Circulating telopeptide type I is a peripheral marker of thyroid hormone action in hyperthyroidism and during levothyroxine suppressive therapy.

The aim of the present investigation was to evaluate the clinical performance of serum carboxy-terminal-1-telopeptide (ICTP), a new marker of bone resorption, in identifying peripheral overexposure to thyroid hormones, as compared with serum osteocalcin (OC) and serum sex hormone binding globulin (SHBG). Serum ICTP, SHBG, and OC were assayed by specific radioassays in three study groups. Group 1: 50 perimenopausal women on long-term levothyroxine (LT4) suppressive treatment; group 2: 29 women with untreated hyperthyroidism; group 3: 36 normal euthyroid women matched with group 1 patients for age, alcohol, smoking habits, and lifestyle. Serum concentrations of SHBG, ICTP, and OC were markedly increased in hyperthyroid patients, whereas only serum ICTP was slightly but significantly increased in LT4 treated patients. Serum ICTP had higher diagnostic value for hyperthyroidism when compared with SHBG and to OC (sensitivity: 100%, 71%, 55%; accuracy: 97%, 88%, and 76%, respectively). In group 1, increased serum ICTP was observed in 30 of 50 patients, whereas increased SHBG and OC were found only in 11 of 50 (p < .001). Serum free thyroid hormone concentrations correlated with circulating ICTP and SHBG, and the correlation with serum OC was of lower significance. In conclusion, serum ICTP is a sensitive and reliable marker of peripheral thyroid hormone activity at the bone level; its clinical performance is higher than OC and even better than SHBG. Thus, serum ICTP is better than other peripheral markers in monitoring LT4 suppressive therapy in patients at increased risk for osteoporosis such as perimenopausal women.

[Low levels of dehydroepiandrosterone sulfate in adult males with insulin-dependent diabetes mellitus]. / Bassi livelli di deidroepiandosterone solfato in maschi adulti affetti da diabete insulino dipendente.

UNLABELLED: Studies on animals and humans have suggested that dehydroepiandrosterone sulphate (DHEAS) has antiatherogenic effects. It has been hypothesized that insulin may have an atherogenic role and it has been reported recently that, surprisingly, DHEAS levels decreased in normal men and women during the hyperinsulinemic-euglycemic technique. Since a hyperinsulinemia frequently occurs during insulin therapy in patients with insulin dependent diabetes mellitus (IDDM), the present work was undertaken to determine whether DHEAS serum concentrations were decreased in IDDM patients as compared to controls and if so, to discover the possible causes. To this, purpose, out of 805 outpatients afferent to our Diabetes Centre from 1989 to 1992, three groups were selected on the basis of the criteria described below. Known interferences with the DHEAS serum concentrations such as gender (all males), age (aged 20-40 years) and Body Mass Index (BMI < 30) were excluded. Group A (cross-sectional study) was made up of 15 IDDM patients on insulin treatment with good metabolic control (HbA1C < 8%); group B (control study) was made of 18 healthy subjects (these patients were selected also on the basis of their normal oral glucose tolerance test) and group C (longitudinal study) was made up of 7 IDDM patients who had been examined previously and who were on insulin treatment. METHODS: In all three groups serum concentrations of DHEAS, 17 OH progesterone (17 OHP), delta 4 androstenedione (A4) and cortisol (F) were measured. In 10 patients from group A and in 9 patients from group B the ACTH test (9.25 mg IM Synacthen) was administered and the same hormonal pattern was measured after 60 min. In group C the same hormonal evaluation was performed 5 +/- 2.8 months after commencement of insulin therapy. RESULTS: DHEAS serum concentrations were significantly decreased in group A (median 2.9; range 1.1-5.2 mumol/l) with respect to group B (median 5.7; range 3.0-9.5 mumol/l) (p < 0.0012). However, the serum concentrations of 17 OHP (median 3.9 nm/l; range 2.9-6.9 nm/l and A4 (median 5.2 nm/l; range 1.8-10.2 nm/l) were also significantly reduced, while cortisol levels and the 17 OHP/A4 ratio were comparable to group B. After administration of ACTH, the delta increment in cortisol percentage showed a frank increase (55.1%) in group A with respect to group B (33.1%) (p < 0.01). The rise in DHEAS showed a lower increase in group A (10.2%) with respect to group B (65.5%) even though not statistically significant, while the other hormones showed an overlap between the two groups. In group C the serum concentrations of hormones before insulin therapy did not show any statistical differences with respect to the values in group B. A second evaluation, which was performed during insulin therapy, showed that only the 17 OHP/A4 ratio tended towards higher values with respect to pretherapy values (1.1 and 0.6 respectively; p = 0.07). In conclusion our data confirm low DHEAS levels during chronic insulin administration therapy. The underlying mechanism could be a general aspecific reduction in the activity of P 450 C 21 SCC enzymes in contrast with the specific inhibition of 17.20-lyase obtained during insulin bolus. Whether the low serum concentrations of DHEAS can determine an atherogenic effect of insulin needs further investigation, but the hormone could constitute a new parameter for the follow-up of patients affected by diabetes mellitus.

Visual evoked potentials in hypothyroidism: a long-term evaluation.

Visual Evoked Potentials (VEP) were measured in 9 new-diagnosed hypothyroid female patients--mean age 46 +/- 12 ys--before treatment, during (with monthly evaluations) thyroid hormone replacement therapy and after long-term therapy, at the achievement as well as one year after having achieved and maintained euthyroidism. Three of the hypothyroids had abnormally prolonged latencies (m.v. 131.7 +/- 7.9 ms), while 7 had lower than normal amplitude (m.v. 2.3 +/- 2.8 microV). No remarkable change of amplitude was observed after the achievement of euthyroidism, after a mean time of 5.9 +/- 4.9 months (range 2-14 months). A significant shortening of latency (m 128.3 +/- 7.6 ms), even still higher than the control value (m 122.7 +/- 3.7 ms) was found. Significant correlation between P100 latency and thyroid hormone levels was found for TT4 (r = 0.3353; p = 0.005), TT3 (r = 0.2568; p = 0.032) and FT4 (r = 0.3572; p = 0.002). No further improvement in P100 latency (m 129.5 +/- 7.2 ms; p = 0.037) was found one year after the achievement of euthyroidism, while a remarkable amplitude increase (m 9.2 +/- 3.4 micro; p = 0.001) was observed. Our findings indicate that, as well as other studied parameters, VEP are reversibly alterated in hypothyroidism, probably in relation to metabolic rather than to structural alterations. Moreover, VEP can represent a useful neurophysiologic parameter for quantitation of SNC involvement in hypothyroidism.