bluuebunny/crossref_metadata_2025 huggingface dataset:
Diabetes mellitus in phaeochromocytoma Fasting blood glucose levels before and after surgery in 60 patients with phaeochromocytoma
Authors: Stenström Gunnar , Sjöström Lars , Smith Ulf
Published: December 2008

Abstract. Sixty patients undergoing operation for phaeochromocytoma were investigated in the pre- and postoperative states with respect to fasting blood glucose levels. When 6 previously known or suspected diabetics were excluded, preoperative diabetes (fasting blood glucose levels ≥ 7.0 mmol/l) were found in 3 of 13 (23%) with sustained hypertension, in 6 of 12 (50%) with sustained hypertension associated with paroxysms and in 4 of 24 (17%) with paroxysmal hypertension. None of the 5 patients with atypical clinical symptoms had glucose levels ≥ 7.0 mmol/l. In the groups of patients with particularly high urinary excretion of catecholamines and vanilmandelic acid higher blood glucose levels were also found. The postoperative blood glucose levels in the follow-up study were normal and < 5.8 mmol/l in all cases except in 3 of the 4 still living patients with a previously known diabetes and in 1 patient with a malignant tumour.

Thus, manifest diabetes, defined as fasting glucose levels ≥ 7.0 mmol/l, is frequently present in patients with phaeochromocytoma (24% in the present study) and the diabetes is reversed by removal of the tumour.
In vivo evidence of cortisol secretion by aldosterone-producing adenomas
Authors: Nomura Kaoru , Naruse Mitsuhide , Naruse Kiyoko , Demura Hiroshi , Shizume Kazuo
Published: December 2008

Abstract. This study was done to confirm that aldosterone-producing adenomas secrete cortisol in vivo. Plasma cortisol and aldosterone concentrations were measured in samples obtained by selective adrenal-vein sampling in 8 patients with primary aldosteronism due to unilateral adenoma. All cases revealed higher adrenal-vein plasma cortisol concentrations on the adenoma side than the opposite, irrespective of adenoma location. These concentrations correlated significantly with plasma aldosterone concentrations (r = 0.972, P < 0.001) in effluents from the adenoma side, but not from the opposite. Plasma concentrations also correlated significantly with estimated adenoma volume (r = 0.918, P < 0.05). These findings strongly suggest that aldosterone-producing adenomas secrete cortisol in vivo. In a second study, we used metyrapone to test 6 patients with adenomas. Their responsiveness to cortisol and corticotrophin was found to be the same as that in normal subjects, suggesting that adenoma-secreted cortisol did not disturb the relationship between corticotrophin and cortisol. We thus concluded that cortisol is secreted concomitantly with aldosterone from aldosterone-producing adenomas under corticotrophin influence.
The effect of potassium loading and sodium depletion on DOC induced hypertension in sheep
Authors: Mills E. H. , Coghlan J. P. , Denton D. A. , Spence C. D. , Whitworth J. A. , Scoggins B. A.
Published: December 2008

Abstract. This study examines the physiological effects of 1 1-deoxycorticosterone (DOC) at 2 rates of continuous iv infusion for 5 days in conscious sheep. DOC treatment, in sheep on Na and K intake 80 and 120 mmol/day respectively, increased mean arterial pressure (MAP) by 12 mmHg at 50 mg/day and by 10 mmHg at 5 mg/day. Both rates of infusion raised plasma [Na] and lowered plasma [K]. Urinary Na excretion fell on the first day of infusion. On cessation of infusion there was a natriuresis. A high K intake of approximately 800 mmol/day for 7 to 10 days prior to and during DOC (5 mg/day) treatment abolished the rise in blood pressure, the rise in plasma [Na], the intitial Na retention and the post-DOC natriuresis. Plasma [K] rose with high K intake and fell with DOC. Na depletion prior to DOC infusion (5 mg/day) prevented the rise in MAP. Urinary Na excretion remained low and plasma [K] fell. This study shows that K loading abolishes DOC hypertension in sheep by a mechanism which may involve modification of the Na retaining effects of the steroid.
Changes in serum somatomedin and growth hormone concentrations after 3 weeks oestrogen substitution in post-menopausal women; a pilot study
Authors: Duursma S. A. , Bijlsma J. W. J. , Van Paassen H. C. , van Buul-Offers S. C. , Skottner-Lundin A.
Published: December 2008

Abstract. Oestrogens have a preventive effect on bone loss in post-menopausal women; however, little is known about their mechanism of action. The aim of this study was to investigate the changes in somatomedins (SM) and growth hormone (GH) concentrations in serum in postmenopausal women after 3 weeks of substitution with 20 μg ethinyloestradiol. A significant decrease was observed in the mean serum levels of SM. measured by bioassay (0.66 ± 0.07 vs 0.38 ± 0.07. P < 0.01), radioimmunoassay (0.62 ± 0.08 vs 0.34 ± 0.03, P < 0.01) and radioreceptorassav (1.14 ± 0.11 vs 0.90 ± 0.09, P < 0.01). The mean serum GH concentration increased (9.4 ± 3.2 vs 16.5 ± 4.6, P < 0.01). A positive role of SM and GH in the changes of bone metabolism after oestrogen substitution in post-menopausal women is discussed.
Abnormality of testicular FSH receptors in infertile men
Authors: Namiki M. , Koide T. , Okuyama A. , Sonoda T. , Itatani H. , Miyake A. , Aono T. , Terada N. , Matsumoto K.
Published: December 2008

Abstract. To ascertain whether abnormalities in testicular binding of follicle stimulating hormone (FSH) are related with spermatogenic impairment found in idiopathic male infertility, we measured FSH receptors in testicular tissues obtained by biopsy from 37 infertile men.

Since there had been few reports on the characterization of human testicular FSH receptors, we first established conditions for FSH receptor assay in small amounts of human testicular tissues taken by biopsy. Thirty-seven infertile men were divided into 3 groups by histological grading using Johnsen's score count, and testicular FSH receptors among these groups were compared. Although 6 of 12 infertile men with low Johnsen's score count and 3 of 9 men with middle score count had no obvious FSH binding sites with high affinity, all 16 men with high score count had high affinity FSH binding sites.

The present findings demonstrate that the decrease in testicular high affinity binding sites for FSH is related with the degree of spermatogenic impairment found in idiopathic male infertility.
Thyroid hormone regulation of β-adrenergic receptors and catecholamine sensitive adenylate cyclase in foetal heart
Authors: Das Dipak K. , Bandyopadhyay Dibyendu , Bandyopadhyay Suchitra , Neogi Anita
Published: December 2008

Abstract. The effect of thyroid hormone on the β-adrenergic receptor in foetal cardiac membranes was analysed by measuring the binding of (−)[3H]DHA. The specific activities (per mg protein) of β-adrenergic receptors decreased with advancing gestational age, whereas the total activities (per heart) inceased under the similar conditions. The change in the binding affinities was not statistically significant. 1; 3,5,3'-l-triiodothyronine (T3) stimulated the (−)[3H]DHA binding capacities of the cardiac membranes of foetuses of all age groups. The enhancement in the receptor activity was completely inhibited actinomycin D or cycloheximide. The contents of epinephrine, norepinephrine and cAMP increased with advancing gestational age; but T3 had no significant effect on the catecholamines or cAMP. Similarly, the activities of the basal, NaF stimulated and Gpp(NH)p stimulated adenylate cyclase remained unaltered by T3, but the activites increased progressively with foetal maturity. The absolute values of catecholamine stimulated adenylate cyclase activities in the hearts of T3 treated foetuses were, however, higher compared to those in the untreated foetuses. The enhancement of the activities were totally blocked by the action of actinomycin D, cycloheximide or propranolol. Our results indicate that thyroid hormone enhances the number of β-adrenergic receptor binding sites by synthesizing new receptor proteins resulting in increased catecholamine sensitivity.
Starvation-induced changes in insulin binding to hypothalamic receptors in the rat
Authors: Melnyk Roman B. , Martin J. M.
Published: December 2008

Abstract. In order to determine whether insulin binding to receptors in the central nervous system can be modified by changes in energy balance, hypothalami from 48 h food deprived and 14 day food restricted (8 or 4 g chow/day) rats were removed and insulin binding to partially purified membranes from both medial and lateral hypothalamic regions was studied. Hypothalamic insulin concentration was measured in similarly treated animals. Although hypothalamic insulin concentration did not vary, insulin binding to lateral receptors was significantly lower than that obtained from the medial region. After prolonged food restriction, binding to medial receptors was significantly reduced in comparison to controls, whereas binding in the lateral region remained unchanged; differences were most pronounced at near-physiological insulin concentrations. Changes in per cent specific [125I]insulin binding were associated with corresponding changes in maximal insulin-binding capacity, the latter being inversely related to receptor affinity for this hormone. These results are consistent with the hypothesis that insulin, acting via hypothalamic receptors, may serve as a metabolic feedback signal linking the periphery with central body weight regulatory mechanisms.
Elevated secretion of androstenedione in a patient with a Leydig cell tumour
Authors: Boulanger P. , Somma M. , Chevalier S. , Bleau G. , Roberts K. D. , Chapdelaine A.
Published: December 2008

Abstract. In this study, we report the case of a 48-year old man with a well-encapsulated Leydig cell tumour, azoospermia, decreased libido and impotence. The basal peripheral blood levels of testosterone, dihydrotestosterone, 5α-androstane-3α,17β-diol and oestradiol were normal and oestrone was moderately increased. In contrast, androstenedione was extremely elevated at 521 ng/dl (normal: 88 ± 60 ng/dl). Upon hCG stimulation, plasma testosterone increased 2.1-fold while androstenedione increased 1,4-fold. Plasma LH and FSH were also elevated and their response to LRH was exaggerated. At the time of surgery the levels of androstenedione in the spermatic vein plasma, as well as in the testicular tumour were elevated. In contrast, testosterone levels in the spermatic vein blood were decreased indicating a partial deficiency of 17β-hydroxysteroid dehydrogenase in the tumoural tissue. A follow-up study revealed that the contralateral testis did not respond to hCG although the sex steroid concentrations in the peripheral plasma were within normal limits. Plasma gonadotrophins remained elevated. These results demonstrate that this Leydig cell tumour secreted high amounts of androstenedione into the blood and that the contralateral testis exhibited an impaired androgenic function.
Lack of melatonin action on testosterone production by superfused rat interstitial cells
Authors: Jarrige Jean-Francois , Thieblot Philippe , Boucher Daniel
Published: December 2008

Abstract. The direct effect of increasing doses of melatonin (10−8 to 10−5 m) on testosterone production by superfused rat interstitial cells was studied.

A constant basal testosterone output was observed for approximately 3 h after the initial high release. A continuous hypothalamo-pituitary stimulation induced a rapid testosterone response reaching peak values in 40–60 min, then decreasing progressively. Basal testosterone release was not modified by 20 or 140 min melatonin infusions. Furthermore, melatonin induced no alteration of the stimulative testosterone response when directly infusing the cells. This study demonstrates that melatonin in vitro has no direct effect on testosterone production by adult rat interstitial cells. It would seem, therefore, that the well known inhibitory influence of melatonin on rat reproductive function is not produced by a direct effect on Leydig cells.
Specific receptors for epidermal growth factor in human bone tumour cells and its effect on synthesis of prostaglandin E2 by cultured osteosarcoma cell line
Authors: Hirata Yukio , Uchihashi Masahito , Nakashima Hiroko , Fujita Takuo , Matsukura Shigeru , Matsui Katsuaki
Published: December 2008

Abstract. Using tumour cell lines derived from human bone tumours, specific binding sites for epidermal growth factor (EGF), a potent growth stimulator in many tissues, and its effect on synthesis of prostaglandin (PG) E2, a potent bone-resorbing factor, by cultured osteosarcoma cell line were studied.

Three tumour cell lines, one osteosarcoma (HOSO) and two giant cell tumours of the bone (G-1 and G-2), all possessed specific binding sites for 125I-labelled EGF: the apparent dissociation constant was ~4–10 × 10−10 m and the maximal binding capacity was 50 000–80 000 sites/cell. EGF had no mitogenic effect in these cell lines. However, these cell lines did not have specific binding sites for 125I-labelled parathyroid hormone (PTH) or calcitonin. HOSO line produced and secreted PGE2 into medium, while no significant amount of PGE2 was demonstrated in G-1 or G-2 line. EGF significantly stimulated PGE2 production in HOSO line in a dose-dependent manner (0.5–50 ng/ml); its stimulatory effect was completely abolished by indomethacin, an inhibitor of PG biosynthesis. Exogenous PGE1 significantly stimulated cyclic AMP formation in HOSO line, whereas PGF2α, PTH, calcitonin, or EGF had no effect. None of these calcium-regulating hormones affected cyclic AMP generation in either G-1 or G-2 line.

These data indicate that human bone tumour cells have specific EGF receptors unrelated to cell growth, and suggest that EGF may be involved in bone resorption through a PGE2-mediated process in human osseous tissues.
Seasonal variations of serum 1,25-dihydroxyvitamin D3 and alkaline phosphatase in relation to the antler formation in the fallow deer (Dama dama L.)
Authors: Eiben B. , Scharla St. , Fischer K. , Schmidt-Gayk H.
Published: December 2008

Abstract. Serum 1,25-dihydroxyvitamin D3 and serum alkaline phosphatase increased several fold during the antler formation period in July. Both maxima were observed in the second half of the antler formation period, where the mineralization of the antler takes place. In contrast serum levels of calcium and 25-hydroxyvitamin D3 showed no alternation or seasonal variation.
Infarction of FSH-secreting pituitary adenoma
Authors: Koršić Mirko , Lelas-Bahun Nada , Šurdonja Pavle , Bešenski Nada , Horvat Stjepan , Plavšić Vesna
Published: December 2008

Abstract. A patient with an FSH-producing adenoma is reported. Two hours after LRH administration (100 μg iv) the clinical signs of tumour infarction developed. The patient followed a severe clinical course. FSH levels normalised but further deterioration of pituitary function was documented. Worsening of the vision without improvement after surgical resection of the adenoma was observed.

The role of LRH testing in adenoma infarction is discussed.
Dynamic testing of prolactin and growth hormone secretion in patiens with neuroendocrine disorders
Authors: Müller E. E. , Cavagnini F. , Martinez-Campos A. , Maraschini C. , Giovannini P. , Novelli A. , De Leo V.
Published: December 2008

Abstract. Prolactin (Prl) and growth hormone (GH) responses to different pharmacologic probes acting at the central nervous system (CNS) or the anterior pituitary (AP) level were evaluated in patients with distinct neuroendocrine disorders. Thirteen patients with Prl-secreting tumours (PST), 10 acromegalics (A) and 8 patients with hypothalamic lesions (HL), as assessed on clinical, radiological and surgical grounds, underwent on separate occasions acute testing with the opioid peptide FK 33-824 (0.5 mg iv), the indirect dopamine (DA) agonist nomifensine (NOM, 200 mg po), the DA receptor antagonist domperidone (DOM, 10 mg iv), TRH (200 μg iv) and insulin (ITT, 0.10-0.15 IU/kg iv). All patients were evaluated pre-surgery and 4 of them also post-surgery. Prl and GH were evaluated by RIA at different time intervals following treatments.

Peculiar features of Prl and GH response could be evidenced in the patients as follows: Prl: PST patients did not respond either to stimulation by FK 33-824 (12/13) or to inhibition by NOM, (9/10), but 2/8 and 4/12 of them did respond to DOM or TRH stimulation, respectively; 8/10 A and all of the HL patients did not suppress plasma Prl following NOM, but many of them did respond to FK 33-824 (6/10 A, 5/8 HL) and TRH (9/10 A, 6/8 HL); as for GH, PST patients could be divided into FK 33-824 responders (8/12) and non-responders, whereas in only one of the A and in none of the HL patients a consistent response to the peptide was present; a major difference between A and HL patients was the ability of TRH to elicit a GH rise in the former (8/10) but not the latter (0/6). In conclusion, concomitant application of different CNS- or AP-acting stimuli seems to enable better functional connotation of individual disorders, and hence, provide information of value for the underlying pathophysiology.
DDAVP (1-desamino-8-d-arginine vasopressin) clearance rate
Authors: Stegner Hendrik , Artman Henry G. , Leake Rosemary D. , Fisher Delbert A.
Published: December 2008

Abstract. Utilizing a highly sensitive radioimmunoassay (RIA) for 1-desamino 8-d-arginine vasopressin (DDAVP) and a constant infusion kinetic protocol we measured DDAVP clearance rates (CR) in 6 non-pregnant ewes. Despite mean (and sem) plasma DDAVP levels as high as 5349 (± 151) pg/ml, no changes in blood pressure or heart rate were observed. The CR of DDAVP was 3.6 (± 0.2) ml/kg × min. This CR is only 23% of the mean arginine vasopressin (AVP) CR measured in similar animals in an earlier study. The relatively decreased CR of DDAVP appears to account largely for the approximately 5-fold prolongation of antidiuresis of this synthetic derivative relative to AVP.
Alteration of the development of mammary hyperplastic alveolar nodules and uterine adenomyosis in SHN mice by different schedules of treatment with CB-154
Authors: Mori T. , Nagasawa H.
Published: December 2008

Abstract. The effect of different schedules of bromocriptine-mesilate (CB-154; 0.2 mg/day) treatment on the development of precancerous mammary hyperplastic alveolar nodules (HAN) and uterine adenomyosis was investigated in a virgin SHN strain of mice. CB-154 treatment for 7 weeks beginning at 4 weeks of age enhanced the development of HAN at an advanced age, the shorter period of treatment having no effect. In contrast, spontaneous development of adenomyosis was markedly inhibited in mice treated with CB-154 for more than 4 weeks begining at 4 weeks of age, but not for less than 3 weeks of the treatment. The inhibitory effect of CB-154 was not counteracted by pituitary grafting. Furthermore, CB-154 treatment between 11 and 18 weeks of age also accelerated HAN formation, but had no effect on the development of adenomyosis. These results indicate that in mice a certain period of CB-154 treatment is necessary to produce changes in the development of HAN and adenomyosis, and that the inhibitory effect of CB-154 on the development of adenomyosis is age-dependent. The different response between mammary gland cells and uterine cells to CB-154 exposure is discussed with special reference to cell proliferation.
Effects of acute stimulation with luteinizing hormone-releasing hormone (LRH) on biologically active and immunoreactive serum luteinizing hormone (LH) in pubertal boys
Authors: Montanini Vanna , Celani Marco Francesco , Baraghini Gian Franco , Carani Cesare , Marrama Paolo
Published: December 2008

Abstract. The responses of biologically active LH (BIO-LH) and immunoreactive LH (RIA-LH) to acute stimulation with LRH (0.1 mg iv) were studied in 8 pubertal boys (9–15 years, 2nd–4th Tanner's stage), and in 10 healthy adult men (20–46 years). Serum levels of BIO-LH were assessed by an in vitro bioassay method based upon testosterone production by mechanically dispersed mouse Leydig cell preparations. In pubertal boys the mean BIO-LH/RIA-LH (B/I) ratio of basally secreted LH was significantly lower than in adult men (1.2 ± 0.2 (sem) and 2.2 ± 0.2 respectively, P < 0.01). After acute administration of LRH the mean B/I ratio of circulating LH showed a significant increase from the basal value in pubertal boys (2.6 ± 0.2, P < 0.01 vs basal values), whereas no significant difference in LH B/I ratios were demonstrated throughout the study period in adult men (2.1 ± 0.1, P = NS vs basal values). In agreement with this finding, the mean relative maximum response for BIO-LH (BIO-LH Δ%) was higher in pubertal boys than in adult men (1702.7 ± 500.3 and 499.6 ± 65.4% respectively, P < 0.05), whereas the mean RIA-LH Δ% was similar in both groups (609.1 ± 85.1 and 534.1 ± 75.5% respectively, P = NS). No significant differences were shown in the BIO-LH Δ area between pubertal boys (4.9 ± 0.9 area units × 103) and adult men (6.7 ± 1.2 area units × 103, P = NS), whereas the mean RIA-LH Δ area was significantly lower in the former group (1.9 ± 0.4 area units × 103 vs 3.2 ± 0.5 area units × 103, P < 0.05). Our study emphasizes that the pubertal pituitary possesses a greater responsiveness for BIO-LH than the adult pituitary, and that in pubertal boys acute stimulation with LRH evokes the release of a more bioactive form of LH.
Characterization of growth hormone release in response to external heating Comparison to exercise induced release
Authors: Christensen Stig Engkjær , Jørgensen Otto Lunde , Møller Niels , Ørskov Hans
Published: December 2008

Abstract. The effects of increases in body temperature on growth hormone (GH)-release were studied in 10 young normal males in the fasting state as well as postprandially.

The temperature increase of one degree centigrade was attained by external heating using thermostatically controlled water blankets covered by heat-reflecting aluminium foil. The increase in plasma GH after heating was partially suppressed in the non-fasting state reaching a mean of 7.9 ± 3.5 (sem), ng/ml, range 1.0–36 ng/ml. In contrast all subjects exhibited higher increases, mean 18.3 ± 4.0 ng/ml, range 7–44 ng/ml, in response to heating when fasting.

The results were compared in the same subjects to the plasma GH-responses obtained during exercise (450 kpm/min for 40 min) inducing a similar increase in body temperature of about one degree centrigrade. Nevertheless the response in plasma GH (8.4 ± 3.3 ng/ml, range 0.4–34 ng/ml) was smaller than obtained by the heat test despite a rate of temperature increase on exercise which was about twice as high. Furthermore, the same exercise performed in a cold room under circumstances which precluded any major rises in core temperature resulted in complete inhibition of GH-release. The results indicate that exercise per se does not stimulate GH-secretion, indeed it may inhibit the response expected to be evoked by the exercise-induced rise in temperature.

Evidence is also presented that it is core and not cutaneous temperature which modulated GH release.

The procedure used for inducing the rise in temperature and plasma GH may be used as a simple, acceptable and safe clinical test for GH-insufficiency.
Age-related alterations of pituitary-thyroid function in normal female subjects and in female patients with simple goitre
Authors: Yamada Takashi , Naka Motoji , Komiya Ichiro , Ichikawa Kazuo , Aizawa Toru , Hashizume Kiyoshi , Takasu Nobuyuki , Watanabe Takuji
Published: December 2008

Abstract. Age-related alterations in pituitary-thyroid function were studied in 173 female patients with simple goitre and in 70 normal female subjects. They were divided into 4 groups according to age: A group, less than 19 years; B group, 20 to 29 years; C group, 30 to 39 years; D group, 40 to 59 years.

Serum triiodothyronine (T3) concentrations decreased progressively but insignificantly with age in female patients with simple goitre and in normal female subjects, whereas serum thyroxine (T4) concentrations remained constant throughout the studied age range. Only in female patients with simple goitre, did basal serum TSH concentrations show a tendency to increase with age. However, thyrotrophin-releasing hormone (TRH)-stimulated increase of serum TSH was progressively augmented with age both in female patients with simple goitre and in normal female subjects; the magnitude of change was greater in the former group.

As reflected by acute increases of serum T3 and T4 concentrations, thyroidal responsiveness to endogenous TSH was progressively depressed with age in female patients with simple goitre and in normal female subjects. This age-related thyroidal refractoriness to TSH was more apparent when the changes were expressed as ΔT3(stimulated T3 – basal T3)/ΔTSH (maximum TSH after TRH – basal TSH), and ΔT4(stimulated T4 – basal T4)/ΔTSH. ΔT4/ΔTSH was lower in female patients with simple goitre than in normal female subjects in all age groups. However, the difference was significant only for ΔT4/ΔTSH in group A. Thyroidal responsiveness to exogenous TSH also gradually declined with age in female patients with simple goitre.

Our data indicate 1) TRH-stimulated TSH secretion increases with age probably to overcome age-related thyroidal refractoriness to TSH and 2) although the thyroid of patients with simple goitre is slightly less responsive to TSH than that of normal subjects for all age groups, the difference was significant only for young patients.
A case of primary hyperparathyroidism, primary hyperaldosteronism and Cushing's disease
Authors: Herd Gordon W.
Published: December 2008

Abstract. The rare association of parathyroid adenoma with primary hyperaldosteronism, occurring in each of 2 patients, was recently reported from this unit. The present communication records the subsequent development, in one of these patients, of Cushing's syndrome with an anterior pituitary adenoma. Screening for other endocrine abnormalities was negative. A literature search failed to produce any other cases of the association of these three conditions in one patient.
Hormonal and non-hormonal protein biosynthesis in the pancreatic beta cell of the intact rat after prolonged hyperglycaemia
Authors: Logothetopoulos J. , Valiquette Nancy
Published: December 2008

Abstract. We examined the relative changes in the rates of biosynthesis of (pro)insulin and of non-hormonal beta cell proteins in rats with pronounced hyperglycaemia for up to several days. Labelling of pancreatic cells in vivo eliminated certain pitfalls that we encountered when isolated pancreatic islets from these rats were labelled in vitro. Rats were infused with glucose or buffer solutions for 24 and 72 h. Glucose-infused rats had sustained hyperglycaemia throughout the infusion periods. l[4,5-3H]leucine or l[2,3-3H]tryptophan (an amino acid absent from proinsulin) was injected iv 30 min before the rats were killed. Pancreatic islets were isolated by enzymatic digestion of the pancreas. Pancreatic islets from the rats injected with [3H]leucine were processed for measurement of [3H]proinsulin and [3H]insulin by a double antibody immunoprecipitation procedure. Islets from rats injected with [3H]tryptophan were processed for autoradiography, in order to assess the incorporation of label into non-hormonal sedentary beta cell proteins. Incorporation of [3H]leucine into proinsulin and insulin per beta cell was estimated to be about 2–2.5 (24 h infusion) and 3.5–4 (72 h infusion) times greater in the hyperglycaemic than in normoglycaemic rats. Incorporation of [3H]tryptophan into non-hormonal beta cell proteins showed similar increments in the hyperglycaemic rats. Contrary to our expectation these results indicate that glucose does not exert a significant preferential effect on insulin biosynthesis even after sustained stimulation of the beta cells. Instead, glucose seems to increase equally the incorporation of labelled amino acids into proinsulin and into non-hormonal, beta cell proteins.
Serum sex hormone-binding globulin during puberty in girls and in different types of adolescent menstrual cycles
Authors: Apter D. , Bolton N.J. , Hammond G. L. , Vihko R.
Published: December 2008

Abstract. Serum sex hormone binding globulin (SHBG) concentrations were measured by an immunoradiometric assay, as part of a longitudinal study of puberty in girls, and were related to age. pubertal stage, age at menarche, weight, nature of the menstrual cycle and serum concentrations of sex steroids. A slow but very significant decrease was seen in SHBG from 77 nmol/l at 8–10 years of age to about 50 nmol/l after 15 years of age. Serum SHBG concentrations showed weak negative correlations with those of androstenedione and testosterone during puberty. The closest associations found between SHBG and the parameters measured were negative correlations with weight and body fat percentage in both pre-menarcheal and post-menarcheal girls, even after the effect of age was accounted for by calculating partial correlation coefficients. Girls who experienced early menarche (before 13.0 years) had lower SHBG but higher oestradiol serum concentrations at 10.0–15.9 years of age compared to girls with later menarche. In ovulatory menstrual cycles, a significant increase in SHBG was found from the early to the late part of the cycle, whereas no changes took place in anovulatory cycles. Serum concentrations of SHBG showed positive correlations with those of oestradiol and progesterone in specimens taken in the late part of the cycle.

In view of the weak relationships between serum SHBG and sex steroid concentrations, and the strong relationships between SHBG, weight and body fat percentage, factors other than steroids have to be considered in the regulation of SHBG levels during puberty.
Growth hormone releasing factor infusion does not sustain elevated GH-levels in normal subjects
Authors: Losa Marco , Bock Lilian , Schopohl Jochen , Stalla Günter K. , Müller O. Albrecht , von Werder Klaus
Published: December 2008

Abstract. To evaluate the dynamics of GH-secretion after infusion of growth hormone releasing factor, human pancreatic growth hormone releasing factor (hpGRF1-44) was infused over 2 and 5 h at a dosage of 100 μg hpGRF1-44/h into 11 healthy subjects. The infusion was started and terminated with a 50 μg hpGRF1-44 bolus injection. In 5 subjects 200 μg TRH was given 4 h after starting the infusion. In addition, 4 healthy subjects received 50 μg hpGRF1-44 bolus injection every 2 h. GRF, somatostatin, GH, Prl, and TSH were measured by radioimmunoassay.

The initial 50 μg GRF bolus increased GH-levels in all 11 subjects with a maximum at 30 min (24.1 ± 5.1 ng/ml ± se). However, though hpGRF1-44 was continuously infused and GFR-levels remained elevated, GH decreased to a minimum 270 min after start of infusion (2.6 ± 0.6 ng/ml). The GH-response to the second bolus at the end of the infusion was lower compared to the first response (14.6 ± 3.4 ng/ml after 2 h and 7.6 ± 2.5 ng/ml after 5 h). TRH did not lead to a GH-increase during hpGRF1-44 infusion though Prl and TSH rose normally. The intermittent bolus injection of 50 μg hpGRF1-44 led to continuously decreasing GH-responses to the same GRF-dosage (I. bolus: 16.5 ± 1.6 ng/ml; II. bolus: 4.2 ± 0.8 ng/ml; III. bolus: 3.4 ± 0.5 ng/ml). No change in somatostatin levels was observed.

These findings show that GRF infusion or bolus injection in short intervals does not sustain elevated GH-levels. Pituitary GH is either not readily available for continuous GRF-stimulation or GH-secretion may be antagonized by increasing portal somatostatin levels which are not reflected in the peripheral circulation.
The role of androgens in the effect of diabetes mellitus on hepatic drug metabolism in the male rat
Authors: Skett Paul , Cochrane Rosemary A. , Joels Lesley A.
Published: December 2008

Abstract. Diabetes mellitus exerts a sex-dependent effect on hepatic drug metabolism in the rat and it has been suggested that this is due to a reduction in serum androgen levels. This study shows that the effect of diabetes is only seen in the presence of androgen and that testosterone can reverse the effect of diabetes on drug metabolism. Diabetes, however, does not consistently cause a reduction in serum testosterone. Diabetes and androgens, therefore, are postulated to interact in their effects on drug metabolism by action on a common mediator. It is suggested that this mediator is growth hormone, which is known to be affected by the androgens and insulin and to be involved in sex differences in drug metabolism in the rat.
Hormonal modulation of mouse plasma concentration of epidermal growth factor
Authors: Perheentupa J. , Lakshmanan J. , Hoath S. B. , Fisher D. A.
Published: December 2008

Abstract. To understand the physiological role of plasma epidermal growth factor (EGF) we studied in adult female mice the effect of endocrine manipulations on serum EGF concentration (S-EGF). Starting 1 month after sham operation (sh) or excision (SX) of the submandibular salivary gland (SMG), groups of 6 mice were given sc injections of T4 (0.4 μg/g daily), testosterone propionate (TP, 25 μg/g every 48 h), T4 + TP, or SMG extract (20 μg EGF daily) for 10 days. They were exsanguinated via the abdominal vena cava on day 11. During treatment the SX mice gained 55% less weight and their S-EGF was 25% lower compared with the sh mice. Hormone effects were clear in the SX mice: T4 caused a 35% decrease in S-EGF and a 5-fold increase in SMG-EGF concentration. TP caused a 1.6-fold increase in S-EGF and a 6-fold increase in SMG-EGF. Twenty-four hours after the last injection of SMG extract S-EGF remained 1.6-fold elevated. We conclude that plasma EGF is largely independent of SMG, and is modified by hormones in ways different from known tissue effects. This is consistent with an endocrine role of EGF.
Negative feedback effects of oestradiol-17ß on luteinizing hormone in female rhesus monkeys under different seasonal conditions
Authors: Herndon J. G. , Blank M. S. , Mann D. R. , Collins D. C. , Turner J.J.
Published: December 2008

Abstract. Suppression of luteinizing hormone (LH) by sc implanted oestradiol-17ß (E2) pellets was examined in 4 ovariectomized female rhesus monkeys during the breeding season, the non-breeding season and during the transition between the breeding and non-breeding season. Immunoreactive LH was suppressed to 58, 78 and 75% of untreated levels for the respective seasonal conditions. Bioactive LH was suppressed to 29, 49 and 33% of baseline. Bioactive LH (determined by testoster-one release from rat interstital cells) was significantly correlated (r = 0.84) with immunoactive LH from the same samples. It is concluded that E2 treatment of ovariectomized female rhesus monkeys results in suppressed levels of LH, regardless of the time of year.
Effect of insulin on porcine granulosa cells: implications of a possible receptor mediated action
Authors: Otani Tetsuo , Maruo Takeshi , Yukimura Nobuyuki , Mochizuki Matsuto
Published: December 2008

Abstract. The mechanism of direct action of insulin on porcine granulosa cells cultured in vitro was investigated. Specific receptors for insulin with two classes of binding sites were present. No significant difference in receptor characteristics was observed between granulosa cells obtained from small (1–2 mm), medium (3–5 mm) or large (6–11 mm) follicles. Insulin (25 mIU/ml) augmented both basal and hCG-stimulated progesterone secretion. Insulin was also essential for hCG-stimulated morphological luteinization of cultured porcine granulosa cells obtained from small follicles. Furthermore, 2 h preincubation with insulin (100 mIU/ml) increased glucose incorportation by cultured porcine granulosa cells as determined by pulsing with d-[14C](U)-glucose. The same dose of insulin also stimulated the glucose-6-phosphate independent form of glycogen synthase.

These results suggest that porcine granulosa cells possess insulin receptors and that insulin, mediated by its specific receptors, enhances glucose metabolism by stimulating glycogen synthase. Thus, insulin may play a pivotal role in morphological and funtional differentiation of porcine granulosa cells.
Decreased prolactin secretion by decidual tissue of pre-eclampsia in vitro
Authors: Golander Avraham , Kopel Ram , Lazebnik Noam , Frenkel Yair , Spirer Zvi
Published: December 2008

Abstract. In vitro prolactin (hPrl) secretion by explants of decidual tissue was studied in pre-eclampsia and normal controls. Our results indicate diminished hPrl production by decidua of pre-eclampsia as compared to the normal controls. Incubation of normal decidual tissue in the presence of serum obtained from pre-eclamptic patients did not induce an inhibitory effect on hPrl production.
Involvement of endogenous prostaglandins in salt-induced hypertension
Authors: Ogihara Toshio , Gotoh Seiji , Tabuchi Yoshikatsu , Kumahara Yuich
Published: December 2008

Abstract. Insufficient production of prostaglandins, which are possible antihypertensive agents, may be a pathogenetic factor in hypertensive patients on salt loading. We compared the levels of plasma PGE2, plasma renin activity (PRA) and urinary 6-Keto-PGF1α (6-O-PGF1α), a major stable metabolite of PGI2, on day 5 of salt deprivation and also on day 5 of subsequent salt loading in 17 patients with essential hypertension.

Salt loading decreased plasma PGE2, and slightly increased urinary 6-O-PGF1α. On salt loading, a positive correlation was found between the levels of plasma PGE2 and urinary sodium excretion. On salt deprivation, PRA was significantly correlated with plasma PGE2. The per cent change in mean blood pressure on changing from salt restriction to salt loading was inversely correlated with the per cent change in PGE2, and positively correlated with the per cent change in 6-O-PGF1α excretion.

These findings suggest that on salt restriction, PGE2 is involved in the renin-angiotension system and that on salt loading, PGE2 is produced to compensate for the excessive sodium. The finding that PGE2 production was attenuated progressively as the mean blood pressure increased on salt loading in patients with essential hypertension suggests that insufficient compensatory PGE2 production is a pathogenetic factor in salt-induced hypertensive patients. In contrast, PGI2 may be produced adaptively to regulate blood pressure during changes in salt balance.
Intracellular localization of salivary peptide P-C-like immunoreactivity in the human pancreatic B-cells
Authors: Ito Seiki , Suzuki Toshimitsu , Izumi Tooru , Momotsu Takeshi , Isemura Satoko , Saitoh Eiichi , Sanada Kazuo , Shibata Akira
Published: December 2008

Abstract. In order to clarify the intracellular localization of salivary peptide P-C-like immunoreactivity in human pancreatic B-cells, an immunohistochemical study at electron microscopic levels was carried out by the protein A-gold technique using antisera against insulin and salivary peptide P-C. Both salivary peptide P-C-like immunoreactivity and insulin-like immunoreactivity were present only in the insulin secretory granules of the pancreatic B-cells. However, the former immunoreactivity was lacking in many insulin secretory granules of foetal pancreatic B-cells while the latter immunoreactivity was seen in all insulin secretory granules. Salivary peptide P-C-like immunoreactivity was not found in the other kinds of cells in the islets. In a previous immunohistochemical study at light microscopic level, salivary peptide P-C-like immunoreactivity appeared in a few pancreatic B-cells at about the 16th week of gestation, in an increasing number during gestation, and was seen in all pancreatic B-cells a few months after birth. The present finding together with the above results suggest that absence of salivary peptide P-C-like immunoreactivity in some foetal pancreatic B-cells may be due to the underdevelopment of salivary peptide P-C-like immunoreactivity in each insulin secretory granule. From the examination of cross-reactivity of antisera against salivary peptide P-C to other kinds of salivary peptides and salivary Protein C, and from the results of an indirect immunofluorescence technique using three kinds of antisera including antisera against salivary peptide P-C, salivary peptide P-B and salivary Protein C, it was thought that salivary peptide P-C-like immunoreactivity in human pancreatic B-cells belongs neither to salivary Protein C nor to salivary peptide P-B nor to salivary peptide P-E, but either to salivary peptide P-C itself or to an unknown substance which has common antigenic determinants with salivary peptide P-C, salivary peptide P-B and salivary Protein C. Salivary peptide P-C-like immunoreactivity was not found in the pancreatic B-cells of other mammals. Thus, although a new substance other than insulin is present in the insulin secretory granules of the human pancreatic B-cells, its pathophysiological function remains unclear.
Epidermal growth factor stimulates secretion of rat pituitary luteinizing hormone in vitro
Authors: Miyake Akira , Tasaka Keiichi , Otsuka Shirou , Kohmura Hiroko , Wakimoto Hiroshi , Aono Toshihiro
Published: December 2008

Abstract. The effects of epidermal growth factor (EGF) on pituitary luteinizing hormone (LH) release and on the releases induced by oestradiol (E2) and LH-releasing hormone (LRH) were examined in a sequential double chamber perifusion system. In this system the mediobasal hypothalami (MBH) and/or pituitaries excised from normally cycling female rats in dioestrus were perifused with test media.

Perifusion with EGF at 1 ng/ml for 30 min induced significant release (80–100% increase, P <0.05) of LH from hypothalamo-pituitary pairs, but not from the pituitary alone. Perifusion of the pituitary alone with medium containing 1 ng/ml EGF, resulted in significant release of LH (70–140% increase, P < 0.05) after adminnistration of 10−7 m E2, but did not significantly influence LH release in response to 20 ng/ml LRH.

These findings suggest that EGF may be involved in the regulation of pituitary gonadotrophin secretion by a direct effect on the hypothalamus and indirectly by increasing the pituitary responsiveness to E2.
Cushing's syndrome associated with bilateral adrenal adenomas
Authors: Mimou Naonori , Sakato Schun-ichi , Nakabayashi Hajime , Saito Zenzo , Takeda Ryoyu , Matsubara Fujitsugu
Published: December 2008

Abstract. The fifth case of Cushing's syndrome with bilateral adrenocortical tumours is described. By the hormonal dynamic studies both tumours have been shown to be autonomous in the secretion of cortisol. Histopathologically, both tumours were identified as benign adrenocortical adenomas without nodules, and the right one was a so-called black adenoma. A high concentration of cortisol was obtained from both tumour tissue extracts. The differential diagnosis of Cushing's syndrome due to bilateral adrenocortical adenomas from primary adrenocortical nodular dysplasia is briefly discussed.
Oxytocin can affect follicular development in the adult mouse
Authors: Robinson G. , Evans J. J. , Forster M. E.
Published: December 2008

Abstract. Injection of oxytocin into normal adult cycling mice caused alterations in ovarian histology. Oxytocin was administered early on the day of pro-oestrus and it induced the appearance of large numbers of corpora lutea by late pro-oestrus, suggesting oxytocin stimulated ovulation. When mice were examined very early on the day of normal oestrus the ovarian population of follicles was different in the experimental group from that in the control mice, there being increased numbers of preantral and antral follicles in treated animals. As oxytocin can cause an alteration in the timing of follicular maturation and ovulation processes study of communications between the adenohypophysis and areas containing oxytocin might be important for understanding physiological details of ovulation. The relative times at which, for instance, antral follicle and corpora lutea populations increased suggested that oxytocin might have more than one activity which affects ovarian behaviour.
Effect of [Asu,]eel calcitonin on prolactin release in normal subjects and patients with prolactinoma
Authors: Kaji Hidesuke , Chihara Kazuo , Minamitani Naoto , Kodama Hitoshi , Kita Tetsuya , Fujita Takuo
Published: December 2008

Abstract. The effect of [Asu]eel calcitonin (ECT), an equipotent analogue of eel CT, on prolactin (Prl) secretion was examined in 12 healthy male subjects and in 6 patients with prolactinoma. In healthy subjects, ECT (0.5 μg/kg body weight · h) or saline was infused for 2 h and TRH was injected iv as a bolus of 500 μg at 1 h of ECT or saline administration. ECT did not affect basal Prl levels during 1 h of infusion. TRH caused a significant increase of plasma Prl with peak values of 75.2 ± 11.6 ng/ml in ECT-infused subjects, which did not differ from those infused with saline (68.5 ± 8.3 ng/ml). Next, an iv bolus injection of regular insulin (0.1 U/kg body weight) was followed by an infusion of ECT or saline alone. Plasma Prl peaks after hypoglycaemic stress were significantly lower in ECT-infused subjects than those in saline-injected controls (ECT, 16.5 ± 3.1 vs 33.5 ± 9.6 ng/ml, P < 0.05). In patients with prolactinoma, basal levels of plasma Prl ranging from 42.0–4130 ng/ml failed to change during iv infusion of ECT. Moreover, ECT (10−9–10−6m) did not affect Prl release from prolactinoma tissues perifused in vitro. These findings suggest that ECT may not act directly on the pituitary to modify Prl release. Rather, peripherally administered ECT appears to suppress Prl release via the central nervous system.
Gonadotrophins and ovarian steroids in cattle I. Pulsatile changes of concentrations in the jugular vein throughout the oestrous cycle
Authors: Schallenberger E. , Schöndorfer A. M. , Walters D. L.
Published: December 2008

Abstract. Short-term secretion patterns of LH, FSH, progesterone and oestradiol-17β were evaluated throughout complete oestrous cycles of 6 heifers. Frequent blood samples (in 20-min intervals for 12 continuous h) were taken every 3–5 days from indwelling jugular catheters. There was a high incidence of concomitant LH and FSH pulses ranging from 72% at luteolysis to 83–100% during the luteal phase. Almost the same total number of LH and FSH pulses occurred during the early luteal phase (7.0 vs 7.4/12 h, respectively), however, there was an average of one additional FSH pulse in between the synchronous LH/FSH ones during the mid- and late luteal phase (6.9 FSH vs 3.4 LH pulses/12 h). Basal LH and FSH concentrations remained unchanged from the early until the late luteal period. During and after luteolysis frequency of LH and FSH release (14.5 vs 10.5 pulses/12 h) increased considerably as well as basal concentrations and magnitude of LH pulses. Secretion of both gonadotrophins persisted very frequently (13.3 LH and 10.7 FSH pulses/12 h) during pro-oestrus and oestrus when basal FSH concentrations and FSH pulse maxima approached a nadir. During the mid-luteal phase 45% of pulsatile progesterone occurred concomitantly with each coinciding LH/FSH pulse and 44% of pulsatile progesterone happened after additional single FSH pulses. Distinct short-term changes of oestradiol concentrations were not observed in the jugular vein but concentrations fluctuated randomly ranging from 2–6 pg/ml throughout the luteal period. Prior to and during heat mean concentrations of oestradiol were approximately 2-fold higher (P < 0.05) than during the other periods of the cycle. It is concluded that the frequency of pulsatile LH release is modulated to a much greater extent than FSH by negative feedback of ovarian steroids. Some pulsatile progesterone secretion resulting from the stimulation of FSH (and LH) is still detectable in the jugular vein whereas of oestradiol-17β is not. The additional frequent monitoring of FSH might be more appropriate reflecting pituitary and hypothalamic function than only measuring LH.