Thyroid Function in Acromegaly Before and After Transsphenoidal Hypophysectomy Followed by Cryoapplication

Lamberg, B.‐A.; Pelkonen, Risto; Aro, Antti; Grahne, Bertel

doi:10.1530/acta.0.0820254

Cited by 40 publications

(16 citation statements)

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“…The mean serum TSH level in the acromegalic patients (0.6 ± 0.4 mU/L) was slightly lower than that in the normal subjects (2.1 ± 0.9 mU/L). However, the peak TSH value in the acromegalic patients (6.8 ±1.1 mU/L) after iv injection of 200 fig TRH was significantly (P < 0.01) lower than that in the normal subjects, consistent with the results of previous studies (9). The patients' serum TG level ranged from 5.0-240 jig/L, with a mean of 51.7 ± 62.7 /*g/L, which was significantly (P < 0.01) higher than that in the normal subjects (12.6 ± 6.4 fig/L).…”

Section: Resultssupporting

confidence: 91%

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Thyroid Volume and Serum Thyroglobulin Levels in Patients with Acromegaly: Correlation with Plasma Insulin-Like Growth Factor I Levels*

Miyakawa

Saji

Tsushima

et al. 1988

The Journal of Clinical Endocrinology & Metabolism

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The pathogenesis of the goiter that is frequently found in patients with acromegaly is not known. Using ultrasonic scanning, we measured thyroid volume in 17 euthyroid patients with acromegaly and examined the relationships among thyroid size, plasma GH and insulin-like growth factor (IGF-I) levels, and serum thyroglobulin (TG) levels. The mean estimated thyroid volume in these 17 patients was 32.8 +/- 15.5 (+/- SD) mL, significantly larger than that in normal subjects (15.4 +/- 3.1 mL), and 64.7% of the patients had multinodular goiter, as identified by ultrasonography. Thyroid volume was positively correlated with plasma GH and IGF-I levels and heel-pad thickness, but not with the serum TSH level. In 7 patients, thyroid volume decreased in association with a decline in plasma GH and IGF-I levels after surgical treatment. The serum TG level was elevated in 7 of the 15 patients in whom it was measured, and the mean value was 51.7 +/- 62.7 (+/- SD) micrograms/L (normal, 12.6 +/- 6.4 micrograms/L). We found no correlations among the serum TG and TSH levels, plasma GH and IGF-I concentrations, and/or thyroid volume. However, serum TG decreased after surgical treatment, just as did plasma IGF-I. These observations together with the results of recent in vitro studies by others suggest that IGF-I is one of the factors involved in goiter formation, but the elevated serum TG levels in acromegaly are controlled not only by IGF-I but also by other factors.

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Section: Resultssupporting

confidence: 91%

“…From 25-53% of acromegalic patients have thyroid enlargement (9,13). To our knowledge, however, there have been no reports on ultrasonographic measurement of thyroid volume in such patients.…”

Section: Discussionmentioning

confidence: 99%

Thyroid Volume and Serum Thyroglobulin Levels in Patients with Acromegaly: Correlation with Plasma Insulin-Like Growth Factor I Levels*

Miyakawa

Saji

Tsushima

et al. 1988

The Journal of Clinical Endocrinology & Metabolism

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“…This seems to be the case. In fact, even though reduced basal and TRH-stimulated TSH levels were recorded in acromegaly [23][24][25], no definitive demonstration of the postulated chronic suppression of TRH neurons by a compensatory hypersecretion of SS [26] has been re ported. On the contrary, the analysis of TSH pulsatility by cluster algorhithm showed a circadian pattern similar to that recorded in normal subjects [27], It is well known that GH stimulates the deiodination of T4 into T3 [28,29] and that T3 exerts a negative feedback on TSH secretion at the pituitary level.…”

Section: Discussionmentioning

confidence: 99%

Serum Thyrotropin Response to Combined Arginine and Thyrotropin-Releasing Hormone Administration Provides Evidence for an Altered Somatostatinergic Tone in Acromegaly

Merola

Colao²,

Cataldi³

et al. 1992

Horm Res

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The aim of this study was to evaluate plasma thyrotropin (TSH), prolactin (PRL) and growth hormone (GH) responses to the TSH-releasing hormone (TRH) test and to a combined arginine-TRH test (ATT-TRH) in 10 normal subjects and in 15 acromegalic patients. In controls, TSH responsiveness to TRH was enhanced by ATT (p < 0.001). When considering the 15 acromegalic patients as a whole, no significant difference in TSH responses was detected during the two tests. However, patients without suppression of plasma GH levels after oral glucose load showed an increased TSH responsiveness to the ATT-TRH test if compared to TRH alone (p < 0.025), while patients with partial suppression of plasma GH levels after glucose ingestion showed a decreased TSH responsiveness to ATT-TRH (p < 0.05). No difference was recorded in PRL and GH responses, evaluated as area under the curve, during TRH or ATT-TRH tests in controls and in acromegalics. In conclusion, (1) normal subjects have an enhanced TSH response to the ATT-TRH test and (2) acromegalic patients without suppression of GH levels after oral glucose load show a TSH responsiveness to the ATT-TRH test similar to that of controls, while acromegalics with partial GH suppression after oral glucose load have a decreased TSH responsiveness to the ATT-TRH test. These data suggest that acromegaly is a heterogeneous disease as far as the somatostatinergic tone is concerned.

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“…Second, depressed activity of cholinergic neurotransmission secondary to GH excess may facili tate hypothalamic SRIH release. This fact may be linked with the subnormal TSH responses to TRH that fre quently occur in euthyroid acromegalic patients [25], Third. SRIH availability within somatotroph tumors, however, might be limited due to alterations in its micro vascularization [26] or because a relatively insufficient SRIH concentration could exist in proportion to the ade noma cell mass.…”

Section: Discussionmentioning

confidence: 99%

Effects of Pirenzepine, Bromocriptine and Their Association on Basal and GHRH- and TRH-Induced GH Secretion in Acromegaly

Fiszlejder

Penacini²,

Ratz³

et al. 1991

Horm Res

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In order to ascertain if pirenzepine (Pz), an antimuscarinic drug, could inhibit GH secretion in acromegaly, 8 patients were submitted to 3 successive treatment courses of 9 days each: Pz, bromocriptine (BRC) and Pz plus BRC. No change in basal levels of GH after Pz administration was seen, but its reduction (p < 0.05) by BRC was observed. Pz plus BRC did not improve this response. None of these drugs abolished the paradoxical GH response to TRH. In 7 normal controls, Pz suppressed the GH responsiveness to GHRH (p < 0.001), but not in acromegalic patients. BRC, instead, blunted this response. In conclusion, cholinergic control of GH secretion is altered in acromegaly. Pz, either when administered alone or associated with BRC, is not useful for the treatment of this disease.

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Thyroid Function in Acromegaly Before and After Transsphenoidal Hypophysectomy Followed by Cryoapplication

Cited by 40 publications

References 0 publications

Thyroid Volume and Serum Thyroglobulin Levels in Patients with Acromegaly: Correlation with Plasma Insulin-Like Growth Factor I Levels*

Thyroid Volume and Serum Thyroglobulin Levels in Patients with Acromegaly: Correlation with Plasma Insulin-Like Growth Factor I Levels*

Serum Thyrotropin Response to Combined Arginine and Thyrotropin-Releasing Hormone Administration Provides Evidence for an Altered Somatostatinergic Tone in Acromegaly

Effects of Pirenzepine, Bromocriptine and Their Association on Basal and GHRH- and TRH-Induced GH Secretion in Acromegaly

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