The effect of dexamethasone on TSH and prolactin secretion after TRH stimulation

Serum thyrotropin (TSH) and prolactin levels were measured after intravenous administration of 400 μg of synthetic thyrotropin-releasing hormone (TRH) in 13 normal subjects and six hypothyroid patients before and after three days of administration of dexamethasone 2 mg per day. In the normal subjects dexamethasone suppressed baseline serum levels and secretion of TSH after TRH stimulation. On the other hand, it had no effect on the hypothyroid patients. In the control group dexamethasone also suppressed baseline serum levels but not secretion of prolactin after TRH stimulation. Dexamethasone had no effect on prolactin levels in the hypothyroid group. It is concluded that in normal patients short-term administration of dexamethasone has an inhibitory effect on TSH secretion at the pituitary level. As for prolactin, our results could indicate that TRH is a more potent stimulator of prolactin secretion than of TSH secretion, or that TSH and prolactin pituitary thresholds for TRH are different.     

Pituitary hormone reserve in the Laurence-Moon-Bardet-Biedl syndrome

A patient who presented with hypgonadism was found to have classical features of the Laurence-Moon-Bardet-Syndrome. He had oligospermia and low serum testosterone. Basal serum thyroid stimulating hormone (TSH), prolactin (PRL), growth hormone (GH), cortisol, luteinising hormone (LH) and follicle stimulating hormone (FSH) were normal. Stimulation with thyrotropin releasing hormone. (TRH) showed normal pituitary reserve for TSH and PRL. Adequate insulin hypoglycaemia caused a normal rise of GH and cortisol. LH and FSH showed normal peaks after luteinishing hormone releasing hormone (LHRH). These results indicate normal pituitary hormone reserve and hypogonadotrophic hypgonadism secondary to hypothalamic dysfunction.     

Growth hormone, prolactin and thyrotrophin responses to thyrotrophin-releasing hormone in diabetic patients.

Growth hormone (GH), prolactin (PRL) and thyrotrophin (TSH) responses to thyrotrophin-releasing hormone (TRH) were studied in 15 insulin-dependent diabetic patients. Basal plasma GH levels were raised above 5 mu./l in 6 patients and following the injection of TRH there was a significant rise in plasma GH levels in 9. The mean rise in plasma GH from basal to peak values was significant in the group as a whole (P < 0.01). Basal PRL and TSH levels were normal and rose normally in response to TRH. GH release may be qualitatively abnormal in some diabetics and any such loss of specificity of GH-releasing mechanisms would further contribute to the raised GH levels found in many diabetics which would be of importance if GH is a factor in the aetiology of diabetic microangiopathy.     

Thyroid failure and protirelin (thyrotropin-releasing hormone) test abnormalities in depressed outpatients

Forty-four consecutive outpatients referred to a psychiatric hospital for evaluation of depression and anergia were assessed by means of the protirelin (thyrotropin-releasing hormone) test. Nineteen patients (43%) had a blunted thyrotropin (TSH) response to protirelin, while six patients (13.5%) had augmented TSH responses indicating some degree of hypothyroidism. One patient had a low thyroxine level, while three patients had elevated basal TSH levels. Five of the six patients with augmented TSH responses were found to have antithyroid antibodies. These results suggest that a majority of depressed outpatients have abnormalities on the protirelin test and that the TSH response to protirelin is useful in both confirming a diagnosis of major depression and assessing thyroid status.     

Graves' ophthalmopathy and subclinical hypothyroidism: diagnostic value of the thyrotropin releasing hormone test.

Five patients with Graves' ophthalmopathy and no previously documented clinical or laboratory evidence of hyperthyroidism were studied. Their serum levels of thyroxine and triiodothyronine (T3) and their T3 uptake were normal. Although the baseline serum level of thyrotropin (TSH) was normal in two patients, it was increased on the other three, and when TSH releasing hormone (TRH) was administered the T3 response was impaired in three patients and the TSH response was exaggerated in all five. These findings facilitated the diagnosis of subclinical hypothyroidism and distinguished the patients from those with Graves' ophthalmopathy and normal thyroid function or subclinical hyperthyroidism. Thyroid antibodies were detected in the serum of four of the five patients, suggesting the coexistence of chronic autoimmune thyroiditis; this disorder could account in part for the subclinical hypothyroidism, which was even present in the two patients in whom thyroid-stimulating immunoglobulin was found in the serum. These observations indicate the value of a TRH stimulation test in detecting subclinical hypothyroidism in patients with Graves' ophthalmopathy who appear from clinical and routine laboratory studies to have normal thyroid function but could have normal function or subclinical hyperthyroidism.     

甲亢、甲减病人血清PRL和GH对TRH试验的反应

观察了甲亢病人(n=7),甲减病人(n=14)血清GH,PRL对TRH试验的反应。结果显示:1.甲亢、甲减及正常对照三组间血清GH基础值无明显差异;甲亢组及正常对照组血清GH对TRH均无明显反应,但甲减组中二个病人血清GH对TRH有明显反应。2.甲亢病人血清PRL对TRH的反应减弱,甲减病人血清PRL对TRH的反应增强。     

Beta-adrenoceptor-blocking drugs, growth hormone and acromegaly.

Chronic treatment with oxprenolol or propranolol in active hypertensive patients was associated with elevation of serum growth hormone (GH). Propranolol, 80 mg orally, caused a marked rise in GH in 3 of 4 acromegalic patients.     

Office screening of pituitary reserve

Deficiency of the anterior lobe of the pituitary due to disease in the pituitary-hypothalamic area may involve any or all pituitary hormones to varying degrees but, usually, growth hormone (GH) and gonadotropins (FSH and LH) are more commonly affected than thyrotropin (TSH), corticotropin (ACTH) and prolactin. Of these 6 hormones TSH and ACTH are of life sustaining importance.     

癌症患者腺垂体激素分泌功能的变化研究

目的 研究癌症患者腺垂体激素分泌功能的变化。方法 用放射免疫法[fj-2008ps1]测定171例癌症患者与46例正常对照组的泌乳素(PRL)，生长激素(GH)，促卵泡生成激素(FSH)，促黄体生成激素(LH)和促甲状腺激素(TSH)的血清水平。结果 癌症患者组与正常对照组比较患者血清PRLGH，LH和FSH均增高，但TSH无显著差异；肿瘤转移组与非转移组比较则无显著差别；不同脏器恶性肿瘤间垂体激素水平也无显著差异。结论 癌症患者腺垂体激素分泌功能亢进，除TSH水平变化不显著外，其他4种垂体激素水平皆升高显著，这有助于我们了解癌症患者的机体变化。     

Growth hormone responses to hp GRF 1-44 amide, bromocriptine and stress in acromegaly are correlated

The results of testing growth hormone (GH) reserve using human pancreatic growth hormone-releasing factor 1-44 amide (hp GRF 1-44 amide) have been compared with the GH responses in a variety of other dynamic tests in seven acromegalic patients. The GH release following hp GRF 1-44 amide correlated with the GH suppression following bromocriptine, but showed an inverse correlation with the GH release following stress tests (insulin-induced hypoglycaemia/glucagon). There was no correlation between the GH responses in these three tests and any of the other tests: TRH, GnRH and glucose. A hypothesis is proposed to explain these findings on the basis of varying degrees of GH secretion from adenomatous and normal pituitary somatotrophs in acromegaly.     

PRE- AND POST-OPERATIVE HYPOTHALAMIC-PITUITARY- THYROIDAL AXIS FUNCTION IN PATIENTS WITH PROLACTINOMA, GROWTH HORMONE TUMOUR AND ACTH TUMOUR

Pre- and postoperative hypothalamic-pituitary-thyroid axis function was studied in 38 patients with pituitary adenomas (PRL, GH and ACTH tumours), of whom 35 were surgically confirmed and three diagnosed by clinical signs, CT scanning and hormone assessments. About ten days after operation, the same study was repeated in 10 patients with prolactinoma and 7 with growth hormone (GH) tumour. The preoperative abnormal serum TSH response to TRH was found in 8/20 patients with prolactinoma, 9/16 with GH tumour, and 2/2 with Cushing's disease due to ACTH microadenoma. The incidence of abnormal TSH response to TRH was not significantly increased in patients with larger adenoma in either PRL or GH tumour group. In 8 cases of prolactinoma, metoclopramide (MCP, 10 mg, P.O.) test was also performed and there was a significant positive correlation between TSH responses to TRH and to MCP. Serum TT3 in the GH tumour group was within normal ranges, but significantly higher than that of the normal and prolactinoma groups. After operation, TT3 was significantly decreased as compared with that before operation and there were marked changes in TSH response to TRH. In conclusion, there were some abnormalities in TSH control in patients with non-TSH pituitary tumour, and in serum TT3 control in patients with GH tumour. The surgical treatment of pituitary adenoma can lead to transient decrease in TSH reserve and serum TT3 level probably resulting from both stress and/or destruction of thyro-trophs by the operation.     

Isolated thyrotropin deficiency due to a pituitary tumour.

Hypothyroidism due to isolated deficiency of thyrotropin (TSH) associated with an enlarged sella turcica, presumably the result of a nonfunctioning pituitary adenoma, occurred in a 58-year-old man. Low serum concentrations of TSH and thyroid hormones, together with the lack of TSH response to administration of thyroid releasing hormone, indicated a pituitary deficiency of TSH. Serum values of other pituitary hormones were normal.     

Galanin协同生长释放素（GHRH）促进生长激素（GH）的释放

Galanin是新发现的促进GH释放的下丘脑激素。已知给正常人反复注射GHRH会导致GH释放的减低。我们研究了6例正常人对重复注射GHRH同时滴注galanin的GH反应。结果表明重复注射GHRH后GH释放明显减低,但在重复注射同时合用galanin则GH释放显著增强。galanin和GHRH联合应用克服了因重复注射GHRH所致的GH反应降低。其机理可能是gatanin抑制下丘脑SRIH的分泌之故。     

Glucagon-initiated human growth hormone release: a comparative study

Human growth hormone (HGH) responses in 20 healthy adults to subcutaneous glucagon, arginine infusion and tolbutamide and insulin hypoglycemia were compared. HGH rose in all four tests. HGH response to glucagon was also studied in 49 patients with suspected pituitary insufficiency, of whom 25 also later received an arginine infusion; an abnormal response to glucagon was the most frequent functional abnormality and often HGH was the only anterior pituitary hormone of which a deficiency was detectable. In seven subjects (two healthy controls and five patients with suspected hypopituitarism) there was a subnormal HGH response to arginine but a normal response to glucagon. It is concluded that glucagon is a simple and effective stimulus to HGH release, equal or superior to arginine, tolbutamide and insulin, and is an important test of anterior pituitary function.     

Recovery of hypothalamic-pituitary-adrenal function after intermittent high-dose prednisolone and cytotoxic chemotherapy

Hypothalamic/pituitary and adrenal (HPA) function was assessed in ten patients who received intermittent high-dose prednisolone and cytotoxic chemotherapy for 5-40 months. Standard insulin hypoglycaemia (IHT), thyrotrophin-releasing hormone and tetracosactrin tests were performed 36 hr after the last dose of prednisolone and subsequently 10 days--52 weeks after completion of all chemotherapy. In the first tests there was evidence of impaired hypothalamic-pituitary function judged by peak adrenocorticotrophic hormone (ACTH), growth hormone (GH) and thyrotrophin (TSH) responses, and corresponding plasma corticosteroid responses were sub-normal in five patients. In the final IHTs, seven patients had persistently subnormal ACTH responses but all the corresponding plasma corticosteroid responses returned to normal. Mean peak corticosteroid responses to insulin and tetracosactrin and peak GH responses were significantly greater than in the first tests. Such chemotherapy regimens may have prolonged effects on hypothalamic/pituitary function but the demonstration of normal corticosteroid responses to hypoglycaemia and tetracosactrin indicates that these patients' stress responses will be normal as early as 10 days after treatment is stopped.     

多囊卵巢综合征患者促甲状腺激素浓度与血脂关系的研究

目的研究不同浓度血清促甲状腺激素（thyroid-stimulating hormone,TSH）的多囊卵巢综合征（polycystic ovary syndrome,PCOS）患者临床特征及内分泌代谢指标之间的差异。方法选择110例多囊卵巢综合征患者,测量身高、体质量、腰围、臀围;应用化学发光法分析测定血清TSH、总胆固醇（total cholesterol,TC）、低密度脂蛋白胆固醇（low-density lipoprotein cholesterol,LDL-C）、高密度脂蛋白胆固醇（high-density lipoprotein cholesterol,HDL-C）、三酰甘油（triglycerides,TG）、空腹血糖（fasting blood glucose,FBG）、空腹胰岛素（fasting serum insulin,INS）、卵泡刺激素（follicle stimulating hormone,FSH）、黄体生成素（luteinizing hormone,LH）、睾酮（testosterone,T）、催乳素（prolactin,PRL）、雌二醇（estrogen,E2）;计算体质量指数（body mass index,BMI）、腰臀比（waist hip ratio,WHR）、黄体生成素与卵泡刺激素的比值（LH-to-FSH ratio,LH/FSH）;采用稳态模型评估的胰岛素抵抗指数（homeostasis model assessment insulin resistance,HOMA-IR）,按血清TSH浓度将其分为2组：A组71例,TSH0.05）。结论 TSH与脂代谢指标有相关性,TSH≥2.5 mIu/L的PCOS患者,脂代谢发生了显著的变化。     

Dopamine in the pituitary adaptation to starvation in man

To investigate the role of the dopaminergic system in the pituitary adaptation to energy deprivation, the effect of metoclopramide, a dopamine receptor blocker, on prolactin (PRL), TSH, FSH and LH secretion was investigated in 6 healthy men in the fed state and at 36 h starvation. All underwent a further 36 h of starvation on a separate occasion to assess the effect of starvation on the TSH and PRL responses to TRH and the LH and FSH responses to gonadotrophin releasing hormone (GnRH). In all subjects starvation produced the expected reduction in serum T3 and an average decrease of 53% in the cumulative TSH response to TRH. The basal serum PRL and its response to TRH and metoclopramide remained unchanged with 36 h starvation. The FSH response to GnRH also remained unchanged, but the LH response was significantly greater during starvation. We conclude that factor(s) other than dopamine influence not only thyrotrophic activity but also other aspects of pituitary function during energy deprivation.     

Bromocriptine therapy in acromegaly. A long-term review of 35 cases.

Bromocriptine (CB-154, Parlodel, Sandoz) was given to 35 acromegalic patients for a period of 6-36 months. Basal and post-therapy endocrine functions including estimation of serum growth hormone (GH) profile; and GH kinetics during oral glucose tolerance test, augmented insulin tolerance test and thyrotrophin releasing hormone test were determined. The pituitary tumour size was delineated by a pneumoencephalogram. The mean GH levels ranged from 14 micrograms/l to 316 micrograms/l. Bromocriptine suppressed GH values to 5 micrograms/l or less in 16 patients and less than 10 micrograms/l in a further 6 patients. In 33 patients GH values fell to 50% of the basal value or less. There was no significant GH reduction in 2 ''nonresponders''. Bromocriptine did not block the stress-induced GH secretion. It did not disturb pituitary functions other than prolactin which was suppressed much earlier and was maintained with smaller doses. GH suppression on the other hand was shortlived and rebounded when the drug was omitted. It had no adverse effect on tumour size in 2 patients having suprasellar extension of the tumour. Bromocriptine improved carbohydrate tolerance and sexual function although it did not affect insulin and gonadotrophin values. It seems reasonable to offer a trial of bromocriptine in all patients with acromegaly where therapy is deemed necessary as it is well tolerated, has insignificant side effects and no adverse drug interactions. Its high cost and prolonged course are obvious disadvantages. Caution should be exercised in cases with suprasellar extension and visual field involvement.     

Serum ghrelin and leptin levels in adult growth hormone deficiency syndrome

BACKGROUND: In spite of the increasing information that has recently been accumulated on the involvement of ghrelin and leptin in the control of energy balance, the relationship between ghrelin and leptin and the growth hormone (GH)-insulin-like growth factor 1 (IGF-1) axis in the pathological condition characterized by GH deficiency has been poorly clarified. Therefore, we performed this study to examine the correlation of the plasma levels of ghrelin and leptin with the anthropometric and biochemical markers in GH-deficient (GHD) adults as compared to their healthy cohorts. METHODS: In 60 male adults (GHD; n = 12, healthy control; n = 48, average age: 54 years), we investigated the correlations between the serum leptin and ghrelin levels with the anthropometric and biochemical factors in the control group, as compared to the GHD patients. The diagnosis of GH deficiency was made when peak response for serum GH was <5 microg/L to a GH-provocative test (L-dopa test). All subjects underwent assessment of waist circumference, body mass index (BMI) and percentage body fat for their body composition. Plasma ghrelin, leptin, insulin, GH and IGF-1 were measured. RESULTS: Groups were matched for age, BMI, waist circumference and percent of body fat. Ghrelin and leptin levels were not significantly different between the two groups. There was no correlation between the peak GH level or the GHAUC and the ghrelin concentrations in the GHD subjects. Plasma leptin correlated positively with percentage of body fat, total cholesterol and LDL-cholesterol, but it had no correlation with the peak GH or area under the curve for growth hormone (GHAUC) in the GHD subjects. Plasma ghrelin concentrations were not correlated with the biochemical and anthropometric markers in the subjects with GHD, and ghrelin showed no significant differences in the GHD and control subjects. Leptin concentrations were positively correlated with body fat, but they were not correlated with the levels of either IGF-1 or GH in the GHD patients. CONCLUSIONS: It is possible that ghrelin concentrations appeared normal in the GHD subjects because of the opposing influences of increased adiposity, which reduce ghrelin secretion, and GHD, which may increase it. Further studies are needed to clarify these controversies about the relation of ghrelin and leptin with the GH and IGF-1 levels.     

Diagnostic value of thyrotrophin releasing hormone tests in elderly patients with atrial fibrillation

A prospective study was carried out to compare clinical and biochemical thyroid states with responses of thyroid stimulating hormone (TSH) to thyrotrophin releasing hormone (TRH) in elderly patients with either atrial fibrillation (n = 75; mean age (SD) 79.3 (6.0) years) or sinus rhythm (n = 73; mean age 78.4 (5.6) years) admitted consecutively to the department of geriatric medicine. No patient in either group had symptoms or signs of hyperthyroidism. Overall, the TSH responses to TRH did not differ significantly between the two groups. Ten (13%) of the patients with atrial fibrillation (of whom four had raised thyroid hormone concentrations) and five (7%) of the patients with sinus rhythm showed no TSH response to TRH while 26% of each group (20 and 19 patients, respectively) showed a much reduced response. Only one of 13 patients with apparently isolated atrial fibrillation showed no TSH response to TRH, and none of these 13 patients was hyperthyroid. In particular, three patients (two with atrial fibrillation and one with sinus rhythm) who showed no TSH response to TRH at presentation exhibited a return of TSH response to TRH at follow up six weeks later. In conclusion, reduced or absent TSH responses to TRH are common in sick elderly patients whether they have atrial fibrillation or sinus rhythm and whether they are euthyroid or hyperthyroid biochemically. An absence of response is therefore an uncertain marker of hyperthyroidism in these groups of patients, and diagnosis and ablative treatment should be based at least on the presence of raised circulating free triiodothyronine or free thyroxine concentrations, or both.