Thyrotropic-stimulating Hormone Research Articles

Iodine Nutritional Status of Pregnant Women After 14 Years of Lipiodol Supplementation: a Cross-Sectional Study in Historically Iodine-Deficient Areas of China.

Southern Xinjiang has a history of serious iodine deficiency. Since 2007, pregnant women in this area have taken iodized salt and oral lipiodol preparations to prevent iodine deficiency disorders. However, the current status of iodine nutrition and thyroid function in this population is unknown. A cross-sectional study was conducted on 555 pregnant women from 5 counties (cities) in southern Xinjiang and 429 pregnant women from 3 counties in northern Xinjiang. The participants were given a questionnaire and serum concentrations of free triiodothyronine (FT3), free thyroxine (FT4), thyrotropic stimulating hormone (TSH), thyroglobulin antibody (Tg-Ab), and thyroid peroxidase antibody (TPO-Ab), and the urine iodine concentration (UIC) was measured. The median UIC and interquartile range [M (IQR)] of the 984 pregnant women in the study was 189.38 (143.15, 288.77) μg/L. Positive Tg-Ab and TPO-Ab titers were detected in 6.74% and 9.55%, 8.30% and 9.84%, and 7.39% and 10.55% in T1, T2, and T3, respectively. The incidence of subclinical hypothyroidism, clinical hypothyroidism, and isolated hypothyroxinemia in pregnant women in areas where lipiodol pills were taken was 4.32%, 0%, and 1.44%, respectively, which was significantly lower than those in areas where lipiodol pills were not taken. The median UIC (IQR) of pregnant women in the two regions was 213.80 (130.44, 331.77) μg/L and 168.30 (155.0, 254.8) μg/L, the UIC of pregnant women who took lipiodol pills was higher than in those who did not take lipiodol pills, and the difference was statistically significant (p < 0.05). According to WHO standards, all pregnant women in southern Xinjiang are in a state of adequate iodine nutrition. Taking lipiodol pills has improved the iodine nutrition level of pregnant women in this area. The results of this study did not find that oral lipiodol pills had adverse effects on pregnant women's thyroid function, but it is necessary to further study the effect of oral lipiodol pills on the offspring.

Preoperative oral thyroid hormones to prevent euthyroid sick syndrome and attenuate myocardial ischemia-reperfusion injury after cardiac surgery with cardiopulmonary bypass in children: A randomized, double-blind, placebo-controlled trial.

Background:Both euthyroid sick syndrome and myocardial ischemia-reperfusion injury are common and have been significantly associated with morbidity and mortality after pediatric cardiac surgery with cardiopulmonary bypass. This single-center, prospective, double-blind, randomized placebo-controlled clinical pilot trial was designed to assess if preoperative oral thyroid hormone therapy could prevent the occurrence of euthyroid sick syndrome (ESS) and attenuate myocardial ischemia-reperfusion injury (IRI) after cardiac surgery with cardiopulmonary bypass (CPB) in children.Methods:Forty children aged 3 to 12 year, scheduled for elective congenital heart disease repair surgery with CPB, were randomized into 2 groups of equal size to receive the following treatments in a double-blind manner: placebo (control group) and thyroid tablet 0.4 mg/kg (trial group) taken orally once a day for 4 days before surgery. The perioperative serum thyroid hormone levels and hemodynamic variables were determined. The extubation time, duration of intensive care unit (ICU) stay, and use of inotropic drugs in the ICU were recorded. The myocardial expressions of heat shock protein 70 (HSP70), myosin heavy chain (MHC) mRNA, and thyroid hormone receptor (TR) mRNA were detected. The serum creatine kinase-MB (CK-MB) activity and troponin I (TnI) positive ratio at 24 hour after surgery were assessed.Results:There were no significant differences in hemodynamic variables at all observed points, extubation time, and duration of ICU stay between groups. As compared with baselines on administration, serum triiodothyronine (T3) and free T3 (FT3) levels on the first, second, and fourth postoperative day, and serum thyrotropic-stimulating hormone (TSH), tetraiodothyronine (T4), and free T4 (FT4) levels on the first postoperative day were significantly decreased in the 2 groups. Serum T3, FT3, and T4 levels on the first and second postoperative day, and serum FT4 level on the first postoperative day were significantly higher in the trial group than in control group. As compared with the control group, the number of patients requiring inotropic drugs in the ICU, serum CK-MB activity, serum positive TnI ratio, and myocardial expression of MHCβ mRNA were significantly decreased, and myocardial expressions of both HSP70 and MHCα mRNA were significantly increased in the trial group.Conclusions:In children undergoing cardiac surgery with CPB, preoperative oral small-dose thyroid hormone therapy reduces severity of postoperative ESS and provides a protection against myocardial IRI by increasing HSP70 and MHCα expression.

Investigating the relationship between 25-hydroxyvitamin D and thyroid function in second-trimester pregnant women

This study aims to explore the correlation between serum 25-hydroxyvitamin D and thyroid hormones during the second trimester. In total, 277 pregnant women at 13–28 weeks of gestation were enrolled. According to the level of thyrotropic-stimulating hormone, they were divided into a reduced TSH group, a normal TSH group and an elevated TSH group. In this study, we found that the prevalence of vitamin D deficiency was as high as 94.58%. The 25-hydroxyvitamin D level in the reduced TSH group was lower than that in the normal thyroid function group (p = .0005), and the 25-hydroxyvitamin D level in the elevated TSH group was higher than that in normal TSH group (p=.0339). A positive correlation was observed between 25-hydroxyvitamin D and thyrotropic-stimulating hormone (r = 0.3034, p = .0000). Furthermore, 25-hydroxyvitamin D was negatively correlated with the free thyroxine level (r = −0.1286, p = .0323) as well as the free triiodothyronine level (r = 0.1247, p = .0380). These data suggest that the relationships between 25-hydroxyvitamin D and thyroid parameters were characterized during the second trimester. Pregnant women in the second-trimester who are diagnosed with transient hyperthyroidism should be evaluated for the possibility of vitamin D deficiency.

Effect of hypothyroxinemia on the emotion in developing rats

Objective To investigate the effect of hypothyroxinemia on emotion and hippocampus neurons in developing rats.Methods Sixty-nine healthy postnatal day (PD) 1 rats were randomly divided into control group (n =36) and experimental group (n =33).On PD1,experimental group was bilaterally thyroidectomized to establish hypothyroxinemia model,the control group was only given thyroid exposure operation without thyroid resection.On PD10,21,40,serum triiodothyronine (T3),thyroxine (T4),thyrotropicstimulating hormone (TSH) were detected by radioimmunoassay.Tail suspension test,forced swimming test,the elevated-plus maze and open field were respectively employed to detect the anxiety/depression like behavior on PD30,31,32,33.Nisslg staining was used to determine the survival of neurons at PD10,21,40 in hippocampus CA1,CA3,DG regions.Results Serum T4 levels on PD10,21,40 in experimental group decreased significantly as compared with control group (P ＜0.01),while there was no significant difference in serum T3 or TSH level (P ＞ 0.05).In the tail suspension test,immobility time of experimental group [(197.00 ± 19.50) s] was longer than control group [(158.33 ± 32.90) s,P ＜0.05].In the forced swimming test,immobility time of experimental group[(92.11 ± 35.24) s] was longer than control group [(62.00 ± 23.73) s,P ＜ 0.05].In the elevated plus-maze test,total number of arm entries and closed arm entries in experimental group were increased as compared with control group(P ＜ 0.05),percentage of closed arm/total time of experimental group was decreased as compared with control group(P ＜ 0.05).In the open field,there was no obvious difference between the two groups(P ＞ 0.05).On PD10,21,40,the amount of neurons in DG region of experimental group were less than control group(P ＜0.05),while there was no significant difference in CA1 or CA3 on PD10,21,40(P ＞0.05).Contusions Hypothyroxinemia can cause depression,hyperactivity and hippocampus neuron damage of developing rats. Key words: Hypothyroxinemia; Rat; Depression; Anxiety; Emotion; Hippocampus

Thyroid-stimulating hormone decreases insulin receptor substrate 1 expression via stimulating TNF-αsecretion in 3T3-L1 adipocytes

3T3-L1 adipocytes transfected with TSH receptor (TSHR) shRNA were incubated with bovine TSH.The concentration of tumor necrosis factor (TNF)-α in culture medium was measured by enzyme linked immunosorbent asssy.Protein level of insulin receptor substrate 1 (IRS-1) was quantified by Western blotting.Tyrosine phosphorylation of IRS-1 was measured by immunoprecipitation.The results showed that 1 mIU/ml TSH significantly sitmulated TNF-α release in 3T3-L1 adipocytes [(341.85 ± 12.00 vs 522.67 ± 36.22) ng/L,P＜0.01],along with the decreases in IRS-1 protein expression and its tyrosine phosphorylation (P＜ 0.01).These effects disappeared when TSHR expression was down-regulated with RNA interference in 3T3-L1 adipocytes.In addition,WP9QY,a TNF-α antagonist,blocked TSH-decreased IRS-1 expresssion.These results suggest that TSH downregulates IRS-1 protein expression and its tyrosine phosphorylation through stimulating production of TNF-α,and thus contributes to the development of insulin resistance. Key words: Insulin resistance; Thyrotropic-stimulating hormone ; Tumor necrosis factor-alpha; Insulin receptor substrate 1 ; Small hairpin RNA

Relationship of serum thyroid stimulating hormone level with differentiated thyroid cancer

Objective To investigate the association between preoperative serum TSH level and differentiated thyroid cancer (DTC).Methods The relationship between TSH concentration and differentiated thyroid cancer in 400 qualified patients with thyroid nodules was retrospectively analyzed from January 2009 to December2011 in our hospital.Based on the TSH values,the patients were divided into five groups.Results Preoperative serum TSH level in DTC group was higher than that in benign thyroid nodales group [(2.94 ± 1.74 vs1.92 ± 1.45) μ IU/ml,P＜0.01].The risk of DTC increased as serum level of TSH rose in the patients with thyroid nodule.The incidences of DTC were 27.8％,34.0％,40.0％,63.4％,and 70.2％ respectively in groups with TSH＜0.27,0.27-1.44,1.45-2.19,2.20-4.20,and ＞4.20 μIU/ml groups.TSH level in the group with cervical lymph node metastasis was higher than that without metastasis (P＜0.01).Conclusions The likelihood of thyroid cancer increases with increased serum TSH concentration.High TSH level seems to be associated with lymph node metastasis.Preoperative serum TSH level might be a risk predictor for DTC. Key words: Thyroid nodules ; Differentiated thyroid cancer ; Thyrotropic stimulating hormone

Study on the prevalence of thyroid diseases during pregnancy in excess and sufficient water iodine area in Jiangsu Province

Objective To study the prevalence of thyroid disease in pregnant women living in both excess and sufficient water iodine area of in Jiangsu Province,and to establish an epidemiological database of thyroid disorders among pregnant women in different water iodine area in Jiangsu Province in order to guide our clinical practise.Methods Fengxian and Suining of Xuzhou were selected as excess and sufficient water iodine region.All the 439 pregnant women within the first trimester were enrolled in our study.The name,age,and previous history were recorded on questionnaire.The samples of fasting blood were obtained.Serum parameters such as free triiodothyronine ( FT3 ),free thyroxine ( FT4 ),total thyroxine ( TT4 ),thyrotropic stimulating hormone ( TSH ),and thyroid peroxidase (TPOAb) were measured by electrochemiluminescence assay.The data of the eligible 396 subjects were stored and analyzed by Epidata after excluding subjects with previous thyroid dysfuncion,renal disease,heart disease,and pregnancy-induced hypertension syndrome.Results Among the 396 subjects,197 women ( 49.7％ ) had thyroid disorders. The prevalence of hyperthyroidism, subclinical hyperthyroidism, hypothyroidism, subclinical hypothyroidism,hypothyroxinaemia,and thyroid autoimmunity were 0.5％,6.3％,3.3％,29.3％,9.3％,and 1.0％,respectively.The prevalence of subclinical hypothyroidism was significantly higher in excess water iodine region (32.4％) than that in sufficient water iodine area ( 19.6％ ),while the prevalence of other types of thyroid diseases such as subclinical hyperthyroidism,hyperthyroidism,hypothyroidism,hypothyroxinaemia,and TPOAbpositive cases in either excess or sufficient water iodine regions was not different.Conclusions Subclinical hyperthyridism,hypothyroxinaemia,and subclinical hypothyroidism are the main thyroid disorders in pregnant women in both excess and sufficient water iodine area.The prevalence of subclinical hypothyroidism increases obviously in excess water iodine region,indicating the relationship between thyroid disease and high iodine intake. Key words: Pregnancy; Thyroid diseases; Prevalence; Excess iodine region; Sufficient iodine region

Study on the expression of uncoupling protein 2 in the kidney of the rats with hypothyroidism

To observe the change in the expression of uncoupling protein 2 (UCP2) in kidney mitochondria in rats with hypothyroidism, and study the mechanism of renal injury due to hypothyroidism. The Wistar rats were randomly divided into control group (n=10) and hypothyroidism group (n=10). The hypothyroidism rat model was reproduced by low-iodine diet. The intake of iodine in control group and hypothyroidism group were 10.00 μg/d and 1.24 μg/d, respectively. The rats were raised under these conditions respectively for 3 months after they adapted to the feeding for 1 week. Then the thyroid function parameters were measured in blood, and the expressions of UCP2 protein and mRNA in renal tissue were measured by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) methods. The thyrotropic-stimulating hormone (TSH, mU/L) in hypothyroidism group was significantly higher than that in control group (4.88±1.37 vs. 1.65±0.33, P<0.05). The levels of total triiodothyronine (TT(3)), total thyroxine (TT(4)), free triiodothyronine (FT(3)) and free thyroxine (FT(4)) in serum in hypothyroidism group were significantly lower than those in control group [TT(3) (nmol/L) : 0.54±0.07 vs. 0.98±0.17, TT(4) (nmol/L): 7.82±2.18 vs. 48.78±3.65, FT(3) (pmol/L): 2.28±0.22 vs. 2.99±0.10, FT(4) (pmol/L): 11.38±1.74 vs. 29.27±0.95, all P<0.01]. The immunohistochemistry study revealed that the UCP2 protein expression in both renal glomeruli and tubule tissues in the hypothyroidism group was significantly lower than that of control group (renal glomeruli: 0.17±0.02 vs. 0.24±0.04, renal tubule: 0.19±0.02 vs. 0.25±0.02, both P<0.01). The RT-PCR showed that the UCP2 mRNA expression in the hypothyroidism group was significantly lower than that of control group (0.70±0.19 vs. 1.30±0.09, P<0.01). Hypothyroidism may produce damage to kidney, which is related to the down-regulation of UCP2 expression in the mitochondria of renal cells.

Comparison of stress reaction between retroperitoneal laparoscopic nephrectomy and mini-incision open nephrectomy

Objective To compare the degrees of stress reaction both retroperitoneal laparoscopic nephre-ctomy (LN) and mini-incision open nephrectomy (MION). Methods Twenty-four patients with nonfunctioning atrophic kidney who had received nephrectomy in our hospital from January 2004 to November 2008 were analyzed retrospectively and divided into LN group and MION group randomly. Serum thyroxin (T3), thyrotropic-stimulating hormone (TSH), cortisol, glucose., peripheral blood leucocyte and temperature were measured and recorded during the perioperative period, Results There was no statistical difference in stress reaction degree between LN group and MION group. Conclusion The stress reaction in MION is no more than those of LN, which demonstrated that mini-incision open nephrectomy is a safe, effective and microinvasive therapy for nonfunctioning atrophic kidney. Key words: Laparoscopy; Mini-incision Open nephrectomy; Stress reaction

Hard nut to crack in diagnosis of pituitary hyperplasia secondary to primary hypothyroidism and reasons of misdiagnosis

To analyze the difficulty in diagnosis of pituitary hyperplasia secondary to primary hypothyroidism and reasons of misdiagnosis. Ten patients with clinical manifestations of primary hypothyroidism, 3 males and 7 females, aged 7 - 26, underwent MR imaging and serum hormone examination before and after thyroid hormone replacement therapy. T1-weighted images without and with contrast material enhancement in sagittal and coronal planes were obtained. Serum free triiodothyronine, free thyroxine, thyrotropic-stimulating hormone and prolactin (PRL) levels were measured. Obvious symmetrical enlargement of the pituitary gland with homogeneous signal intensity was revealed by MRI in all the patients. The height of the pituitary ranged 1.2 - 2.2 cm. The pituitary glands appeared homogeneously enhanced after Gd-DTPA administration. After 3 - 6 months of L-thyroxin replacement therapy, follow-up MRI showed that the pituitary glands reduced in size markedly in 9 cases, and the plasma thyroxine, TSH, and PRL levels of these 9 cases turned normal. One patient was misdiagnosed as with macroadenoma and was treated with gamma knife, resulting in permanence hypothyroidism. Symmetrical enlargement of pituitary gland with homogeneously enhancement on MRI has great diagnostic value in pituitary hyperplasia with primary hypothyroidism. Thyroid hormone replacement therapy can cause regression of the enlarged pituitary, thus avoiding unnecessary surgery.

Changes of endocrine and immune function in subjects of yang deficiency constitution

To investigate the changes of endocrine, cyclic nucleotide and immune systems in subjects of yang deficiency constitution, and to explore the relationship among characteristics and causes of yang deficiency constitution, the physiological and biochemical parameters. Based on the diagnostic criteria for the clinical epidemiological investigation, sixty subjects of yang deficiency constitution and fifty of normal constitution were selected. Eight milliliters venous blood were taken from overnight fasted subjects at 8:00-9:00. The sera were obtained by centrifugation of the blood at the speed of 3000 r/min for 5 minutes, and they were stored at -70 degrees C until use. The serum levels of corticosterone, cortisol, adrenocorticotrophic hormone (ACTH), cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), free triiodothyronine (FT3), free thyroxine (FT4), thyrotropic-stimulating hormone (TSH), interleukin-1beta and interleukin-2 were measured by enzyme-linked immunosorbent assay; the cAMP/cGMP ratio was also computed; and the differences of the above indexes were compared between the two types of subjects. The serum levels of corticosterone, interleukin-1beta, TSH and cAMP/cGMP ratio of yang deficiency constitution significantly increased as compared with those of normal constitution, and the serum levels of cortisol, ACTH, cGMP and FT4 of yang deficiency constitution significantly decreased in comparison with those of normal constitution. Subjects of yang deficiency constitution may be not only related to hypothalamic-pituitary-adrenal axis and hypothalamic-pituitary-thyroid axis, but also related to the functional disorders of cyclic nucleotide and immune systems.

A study on the thyroid injury induced by combined deficiency of selenium,protein and vitamin E in rats

Objective To explore the effect of associated deficiency of selenium,protein and vitamin E(VE)on the thyroid iniury and thyroid hormone metabolism of the rats in a long-term.Methods The Wistar rats were randomly divided into four groups:Group A with selenium deficiency and low protein and VE;Group B with selenium deficiency,low protein but adequate VE;Group C,adequate selenium and protein but low VE;Group D,adequate selenium.protein and VE.The rats were killed at the end of 26th week.Glutathione peroxidase(GSH-Px)activity in the rat blood and type I 5'-deiodinase activity of the rat liver were determined.The content of triiodothyronine(T3),tetraiodothyronine(T4),thyrotropic-stimulating hormone(TSH),activated oxygen(ROS)and malonaldehyde(MDA)were detected in serum. The changes of thyroid histopathology were observed under light microscope.Results ①The interactive effect of selenium+protein and VE was not significant on GSH-Px and ID I activity(F=0.003,0.871,P＞0.05),but it was significant on MDA and ROS content(F=13.057,6.706,P＜0.05 or＜0.01). ②Selenium+protein and VE could influence T3 and T4 content(F=431.977,28.271,6.570,41.419,P＜0.05).The interactive effect of selenium±protein and VE was not significant on T3 and T4 content(F=0.871,0.136,P＞0.05).Whether in the condition of low selenium and protein or supplementary,T4 contents of supplementary VE group[(79.095±12.199),(64.392±6.261)μg/L]were respectively higher than the low VE group[(61.068±6.648),(44.176±7.090)μg/L],the difference being statistically significant(t = 3.670,6.045, P ＜ 0.01). In the condition of low VE, T3[(0.718 ± 0.079)μg/L] and T4[(44.176 ±7.090)μg/L] content of supplementary selenium and protein group was lower than that in the low selenium and protein group[ (0.966 ± 0.156), (61.068 ± 6.648)μg/L], the difference being statistically significant (t = 4.568,4.916, P ＜0.01 ). With supplementary VE, T4 content of supplementary selenium and protein group[ (64.392 ± 6.261 )μg/L] was lower than that in the low selenium and protein group [(79.095 ± 12.199)μg/L], the difference being statistically significant (t = 3.033, P ＜ 0.01 ). ③Degeneration and necrosis of follicular epithelial cell were induced by diet of low selenium, protein and VE, which could be relieved by supplymentary VE. The sparseness of intracavitary glue was observed occationally in the supplementary selenium and protein but low VE group. Conclusions Long-term deficiency of selenium, protein and VE results in the decrease of the selenoenzymes of rats, which causes accumulation of the oxidative products, as well as thyroid pathological injury and thyroid hormone metabolism disorder, but supplement of adequate VE can reduce the oxidative damage in rats having low selenium and protein diet. Key words: Selenium; Proteins; Vitamin E; Deficiency diseases; Thyroid gland; Oxidative stress

Type B pigmentary demarcation lines in a Chinese amenorrheic woman

A 51‐year‐old Chinese woman (phototype III) presented to our dermatology clinic with a 3‐month history of asymptomatic pigmented maculae on the lower limbs that developed in the 11th month of amenorrhea. She had noticed no other areas of pigmentary change and denied any inflammatory episode or topical medication before their development. No personal or family history of hormonal imbalance or pigmentary demarcation lines (PDLs) was found. Physical examination revealed broad, band‐like pigmentation symmetrically distributed all over the flexor aspects of the lower limbs (Fig. 1). The medial borders of the pigmented areas were sharply demarcated, but the lateral borders merged imperceptibly into the normal skin. The patient was otherwise healthy. Laboratory examination, including full blood count, liver tests, triiodothyronine (T3), thyroxine (T4), and thyrotropic‐stimulating hormone (TSH), were normal. Hormonal investigations (Table 1) were within normal limits, except that estradiol (E2) was sharply decreased and follicle‐stimulating hormone (FSH) was highly elevated. Ultrasonic B‐mode examination showed a normal uterus and ovaries. No treatment was applied to the lesions. At a follow‐up visit, 16 months after onset, the pigmentary lines had resolved spontaneously. Moreover, the titers of hormones in serum had moved closer to normal values (Table 1).Pigmentary demarcation lines on the buttocks and flexor aspect of the legs. The outer part is darkerimage Hormone investigations on the serum of our patient with pigmentary demarcation lines (PDLs) 3 months after onset 16 months after onset Normal results Abnormal results Normal results Abnormal results 1. Prolactin 1. Estradiol, 12.9 pmol/L Normal, 40.0–100 pmol/L 1. Prolactin 1. Estradiol, 36.46 pmol/L Normal, 40.0–100 pmol/L 2. Luteotropic hormone 2. Follicle‐stimulating hormone, 94.3 U/L Normal, 1.5–33.4 U/L 2. Luteotropic hormone 2. Follicle‐stimulating hormone, 53.2 U/L Normal, 1.5–33.4 U/L 3. Progestone 3. Progestone 4. Total testosterone 4. Total testosterone 5. Free triiodothyronine 5. Free triiodothyronine 6. Free thyroxine 6. Free thyroxine 7. Thyroid‐stimulating hormone 7. Thyroid‐stimulating hormone

Studies on the nature of plasma thyroid stimulating activity in hyperthyroidism.

SummaryPrevious reports from this and other laboratories indicate the importance of the activity of abnormal plasma long‐acting thyroid stimulator (LATS) characteristic of thyrotoxicosis in relation to the various clinical features of the disease.Studies on the nature of this agent have now been carried out by comparison of its thyroid stimulating activity in the 131I‐labelled mouse with that of bovine pituitary thyrotropic stimulating hormone (TSH) and plasma from hypothyroid patients in which an excess of pituitary TSH has been demonstrated, as well as by chemical studies.A short‐acting response with a maximum at three hours is characteristic of pituitary TSH. A long‐acting response with maximum at eight hours or longer is characteristic of LATS. However, in the present study a long‐acting response with a maximum at eight hours has been demonstrated after multiple injections of bovine TSH. A long‐acting response can also be produced by injecting bovine TSH after it has been mixed with an appropriate concentration of rabbit antiserum to bovine TSH. These findings indicate that the pattern of response is not necessarily a distinguishing feature differentiating LATS and TSH.In contrast to the activity of TSH, LATS activity is unaffected by an antiserum to bovine TSH prepared in the rabbit. However, LATS activity is diminished by mixing it with an antiserum to human 7S gamma globulin prepared in the sheep, which in turn fails to affect the thyroid stimulating activity of bovine TSH on plasma from hypothyroid patients. These findings indicate that there is a distinct immunological difference between LATS and TSH.Large plasma samples from three thyrotoxic patients have been subjected to gel filtration (with the use of a “Sephadex” G‐200 apparatus). LATS activity was mainly confined to the 7S gamma globulin peak; although there was a degree of overlap into the macroglobulin and albumin peaks, starch gel electrophoresis revealed 7S gamma globulin was invariably a component of these fractions. Further purification was achieved by DEAE‐ “Sephadex” chromatography. This produced three fractions—the first two were found to have LATS activity and to contain 7S gamma globulins on starch gel electrophoresis, while the third contained beta globulins and albumin but was devoid of 7S gamma globulin and was inactive in the mouse assay.These findings are consistent with the findings of other laboratories, in that they clearly indicate that LATS belongs to the 7S gamma globulins and is therefore probably an antibody. These data strongly support clinical evidence indicating the importance of immunological mechanisms in the pathogenesis of hyperthyroidism. The possibility of hyperthyroidism being an autoimmune disorder is discussed.

Altered metabolism of I 131 by the endostyle and notochord of ammocoetes larvae I. Effects of treatment with thyrotropic stimulating hormone

Ammocoetes larvae of the lamprey, Petromyzon marinus, L. were treated with 2 and 6 U.S.P. units of bovine thyrotropic stimulating hormone (TSH) prior to the administration of a tracer dose of I 131. The endostyles and notochords were studied for per cent concentration of the isotope and then analyzed by means of radio-chromatography, for the formation of iodinated amino acids. Both the subpharyngeal gland and the notochord of ammocoetes were responsive to TSH. However the two organs reacted differently and independently to the hormone. In the endostyle the mechanisms for I 131 accumulation and the formation of iodinated amino acids were affected by TSH. In the notochord, TSH was able to increase the uptake of I 131 and the percentage of radioiodide demonstrable by radiochromatography. The activity of the hypophyseal hormone occurred within certain limits of time, and it was influenced by the mode of administration.