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Pituitary-hormone secretion by thyrotropinomas.

Roelfsema F, Kok S, Kok P, Pereira AM, Biermasz NR, Smit JW, Frolich M, Keenan DM, Veldhuis JD, Romijn JA - Pituitary (2009)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Albinusdreef 2 NL2333ZA, Leiden, The Netherlands. f.roelfsema@lumc.nl

ABSTRACT
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.

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TSH and GH profiles of 2 patients with a thyrotropinoma. Note the similarity of the patterns of both hormones
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Fig6: TSH and GH profiles of 2 patients with a thyrotropinoma. Note the similarity of the patterns of both hormones

Mentions: We also investigated cross-correlations between 24-h TSH concentrations and each of GH, α-subunit and PRL. Profiles of the serum concentrations of GH and TSH in two patients were rather similar, as illustrated in Fig. 6. The cross-correlation outcomes are shown in Table 3. Three patients had a highly significant correlation between serum TSH and GH concentrations. In contrast, in healthy controls no correlation between these two hormones could be demonstrated. In two of 5 patients a significant correlation could be demonstrated between serum TSH and α-subunits concentrations, where an almost 100% concordance was expected when α-subunits are truly co-secreted with TSH. Unfortunately, we have no comparable data in controls subjects. The cross-correlation between TSH and prolactin was significant in all patients. However, two-thirds of healthy controls also showed a significant correlation between these two hormones, with a median correlation coefficient of 0.300, range 0.176–0.360.Fig. 6


Pituitary-hormone secretion by thyrotropinomas.

Roelfsema F, Kok S, Kok P, Pereira AM, Biermasz NR, Smit JW, Frolich M, Keenan DM, Veldhuis JD, Romijn JA - Pituitary (2009)

TSH and GH profiles of 2 patients with a thyrotropinoma. Note the similarity of the patterns of both hormones
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2712623&req=5

Fig6: TSH and GH profiles of 2 patients with a thyrotropinoma. Note the similarity of the patterns of both hormones
Mentions: We also investigated cross-correlations between 24-h TSH concentrations and each of GH, α-subunit and PRL. Profiles of the serum concentrations of GH and TSH in two patients were rather similar, as illustrated in Fig. 6. The cross-correlation outcomes are shown in Table 3. Three patients had a highly significant correlation between serum TSH and GH concentrations. In contrast, in healthy controls no correlation between these two hormones could be demonstrated. In two of 5 patients a significant correlation could be demonstrated between serum TSH and α-subunits concentrations, where an almost 100% concordance was expected when α-subunits are truly co-secreted with TSH. Unfortunately, we have no comparable data in controls subjects. The cross-correlation between TSH and prolactin was significant in all patients. However, two-thirds of healthy controls also showed a significant correlation between these two hormones, with a median correlation coefficient of 0.300, range 0.176–0.360.Fig. 6

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Albinusdreef 2 NL2333ZA, Leiden, The Netherlands. f.roelfsema@lumc.nl

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus