Absence of thyrotropin-induced increase in leptin levels in patients with history of differentiated thyroid carcinoma undergoing recombinant human thyrotropin testing.

BACKGROUND: Some extra-thyroid effects of TSH have been described in vitro and in vivo. TSH has recently been suggested to induce interleukin-6 secretion by adipocytes. Leptin is the main protein secreted by adipose tissue. OBJECTIVE: The aim of our study was to evaluate the acute effect of the recombinant human TSH (rhTSH)-induced TSH surge on serum leptin levels in thyroidectomized patients undergoing levothyroxine (L-T4) suppressive therapy for differentiated thyroid carcinoma (DTC). DESIGN: A cohort of 15 female DTC patients was evaluated. Standard rhTSH testing was performed. Leptin, TSH, thyroid hormones, and thyroglobulin were measured before and 3, 6, and 9 days after rhTSH testing. Some metabolic parameters were also evaluated at the baseline. RESULTS: Baseline leptin levels were 12.2+/-3.2 microg/l. Only body mass index (BMI) correlated significantly (p<0.05) with leptin levels. After rhTSH administration, TSH levels increased significantly (p<0.001), while thyroid hormones remained unchanged. Twenty hours after the last rhTSH administration, leptin (11.8+/-3.0 microg/l) levels were unchanged. The maximal TSH level was negatively related with BMI (p<0.05), but no correlation between maximal TSH and leptin levels after rhTSH was noted. CONCLUSIONS: Our in vivo experimental model suggests that an acute TSH increase after rhTSH testing is ineffective in changing circulating leptin levels.

The rational use of fine needle aspiration biopsy (FNAB) in diagnosing thyroid nodules.

AIM: Fine needle aspiration biopsy (FNAB) plays a crucial role in the diagnosis of thyroid nodules and enables the number of surgical operations to be reduced. Theoretically, FNAB should be carried out on all nodules, though currently only those displaying certain characteristics are biopsied. Indeed, to perform FNAB on all nodules may be regarded as an excess of zeal. Therefore, it seems advisable that the endocrinologist should be able to confirm on the spot the necessity and utility of FNAB. METHODS: We evaluated on a sample of 263 consecutive requests (209 female, 57 male; age 56.7+/-13.7 years) for FNAB in 2004: 1) the appropriateness of the investigation, 2) expected efficacy, 3) practical efficacy, 4) efficiency. FNAB was performed under echo-guidance in accordance with the standard technique. In 50%, 36%, 6%, 3%, 2% and 1% of cases, the echographic diagnosis was of MNG, UNG, pseudo-nodular lesion in ATD, lymph-node, neck cyst, suspected parathyroid lesion and tumefaction of the salivary glands, respectively. A pre-FNAB clinical risk score was assigned to each case on the basis of clinical and echographic data, with a maximum possible score of 11. The results of FNAB were subdivided into 5 categories according to the criteria of the BTA (Thy1-Thy5). After FNAB, a decisional category was assigned, ranging from ''observation'' to ''surgery''; this was subsequently (7-18 months) compared with the management strategy adopted by the attending physician. Information was gathered by means of telephone enquiry. RESULTS: 1) Appropriateness: on the basis of clinical and echographic findings, FNAB was not judged appropriate in 24% of cases because of either the lack of confirmation of a significant target (34%) or a low pre-FNAB risk score (range 0-2) (66%). The decisional category was ''observation'' in 87% of cases and ''further investigation'' in 13%. 2) Expected efficacy: FNAB was performed in 76% of cases. The biopsies (3%) performed on swollen lymph-nodes and extra-thyroid neck tumefactions, in which biochemical evaluation was positive, proved to be diagnostic but not classifiable according to the BTA. In 82% of the remaining cases, the result was Thy2 (observation) or Thy 4-5 (surgery). Thy3 results (surgery) were rare (1%). Thy1 results (16%) were yielded by the aspiration of colloid cysts (29%), solid lesions (10%) characterised by means of PTH-FNAB and Tg-FNAB, nodules (9%) no longer detectable on repetition of FNAB, nodules (16%) in which FNAB was already a repetition of a non-diagnostic investigation (2003), and nodules (9%) in which the presence of normal thyrocytes, ''hot'' scintigraphic image and prior decision of the surgeon advised against repeating FNAB. Of the patients with Thy1 results, 26% refused to repeat FNAB. In all, 95% of FNAB supported by biochemical evaluation yielded results that usefully contributed to patient management. The correlation between pre-FNAB clinical risk and cytological score according to the BTA proved significant (P<0.001). No difference in diameter was recorded between nodules with adequate cytology (23.3+/-0.9 mm) and those with inadequate cytology (25.2+/-1.6 mm). 3) Practical efficacy: 75% of patients were reached by telephone. In most cases, observation was the most frequent clinical choice, after echography and/or FNAB. The decisional category assigned after FNAB correlated significantly (P<0.001) with the approach adopted by the attending physician. d) Efficiency: following FNAB, 11 patients were assigned to surgery. DTC was detected in 100% of these cases (1 follicular carcinoma, 1 insular carcinoma, 9 papillary carcinoma). The success of FNAB (9/11) in detecting lesions that proved malignant on histological examination (11/11) was significant (P<0.05). Of the 2 Thy 3 cases, 1 was follicular carcinoma and 1 was follicular adenoma with adjacent papillary carcinoma. The incidence of thyroid carcinomas in the population studied was 5.5%. CONCLUSIONS: 1) Together with clinical-biochemical evaluation, echo-guided FNAB re-mains the first-line diagnostic test in the management of thyroid nodules; 2) a pre-FNAB clinical risk score is useful in limiting the number of probably inappropriate investigations; 3) efficacy, in terms of cytology results that are useful for patient management after FNAB (and after biochemical evaluation, when indicated) is high, enabling patients to be stratified in classes with different subsequent pathways; 4) in the vast majority of cases, FNAB influences subsequent clinical decisions; 5) false negatives cannot be excluded, while false positives are practically nil; 6) further indications may be yielded by studies on larger populations, and new prospects may emerge from the application of other techniques associated to FNAB.

Circulating nitric oxide in women affected by weight loss amenorrhea during pulsatile gonadotropin-releasing hormone therapy.

No specific markers of the severity or prognosis of hypothalamic-pituitary-gonadal axis disturbances associated with weight loss amenorrhea (WLA) are currently available. Circulating nitric oxide (NO), which is involved in the control of the reproductive function in women and is correlated with body mass index (BMI), at least in over-weight and obese subjects, might be a marker of the severity and/or progression of WLA. To test this hypothesis, we studied circulating NO levels in 11 women (age 27.1 +/- 1.59 yr) affected by WLA for 5.1 +/- 1.0 yr; in all patients hormonal therapy had been discontinued 10.0 +/- 3.15 months earlier. NO, determined by measuring its stable catabolite nitrite/nitrates (NOx), was compared with some clinical parameters and sex hormone levels. Subsequently, changes in NOx during pulsatile GnRH therapy (120 ng/kg bw sc every 120 min) were compared with the clinical and hormonal data. Fifteen normal women (27.3 +/- 1.6 yr) served as a control group. NOx was significantly lower (p<0.01) in WLA (8.8 +/- 2.0 micromol/l) than in control (18.7 +/- 2.5 micromol/l) subjects. No correlation between NOx and clinical parameters was noted in either WLA or control subjects. As a result of GnRH therapy, ovulatory cycles reappeared in 91% of WLA women. During the 1st cycle, periovulatory 17beta-estradiol levels were 110% higher than those noted in controls. During the 2nd cycle, NOx showed a slight increase in the follicular phase (+12% vs 1st cycle) followed by a drop during the luteal phase (-40% from the follicular phase); indeed, at that time, NOx correlated negatively with progesterone in both WLA (rS -0.32, p<0.05) and control (rS -0.48, p<0.05) subjects. NOx correlated with BMI at the time of the 2nd cycle (rS 0.71, p<0.05). In conclusion, this study shows that in WLA patients: 1) NO is low, as in other conditions of chronic anovulation; 2) it does not correlate with clinical data; 3) it takes longer than sex steroids to increase and show normal-like fluctuations; 4) its fluctuations are restored earlier in patients with greater BMI.

Circulating nitric oxide is modulated by recombinant human TSH administration during monitoring of thyroid cancer remnant.

During the administration of recombinant human TSH (rhTSH) to monitor differentiated thyroid carcinoma, mild side effects, such as nausea and headaches, often occur. The origin of these is not clear. Since changes in TSH and thyroid hormones can modulate some endothelial-derived factors, we aimed at testing whether rhTSH administration induces changes in nitric oxide. We studied 25 patients (56.6+/-12.6 yr) who had undergone thyroidectomy followed by ablative radioiodine for papillary thyroid cancer and who were under follow-up. While L-thyroxine therapy continued, thyroglobulin (Tg), TSH, free-T3, free-T4 and nitrite-plus-nitrate (NOx) concentrations were evaluated before and after rhTSH administration (0.9 mg i.m. on 2 consecutive days). Mean TSH showed a huge increase from baseline (0.1+/-0.0 mIU/l) to day 3 (216.3+/-17.5 mIU/l, p<0.001), which was not accompanied by changes in thyroid hormones. Mean baseline NOx levels were 12.6+/-1.2 micromoles/l and showed a significant increase on day 3 (20.1+/-1.2 micromoles/l, p<0.05 vs day 0), followed by progressive reduction from day 6 (18.1+/-2.8 micromoles/l) to day 9 (10.6+/-1.3 micromoles/l, p<0.05 vs day 0). There was a significant (p=0.04) correlation between the percentage increase in TSH and the percentage increase in NOx. On the other hand, increase in TSH did not correlate with the percentage decrease in NOx from day 6 to day 9. No correlation was noted between the increase in TSH or NOx and the occurrence or severity of the symptoms. Our study shows that, during rhTSH testing, circulating nitric oxide increases. This endothelial-derived factor might, in turn, mediate the occurrence of vasomotor headache and nausea in some particularly susceptible patients.

Circulating nitric oxide changes throughout the menstrual cycle in healthy women and women affected by pathological hyperprolactinemia on dopamine agonist therapy.

The aim of the study was to evaluate circulating nitric oxide (NO) levels throughout ovulatory cycles in healthy women and women under long-term treatment with dopamine agonists. Fifty women (aged 32.5 +/- 1.2 years) affected by pathological hyperprolactinemia (prolactin (PRL)-secreting microadenoma, 63%; idiopathic, 19%; 'empty sella', 12%; and PRL-secreting macroadenoma, 6%) and on dopamine-agonist therapy (range 1-10 years) were studied; 37 healthy women (aged 30.4 +/- 1.4 years) served as a control group. Blood samples were collected on days 7, 14 and 21 of the menstrual cycle in order to assay NO, PRL, 17 beta-estradiol and progesterone. In all subjects, ovulatory cycles were recorded. PRL levels were comparable between the two groups and significantly rose during the luteal phase. NO levels recorded throughout the menstrual cycles of healthy controls were significantly higher than those recorded in subjects treated with dopamine-agonist; NO levels in the latter were no different from those recorded in non-treated, non-ovulatory hyperprolactinemic women. However, in both healthy controls and dopamine-agonist-treated women, NO was negatively correlated with progesterone concentration and significantly reduced on day 21. In dopamine-treated patients, NO levels did not correlate with the dose or the duration of dopamine-agonist therapy. We conclude that, in our hyperprolactinemic women on therapy, physiological NO secretion is not fully restored, despite restoration of ovulatory cycles by dopamine-agonist therapy.

Opioid tonus and luteinizing hormone secretion in anorexia nervosa: priming effect with serotonin precursor L-5-hydroxytryptophan during pulsatile gonadotropin-releasing hormone administration.

In anorexia nervosa (AN) luteinizing hormone (LH) release is often impaired during opioid blockade. We investigated whether a restoration of the endogenous sex steroid milieu, together with a rise in central serotonergic tone, could increase LH responsiveness to Naloxone (NAL) in seven young women affected by AN. The spontaneous pulsatility of gonadotropins and their response to gonadotropin-releasing hormone (GnRH) and NAL challenges were tested before and after 13 days of pulsatile GnRH treatment and oral administration of L-5-hydroxytryptophan. Low and unpulsatile gonadotropin levels, responsive to GnRH, but not to NAL, were found before treatment. Pulsatile GnRH brought about a quasi-normal secretory pattern and 17 beta-estradiol increased to preovulatory levels in six of seven patients. On day 13 the lack of response to NAL administration was still present, however. A neuroendocrine disorder seems to be present in AN, which appears more complex than in other forms of hypothalamic amenorrhea.

Delayed puberty in uremia: pituitary-gonadal function during short-term pulsatile luteinizing hormone-releasing hormone administration.

Pubertal development is frequently delayed or disordered in children with chronic renal failure. Both neuroendocrine and peripheral alterations due to uremia have been hypothesized to explain the impairment in the pituitary gonadal axis. The aim of the present study was to evaluate quantitative (immunological) and qualitative (biological) LH secretion, as well as FSH and sex steroids, before and during 7 days of sc LHRH administration (136-150 ng/kg bw every 120 min) in 5 uremic children (13.1-14.8 yr) with delayed puberty. Six nonuremic children (13.2-17.8 yr) with delayed puberty underwent the same schedule and served as control group. On day 0 mean immunoreactive LH (I-LH) levels were higher in uremic (4.5 +/- 0.9 mIU/ml) than in nonuremic (1.9 +/- 03 mIU/ml; p < 0.05) subjects while no differences were observed in bioactive LH (B-LH) levels (2.9 +/- 0.7 mIU/ml vs 2.4 +/- 0.3 mIU/ml). In both groups of subjects testosterone was at prepubertal levels. Spontaneous I-LH and B-LH pulses were observed sporadically in both uremic and nonuremic subjects. Short-term pulsatile LHRH administration induced significant increases in B-LH, I-LH, FSH and testosterone. The B/I LH ratio increased from day 0 (0.7 +/- 0.2) to day 7 (1.3 +/- 0.4; p < 0.05) in uremics while it showed wide fluctuations in nonuremic subjects. On day 7, 4 uremic and 5 nonuremic subjects showed a pulsatile release of B-LH after exogenous LHRH pulses. Our data document that in uremia there are qualitative as well as quantitative abnormalities in pituitary gonadal secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological activity of luteinizing hormone in uraemic children: spontaneous nocturnal secretion and changes after administration of exogenous pulsatile luteinizing hormone-releasing hormone--preliminary observations.

Normal pubertal progression is associated with quantitative and qualitative changes in gonadotrophin release. Uraemic children show a delayed or disturbed puberty. We have therefore examined nocturnal gonadotrophin and sex steroid secretion in seven males and three females [age 11-15 years, pubertal stage (PS) 1-3] with chronic renal failure on conservative treatment. In addition to immunoreactive luteinizing hormone (i-LH) we have measured the biological activity of LH (b-LH). Nine children aged 12-17 years with PS 1-3 and normal renal function served as a control group. In two uraemic children, i-LH, b-LH, follicle stimulating hormone and sex steroids were evaluated before and 7 days after pulsatile LH-releasing hormone (LHRH) administration (150 ng/kg body weight subcutaneously every 120 min). Mean i-LH levels were higher in uraemic children than in controls. An increase in i-LH during sleep was found in all controls and in eight of ten uraemic subjects. Mean b-LH levels were lower during sleep and the b/i LH ratio was reduced in uraemic children with PS 2-3 whether asleep or awake compared with controls. Pulsatile administration of LHRH provoked a rise of i-LH and b-LH levels with an increased b/i LH ratio, suggesting an intact pituitary responsiveness. These preliminary data indicate that the gonadotrophin control of LH is abnormal in uraemic children, and that biopotency of LH secretion might be improved after short-term pulsatile LHRH administration.