Pituitary-hormone secretion by thyrotropinomas

Hormone secretion by somatotropinomas, corticotropinomas and prolactinomas exhibits increased pulse frequency, basal and pulsatile secretion, accompanied by greater disorderliness. Increased concentrations of growth hormone (GH) or prolactin (PRL) are observed in about 30% of thyrotropinomas leading to acromegaly or disturbed sexual functions beyond thyrotropin (TSH)-induced hyperthyroidism. Regulation of non-TSH pituitary hormones in this context is not well understood. We there therefore evaluated TSH, GH and PRL secretion in 6 patients with up-to-date analytical and mathematical tools by 24-h blood sampling at 10-min intervals in a clinical research laboratory. The profiles were analyzed with a new deconvolution method, approximate entropy, cross-approximate entropy, cross-correlation and cosinor regression. TSH burst frequency and basal and pulsatile secretion were increased in patients compared with controls. TSH secretion patterns in patients were more irregular, but the diurnal rhythm was preserved at a higher mean with a 2.5 h phase delay. Although only one patient had clinical acromegaly, GH secretion and IGF-I levels were increased in two other patients and all three had a significant cross-correlation between the GH and TSH. PRL secretion was increased in one patient, but all patients had a significant cross-correlation with TSH and showed decreased PRL regularity. Cross-ApEn synchrony between TSH and GH did not differ between patients and controls, but TSH and PRL synchrony was reduced in patients. We conclude that TSH secretion by thyrotropinomas shares many characteristics of other pituitary hormone-secreting adenomas. In addition, abnormalities in GH and PRL secretion exist ranging from decreased (joint) regularity to overt hypersecretion, although not always clinically obvious, suggesting tumoral transformation of thyrotrope lineage cells

Pinealomes fonctionnels familiaux: études biogiques et génétiques préliminaires

Introduction: Sporadic pinealomas are intracranial tumors which incidence account for less than 1/107. This is the second report of secretory familial pinealoma in a mother and sister. We report for the first time neuroendocrine and preliminary genetic studies in these benign tumors. Methods and patients: Radioimmunoassay of urinary 6-sulphatoxymelatonin (a-MT6s) was performed in patients and in 90 control subjects aged 19-67 years. Samples were collected at 19-23 , 23-07 and 07-11 h. Endocrine studies including PRL, TSH, LH, FSH, ACTH, IGF1 and tumoral markers (bHCG, NSE, CEA) levels were measured. Lymphocytes caryotype was determined by CGH. Pituitary and pineal MRI were done in both patients. Results: The daughter was the index case. Diagnosis was done because of headaches. Pineal MRI showed a 17 x 14x 25 mm cystic lesion with gadolinium enhancement and no ventricular dilatation. Circadian rhythm of urinary a-MT6s was present but a-MT6s levels were clearly elevated compared to age-matched controls: 1455 ng/h at 19-23hs (308 261), 6012 ng/h at 23-07hs (1423753) and 3280 ng/h at 07-11hs (579340). The 55 years-old mother reported similar complaints during the daughter's follow-up. A pineal MRI identified a 18 x 20 x 14 mm cystic lesion. There were no signs of intracranial hypertension. None of the women reported sleep disturbances. Circadian rhythm of urinary a-MT6s was lost but a-MT6S levels were clearly elevated : 2380 ng/h at 19-23hs (173 153), 2812 ng/h at 23-07hs (768486) and 1897 ng/h at 07-11hs (480383). Endocrine studies and tumoral markers were in the normal range. No chromosomal abnormalities were found in both women (46,XX). Discussion: Due to the rare occurrence of sporadic pinealomas it is unlikely that such a tumor afflict two members in the same family. Although no histological proof was obtained in our patients, radiological findings and tumoral hypersecretion of melatonin derivated a-MT6s clearly suggest the pineal origin of these tumors. We suggest an autosomal dominant form of transmission with incomplete dominance as the most probable model of inheritance of familial pinealoma