Cervical sympathectomy affects gonadotropin-releasing hormone,luteinizing hormone and testosterone in male rats

To examine the effects of bilateral cervical sympathectomy on the secretion of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH) and testosterone (TS), 24 male rats were divided into four groups: control (C), light (L), sympathectomy (S), and light-sympathectomy (LS) groups. The C and S groups were kept under a 12-h light-dark cycle and the L and LS groups were kept under continuous light for 2 weeks. After 2 weeks, blood was collected and the rats were perfused with a fixative. GnRH neurons in the hypothalamus were stained immunohistochemically, and serum LH and TS levels were measured by radioimmunoassay. Although the difference in the number of GnRH neurons between the C and S groups was not significant, the L group was significantly lower than the C or LS groups. The serum LH and TS levels in the L group were higher than in the other groups. The present results suggest that continuous light increases GnRH secretion in the hypothalamus, followed by increased secretions of LH in the pituitary and TS in the testes, and bilateral cervical sympathectomy under continuous light inhibits these hormonal changes. However, a normal circadian rhythm does not affect gonadotropin secretion. Therefore, long-term and repeated stellate ganglion block may inhibit the increases of GnRH, LH, and TS secretions induced by continuous light.     

Study on testicular tissue in animals with congenital hormone deficiency

Of 3 kinds of animals with congenital hormone deficiency, i.e., mouse with Snell pituitary dwarfism (dw) in which hypoplasia of the pituitary anterior lobe is seen from embryonal stage and which almost lacks in growth hormone (GH), prolactin (PRL), thyroid stimulating hormone (TSH) and adrenocorticotrophic hormone (ACTH); mouse with little dwarfism lacking only in GH (lit); and mouse with congenital primary hypothyroidism in which the thyroidal gland shows hypoplasia, thyroxine (T4) in blood is not measurable and, conversely, TSH level is abnormally high (hyt), the males of dw/dw and hyt/hyt have been proved to be infertile, but it is little known about lit/lit. After performing early recovery experiment by administering GH + T4 to dw/dw, GH to lit/lit and T4 to hyt/hyt from birth, the testicles of 40-day-old mice were investigated morphologically in the normal control group, non-treated group and treated group in order to clarify the relation between hormones and the sperm-generating potency. The total number of sperm-generating cells, which consist of spermatogonia, spermatocytes, spermatids and sperms, showed remarkable decreases, compared with each control group, and the decrease in total cell number was improved favorably by treatment with hormone. In comparison with the control groups, significant decreases were showed in the spermatid number for the dw/dw group, sperm number for the lit/lit group, and spermatid and sperm numbers for the hyt/hyt group. These results indicate that GH and T4 have a potential effect on sperm-generating function.     

Multiple Pituitary Hormone Gradients from Cavernous Sinus Sampling in Patients with Cushing's Disease

Summary  Objective. Cavernous sinus sampling in patients with adrenocorticotropic-hormone (ACTH) secreting pituitary adenomas has been used to identify directly ACTH hypersecretion from the pituitary and to predict the lateralization of a microadenoma. In our previous series, cavernous sinus sampling provided a sufficient central/peripheral (c/p) ratio of ACTH and the correct laterality of the pituitary lesion in all microadenomas situated in the lateral wing. To clarify the diagnostic value of other anterior pituitary hormones in relation to ACTH gradients, we evaluated multiple pituitary hormone gradients between a cavernous sinus and a peripheral vein and between both cavernous sinuses in patients with Cushing's disease.  Methods. Cavernous sinus sampling was done in 11 patients with clinical and biochemical features of ACTH-dependent Cushing's syndrome. In 9, pituitary adenoma was detected during transsphenoidal surgery and histologically confirmed, while 2 others were suspected of having ectopic lesions. Serum ACTH, prolactin (PRL), thyroid stimulating hormone (TSH), growth hormone (GH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) from catheters in both cavernous sinuses and from a peripheral vein were measured. The c/p ratios of each hormone and the intercavernous gradients were evaluated.  Results. The c/p ratio of ACTH indicated the presense of pituitary lesions in all 9 patients with ACTH-secreting microadenomas. In addition, the intercavernous gradients of ACTH indicated the correct localization of microadenomas in all 6 patients with lateralized lesions. As for other hormones, the c/p ratios of GH, PRL, TSH and LH were significantly high in number 7, 6, 6 and 3 patients, respectively. In contrast, the significant step up of FSH was observed only in one patient. The intercavernous gradients of GH and PRL were significantly high in number 5 and 4 patients, respectively.  Conclusions. The intercavernous gradients of GH and PRL tend to indicate the lateralization of a microadenoma. The measurement of GH and PRL during cavernous sinus sampling may provide additional information, in the lateralization of ACTH-secreting microadenomas.     

Plurihormonal pituitary adenoma with concomitant adrenocorticotropic hormone (ACTH) and growth hormone (GH) secretion: a report of two cases and review of the literature

Plurihormonal pituitary adenomas are tumours that show immunoreactivity for more than one hormone that cannot be explained by normal adenohypophysial cytodifferentiation. The most common combinations in these adenomas include growth hormone (GH), prolactin (PRL) and one or more glycoprotein hormone sub-units (β-TSH, β-FSH, β-LH and αSU). The authors report two cases of a plurihormonal pituitary adenoma expressing the rare combination of ACTH and GH. They both underwent successful transphenoidal hypophysectomy (TSH). Long-term post-operative follow-up revealed no evidence of tumour recurrence. Due to the multiple secretions and plurihormonal characteristics clinical diagnosis of composite pituitary adenomas can be difficult. The authors discuss the diagnosis and management of composite pituitary adenomas and review the literature regarding this rare phenomenon.     

Short-term recombinant human growth hormone therapy does not modify growth hormone, thyrotropin and prolactin responses to thyrotropin-releasing hormone in adult dialysis patients.

BACKGROUND: We recently have reported the first randomized, controlled study on the effects of short-term recombinant human growth hormone (rhGH|| therapy on the nutritional status of a group of malnourished adult dialysis patients. In order to evaluate whether rhGH administration exerts any influence on GH, thyrotropin (TSH|| and prolactin (PRL|| responses to TSH-releasing hormone (TRH||, we assessed these responses before and after rhGH therapy. METHODS: GH, PRL and TSH responses to TRH before and 1 month after rhGH therapy in a group of adult dialysis patients were evaluated. Seventeen dialysis patients (11 on continuous ambulatory peritoneal dialysis/six on haemodialysis|| were studied (rhGH group, n=8; control group, n=9||. In the rhGH group, 0.2 IU/kg/day rhGH was administered subcutaneously. Each patient was tested with TRH (400 microg bolus i.v.|| on two separate occasions, just before and immediately after the treatment period. RESULTS: rhGH treatment did not modify baseline serum GH concentrations (6.6+/-2.7 vs 4.1+/-1.1 microg/l||, paradoxical GH responses to TRH (six out of eight patients||, GH peak (11.9+/-4.6 vs 11.2+/-5.3 microg/l, NS|| or area under the secretory curve of GH (GH AUC; 19.1+/-4.5 vs 12.1+/-3.1 microg/h/l||. Both basal PRL (35.5+/-7.1 vs 36.7+/-8.6 microg/l|| and TSH (2.3+/-1.1 vs 2.8+/-1.7 mU/l|| concentrations, as well as their responses to TRH stimulation (PRL peak, 59.9+/-16.6 vs 59. 5+/-11.8 microg/l; TSH peak, 6.2+/-2.6 vs 7.1+/-3.9 mU/l||, were also unaffected by rhGH therapy. CONCLUSION: These results suggest that short-term rhGH therapy does not significantly influence the magnitude of the somatotropic, lactotropic or thyrotropic response to TRH in adult dialysis patients. However, this finding has to be interpreted with caution due to the two different patient groups included in this study.     

Hypothalamic-pituitary-adrenal activity among Armenian adolescents with PTSD symptoms

This study evaluated basal levels and responsiveness to exercise of plasma adrenocorticotropic hormone (ACTH), and serum thyroid stimulating hormone (TSH), growth hormone (GH) and cortisol among adolescents from two differentially exposed groups 61/2 years after the 1988 earthquake in Armenia. Severity of total PTSD and Category C and D symptoms were negatively correlated with baseline cortisol. Preexercise ACTH was significantly lower, and preexercise TSH higher, among adolescents with more exposure. Depressive symptoms were negatively correlated with baseline cortisol and positively with TSH. Mean GH, TSH, and cortisol levels in both groups fell within normal limits. The pre- to postexercise increase in GH, TSH, and cortisol suggests that exercise challenge may be useful in the field investigation of neurohormonal activity among traumatized individuals.     

43例垂体瘤术后成人生长激素水平调查

[摘要]目的了解垂体瘤患者在接受治疗后生长激素的储备功能及生长激素缺乏与多种垂体激素缺乏之间的关系。方法以2008年5月至2013年7月间,以在河北省沧州市中心医院接受治疗的43位垂体瘤患者作为调查对象,进行胰岛素低血糖兴奋试验（11Tr）,分析生长激素（GH）、促性腺激素（Gn）、促甲状腺激素（TSH）、精氨酸加压素（AVP）和促肾上腺皮质激素（ACTH）的分泌功能。结果共入组43例垂体瘤患者,男性29例,女性14例,中位年龄为48岁。其中仅5例Irrr实验兴奋后GH分泌正常,余38例均患严重的生长激素缺乏症,且表现出一种或一种以上的垂体激素缺乏症状。结论垂体瘤术后,生长激素缺乏症的发生率很高;患有一种或一种以上垂体激素缺乏的患者都会伴有生长激素缺乏症。     

Genetic differences in the endocrine responses to the thyrotrophin-releasing hormone stimulation test in patients with a major depressive episode

The thyrotrophin-releasing hormone (TRH) stimulation test is becoming useful in the diagnosis of depression, but the optimum concentration of TRH required remains uncertain. The test was performed on a carefully selected group of patients with primary unipolar major depressive episodes with melancholia, who were severely depressed, using TRH 200 micrograms and 500 micrograms (groups 1 and 2). The thyroid-stimulating hormone (TSH), growth hormone (GH) and prolactin (PRL) levels were measured in response to TRH. Responses obtained were compared with respect to hormonal and genetic subgroups. Comparing groups 1 and 2 revealed significant differences in the GH responses (P = 0,0059). A similar significant difference was found in the GH response (P = 0,0102) elicited by the women in each group. Comparison of the genetic subgroups of groups 1 and 2 revealed a significant difference in the PRL response of both the genetic spectrum (P = 0,0258) and the group without a genetic history (P = 0,0259) of alcoholism or depression. The TSH response in the genetic spectrum group was also significantly higher (P = 0,0008) in group 2. Further investigations of the responses elicited in the different genetic subgroups may reveal important variables for the investigation of the pathogenesis of depression.     

Plasma ACTH,beta-endorphin,prolactin, growth hormone and luteinizing hormone levels after thermal stress,heat and cold

In the present study we have examined the response of ACTH, beta-EP, PRL, GH and LH to heat and cold exposure (90° and 4°C, respectively) in eight young healthy subjects. Sauna-induced hyperthermia resulted in an increase of plasma ACTH, beta-EP, PRL and GH, but the exposure to cold did not stimulate the secretion of these hormones. This study indicates that hyperthermia represents a form of stress which can trigger a well-defined neuroendocrine response, whereas cold exposure, at least under these experimental conditions, is unable to elicit significant hormonal changes.     

Combined acromegaly and subclinical Cushing disease related to high-molecular-weight adrenocorticotropic hormone

A 36-year-old man with a 1-year history of diabetes mellitus was referred to the authors' hospital for further endocrinological evaluation of acromegaly. On physical examination, typical acromegalic features but no typical cushingoid features were observed. The clinical diagnosis of growth hormone (GH)-producing pituitary adenoma was confirmed by MR imaging findings, nonsuppression of serum GH levels during a 75-g oral glucose tolerance test (trough GH 6.33 ng/ml), and elevated serum insulin-like growth factor-I levels (1361.3 ng/ml). Moreover, autonomic adrenocorticotropic hormone (ACTH) secretion was suspected, based on inadequate suppression of ACTH or cortisol levels by an 0.5-mg overnight dexamethasone suppression test. Analysis of the patient's plasma by using the gel filtration method revealed the presence of a high-molecular-weight (HMW) form of ACTH known to exhibit low biological activity. Transsphenoidal adenomectomy was performed for the pituitary tumor. Immunohistochemical investigation of the resected specimen showed strong and diffuse immunoreactivity to GH and focal immunoreactivity to ACTH. Although there have been a few cases of pituitary adenoma that produced GH and ACTH concomitantly, this is the first report of the detection of HMW ACTH in patients with GH- and ACTH-producing adenomas. Furthermore, the previous cases also did not exhibit typical cushingoid features. It is suggested that the secretion of ACTH in patients with concurrent GH- and ACTH-secreting adenomas might consist of the HMW form and that the HMW ACTH is consequently associated with a subclinical Cushing state.     

Cervical sympathectomy inhibits axonal transport of gonadotropin-releasing hormone during continuous exposure to light in male rats

To examine the effects of cervical sympathectomy on the transport of gonadotropin-releasing hormone (GnRH) between the hypothalamic neurons and the median eminence, 16 male rats were assigned into four groups: control (C), light (L), light-sympathectomy (LS), and light-colchicine (LC). The C group was kept under a normal circadian rhythm for 2 weeks, and the L group was kept under continuous exposure to light for the same period. The LS group underwent bilateral cervical sympathectomy before being kept under continuous light conditions for 2 weeks. The LC group received colchicine into the cerebral ventricle after being kept under continuous light for 12 days; subsequently, this group was also housed for 2 days under continous light. After these procedures, blood was collected and serum luteinizing hormone (LH) levels were measured. All rats were perfused with a fixative, and GnRH neurons around the anterior commissure, as well as GnRH fibers and granules in the median eminence, were stained immunohistochemically. The L group showed a decreased number of GnRH neurons, increased concentrations of GnRH fibers and granules, and an increased LH level; however, in the LS and LC groups, these changes were not seen. The response in the LS group resembled that in the LC group. Considering the action of colchicine, which inhibits axonal transport, it is suggested that cervical sympathectomy also inhibits axonal transports of GnRH between the GnRH neurons and the median eminence during continuous exposure to light.     

The effects of heat stimulation and cold stress on the rats with cervical sympathectomy

BACKGROUND: To investigate the general action of stellate ganglion block (SGB), we examined the effects of heat stimulation and cold stress on the behavior and stress hormone of the bilateral cervical sympathectomy rats as a long-term and repeated SGB model. METHODS: Wistar's male rats were divided into three groups: control (C), sham operation (S) and sympathectomy (Sx) groups. After 2 weeks, two experiments were done. One was measurement of escape response time from the heat stimulus and the other was hormone measurement. Serum adrenocorticotropic hormone (ACTH), alpha-melanocyte stimulating hormone (alpha-MSH) and beta-endorphine (beta-END) levels were measured assigning 3 groups to 2 subgroups with and without cold stress. RESULTS: Escape response time was significantly extended in the Sx group. ACTH in the Sx group was significantly higher than in other groups, but changes of ACTH by cold stress were similar in 3 groups. In the Sx group alpha-MSH was hardly changed by cold stress while alpha-MSH was significantly decreased in the S group. Changes of beta-END by cold stress were similar in the S and Sx groups. CONCLUSIONS: These results suggest that SGB works systemically through hypothalamus endocrine system and affects stress hormone differently.     

Role of cell and explant culture in the diagnosis and characterization of human pituitary tumours

Summary The pattern of hormone secretion by human pituitary tumours in cell or explant culture has been shown to be of value in establishing the nature of the tissue. There was complete agreement between the diagnosis reached by conventional immunocytochemical techniques and by examining the secretion of hormones in culture. Culture techniques, however, have some advantages over immunocytochemical analysis. In particular, immunocytochemical techniques can only be used to examine a small, possibly unrepresentative, portion of the pituitary tissue, whereas the in vitro culture systems make use of the whole tissue. In addition, in vitro culture is simpler to employ and can be carried out relatively rapidly. Cell and explant culture was therefore used to examine the nature of human pituitary tumours.To determine the incidence of mixed GH-PRL secreting pituitary tumours in acromegaly, the pattern of hormone secretion in vitro by 98 somatotrophic tumours was examined. Thirty-seven per cent were found to be pure somatotrophic tumours and 59.2% secreted both GH and PRL, but no other hormone, indicating that these tumours were of mixed nature. This latter group could be divided into those removed from patients with hyperprolactinaemia (35.7% of all tumours) and those from patients with normal pre-operative serum PRL levels (23.5%). A further small group (3.1%) of tumours secreted only GH in culture, despite elevated pre-operative serum PRL levels, indicating that the hyperprolactinaemia in these patients was due to pituitary stalk compression by the somatotrophic tumour, thereby preventing prolactin release inhibiting factor reaching the lactotrophs and allowing uncontrolled PRL secretion.Pituitary tumours, pre-operatively diagnosed as functionless could be classified on a secretory basis, most producing gonadotrophins (57.3%), whilst 7.3% secreted GH, 8.5% secreted PRL and 1.2% secreted ACTH. Presence or absence of PRL secretion by functionless tumours was correlated with 88 patients whose pre-operative serum PRL was measured. The findings indicated that, in this series, 12.7% of tumours diagnosed as functionless were, in fact, prolactinomas. Additionally, 18.3% of functionless tumours failed to secrete PRL in vitro but were removed from patients with elevated PRL levels. These results suggest that the pre-operative hyperprolactinaemia in these cases was due to compression of the pituitary stalk by the tumour. It is concluded that in vitro pituitary culture techniques can be used to diagnose and characterize the nature of pituitary tumours.     

Plasma and pituitary content of growth hormone luteinizing hormone, and prolactin in uremic rats. Effects of chronic infusion of insulin

The influence of chronic renal failure on pituitary content and on serum concentrations of growth hormone (GH), prolactin (PRL), and luteinizing hormone (LH) was studied in chronically uremic rats by comparison with control rats fed ad libitum and diet-restricted rats pair-fed with uremic rats. A decrease of pituitary GH content was found in uremic and diet-restricted rats, in association with a normal circulating GH level. A decrease of pituitary PRL and LH content with respectively high and normal serum values was observed in uremic but not in diet-restricted rats. These data strongly suggest that GH disturbances are related to malnutrition, whereas PRL and LH abnormalities are related to the uremic state per se. As hypoinsulinemia was observed in uremic rats, and as insulin is largely implicated in growth, we have investigated the effects of chronic infusion of insulin, using miniosmotic pumps, on pituitary hormone content. In spite of normalization of circulating insulin levels in uremic rats treated with insulin, pituitary GH, LH, and PRL contents were unaffected. Thus, insulin deficiency did not appear to be responsible for the diminished pituitary reserve of these hormones.     

Physiology of the pituitary, thyroid and adrenal glands

The pituitary gland is made of clusters of cells producing specific hormones that control growth (growth hormones, GH), thyroid function (TH), adrenal function (ACTH), gonadal function (FSH and LH). In addition, the neurons that join the posterior pituitary (neurohypophysis) secrete vasopressin - the antidiuretic hormone involved in maintaining water balance.The negative feedback loop is the basic mechanism to control the regulation of all endocrine glands. Hypothalamic peptides - releasing hormones (e.g. TRH, CRH) reach the hypophysis via the portal venous system and induce the secretion of specific stimulating hormones (e.g. TSH, ACTH) that drive the end-target endocrine cells to secrete hormones (e.g. thyroid hormones - T3 and T4 or adrenal hormones - cortisol, DHEAS). The plasma levels of these circulating hormones inhibit the pituitary (short feedback) or the hypothalamus (long feedback) and limit the further release of releasing- and stimulating- hormones.The effects of circulating hormones on different tissues are mediated via specific receptors on the cell membrane (e.g. vasopressin receptors), in the cytoplasm (steroid receptor for cortisol) or in the nucleus (e.g. thyroid hormone receptors). Understanding the physiological effects of peripheral hormones helps understanding the mechanisms by which clinical signs and symptoms developed in diseases characterised by excessive hormone secretion (e.g. thyrotoxicosis, Cushing syndrome, phaeochromocytomas) or lack of hormone secretion (e.g. diabetes insipidus).     

Neuroendocrine stress response in gynecological laparoscopy: TIVA with propofol versus sevoflurane anesthesia

Study ObjectiveTo compare intraoperative and postoperative neuroendocrine stress responses during total intravenous anesthesia (TIVA) using propofol and remifentanil versus sevoflurane anesthesia, during laparoscopic surgery.DesignProspective, randomized study.SettingTertiary-care university hospital.Patients46 ASA physical status I patients undergoing laparoscopic surgery for benign ovarian cysts.InterventionPatients were randomly allocated to two groups to receive either TIVA (Group A = 23) or sevoflurane anesthesia (Group B = 23).MeasurementsPerioperative plasma levels of norepinephrine (NE), epinephrine (E), adrenocorticotropic hormone (ACTH), cortisol, growth hormone (GH), prolactin (PRL), and thyroid hormones (TSH, FT₃, FT₄) were measured. Blood samples were collected preoperatively, 30 minutes after the beginning of surgery, after extubation, and two and 4 hours after the end of surgery (times 0, 1, 2, 3, and 4).Main ResultsIn Group A, perioperative levels of NE, E, ACTH, cortisol, and GH compared with preoperative values significantly decreased; in Group B they increased (Groups A vs. B: time 1, P < 0.001 for all markers; time 2, P < 0.001 for E, ACTH, cortisol, and GH; time 3, P < 0.01 for cortisol, NE, and E, and P < 0.05 for ACTH and GH). Perioperative PRL levels were significantly enhanced in both groups versus preoperative values. In both groups, TSH levels increased while FT₃ levels decreased significantly relative to basal values. In both groups, perioperative FT₄ levels significantly increased compared with preoperative values.ConclusionsTIVA inhibited the ACTH-cortisol axis and reduced NE, E, and GH levels, but it enhanced PRL and had a weak effect on thyroid hormone concentrations as compared to sevoflurane anesthesia.     

Kinetics of secretion of luteinizing hormone subunits and free alpha, and effects of gonadotropin releasing hormone

While GnRH is known to stimulate release of pituitary gonadotropins, its acute effects on the kinetics of secretion of the various hormones and subunits are not well characterized. Pulse-chase experiments were therefore performed to compare the time course of secretion of newly synthesized LH subunits and free alpha from rat pituitary quarters, and to study the effects of GnRH. After a 1-h pulse labeling with [35S]cysteine in the presence or absence of 10(-8) M GnRH, cultures were chased with excess unlabeled cysteine for 1, 2, 4, 8, or 20 h. Tissue lysates and media were immunoprecipitated sequentially with antisera to PRL, GH, LH beta and LH alpha, and the products were analyzed by gel electrophoresis. Labeled LH alpha was completely secreted by 4 h of chase without GnRH, and by 2 h with GnRH, as shown by its appearance in media and depletion from pituitary. Newly synthesized LH beta was depleted only at 8 h with GnRH from pituitary, suggesting much slower secretion. Incorporation of 35S into LH beta was approximately half that into LH alpha. Newly synthesized free alpha subunit was secreted between 4 and 20 h without GnRH, and by 8 h with GnRH. Free alpha incorporated a similar amount of radioactivity as LH beta. GnRH had no effect on the timing of the secretion of labeled total protein, PRL, GH, or TSH subunits. The amount of label incorporated during the pulse was greatest for PRL, approximately 15% of total protein label. GH incorporated approximately 20% as much label as PRL, with the glycoprotein subunits somewhat lower. The total amount of 35S incorporated into each protein studied was not affected by GnRH. The data indicate that short term in vitro GnRH exposure during a 1-h pulse labeling and chase acts to accelerate early secretion of LH alpha, LH beta and free alpha but does not affect overall protein synthesis. The peptide hormones PRL and GH incorporated the greatest amount of label and were the most briskly secreted hormones, while LH alpha led the glycoprotein subunits in the amount of incorporation and rapidity of secretion.     

Usefulness of inferior petrosal sinus venous endocrine markers in Cushing's disease

Bilateral and simultaneous sampling of the inferior petrosal sinuses in patients with Cushing's disease has been used to establish the presence and laterality of adrenocorticotropic hormone (ACTH)-producing microadenomas prior to transsphenoidal surgery. Successful preoperative lateralization depends upon equivalent dilution of pituitary venous blood on the two sides since samples which are diluted by unequal amounts of non-pituitary blood may lead to erroneous results. To assure valid sampling results, the use of other pituitary hormones, measured simultaneously, has been proposed to correct the ACTH concentrations from the inferior petrosal sinuses against unequal dilution by non-pituitary venous blood. This proposal presumes that ACTH-secreting microadenomas will not cause unequal delivery of the other pituitary hormones into the two inferior petrosal sinuses. The inferior petrosal sinus concentrations of prolactin (PRL), thyrotropin (TSH), and the alpha subunit of human chorionic gonadotropin (alpha-HCG) were evaluated as indicators of pituitary venous blood dilution in 11 patients with Cushing's disease. Four patients with ectopic ACTH syndrome served as controls. Blood was withdrawn simultaneously from catheters in both inferior petrosal sinuses and from a peripheral vein for measurement of ACTH, PRL, TSH, and alpha-HCG. The ACTH concentrations were then corrected for dilution by non-pituitary blood by dividing the ACTH concentration from each side by the ratio of the inferior petrosal sinus to peripheral blood concentrations of PRL, TSH, and alpha-HCG for that side. At surgery, all 11 patients had ACTH-secreting microadenomas on the side predicted by the uncorrected ACTH concentrations. However, in three patients the corrected ACTH values would have led to erroneous results. Among the 18 sets of corrected inferior petrosal sinus measurements in these three patients, the corrected ACTH values failed to show an inferior petrosal sinus gradient in six and localized the tumor to the side opposite the adenoma in four. Incorrect lateralization was obtained with each of the hormones (PRL, TSH, and alpha-HCG) used for correction. Furthermore, the ipsilateral (side of tumor)-to-contralateral inferior petrosal sinus gradient of ACTH in patients with Cushing's disease was generally paralleled by a significant inferior petrosal sinus gradient of PRL, TSH, and alpha-HCG to the side of the tumor, whereas patients with the ectopic ACTH syndrome tended not to exhibit lateralizing (side-to-side) gradients.(ABSTRACT TRUNCATED AT 400 WORDS)     

Growth hormone secretion and sensitivity in men with idiopathic osteoporosis

Previous studies have suggested that insulin-like growth factor-I (IGF-I) and its binding proteins (IGFBPs) have a pathogenetic role in idiopathic osteoporosis. To investigate this question further we compared 20 men with idiopathic osteoporosis with 12 healthy, age-matched men regarding growth hormone (GH) secretion and sensitivity. GH samples were drawn every 30 minutes for 24 hours from 12 of the patients and all controls, and cumulated GH secretion (24hGH) was derived. Peak GH secretion (peakGH) was provoked by an insulin tolerance test. There were no differences between the groups in serum IGF-I (162 ± 30 vs 163 ± 47 μg/liter, mean ± SD), IGFBP-3 (2474 ± 263 vs 2568 ± 197 μg/liter), 24hGH (1.34 ± 1.26 vs 0.79 ± 0.43 U), or peakGH (53.0 ± 21.5 vs 44.1 ± 19.8 mU/liter). Patients and controls were given GH (2.4 U/day) for 1 week. Serum levels of markers for bone turnover increased significantly in both groups, with no difference in response to GH between the groups. The increase in urinary bone resorption markers was only significant in the controls. In the patients, but not in the controls, there were significant positive correlations between indices for GH secretion and markers for bone turnover at baseline and significant negative correlations with relative changes in bone markers during GH treatment. In this study no difference in GH secretion was found between men with idiopathic osteoporosis and controls, but the findings suggest that the GH/IGF-I axis could play a regulatory role in bone metabolism in men with this condition.     

生长激素第三调节途径在人垂体生长激素腺瘤生长激素释放中的作用

目的　探讨新的生长激素（ Ｇ Ｈ） 第三释放调节途径在人垂体 Ｇ Ｈ 腺瘤 Ｇ Ｈ 释放中的作用。方法　采用细胞培养方法观察新合成的 Ｇ Ｈ 释放肽２（ Ｇ Ｈ Ｒ Ｐ２） 对磷脂酰肌醇（ Ｐ Ｉ） 转换和 Ｇ Ｈ 分泌的影响。结果　 Ｇ Ｈ Ｒ Ｐ２ 有强有力的 Ｇ Ｈ 释放和促进 Ｐ Ｉ转换的作用。结论　 Ｇ Ｈ Ｒ Ｐ２ 的 Ｇ Ｈ 释放和促进 Ｐ Ｉ转换的作用机理是通过蛋白激酶 Ｃ 系统而实现,有必要进行深入的研究。