Rossella Emanuele

Dermorphin, a new opioid peptide, stimulates thyrotropin secretion in normal subjects

The effect of a recently described, potent opioid peptide, dermorphin (DER), on TSH secretion in euthyroid subjects has been studied. DER infused at a rate of 5.5 μg/Kg/min for30 min induced a significant increase in serum TSH concentration at 60,90, and 120 min after the infusion was begun. Treatment with naloxone administered 30 min before the DER infusion with a bolus dose of 4 mg, followed by a constant infusion of 1 μ/Kg/min for 150 min, prevented the rise in serum TSH. Naloxone administered alone did not induce any change in TSH concentration. The present findings suggest that DER has a stimulatory effect on TSH secretion, probably mediated by opioid receptors. These results, however, do not solve the question as to whether opioids have a physiological role in the control of pituitary TSH secretion.

Serum concentrations of myoglobin, creatine kinase, lactate dehydrogenase and cardiac isoenzymes in euthyroid, hypothyroid and hyperthyroid subjects.

SummarySerum concentrations of myoglobin, creatine kinase and lactate dehydrogenase were measured in 33 euthyroid, 21 hyperthyroid and 15 hypothyroid subjects. The results showed that myoglobin, creatine kinase and lactate dehydrogenase were increased and decreased in the hypoand hyperthyroid states, respectively. In addition, the concentrations of myoglobin, creatine kinase and lactate dehydrogenase values were inversely related to both the thyroxine and triiodothyronine concentrations. To study the origin of the increased muscle protein values observed in hypothyroidism, the cardiac isoenzyme fractions were measured; the results obtained support the view that the muscle enzymes are mainly derived from skeletal muscles.

The value of serum thyroglobulin measurement as a marker of cancer recurrence in the follow-up of patients previously treated for differentiated thyroid tumor

In order to verify the value of serum thyroglobulin (hTg) determination to detect cancer recurrence, 104 patients previously treated with surgical and 131I total thyroid ablation for differentiated thyroid cancer were studied. Comparison of serum hTg results and 131I total body scans (131I TBS) was attempted. In 87 patients with negative 131I TBS, serum hTg was undetectable in 80% of the patients whereas in 20% detectable amounts of hTg were measured. In 57 patients with positive 131I TBS, serum hTg was measurable in 72% of the patients whereas in 20% was undetectable. These contrasting results of serum hTg measurement and 131I TBS suggest to us the usefulness to use both tests in the detection of thyroid cancer recurrence.

Effect of metoclopramide on maternal and fetal hyperprolactinemia

To investigate the effect of metoclopramide (MET), a dopaminergic antagonist drug, on serum PRL concentration in maternal and cord blood (CB) serum, the drug was injected in 94 at term pregnant women whereas 28 mothers received saline. Maternal serum (MS) samples were obtained before MET injection and at the parturition time. According to the interval of time between MET administration and birth, MS specimens were grouped in 7 groups. CB was obtained from neonates whose mothers were injected with saline, group 0 and from newborns whose mothers were treated with MET, groups 1 to 7. In the 7 groups of women the mean PRL concentration before MET ranged between 307 and 439 ng/ml. After MET injection a significant increase has been observed in all groups with a minimum and maximal mean value of 639 and 931 ng/ml. The highest net increment of PRL has been measured ingroup 1 sampled at 5 to 30 minutes after MET. CB PRL concentration in group 0, saline treated, was not different from the values measured in group 1 to 7, treated groups, with a range between 504 and 703 ng/ml. These findings suggest that maternal lactotropes are still responsive to MET. On the opposite, fetal pituitary does not release PRL after MET injection probably because PRL secretory activity is maximal or because the dopaminergic receptors’ system is still immature.

Effects of somatostatin in a case of severe hypoglycemia due to nesidioblastosis

The Authors have studied the effects of somatostatin (SRIF) treatment in an infant affected by hypoglycemia due to nesidioblastosis. During iv infusion with SRIF we observed a marked increase of blood glucose levels; concomitantly insulin secretion was almost completely suppressed. In contrast, during treatment with protamine zinc-somatostatin (PZ-SRIF), a long acting SRIF preparation, the blood glucose levels did not rise and insulin concentrations were inappropriately elevated. Therefore in this case the long term treatment of hypoglycemia due to nesidioblastosis with PZ-somatostatin was unfeasible.

IODOTHYRONINE AND THYROTROPIN CONCENTRATIONS AFTER IODOAMIDE ADMINISTRATION FOR ANGIOGRAPHIC STUDIES

SummaryIn order to study the effect of iodoamide (a contrast medium widely used for urographic and arteriographic studies) on thyroid function, seventeen subjects were studied before and after arteriographic examinations employing this contrast compound. Serum concentrations of T4, T3, rT3 and TSH were not modified during the observation period by the administration of iodoamide. This finding is in contrast with the observation that iopanoic acid and ipodate, used for cholecystographic examinations, can reduce the serum concentrations of T4 and T3 with a concomitant increase in rT3. Therefore, iodoamide is not useful in the treatment of hyperthyroidism.

Effect of iodine administration on thyroid function in diabetic patients

SummaryIodide-induced hypothyroidism has been observed in subjects treated with compounds with mild antithyroid activity. The hypoglycemic agent tolbutamide belongs to the aminoheterocyclic group, a class of compounds with antithyroid effect. Thus it was thought interesting to study the effect of large doses of iodide on thyroid function in diabetics chronically treated with tolbutamide. Basal thyroid function as assessed by clinical examination and iodothyronine and TSH concentrations was normal in all patients. Furthermore, in diabetics treated with tolbutamide, hormone concentrations were not different from those of patients treated with insulin or diet. Serum T4, T3 and TSH did not show any significant variation throughout the investigation period. Our results suggest that thyroid function is not affected by chronic treatment with tolbutamide even when large doses of iodide are administered.

TSH response to TRH in euthyroid insulin-dependent diabetics

SummaryIn order to establish the exact profile of thyroid function in Insulin Dependent Diabetics (IDD), we have measured T4, T3 basal and TRH stimulated TSH concentrations in 22 IDD. Four patients with positive thyroid antibodies showed increased basal and TRH stimulated TSH concentrations; this situation may be indicative of subclinical hypothyroidism.