Increase in Plasma Growth Hormone Levels Following Thyrotropin-Releasing Hormone Injection in Children with Primary Hypothyroidism

Collu, R.; Leboeuf, G; Letarte, Jacques; Ducharme, J R

doi:10.1210/jcem-44-4-743

Cited by 65 publications

(26 citation statements)

References 25 publications

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“…The normal plasma TSH concentration after 1 month of age is less than 6 pU/ml, and the normal TSH response to TRH is at least twice the basal concentration, but not exceeding 35 pU/ ml [in agreement with previous reports (1 I)]. An abnormal ("paradoxical") plasma GH elevation after TRH injection was defined as at least twice the basal concentration (and above 5 ng/ml) as reported previously (3).…”

Section: Methodssupporting

confidence: 86%

“…Two examples of these alterations are the increased PRL response to TRH (1,2) and the stimulation of GH secretion by TRH in hypothyroid children (3) and adults (4); these responses do not occur in normal subjects (5). It has been shown that many children suffering from congenital hypothyroidism manifest high serum TSH concentrations for prolonged periods despite adequate replacement therapy, clinical euthyrodism, and normal serum levels of thyroid hormones (7)(8)(9)(10).…”

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confidence: 99%

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Thyroid-Stimulating Hormone, Prolactin, and Growth Hormone Response to Thyrotropin-Releasing Hormone in Treated Children with Congenital Hypothyroidism

et al. 1985

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ABSTRACT. The purpose of the present study was to assess thyroid-stimulating hormone (TSH), prolactin, and growth hormone responses to TRH stimulation in 12 congenitally hypothyroid children adequately treated with Lthyroxine from the first weeks of life. Although clinically euthyroid, six of these children were found to have abnormally high basal serum TSH concentrations despite clinical euthyroidism. Serum triiodothyroxine and L-thyroxine concentrations were normal and did not differ whether the children had elevated or normal basal serum TSH. All six of the children with high basal TSH had an exaggerated TSH response to TRH and 4 of them also had an augmented prolactin response to TRH. The children with normal basal TSH concentrations had normal TSH and prolactin responses to TRH. An abnormal ("paradoxical") elevation of growth hormone concentration in response to TRH was found in four of seven children in a separate group of patients who had prolonged, untreated primary hypothyroidism, but such responses were not found in any of the adequately treated children. These findings suggest the following conclusions: 1) the phenomenon of high serum concentrations of TSH ip conjunction with normal L-thyroxine and triiodothyronine levels (and clinical euthyroidism), is prevalent in congenital hypothyroid patients. 2) These patients have an exaggerated response of their pituitary thyrotroph and lactotroph cells to TRH, presumably caused by selective and relative resistance of these cells to the inhibitory effects of thyroid hormones. 3) Congenital hypothyroidism is not associated with abnormal somatotroph cell responses to TRH. (Pediatr Res 19: 1037-1039,1985 Abbreviations GH, growth hormone PRL, prolactin T3, triiodothyronine T4, L-thyroxine TRH, thyrotropin releasing hormone TSH, thyroid stimulating hormone CH, congenital hypothyroidism tary regulation are well known in hypothyroid patients. Two examples of these alterations are the increased PRL response to TRH (1, 2) and the stimulation of GH secretion by TRH in hypothyroid children (3) and adults (4); these responses do not occur in normal subjects (5). It has been shown that many children suffering from congenital hypothyroidism manifest high serum TSH concentrations for prolonged periods despite adequate replacement therapy, clinical euthyrodism, and normal serum levels of thyroid hormones (7-10). It was suggested that this is due to an elevated threshold for thyrotroph cell TSH suppression by thyroid hormones. The purpose of the present study was to examine both the pituitary-thyroid negative feedback relationship and lactotroph and somatotroph regulation in children with congenital hypothyroidism. MATERIALS AND METHODSTRH tests were performed in 19 children. Group A consisted of 12 congenitally hypothyroid patients aged 1.6 to 9.3 yr attending our clinic for congenital hypothyroidism. All were diagnosed by neonatal thyroid screening during the first weeks of life, and all were treated from the time of diagnosis with T4 and followed by one of us (J.S.). Serum...

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Section: Methodssupporting

confidence: 86%

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confidence: 99%

Thyroid-Stimulating Hormone, Prolactin, and Growth Hormone Response to Thyrotropin-Releasing Hormone in Treated Children with Congenital Hypothyroidism

et al. 1985

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“…Some investigators ascribed this paradoxical response to the presence of adenomatous tissue, with de-differentation and the appearance of specific receptors for TRH. 1 On the other hand, a GH response to TRH has been illustrated in other pathological conditions, 2 including renal failure, 3 depression, 4 anorexia nervosa, 5 primary hypothyroidism, 6 insulin-dependent diabetes mellitus, 7 schizophrenia, 8 and aging. 9 This GH response to TRH, absent in normal subjects, 10 is of diagnostic importance in acromegaly: as suggested in our previous study, 11 an increased "somatostatinergic" tone is conceivable in diseases with increased GH levels.…”

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confidence: 99%

Preoperative growth hormone response to thyrotropin-releasing hormone and oral glucose tolerance test in acromegaly: A retrospective evaluation of 50 patients

et al. 2002

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The objective of this study was to investigate the relationship between growth hormone (GH) dynamic tests (thyrotropin- basal IGF-I plasma levels after an overnight fast. From 3 to 12 months after surgery we evaluated (1) GH plasma values after an OGTT, and (2) basal plasma IGF-I, free triiodothyronine (FT 3 ), free thyroxine (FT 4 ), thyroid-stimulating hormone (TSH), and urinary free cortisol. The same tests were performed every year for 5 years. All of the patients were classified into 4 subgroups according to the system of Hardy and Vezina. Preoperatively, "controlled" patients (n ‫؍‬ 29) had a GH paradoxical response to TRH (n ‫؍‬ 28) and an unresponsiveness to OGTT (n ‫؍‬ 29); 23 of them belonged to the I and II classes. Only 5 poorly controlled patients (n ‫؍‬ 21) showed a preoperative paradoxical response to TRH and 9 had a preoperative GH partial inhibition after OGTT; 19 of them belonged to the III and IV classes. Our data suggest that in the preoperative period in acromegalic patients the simultaneous presence of a GH paradoxical response to TRH and lack of GH inhibition after OGTT is inversely related to the tumor size and therefore more likely to be restored to normal by surgical treatment.releasing

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“…However, abnormal GH responses to TRH have also been reported in patients with hypothyroidism (35), anorexia nervosa (36), diabetes mellitus (37), liver cirrhosis (38) and status epilepticus (39). Investigations of these conditions suggest that the paradoxical GH reaction to TRH may be a functional consequence of several pathological states characterized by altered somatostatin control of GH secretion.…”

Section: Discussionmentioning

confidence: 99%

Effects of acute infusion of erythropoietin on paradoxical responses of growth hormone to thyrotropin-releasing hormone in acromegalic patients

Iglesias²,

Sastre³

et al. 2000

European Journal of Endocrinology

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Objective: Our aim has been to evaluate the effects of i.v. infusion of recombinant human erythropoietin (rhEPO) on the responses of growth hormone (GH), prolactin (PRL) and thyrotropin (TSH) to thyrotropin-releasing hormone (TRH) stimulation in acromegalic patients. Methods: We studied 16 patients (8 females, aged 29±68 years) with active acromegaly and 12 control subjects (7 females, 24±65 years). All participants were tested with TRH (400 mg i.v. as bolus) and with TRH plus rhEPO (40 U/kg at a constant infusion rate for 30 min, starting 15 min before TRH injection) on different days. Blood samples were obtained between À30 and 120 min for GH and PRL determinations, and between À30 and 90 min for TSH determinations. Hormone responses were studied by a time-averaged (area under the secretory curve (AUC)) and time-independent (peak values) analysis. Results: Twelve patients exhibited a paradoxical GH reaction after TRH administration with great interindividual variability in GH levels. When patients were stimulated with rhEPO plus TRH there were no changes in the variability of GH responses or in the peak and AUC for GH secretion. Infusion with rhEPO did not induce any signi®cant change in GH secretion in normal subjects. Baseline and TRH-stimulated PRL concentrations in patients did not differ from those values found in controls. When TRH was injected during the rhEPO infusion, a signi®cant (P < 0.05) increase in PRL concentrations at 15±120 min was found in acromegalic patients. Accordingly, the PRL peak and the AUC for PRL secretion were signi®cantly increased in patients. Infusion with rhEPO had no effect on TRH-induced PRL release in control subjects. Baseline TSH concentrations, as well as the TSH peak and the AUC after TRH, were signi®cantly lower in patients than in controls. Infusion with rhEPO modi®ed neither the peak TSH reached nor the AUC for TSH secretion after TRH injection in acromegalic patients and in healthy volunteers. Conclusion: Results in patients with acromegaly suggest that (i) the paradoxical GH response to TRH is not modi®ed by rhEPO infusion, (ii) rhEPO has no effect on TRH-induced TSH release, and (iii) acute rhEPO administration increases the TRH-induced PRL release in acromegalic patients.

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Increase in Plasma Growth Hormone Levels Following Thyrotropin-Releasing Hormone Injection in Children with Primary Hypothyroidism

Cited by 65 publications

References 25 publications

Thyroid-Stimulating Hormone, Prolactin, and Growth Hormone Response to Thyrotropin-Releasing Hormone in Treated Children with Congenital Hypothyroidism

Thyroid-Stimulating Hormone, Prolactin, and Growth Hormone Response to Thyrotropin-Releasing Hormone in Treated Children with Congenital Hypothyroidism

Preoperative growth hormone response to thyrotropin-releasing hormone and oral glucose tolerance test in acromegaly: A retrospective evaluation of 50 patients

Effects of acute infusion of erythropoietin on paradoxical responses of growth hormone to thyrotropin-releasing hormone in acromegalic patients

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