morning of day 6. Fifteen min prior to autopsy the animals were injected iv with a 0.5% solution of Evans Blue. The presence of uterine blue bands and the number of blastocysts recovered from the right and left (control) horns were recorded at 0.25, 0.5, 1, 2 and 4 h after the injection of LRH.
It was determined that the number of blastocysts flushed from the treated horn was significantly reduced below that of the control left horn within 15 min and at every autopsy interval thereafter.
In addition, blue bands appeared in the treated horn as early as 15 min after the injection of LRH demonstrating that implantation had occurred in a few instances. No blue bands appeared in the control horns. The injection of indomethacin did not inhibit the attachment or implantation of blastocysts or the presence of blue bands in the treated horn. A possible role for blastocyst oestrogen is discussed.
Bioactivity of plasma luteinizing hormone in infants and young children
Authors: Torresani T. , Schuster E. , Illig R. 
Published: December 2008

Abstract. Luteinizing hormone (LH) bioactivity was determined by an in vitro microbioassay in 65 plasma samples from 26 infants and young children between 10 days and 6.5 years of age. In addition LH was measured by radioimmunoassay. For both, LH preparation LER-907 was used as standard.
Biologically measured LH values (bio-LH) were always higher than radioimmunologically determined LH values (RIA-LH) as reflected by bio/RIA ratios greater then 1.0.
In male infants bio-LH was elevated up to 7 months of age. Thereafter, it decreased and remained low over the age range of our study. In female infants bio-LH was also elevated, but decreased after 1 month and showed a slight tendency to rise in the age group 3–6.5 years.
The results of RIA-LH showed approximately the same pattern, but at a lower level. In boys RIA-LH levels were highest around 1 month of age, decreased steadily between 2 and 7 months and remained constant thereafter. Girls had rather constant RIA-LH values between 2 months and 3 years of age. In contrast to bio-LH, there is a clear-cut drop of RIA-LH in the age group 3–6.5 years, resulting in a statistically significant increase of the bio/RIA ratio.
In boys the time course of the bio-LH changes coincides with the known elevation of testosterone during the first months of life.
In girls the elevated bio-LH levels observed during the first month are not so far associated with a known steroid correlate.
Our study shows an increased biological activity of circulating LH and a marked dissociation of biologically and radioimmunologically active LH during early infancy, analogous to observations during puberty.
The role of prolactin in the inhibitory action of bromocriptine on growth hormone secretion in acromegaly
Authors: Lamberts S. W. J. , Klijn J. G. M. , van Vroonhoven C. C. J. , Stefanko S. Z. , Liuzzi A. 
Published: December 2008

Abstract. Bromocriptine treatment results in clinical improvement and inhibition of plasma GH levels in only part of the acromegalic patients. The possible role of the simultaneous presence of Prl and GH in GH-secreting pituitary adenomas was investigated with regard to the inhibitory action of bromocriptine on GH secretion and the paradoxical increase of GH release in reaction to TRH.
Surgically obtained pituitary tumour tissue from 35 consecutive acromegalic patients was studied immunohistochemically. In 21 patients no Prl was present in the tumour tissue. These patients had normal plasma Prl levels. In the other 14 patients Prl was present in the tumour tissue. Hyperprolactinaemia was found in 10 of these 14 patients. Plasma GH levels from 2 till 10 h after the administration of 2.5 mg bromocriptine measured before operation were significantly more suppressed in the patients with mixed GH/Prl-containing than in those with pure GH-containing pituitary adenomas, being 38 ± 4% and 65 ± 4% of basal values, respectively (P< 0.01). The response of GH to TRH, however, did not differ significantly between the two groups. Conclusions: 1. In about 70% of patients with 'mixed' GH/Prl containing adenomas, hyperprolactinaemia is present. 2. The simultaneous presence of Prl and GH in a GH-secreting pituitary tumour increases the sensitivity of GH secretion to bromocriptine. 3. The plasma Prl level is of value to predict which patients with acromegaly are likely to respond to bromocriptine with an inhibition of GH secretion.
Relations between thyroid function, hepatic and lipoprotein lipase activities, and plasma lipoprotein concentrations
Authors: Valdemarsson Stig , Hansson Per , Hedner Pavo , Nilsson-Ehle Peter 
Published: December 2008

Abstract. Lipoprotein concentrations and activities of lipoprotein lipase (LPL) and hepatic lipase (HL) were measured in 70 subjects with thyroid function ranging from overt hypothyroidism over subclinical hypothyroidism and euthyroidism to hyperthyroidism.
In parallel with serum T3 (S-T3) concentrations increasing from low in hypothyroidism to high in hyperthyroidism there were gradually higher HL activities over the full spectrum of thyroid function, accompanied by decreasing levels of total and low density lipoprotein (LDL) cholesterol. High density lipoprotein (HDL) cholesterol was lower (P < 0.05) in hyperthyroidism than in euthyroidism but not significantly changed in the hypothyroid groups. HL was correlated to S-T3 (r = 0.77, P< 0.001), LDL cholesterol to log S-T3 (r = -0.76, P < 0.001), and LDL cholesterol to log HL (r = -0.55, P <0.001).
The activity of LPL was decreased (P< 0.001) in overt hypothyroidism compared to euthyroidism but, in contrast to HL, the activity of LPL was not increased in hyperthyroidism. The plasma triglyceride (P-TG) concentration was elevated (P< 0.01) in overt hypothyroidism but not significantly changed in subclinical hypothyroidism or in hyperthyroidism. The LPL activity was correlated to log S-T3 (r = 0.45, P < 0.001), P-TG to log S-T3 (r = -0.37, P< 0.01) and P-TG to log LPL activity (r= -0.71, P<0.001).
Our results demonstrate that thyroid hormones influence HL and LPL activities in different ways, suggesting different mechanisms of action. Changes in HL activity seem to be an important mechanism for the disturbance of cholesterol metabolism in thyroid dysfunction while the thyroid hormone influence on LPL seems to be of importance mainly for the disturbance in triglyceride metabolism.
Oral glucose tolerance test and insulin sensitivity in low insulin responders
Authors: Wajngot A. , Luft R. , Efendić S. 
Published: December 2008

Abstract. Oral and iv glucose tolerance, insulin response to iv and oral glucose load as well as insulin sensitivity were evaluated in 58 'low insulin responders'. They were selected from a group of 226 healthy subjects with normal fasting blood glucose and normal iv glucose tolerance test on the basis of a low insulin response during a standardized glucose infusion test (GIT). The insulin response to GIT was analysed by parameter identification in a mathematical model (parameter KI). Insulin sensitivity was also measured by computer analysis of GIT (parameter KG) and, in a limited group of subjects, by a somatostatin infusion test.
Thirty-three low insulin responders had normal OGTT, whereas 5 demonstrated borderline-1, 16 borderline-2, and 4 decreased OGTT. The first group of subjects demonstrated normal or enhanced insulin sensitivity. Borderline and decreased OGTT, in most instances, was accompanied by decreased insulin sensitivity, implying that a subgroup of low insulin responders exhibited signs of both impaired insulin response to glucose and insulin resistance. Since these defects characterize manifest type-2 diabetes, these subjects possibly may run a high risk to develop this type of diabetes. On the other hand, low insulin response in combination with increased insulin sensitivity may reflect adaptation of the secretory capacity of B-cells to the need of insulin.
Effects of angiotensin II and ACTH on normal and tumourous human adrenocortical cells
Authors: Belmega Wolfgang , Oelkers Wolfgang , Belkien Lutz , Shirpai Monika , Fiedler Ulrich , Häring Rudolf 
Published: December 2008

Abstract. Isolated adrenocortical cells from 6 patients with a 'normal' zona fasciculata, 4 patients with a 'normal' zona glomerulosa, and tumour cells from 1 adrenocortical adenoma and 1 carcinoma were incubated with and without increasing concentrations of ACTH 1–24 (10−13 m to 10−9 m) or Asp1-Ile5-angiotensin II (10−11 m to 10−7 m). In 4/5 'normal' cases, cortisol was clearly stimulated by 10−13 m ACTH. The maximum of the dose-response curve (5-fold stimulation) was reached at 10−10 m ACTH. Angiotensin II (All) started to stimulate 'normal' cells at 10−11 m with a maximum (2-fold stimulation) at 10−9 m. Aldosterone production by 'normal' cells was less markedly stimulated by ACTH and All, although the threshold doses for both peptides were similar to those of the cortisol response curves.
The cells of the adrenocortical adenoma from a patient with Cushing's syndrome produced large amounts of cortisol and small amounts of aldosterone, both steroids being clearly stimulated by ACTH and AII. The adrenocortical carcinoma cells produced small amounts of cortisol and no aldosterone. Cortisol production responded to ACTH, but not to AII.
The results suggest that an activated renin-angiotensin system may stimulate the zona fasciculata, since 10−11 m All (= 10 pg AII/ml) is a normal plasma All concentration on an unrestricted diet. Clinical evidence supporting this thesis is reviewed. However, cortisol production itself will rarely be increased by All in vivo, since a downregulation of ACTH would occur.
Synaptosomal T3 binding sites in rat brain: their localization on synaptic membrane and regional distribution
Authors: Mashio Yasuo , Inada Mitsuo , Tanaka Kiyoshi , Ishii Hitoshi , Naito Koichi , Nishikawa Mitsushige , Takahashi Kiyoyuki , Imura Hiroo 
Published: December 2008

Abstract. Previous studies have shown the existence of specific high affinity T3 binding sites in rat cerebrocortical synaptosomes. In this study, to define the localization of the binding sites, T3 binding to disrupted synaptic membrane fractions was compared with the binding to intact synaptosomes obtained from the rat cerebral cortex. Scatchard analysis revealed two orders of T3 binding sites with almost identical apparent dissociation constant (Kd) in synaptosomes and synaptic membrane fractions. However, the maximal binding capacity (MBC) of the higher affinity binding sites for synaptic membrane fractions was significantly greater than that for intact synaptosomes (4.2 ± 0.2 vs 3.0 ± 0.3 pg T3/mg protein).
Regional distribution of the synaptosomal T3 binding sites in various areas of the rat brain was also studied. The Kd values were not significantly different in discrete brain regions. On the other hand, the MBCs of the higher affinity binding sites were greater in the cerebral cortex and hypothalamus (72.8 ± 1.4 and 64.8 ± 9.5 pg T3/g tissue) than in the cerebellum (22.1 ± 1.6 pg T3/g tissue). Similar difference was also observed in the lower affinity sites.
These results indicate that the specific T3 binding sites in brain synaptosomes are localized mainly on synaptic membranes and that the MBC is different in discrete brain regions.
Different aetiologies in post-partum thyroiditis?
Authors: Dahlberg Per Anders , Jansson Rolf 
Published: December 2008

Abstract. During a 4 year period 19 women with post-partum onset of thyroid dysfunction have been seen in our clinic. Five women had high radioiodine uptake thyrotoxicosis (Graves' disease). Twelve women had hypothyroid symptoms starting within 3–6 months of delivery. All of these women had thyroid microsomal and/or cytoplasmic autoantibodies and thyroid lymphocytic infiltration suggesting aggravation of pre-existing subclinical autoimmune thyroiditis (Hashimoto's disease). At follow-up thyroid function gradually improved in all but signs of persistent thyroid hypofunction remained in seven. Thus women developing symptomatic postpartum hypothyroidism should be followed regularly and when thyroxine treatment is commenced in the post-partum period, it has to be continued indefinitely in many cases.
Two women presented with transient low radioiodine uptake thyrotoxicosis and a small painless goitre. Thyroid cytology revealed thyroiditis but they had no thyroid autoantibodies. When followed after a succeeding delivery none of these women developed post-partum thyroid dysfunction in contrast to women in the autoimmune group. Probably the aetiology of thyroid dysfunction in these 2 women was different.
Effects of neonatal exposure to TRH on development of the pituitary-thyroid axis in rats
Authors: Kawai Yoshiaki , Azukizawa Mizuo , Ashida Nobuyuki , Kumahara Yuichi , Miyai Kiyoshi 
Published: December 2008

Abstract. TRH (10 and 1000 μg/kg body weight) was administered ip daily to neonatal rats from day 0 to 9 after birth (Neo-TRH rats) and their pituitary-thyroid axis was examined on days 4, 10, 21 and 90. The pituitary TSH content in Neo-TRH rats was significantly smaller than in controls on days 4 and 10. The serum TSH levels in Neo-TRH rats were significantly lower than those in controls on days 4 (male group only), 10 and 21 (only 10 μg/kg group).
The serum T4 levels in Neo-TRH rats were lower than in controls on day 10. The reduced pituitary TSH content and serum TSH and T4 were restored to control levels on day 90. However, the response of serum TSH to exogenous TRH (10 μg/kg/ip) was blunted in Neo-TRH rats on days 10, 21 and 90. It is concluded that repetitive administration of TRH during the neonatal period suppresses the pituitary-thyroid axis in neonatal life, even after the basal hormone level has been restored to normal.
Familial hypocalciuric hypercalcaemia: observations on vitamin D metabolism and parathyroid function
Authors: Davies M. , Adams P. H. , Berry J. L. , Lumb G. A. , Klimiuk P. S. , Mawer E. B. , Wain D. 
Published: December 2008

Abstract. Serum vitamin D metabolites, the renal tubular maximum reabsorptive rate for phosphate (TMP/GFR) nephrogenic cyclic AMP (NcAMPI, and CaE (urinary calcium excretion per litre of glomerular filtrate) were measured in 14 adults with familial hypocalciuric hypercalcaemia (FHH). The findings were compared with analyses in 14 patients with surgically proven primary hyperparathyroidism matched for serum calcium, creatinine clearance and vitamin D status (assessed by serum concentrations of 25 hydroxyvitamin D). Vitamin D metabolites were also measured in 16 normocalcaemic relatives of patients with FHH. The serum concentration of 24, 25 dihydroxycholecalciferol was appropriate for the prevailing 25 hydroxyvitamin D and no difference was found between groups. The serum concentration of 1, 25 dihydroxycholecalciferol was significantly greater in primary hyperparathyroidism (P < 0.0005) compared with patients with FHH and their normocalcaemic relatives. TMP/GFR was reduced in both primary hyperparathyroidism (0.53 ± 0.12 mmol/l GF, mean ± sem) and FHH (0.86 ±0.14 mmol/l GF). Patients with primary hyperparathyroidism showed an increase in NcAMP output in the urine (38.5 ± 16 mmol/l GF) which was significantly greater (P < 0.0001) than the normal NcAMP (13.5 ± 9.2 nmol/l GF) found in FHH. CaE was low in FHH indicating increased renal tubular reabsorption of calcium.
It is concluded that there is no abnormality of vitamin D metabolism in FHH comparable with the changes observed in primary hyperparathyroidism. It is suggested that the biochemical abnormalities in FHH cannot be explained solely upon an increased sensitivity of the renal tubules to the effects of endogenous parathyroid hormone.
Immunoreactive thyroglobulin-like material derived from saliva
Authors: Shah D. H. , Dandekar S. R. , Jeevanram R. K. , Thakare U. R. , Ajaykumar B. S. , Ganatra R. D. 
Published: December 2008

Abstract. The presence of an immunoreactive thyroglobulin-like material in saliva from normal subjects and from 35 patients with thyroid carcinoma was detected by radioimmunoassay. The levels of this material in saliva were markedly elevated in patients with extensive metastases.
Concentrated saliva samples from normal subjects and from patients with thyroid carcinoma were fractioned on Sepharose-6B and each fraction was assayed for thyroglobulin content by RIA. Several protein peaks of varying molecular size with thyroglublin-like immunoreactivity were observed. The physiological significance of these molecules in saliva remains to be established.