bluuebunny/crossref_metadata_2025 huggingface dataset:
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

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

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

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

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

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

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

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

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

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

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

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

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.
Effect of dihydroergocristine administration on serum prolactin and growth hormone levels in normal, hyperprolactinaemic, and acromegalic subjects: further evidence for pituitary dopamine deficiency in these conditions
Authors: Ferrari C. , Romussi M. , Benco R. , Rampini P. , Mailland F.
Published: December 2008

Abstract. To evaluate further the pharmacological properties of dihydroergocristine in vivo, this drug (6 mg) or a placebo were administered orally on separate days to 11 healthy controls, 11 patients with adenomatous (n = 4) or idiopathic hyperprolactinaemia (n = 7), and 5 acromegalics with raised serum prolactin levels; serum prolactin (Prl) and growth hormone (GH) were measured at hourly intervals for 6 h. Dihydroergocristine induced a significant Prl decrease versus placebo in hyperprolactinaemics and acromegalics, but had no effect in healthy subjects. GH levels did not change in normals and hyperprolactinaemics, but decreased significantly in acromegalics. The Prl decrease induced by dihydroergocristine was significantly lower than that induced by l-dopa (500 mg po) in 9 hyperprolactinaemics so tested. Nomifensine (200 mg po) administered to 7 hyperprolactinaemics had no effect. Similarly, the GH decrease induced by the drug in acromegalics was significantly lower than that exerted by l-dopa, while nomifensine had no effect. Five hyperprolactinaemic patients were also given 12–18 mg dihydroergocristine daily for 3 months. There was evidence of partial or total Prl suppression and resumption of menses in all patients. These data indicate that dihydroergocristine is a relatively weak dopamine agonist at pituitary level and that oral doses, insufficient to exert Prl-lowering activity in normal subjects, are able to inhibit Prl and GH release in hyperprolactinaemics and dopamine-responsive acromegalics. These findings further support the existence of a 'denervation' supersensitivity to dopamine in these conditions, in which dopamine deficiency at pituitary level has been suggested on the basis of other experiments.
Hyperthyroidism and acromegaly caused by a pituitary TSH- and GH-secreting tumour
Authors: Lamberg B.-A. , Pelkonen R. , Gordin A. , Haltia M. , Wahlström T. , Paetau A. , Leppäluoto J.
Published: December 2008

Abstract. A female patient with acromegaly, TSH-induced hyperthyroidism and a large eosinophilic pituitary adenoma is reported. Granules in the adenoma cells were by immunohistochemical methods shown to contain GH and with monoclonal TSH-antibodies it was shown that 5–10 per cent of the cells secreted TSH. The basal serum TSH was elevated in the hyperthyroid phases and was not suppressible by exogenous T3 but decreased markedly with dexamethasone. There was a small subnormal rise in serum TSH after TRH injection which was totally suppressed by T3 (but not dexamethasone). l-dopa, bromocriptine and somatostatin caused a 20–30 per cent decrease in serum TSH. The α-subunit concentration was also elevated and was equally depressed by bromocriptine and somatostatin. The urinary excretion of TRH was within reference limits. This mixed tumour obviously secreted an excess of both GH and TSH causing acromegaly and hyperthyroidism.
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.
Decreased beta-adrenergic receptor density in mononuclear leukocytes from thyroidectomized patients
Authors: Cognini G. , Piantanelli L. , Paolinelli E. , Orlandoni P. , Pellegrini A. , Masera N.
Published: December 2008

Abstract. Beta-adrenergic receptor characteristics were investigated in peripheral blood mononuclear leukocytes taken from patients before and after partial thyroidectomy. In order to discriminate the effect of surgical stress per se from that of thyroidectomy, the analysis was also performed on patients before and after cholecystectomy. Receptor characteristics were determined by using dihydroalprenolol as ligand in direct equilibrium binding experiments. The binding affinity showed no changes either when two different surgical treatments were compared or when the same patient was analysed before and after the operation. On the contrary, a significant decrease in receptor density was found in thyroidectomized patients when compared pre- and post-operatively. This fall in receptor number seems to be linked with thyroid function since no statistically significant changes were observed in cholecystectomized patients in relation to surgical operation. This view is further supported by data on T3 serum levels, which show a significant fall after thyroidectomy but no statistically significant modifications after cholecystectomy. It is concluded that betaadrenoceptor modulation plays an important role in the relationship between thyroid and beta-adrenergic system.
Immunomodulatory role of thyroid hormones: in vivo effect of thyroid hormones on the blastogenic response of lymphoid tissues
Authors: Chatterjee Sadhana , Chandel Amar Singh
Published: December 2008

Abstract. In an attempt to find out the mechanism of immunomodulation by thyroid hormones (T3 and T4), their in vivo effect on the blastogenic response of lymphocytes from various lymphoid tissues of hormonetreated and thyroidectomized rats were studied. The blastogenic response of lymphocytes from thymus, peripheral blood and mesenteric lymph nodes to pokeweed mitogen (PWM) was found to be increased significantly following T3 or T4 administration for 15 days or 30 days. However, the response to phytohaemagglutinin (PHA) increased only after 1 month of T3 or T4 administration. The blastogenic response of spleen cells to both PHA and PWM was, on the other hand, found to be depressed following 15 days of hormone administration. Thyroidectomy invariably induced significant depression in the blastogenic response to both PHA and PWM in lymphocytes of all the lymphoid tissues. Thyroid hormone (T3) administration was found to restore the blastogenic response of the lymphocytes of thyroidectomized animals.
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.
Neonatal hypothyroidism: effect on the circadian variation of serum TSH in adult male rats
Authors: Poland R. E. , Hart P.J. , Rubin R. T. , Weichsel M. E.
Published: December 2008

Abstract. Newborn rats were rendered hypothyroid during the first post-natal week and then studied as adults. At 80 days of age, groups of control and neonatally treated animals were sacrified at the peak (13.00 h) and trough (07.00 h) of the serum thyroid stimulating hormone (TSH) circadian rhythm. Both control and treated animals showed the normal peak and trough fluctuation of serum TSH, although the animals made hypothyroid neonatally had serum TSH levels which were less than those of the control animals. Serum thyroxine (T4) levels of control and treated animals were similar at the trough of the serum TSH rhythm (07.00 h), but the (T4) levels of the neonatally hypothyroid animals were significantly lower than those found in the control animals at the peak of the TSH rhythm (13.00 h). The results of this experiment indicate that the central nervous system (CNS) regulation of the circadian pattern of serum TSH is maintained in adult animals made hypothyroid neonatally, and supports the results of previous studies which indicate an enhanced sensitivity of TSH secretion to feedback suppression by thyroid hormones.
1α,25-dihydroxyvitamin D3 corrects osteomalacia in hypoparathyroidism and pseudohypoparathyroidism
Authors: Epstein Sol , Meunier Pierre J. , Lambert Phillip W. , Stern Paula H. , Bell Norman H.
Published: December 2008

Abstract. Deficiency of circulating 1α,25-dihydroxyvitamin D (1α,25(OH)2D) regularly occurs in hypoparathyroidism (HP) and pseudohypoparathyroidism (PHP). Osteomalacia is occasionally found in the two diseases. Two patients, one with HP and the other with PHP, both with symptomatic and biopsy-proven osteomalacia, were studied before and after treatment with 1α,25(OH)2D3. Laboratory values before treatment were as follows: serum immunoreactive parathyroid hormone was undetectable in the patient with HP and was elevated in the patient with PHP. Serum 25-hydroxyvitamin D, measured by binding assay, was 131.5 and 61.9 nmol/l (normal: 69.1 ± 15.9 nmol/l); serum 24,25-dihydroxyvitamin D, measured by binding assay, was 13.9 and 3.8 nmol/l (normal: 3.4 ± 1.4 nmol/l); serum 1α,25(OH)2D, measured by bioassay, was 28.6 and 29.0 pmol/l (normal: 77.3 ± 22.8 pmol/l) and, measured by receptor assay, was 36.2 and 41.0 pmol/l (normal: 71.8 ± 35.8 pmol/l) in the HP and PHP patients, respectively. Serum calcium was low and serum inorganic phosphate was high in both cases. Treatment with 1α,25(OH)2D3 (3–5 μg per day for 10–12 months) restored serum calcium and inorganic phosphate to normal, alleviated bone pain and healed the osteomalacia as shown on repeat bone biopsy. Our results provide further evidence that isolated deficiency of 1α,25(OH)2D may cause osteomalacia or rickets.
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.
5α-Reductase activity in stroma and epithelium of rat prostate and epididymis. A contribution to elucidation of the mechanism for development of hyperplastic growth of prostatic tissue
Authors: Djøseland Ole , Bruchovsky Nicholas , Rennie Paul S. , Otal Navdeep , Høglo Sian
Published: December 2008

Abstract. The 5α-reductase activity was assayed in homogenates of stroma and epithelium in the rat ventral prostate and epididymis. Samples consisting of 0.3 mg/ml tissue protein in TES buffer, pH 7.0 were incubated at 37°C for 30 min in the presence of 50 nm [1,2-3H]testosterone and a NADPH-generating system started with 5 × 10−4 m NADP. The yield of 5α-reduced metabolites, as established by using thin-layer chromatography, gave an estimate of enzyme activity. Whereas the specific activity of 5α-reductase was highest in prostatic stroma and epididymal epithelium, most of the total enzyme activity was associated with the epithelium in both the prostate and epididymis. The effect of dihydrotestosterone on specific activity of 5α-reductase was studied by administering the hormone to 7-day castrated rats. In prostate, the specific activity of both stromal and epithelium forms of the enzyme reached a maximum after 4 days of treatment. In epididymis only the epithelial form of 5α-reductase underwent a major change in specific activity, the latter peaking after 8–12 days of treatment. Furthermore, while the total activity of 5α-reductase in the prostatic tissue fractions could be induced by as much as 4-fold the normal control values, the epididymal enzyme could not be induced above the normal level either in the stroma or the epithelium. This may explain the relative resistance of epididymis to abnormal growth stimulation under the influence of hormones.
Clomiphene citrate induces luteinizing hormone release through hypothalamic luteinizing hormone-releasing hormone in vitro
Authors: Miyake A. , Tasaka K. , Sakumoto T. , Kawamura Y. , Nagahara Y. , Aono T.
Published: December 2008

Abstract. The releasing effects of clomiphene citrate (clomiphene) on luteinizing hormone (LH) and LH-releasing hormone (LRH) were examined in a sequential double chamber superfusion system by superfusing the mediobasal hypothalami (MBH) and/or pituitaries excised from normal female rats in dioestrus. When the MBH and the pituitary were superfused in sequence with medium containing 2 × 10−10 m oestradiol (E2), two significant peaks in LH release (60–130% increase, P < 0.05) were observed 40 min and 90 min after the administration of 3 × 10−8 mol clomiphene. Administration of clomiphene in medium without E2 induced a low peak (25–50% increase, P < 0.05) of LH released from the pituitary perfused in series with the MBH. Administration of clomiphene did not cause a marked increase of LH from the pituitary superfused alone, when superfused with or without E2 containing medium. The concentration of LRH in the efflux was significantly increased (50–100%) 40 min and 90 min after clomiphene administration when MBH was superfused with medium containing E2, whereas clomiphene had no effect when superfused with medium alone. These data indicate: 1) that clomiphene induces LRH release from the MBH, that it may induce LH release, in part, by acting directly at the pituitary level; 2) that changes in LH after clomiphene administration coincide with LRH release, and 3) that a certain concentration of E2 may be necessary for the secretion of LRH by clomiphene.
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 effect of active and passive immunization against oxytocin on ovarian cyclicity in ewes
Authors: Schams D. , Prokopp S. , Barth D.
Published: December 2008

Abstract. Active and passive immunization of ewes against oxytocin prolonged the luteal phase of the oestrous cycle, as evaluated by oestrus behaviour and determination of progesterone. Between the animals there was a high variability in response. In general animals with prolonged cycles had lower concentrations of free oxytocin. But in some animals oxytocin antibodies had no effect on cyclicity. Therefore, an individual minimal threshold concentration for oxytocin was presumed. In control or treated animals circulating oxytocin concentrations increased parallel with progesterone concentrations but decreased earlier during the mid luteal phase of the cycle. A new increase in oxytocin concentrations was only observed if a new corpus luteum was formed.
Sex hormone binding globulin in arterial, and in peripheral, hepatic, renal and spermatic venous blood of children and adults
Authors: Belgorosky A. , Scorticati C. , Rivarola M. A.
Published: December 2008

Abstract. Human sex hormone binding globulin (SHBG) was measured in arterial serum and in serum obtained from different venous territories. In 6 children, SHBG ranged from 44.4 ± 4.8 (mean ± sd) in arterial blood to 55.3 ± 5.3 in the hepatic vein (P < 0.01), while it did not change significantly in renal or peripheral tissue venous blood. In 6 male adults, no significant arteriovenous differences were found either in the peripheral tissues or in the splanchnic circulation. In the spermatic vein of 8 subjects, SHGB was significantly lower (17.1 ± 5.7) than in the arterial blood (22.8 ± 7.5), P < 0.025. The arterio-venous difference found in the splanchnic circulation of children supports the hepatic origin of SHBG, and also suggests extra-hepatic clearance of the binding globulin. Testicular uptake of SHBG might be necessary to regulate delivery of androgens to Sertoli cells in the seminiferous tubules.
Prolactin and thyrotrophin responses to thyroliberin (TRH) in patients with growth hormone deficiency: study in 167 patients
Authors: Garnier P. E. , Roger M. , Chaussain J. L. , Canlorbe P. , Job J. C.
Published: December 2008

Abstract. Both thyrotrophin (TSH) and prolactin (Prl) were studied under thyroliberin (TRH) stimulation tests in 167 hypopituitary dwarfs out of GH or T4 treatment. TSH and/or Prl responses were either low, normal or exaggerated and/or protracted. Various abnormal patterns were observed in most of the patients with low T4 but also in many patients with normal T4. The TSH response should be considered together with the value of T4. A normal response of TSH with a low T4 reflects a relative TSH deficiency from pituitary or hypothalamic origin. There was no clear relationship between the cause or type of hypopituitarism and the pattern of the responses of either TSH or Prl. The abnormalities of TSH and Prl were not related to each other except in patients with a past history of breech delivery. Then both TSH and Prl have to be measured after TRH in order to obtain full information from the test about hypothalamopituitary function. The frequency of the exaggerated and/or delayed or protracted responses of TSH and Prl with normal or low T4 is probably mostly related to hypothalamo-pituitary dysfunction. Abnormal responses of TSH or Prl, seldom of both hormones, were observed in otherwise isolated growth hormone (GH) deficiency, leading to a modification of such a diagnosis after the TRH test. Actually, the TRH test may be useful to ascertain the diagnosis of GH deficiency when the GH responses to provocative tests are borderline.
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.
Cerebrospinal fluid rhinorrhoea during treatment of pituitary tumours with bromocriptine
Authors: Wilson J. Dennis , Newcombe Raymond L. G. , Long Francis L.
Published: December 2008

Abstract. Bromocriptine is widely used in the treatment of hyperprolactinaemia. It has also been shown to be effective in reducing the size of large pituitary tumours, particularly those secreting prolactin. We describe CSF rhinorrhoea in two such patients during treatment with bromocriptine and believe that this complication developed as a result of contraction of the tumour exposing a defect in the sella floor. The possibility of this complication, especially in patients with downward extension of tumour, should be noted.
A homologous radioimmunoassay for canine prolactin: plasma levels during the reproductive cycle
Authors: De Coster R. , Beckers J.-F. , Beerens D. , De Mey J.
Published: December 2008

Abstract. A method is described for the purification of canine prolactin, involving preparative isoelectrofocusing. Canine prolactin has a molecular weight of 23 000 daltons, an isoelectric point of 5.7 and exhibits a high degree of homogeneity in polyacrylamide gels stained by means of a silver method. A specific, homologous radioimmunoassay is described using the Bolton-Hunter method for preparation of the labelled ligand, with a sensitivity of 0.1 ng/tube. Basal plasma prolactin levels of 2–4 ng/ml obtained through the oestrous cycle remained fairly constant but a rise of 9 ng/ml was found at the end of dioestrus in non-pregnant bitches. Level also rose 30 days after mating to reach a peak of about 50 ng/ml near parturition and during early lactation.