Gender-related differences in patients with carcinoid syndrome: new insights from an Italian multicenter cohort study

BACKGROUND

The incidence of neuroendocrine neoplasm (NEN) and related carcinoid syndrome (CaS) has increased markedly in recent decades, and women appear to be more at risk than men. As per other tumors, gender may be relevant in influencing the clinical and prognostic characteristics of NEN-associated CS. However, specific data on carcinoid syndrome (CaS) are still lacking.

PURPOSE

To evaluate gender differences in clinical presentation and outcome of CaS.

METHODS

Retrospective analysis of 144 CaS patients from 20 Italian high-volume centers was conducted. Clinical presentation, tumor characteristics, therapies, and outcomes (progression-free survival, PFS, overall survival, OS) were correlated to gender.

RESULTS

Ninety (62.5%) CaS patients were male. There was no gender difference in the site of primary tumor, tumor grade and clinical stage, as well as in treatments. Men were more frequently smokers (37.2%) and alcohol drinkers (17.8%) than women (9.5%, p = 0.002, and 3.7%, p = 0.004, respectively). Concerning clinical presentation, women showed higher median number of symptoms (p = 0.0007), more frequent abdominal pain, tachycardia, and psychiatric disorders than men (53.3% vs 70.4%, p = 0.044; 6.7% vs 31.5%, p = 0.001; 50.9% vs. 26.7%, p = 0.003, respectively). Lymph node metastases at diagnosis were more frequent in men than in women (80% vs 64.8%; p = 0.04), but no differences in terms of PFS (p = 0.51) and OS (p = 0.64) were found between gender.

CONCLUSIONS

In this Italian cohort, CaS was slightly more frequent in males than females. Gender-related differences emerged in the clinical presentation of CaS, as well as gender-specific risk factors for CaS development. A gender-driven clinical management of these patients should be advisable.

Impact of the SARS-CoV2 pandemic dissemination on the management of neuroendocrine neoplasia in Italy: a report from the Italian Association for Neuroendocrine Tumors (Itanet)

INTRODUCTION

The organization of the healthcare system has significantly changed after the recent COVID-19 outbreak, with a negative impact on the management of oncological patients. The present survey reports data collected by the Italian Association for Neuroendocrine Tumors on the management of patients with neuroendocrine neoplasia (NEN) during the pandemic dissemination.

METHODS

A survey with 57 questions was sent to NEN-dedicated Italian centers regarding the management of patients in the period March 9, 2020, to May 9, 2020 RESULTS: The main modification in the centers' activity consisted of decreases in newly diagnosed NEN patients (- 76.8%), decreases in performed surgical procedures (- 58%), delays to starting peptide receptor radionuclide therapy (45.5%), postponed/canceled follow-up examinations (26%), and canceled multidisciplinary teams' activity (20.8%). A low proportion of centers (< 10%) reported having to withdraw systemic anti-tumor medical treatment due to concerns about the pandemic situation, whereas PRRT was withdrawn from no patients.

CONCLUSION

Although the COVID-19 outbreak induced the centers to reduce some important activities in the management of NEN patients, the Italian network was able to provide continuity in care without withdrawing anti-tumor treatment for the majority of patients.

Short Communication

Gluten Exorphins are opioid peptides identified in enzymatic digests of gluten. The effects of Gluten Exorphins are still largely unknown. It has been shown that Gluten Exorphin B5 (Tyr-Gly-Gly-Trp-Leu) stimulates Prolactin secretion in male rats. In this study, we have evaluated the Prolactin response to Gluten Exorphin B4, another exorphin whose structure (Tyr-Gly-Gly-Trp) is identical to that of the NH(2)-terminal sequence of Gluten Exorphin B5. To this aim, five groups of male rats were given the following intravenous treatments: vehicle, Gluten Exorphin B5 3 mg kg-1 body weight, Gluten Exorphin B4 at the doses of 3, 6 and 9 mg kg-1 body weight. At the dose of 3 mg kg-1 body weight, Gluten Exorphin B5 induced a significant increase in Prolactin levels. Gluten Exorphin B4 could not modify Prolactin secretion, even when administered at doses three times higher than those effective for Gluten Exorphin B5. The present study: (1) indicates that Gluten Exorphin B4 does not modify Prolactin secretion in male rats; (2) confirms the ability of Gluten Exorphin B5 to exert a stimulatory action on Prolactin release; (3) suggests that the presence of the carboxy-terminal leucine in Gluten Exorphin B5 is essential for its action on Prolactin secretion.

Primary symptomatic adrenal insufficiency induced by megestrol acetate

Megestrol acetate (MA) is a progestational agent for the treatment of metastatic breast cancer and endometrial cancer. MA has also been used to promote weight gain in malnourished elderly patients, in patients with immunodeficiency virus and in cancer-induced cachexia. In addition to thromboembolic disease, MA may induce hyperglycaemia, osteoporosis, suppression of the gonadal axis, and Cushing's syndrome. MA has also been shown to cause symptomatic suppression of the hypothalamic-pituitary-adrenal (HPA) axis owing to its intrinsic glucocorticoid-like effect. Three additional patients are presented who developed symptomatic adrenal insufficiency while they were receiving 160-320 mg MA daily. The patients were treated with cortisone acetate supplements, had clear evidence of HPA-axis suppression but recovered fully after MA was discontinued. Patients receiving MA might have an inadequate adrenal response during stressful conditions, possibly because 160-320 mg MA daily may not provide adequate protection to prevent the symptoms of adrenal insufficiency. The adverse MA effect on the HPA axis is probably not well recognised in clinical practice, and clinicians need an increased awareness of the endocrine complications secondary to MA treatment.

Natural history of gastro-entero-pancreatic and thoracic neuroendocrine tumors. Data from a large prospective and retrospective Italian epidemiological study: the NET management study

BACKGROUND

The few epidemiological data available in literature on neuroendocrine tumors (NET) are mainly based on Registry databases, missing therefore details on their clinical and natural history.

AIM

To investigate epidemiology, clinical presentation, and natural history of NET.

DESIGN AND SETTING

A large national retrospective survey was conducted in 13 Italian referral centers. Among 1203 NET, 820 originating in the thorax (T-NET), in the gastro-enteropancreatic tract (GEP-NET) or metastatic NET of unknown primary origin (U-NET) were enrolled in the study.

RESULTS

93% had a sporadic and 7% a multiple endocrine neoplasia type 1 (MEN1)-associated tumor; 63% were GEP-NET, 33% T-NET, 4% U-NET. Pancreas and lung were the commonest primary sites. Poorly differentiated carcinomas were <10%, all sporadic. The incidence of NET had a linear increase from 1990 to 2007 in all the centers. The mean age at diagnosis was 60.0 ± 16.4 yr, significantly anticipated in MEN1 patients (47.7 ± 16.5 yr). Association with cigarette smoking and other non-NET cancer were more prevalent than in the general Italian population. The first symptoms of the disease were related to tumor burden in 46%, endocrine syndrome in 23%, while the diagnosis was fortuity in 29%. Insulin (37%) and serotonin (35%) were the most common hormonal hypersecretions. An advanced tumor stage was found in 42%, more frequently in the gut and thymus. No differences in the overall survival was observed between T-NET and GEP-NET and between sporadic and MEN1-associated tumors at 10 yr from diagnosis, while survival probability was dramatically reduced in U-NET.

CONCLUSIONS

The data obtained from this study furnish relevant information on epidemiology, natural history, and clinico-pathological features of NET, not available from the few published Register studies.

An inhibition of the hypothalamic somatostatinergic tone is not the cause of the enhanced growth hormone response to growth hormone-releasing hormone in patients with liver cirrhosis

Animal models of liver cirrhosis (LC) display a reduced hypothalamic somatostatinergic tone. To test whether a similar mechanism could explain the enhanced Growth Hormone (GH) secretory response to GH-Releasing Hormone (GHRH), which is seen in human LC, we studied the effect of the cholinesterase inhibitor pyridostigmine (PD), which is able to reduce the release of hypothalamic somatostatin (SS), on the GHRH-stimulated GH secretion. We considered that if PD were unable to increase GH secretion, this would constitute evidence of an already inhibited endogenous somatostatinergic tone. If proved, this in turn could explain the enhanced GH response to GHRH seen in LC. Ten LC patients and nine controls were given GHRH (100 microg, intravenously), or PD (120 mg, orally) plus GHRH. After GHRH alone, the GH peak was four times higher in LC than in controls (40.85+/-15.7 ng/ml in LC and 9.35+/-2.5 ng/ml in controls). In LC, PD administration markedly increased the GH response to GHRH (GH peak: 98.0+/-19.7 ng/ml; +240% vs. GHRH alone). The ability of PD to increase the GH response in patients with LC suggests that in this condition the enhanced GH response to GHRH is not due to a completely inhibited endogenous somatostatinergic tone. SS appears instead to maintain its modulator role on GH secretion in human LC, in contrast with what observed in animal models.

Successful treatment of retrograde ejaculation with the alpha1-adrenergic agonist methoxamine: case study

We treated two patients affected by retrograde ejaculation (RE) with the pure alpha1-adrenergic agonist methoxamine; the drug was self-administered intramuscularly by the patients 30 min prior to intercourse or masturbation. A previous trial with oral imipramine had been ineffective in both patients. Sperm count increased substantially, particularly in the first patient who had insulin-dependent diabetes and was seeking fertility. In this patient, total ejaculated sperm increased from 22 millions to 488 and 419.5 millions on two different occasions, with good motility; two clinical pregnancies were obtained in the partner of this patient after 3 and 4 months of treatment, respectively. The second patient did not desire fertility. In both patients, no side effects were seen except for slight piloerection; blood pressure values increased slightly, and heart rate was unchanged. We conclude that self-administered methoxamine can be a useful, noninvasive and inexpensive treatment of RE, when oral agents are ineffective.

Anti-human versus anti-guinea pig tissue transglutaminase antibodies as the first-level serological screening test for coeliac disease in the general population

BACKGROUND

So far the reliability of the anti-guinea pig and anti-human tissue transglutaminase antibodies for the coeliac disease diagnosis has been evaluated in selected groups of patients.

AIM

To compare the diagnostic accuracy of anti-human versus anti-guinea pig tissue transglutaminase in the coeliac disease screening of the general population.

SUBJECTS

Two healthy Italian populations living in Marche region and in Western Sardinia.

METHODS

Both anti-guinea pig and anti-human tissue transglutaminase were determined using an enzyme-linked immunosorbent assay-based commercially available kit (Eu-tTG, Eurospital, Trieste, Italy).

RESULTS

During the period 1999-2001, 3541 subjects (1500 from "continental" Italy and 2041 from Sardinia) were screened for coeliac disease using both anti-guinea pig and anti-human tissue transglutaminase as first-level tests. Both these tests were negative in 3439/3541 sera, while 29 resulted positive for both of them and 73 showed discordant results. Overall, 50 intestinal biopsies were performed in 22, 21 and 7 subjects with positivity to both screening tests, to anti-guinea pig and to anti-human tissue transglutaminase alone, respectively. A coeliac disease diagnosis was made in 25 subjects giving an overall prevalence of 1:126 individuals. The anti-tissue transglutaminase specificity and sensitivity were 98 and 92% for guinea pig and 99.6 and 96% for human tissue transglutaminase, respectively.

CONCLUSIONS

The anti-human tissue transglutaminase test should definitely replace the anti-guinea pig-derived one as first-level screening tool for identifying all subjects who need the second-level investigations (small intestinal biopsy).

Enhancement of the peripheral sensitivity to growth hormone in adults with GH deficiency

OBJECTIVE

Adults with severe GH deficiency (GHD) need recombinant human growth hormone (rhGH) replacement to restore body composition, structure functions and metabolic abnormalities. The optimal rhGH dose for replacement has been progressively reduced to avoid side effects. The aim of the present study was to define the minimal rhGH dose able to increase both IGF-I and IGF binding protein (BP)-3 levels in GHD and to verify the possible change in GH sensitivity.

DESIGN AND PATIENTS

To this goal, we studied the effect of 4-day treatment with 3 rhGH doses (1.25, 2.5 and 5.0 microg/kg/day) on IGF-I and IGFBP-3 levels in 25 panhypopituitary adults with severe GHD (12 males and 13 females, age: 44.5+/-3.0 years, body mass index (BMI): 27.0+/-0.9 kg/m(2)) and 21 normal young adult volunteers (NV, 12 males and 9 females, age: 30.5+/-2.0 years, BMI: 20.8+/-0.5 kg/m(2)).

RESULTS

Basal IGF-I and IGFBP-3 levels in GHD were lower (P<0.001) than in NV. In NV the 1.25 microg/kg dose of rhGH did not modify IGF-I levels. The dose of 2.5 microg/kg rhGH significantly increased IGF-I levels in men (P<0.001) but not in women, while the 5.0 microg/kg dose increased IGF-I levels in both sexes (P<0.001). IGFBP-3 levels were not modified by any of the administered rhGH doses. In GHD patients, all rhGH doses increased IGF-I levels 12 h after both the first (P<0.01) and the fourth rhGH dose (P<0.001). At the end of treatment percentage increases in IGF-I were higher (P<0.001) in GHD patients than in NV. In contrast with NV, in GHD patients the IGF-I response to short-term stimulation with rhGH was independent of gender. Moreover, GHD patients showed increases in IGFBP-3 after the fourth administration of both 2.5 and 5.0 microg/kg rhGH.

CONCLUSION

The results of the present study demonstrate that the minimal rhGH dose able to increase IGF-I and IGFBP-3 levels in GHD patients is lower than in normal subjects, at least after a very short treatment. This evidence suggests an enhanced peripheral GH sensitivity in GH deprivation.

Acute thyroiditis in a child: misleading result of fine-needle aspiration biopsy

We report a case of acute thyroiditis in a 6-year-old girl, whose initial borderline clinical and sonographic data, coupled with the absence of leucocytes and bacteria on the fine-needle aspiration biopsy, led to the reversal of the initial diagnostic impression of acute thyroiditis and the institution of an inappropriate glucocorticoid treatment. Since both diseases are rare in the paediatric age group and therapy is completely different, we conclude that in borderline cases careful clinical observation and the response to the initial antibiotic therapy should be considered more reliable than any single morphologic or microbiologic result. We also suggest that acute bacterial thyroiditis could be usefully classified into two forms, suppurative and non-suppurative.

Prevalence of silent celiac disease in patients with autoimmune thyroiditis from Northern Sardinia

Celiac disease (CD) is frequently associated with other autoimmune diseases such as Type 1 diabetes mellitus, autoimmune thyroiditis (AT), and Addison's disease. The frequency of these associations varies with the populations studied. We conducted this study to ascertain the prevalence of CD in patients with AT from Sardinia, an area with a very high prevalence of CD. To this aim, 297 consecutive patients with AT (as defined by elevated antithyroid antibody levels and a positive ultrasound scan) were studied. Immunoglobulin A and G-class antigliadin antibodies were assayed in serum; if either or both were positive, antiendomysium antibodies were determined. If two markers were positive, serum ferritin, folate, and vitamin B12 levels were measured and jejunal biopsy was suggested. Thirteen out of the 14 patients who showed at least two positive markers consented to jejunal biopsy and all of them showed histological features of CD. The prevalence of CD in AT patients was 4-fold greater than that observed in the general population (4.37 vs 1.06%, p<0.0001). Ferritin was low in 6 and vitamin B12 in 2 out of 13 patients; serum folates were normal in all patients. Molecular typing of HLA class II alleles showed an increased frequency of the extended haplotype DRB1*0301/DQA1*0501/DQB1*0201. None of our patients had a history of gastrointestinal symptoms. We confirm the increased prevalence of silent CD in patients with AT. Patients with AT ought to be regarded as a high-risk group for CD and should be screened routinely for it; if negative, screening tests should be repeated at regular intervals.

Antiendomysium versus antigliadin antibodies in screening the general population for coeliac disease

BACKGROUND

It has recently been shown that mass screening for coeliac disease, using either the serum antigliadin (AGA) or antiendomysium antibodies (EMA) as screening test, can detect large numbers of cases that had escaped clinical diagnosis. The influence of the diagnostic algorithm on the results of the coeliac screening has not yet been evaluated. Our aim was to compare the validity of the AGA and the EMA protocols in 2096 students living in northwest Sardinia, who took part in a serologic screening for coeliac disease.

METHODS

The sample included 2096 of 2345 eligible students (89%) aged 11-15 years who underwent serum IgG AGA, IgA AGA, and IgA EMA determinations. Total serum IgA level was measured in sera showing isolated IgG AGA positivity. Subjects showing at least one of the following: a) EMA positivity, b) IgA AGA positivity, or c) IgG AGA positivity and IgA deficiency (<5 mg/dl) were asked to submit to a small-intestinal biopsy.

RESULTS

The prevalence of coeliac disease was 19 (16 showing typical enteropathy, 1 potential case, and 2 known cases) of 2096 (0.91%; 95% confidence interval = 0.50-1.31). Seventeen small-intestinal biopsy specimens were needed to confirm 16 cases of manifest coeliac disease (positive predictive value (PPV) = 94%) by the EMA protocol, whereas the AGA protocol required 21 biopsy specimens for 12 cases of coeliac disease (PPV = 57%). None of six IgA-deficient, IgG AGA-positive cases detected by the AGA protocol also had coeliac disease.

CONCLUSIONS

The EMA protocol is superior to the AGA protocol for mass screening of coeliac disease because of higher sensitivity, decreased need for intestinal biopsy, and possibility to detect potential cases of coeliac disease.

Quantitative growth hormone secretion and final adult height

OBJECTIVE

The relationship of quantitative GH secretion to height, growth velocity and puberty is complex and has been the subject of extensive study in children. This study was designed to relate quantitative GH secretion to final height.

SUBJECTS

Twenty tall (> 183 cm, 90th centile for adult height) and 20 short (< 166 cm, 10th centile) postpubertal men who had recently completed linear growth (age range 18-27 years).

MEASUREMENTS

GH dynamics were studied on four occasions; insulin (0.15 units/kg, iv)-induced hypoglycaemia and GHRH (100 mg, iv) with and without the anticholinesterase, pyridostigmine (120 mg orally). Spontaneous nocturnal GH secretion was assessed by 20 minute sampling from 2100 h until 0600 h. GH was measured by IRMA. Analysis was by comparison of peak GH response and area under the curve (AUC). GH profiles were further analysed using the 'pulsar' programme.

RESULTS

The mean height in the tall group was 187.7 cm (range 183-197) compared to 163.5 cm (range 160-166) for the short group. No difference existed between groups in the GH response to hypoglycaemia or GHRH with and without pyridostigmine. Area under the curve, pulse number, length and amplitude for spontaneous nocturnal GH secretion showed no significant difference between the tall and short subjects. Serum IGF-I (mean 230.5 +/- 15. 4 vs. 230.6 +/- 18.9 microg/l) did not differ between the groups.

CONCLUSIONS

Quantitative GH secretion does not appear to be an important determinant of final height in healthy individuals.

Dose-response study of GH effects on circulating IGF-I and IGFBP-3 levels in healthy young men and women

The aim of our study was to define the dose-response effect of a short-term treatment with different recombinant human growth hormone (rhGH) doses (1.25, 2.5, 5.0, 10.0, and 20.0 micrograms . kg-1. day-1 for 4 days) on insulin-like growth factor I (IGF-I) and insulin-like growth factor-binding protein (IGFBP)-3 levels in 21 normal young adults of both sexes. The dose of 1.25 microgram/kg rhGH did not modify IGF-I levels. The dose of 2.5 micrograms/kg rhGH significantly increased IGF-I levels in men (P < 0.05) but not in women, whereas the higher doses increased IGF-I levels in both sexes (P < 0.002). IGFBP-3 levels were not modified by 1.25 or 2.5 micrograms/kg rhGH in either sex. On the other hand, 5.0 micrograms/kg increased IGFBP-3 levels in men (P < 0.05) but not in women, whereas the higher doses increased IGFBP-3 levels similarly in both sexes (P < 0.02). In conclusion, our results demonstrate that IGF-I and IGFBP-3 responses to rhGH are dose and sex dependent. However, IGFBP-3 is less sensitive than IGF-I to rhGH stimulation.

Opioid-receptor blockade blunts growth hormone (GH) secretion induced by GH-releasing hormone in the human male

OBJECTIVE

To investigate the existence of an opioid stimulatory tone on growth hormone (GH) secretion in the human male.

DESIGN

Seven healthy male volunteers, aged 19-30, were studied in the Endocrine Unit of the University of Sassari. GH-releasing hormone (GHRH), 100 micrograms as an intravenous (IV) bolus, as administered with and without preadministration of IV naloxone, 2 mg as a bolus followed by a constant infusion of 2 mg/h. Blood samples were taken for 120 minutes after GHRH administration.

RESULTS

Naloxone significantly blunted the GH response to GHRH, measured either as mean peak value (at times 30 to 90) or as integrated concentrations.

CONCLUSIONS

Naloxone is able to decrease the effect of a maximal dose of GHRH, thus suggesting the existence of an opioid stimulatory tone on GH secretion.

Effects of six-month administration of recombinant human growth hormone to healthy elderly subjects

In aging, both changes in body composition and a decrease in GH secretion are observed. While recombinant human GH (rhGH) therapy was shown to be effective in GH-deficient adults, its effects on normal aging are controversial. This study addressed the effects of six-month administration of low dosages of rhGH in a group of 5 healthy elderly subjects (age range 71-86 years). All subjects received 2 IU rhGH (Saizen, Serono) x 2/week s.c., which was approximately 0.03 mg/kg/week, and were examined before and 1, 3, and 6 months after the start of the therapy, as well as 3 months after therapy was suspended. Hormonal, metabolic and biochemical parameters, as well as bone density at the forearm level, body composition and muscle strength, assessed by isokinetic exercises, were evaluated at each scheduled visit. After the start of the therapy, there was an average 9 +/- 3% increase (median 8%) in IGF-I levels (IGF-I basal: 145.6 +/- 9 ng/mL, IGF-I peak: 176.0 +/- 10; p < 0.001). An increase in lean body weight, a decrease in fat (p < 0.05), and an improvement in muscle strength (p < 0.01) were recorded. No significant variation was observed in the metabolic parameters. During rhGH therapy, an increase in both bone resorption and formation parameters, and a slightly decreasing trend in bone density were noted. In conclusion, low dosages of rhGH in healthy elderly subjects seem to determine some physiological effects, such as a slight increase in IGF-I levels, which in turn may be responsible for the positive effects on body mass composition and muscle strength, without producing side effects. On the other hand, 6-month subcutaneous rhGH therapy at the dosage employed was unable to improve bone density.

Pulsatile gonadotrophin secretion in hypothyroid women of reproductive age

Hypothyroid women may have various disturbances of the reproductive system. Although menstrual cycle disturbances and infertility have been reported in hypothyroidism, gonadotrophin levels have usually been found in the normal range. We have investigated whether female hypothyroid patients of reproductive age have any alteration in the pulsatile secretory pattern of gonadotrophin secretion. LH and FSH were assayed on days 2-5 of the menstrual cycle in blood samples taken every 10 min for 8 h from six hypothyroid women and six age-matched control subjects. Pulsatility was analysed using the Cluster and Detect programs. There was no significant difference in the number of peaks identified (3.7 +/- 0.8 vs 3.7 +/- 0.8 for LH, and 3.7 +/- 0.8 vs 4.2 +/- 0.5 for ESH), the mean duration of peaks (LH: 68.0 +/- 6.9 vs 72.7 +/- 5.1 min; FSH: 81.9 +/- 8.1 vs 71.2 +/- 10.3 min), the area under the peaks (LH: 91.5 +/- 20.4 vs 148.2 +/- 55.1 IU/l per min; FSH: 71.5 +/- 4.5 vs 62.7 +/- 15.0 IU/l per min), and the incremental amplitude from baseline (LH: 2.2 +/- 0.4 vs 3.0 +/- 0.8 IU/l; FSH: 1.4 +/- 0.2 vs 2.1 +/- 0.5 IU/ l). However, the absolute pulse amplitude was greater in hypothyroid patients (LH: 14.5 +/- 1.4 vs 8.3 +/- 1.3 IU/l, P < 0.01; FSH: 9.0 +/- 1.5 vs 5.8 +/- 1.2 IU/l, P = 0.04), as were the integrated concentrations (LH: 6.6 +/- 0.7 vs 3.2 +/- 0.4 IU/l per min, P < 0.01; FSH: 4.3 +/- 0.4 vs 2.1 +/- 0.5 IU/l per min, P < 0.01). Oestradiol values were comparable in the two groups (42.7 +/- 0.4 vs 43.5 +/- 9.7 pg/ml). These results indicate that in hypothyroid women there is an increased baseline level with a normal pulsatility of the gonadotrophin secretion. Similar oestrogen levels in both groups, and normal or near-normal cycles in our patients suggest either a decreased biological potency of the gonadotrophins or a mild ovarian resistance.

L-arginine is unlikely to exert neuroendocrine effects in humans via the generation of nitric oxide

There is now considerable evidence that nitric oxide is an important neuroregulatory agent, but there has been very little investigation of its possible role in neuroendocrine mechanisms in humans. We have investigated the effects of two nitric oxide precursors, L-arginine and molsidomine, under basal conditions on the pituitary hormones growth hormone (GH), prolactin, luteinizing hormone, follicle-stimulating hormone, thyrotrophin, adrenocorticotrophin (ACTH) and vasopressin, and also on serum cortisol; we have also studied the effect of L-arginine on circulating prolactin, ACTH and cortisol in normal human subjects under hypoglycaemic stress. L-Arginine stimulated both GH and prolactin release under basal conditions but had no effect on the other hormones studied, while the nitric oxide donor molsidomine showed no effect on any hormone studied. L-Arginine potentiated the hypoglycaemia-stimulated release of ACTH but did not influence the rise in GH. The current studies suggest that the effects of L-arginine on the stimulation of GH and prolactin release are unlikely to be mediated via the generation of nitric oxide.

Somatostatin infusion suppresses GH secretory burst frequency and mass in normal men

In attempting to elucidate the neuroendocrine mechanisms that regulate pulsatile growth hormone (GH) secretion, we measured serum GH concentrations by an ultrasensitive immunofluorometric method in blood collected every 10 min for 8 h in 11 young healthy male volunteers (age range 21-31 yr) before and during somatostatin (SS) administration (an iv bolus dose of 350 micrograms followed by a continuous infusion at the rate of 6 micrograms.kg-1.h-1, which increases the circulating SS levels to approximately 570 pg/ml). Pulsatile GH secretion was analyzed using the computer-assisted pulse detection program cluster method and deconvolution analysis. The area and frequency of GH peaks were significantly reduced during SS infusion compared with basal values, but detectable pulsatile episodes were still present. These data suggest that, in adult males, SS controls pulsatile GH secretion and can decrease the mass and frequency of GH secretory bursts.

Effect of exogenous growth hormone administration on endogenous growth hormone secretion induced by a met-enkephalin analog

Exogenous growth hormone (hGH) administration in humans attenuates the endogenous growth hormone (GH) response to some pharmacological stimuli; in particular, pretreatment with hGH completely blocks the serum GH response to growth hormone-releasing hormone. In order to evaluate the mechanism(s) whereby opiods induce GH secretion in man, we gave the following treatments to six healthy male volunteers: (a) IV saline; (b) a met-enkephalin analog G-DAMME 250 micrograms IV as a bolus at time 0'; (c) hGH 2 IU as an IV bolus at time -180'; (d) G-DAMME as above, preceded by hGH as above. In our study, G-DAMME stimulated GH secretion both basally (peak 17.9 +/- 6.0 ng/ml) and, to a lesser extent, after hGH pretreatment (6.0 +/- 2.7 ng/ml). Since in our study G-DAMME was able to partially overcome the inhibitory effect of hGH administration, it is suggested that opioids act through an inhibition of somatostatin release and not through a GHRH-dependent pathway. However, an additional direct effect of hGH on pituitary somatotrophes cannot be excluded.

Opioid peptide and alpha-adrenoceptor pathways in the regulation of the pituitary-adrenal axis in man

Opioid peptides are well established as potent inhibitors of the pituitary-adrenal axis, while alpha 1-adrenoceptor drugs have recently been shown to stimulate this axis: both classes of agents appear to work principally above the level of the pituitary, most probable directly on the hypothalamus. There is also evidence that these drugs interact in their control of pituitary-adrenal function, although the specific hypothalamic releasing hormone involved has remained unclear. We have therefore carried out a study into the interaction of methoxamine, an alpha 1-adrenoceptor agonist and naloxone, an opioid antagonist, together with human corticotrophin-releasing hormone (CRH), in a group of healthy volunteers in order to establish the mode of action of these drugs. The following drugs were administered to a group of seven healthy male subjects in a randomized double-blind manner: methoxamine (6 micrograms/kg per min over 3 h); naloxone (10 mg bolus); human CRH (100 micrograms bolus); methoxamine plus CRH; naloxone plus CRH; methoxamine plus naloxone; saline (control). Plasma ACTH and serum cortisol were measured at intervals in each subject, and blood pressure and pulse rate recorded with each sample. Both CRH and naloxone produce a marked rise in ACTH and cortisol, peaking at approximately 45 min after infusion. In combination, the drugs produced a peak response in plasma ACTH at the same time, but its magnitude was greater than that after either drug alone. Methoxamine produced a rise in plasma ACTH which was maximal at approximately 75 min, as well as a peak rise in serum cortisol at 120 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Frequency of and risk factors for allergy in primary school children: results of a population survey

During May 1986, a survey to assess the frequency of allergic disorders was conducted among primary school children of Alghero, Sardinia, using a structured self-administered questionnaire. The following problems were investigated: allergic conjunctivitis, asthma, wheezing, allergic rhinitis, urticaria and eczema. Of the original 1823 questionnaires distributed, 1961 (92.8%) were completed by parents and returned. Overall, 238 children (14.1%) were reported to have shown at least one episode of one or more of the above and were regarded as 'allergic'. Among the potential risk factors investigated, statistically significant differences (P less than 0.05) between allergic and non-allergic children were only found for history of allergy in at least one parent (odds ratio, OR = 2.2) and exposure to passive smoking (OR = 1.4).

[Dietary habits of school children: breakfast]

An investigation on the dietary habits of 944 secondary school children from Alghero, with reference to breakfast consumption and composition, has shown that the percentage of students who eat nothing for breakfast is higher than that reported by other authors. Furthermore it has been noted that consumption decreases among grown up students. Milk and coffee is the most common type of nutriment and also bread and biscuits are well represented. Other types of food, such as jam, yogurt or butter, are instead rarely consumed. Therefore the average caloric intake is of about 400 Kcal.