Alteration in lipid profile is a common observation in patients with thyroid dysfunction, but the current knowledge on the relationship between lipids and thyroid hormone levels in euthyroid state is insufficient. The current study aimed to determine the association between thyroid hormones and thyroid-stimulating hormone (TSH) with lipid profile in a euthyroid male population.
Recent studies revealed a novel association between thyroid-stimulating hormone (TSH) and bone health status in healthy male populations. The present study aimed to validate this association and provide new information on the relationship between TSH levels and calcaneal speed of sound (SOS) in men.
Extruded canola meal (ECM) was included in diet of broiler chickens at 0, 10, 20, and 30% (wt/wt) from 1 to 35 days of age. A total of 240 day-old male chicks were assigned in groups of 5 to 48 battery cages in environmentally controlled chambers and diets were replicated with 12 cages/treatment. From d 29 to 35, birds from each dietary group were exposed to either thermoneutral (23 ± 1°C; unheated) or high (36 ± 1°C; heated) temperature conditions. High ambient temperature, irrespective of ECM inclusion, depressed the growth performance of birds. Inclusion of ECM increased feed conversion ratio (FCR) linearly in unheated birds during d 1 to 28 (P < 0.001) and d 29 to 35 (P = 0.001). However, no adverse effects of ECM inclusion were observed on the growth performance of heated birds. The absence of these detrimental effects could be associated with the lack of triiodothyronine (T3) elevation by ECM inclusion in heated birds. In conclusion, ECM can be fed, at least, up to 30%, without any adverse effect on growth performance of broiler chickens raised under chronic high ambient temperature.
Carbimazole, in 3 divided daily doses, is commonly prescribed for the treatment of thyrotoxicosis. However, based on its long intra-thyroid half-life, the drug may be effective when used as a single or twice daily dose. This study was undertaken to determine the effect of once, twice or thrice daily doses of carbimazole on thyroid function in patients with thyrotoxicosis. Seventy previously untreated thyrotoxic patients were randomly allocated to receive carbimazole 30 mg once (group 1), 15 mg twice (group 2) and 10 mg thrice (group 3) daily. All patients were also prescribed propranolol 20 mg thrice daily for the first 4 weeks. Blood was taken for total T3, T4, TSH, blood counts and liver enzymes determinations at the beginning and at 6 weeks of treatment. Only 48 (68.6%) patients were included in the analysis, as the rest defaulted follow-up (20.0%) or blood samples were not available at review (11.4%). Of the 48 patients, 17 were in group 1, 16 in group 2 and 15 in group 3. Following 6 weeks of treatment, there was no significant difference in the mean serum levels of total T3 and T4 between the 3 groups. However, there was a significant decrease in the mean serum levels of total T3 and T4 as compared to the start of the treatment. Four patients (23.5%) in group 1, 4 patients (25%) in group 2 and 3 patients (20%) in group 3 were still thyrotoxic at 6 weeks of treatment, whilst 10 patients (58.8%) in group 1, 6 patients (37.5%) in group 2 and 3 (20%) in group 3 were biochemically hypothyroid.(ABSTRACT TRUNCATED AT 250 WORDS)
Serum concentrations of thyroid stimulating hormone (TSH) and thyroid autoantibodies in pregnant patients with thyroid disease at various stages of pregnancy were determined by in-house ELISAs. In normal pregnancy, serum TSH levels were significantly elevated (p < 0.05) from 13 weeks of gestation. The normal reference ranges for TSH for the second (0.6-5.0 mIU/l) and third trimester (0.6-5.6 mIU/l) were significantly higher (p < 0.05; p < 0.01 respectively) compared to 0.4-4.5 mIU/l for the first trimester. In pregnant thyroid patients, serum TSH levels correlated highly (p < 0.001) to T4 (r = 0.740), FT4I (r = 0.683) and MicAb (microsomal antibodies) (r = 0.825) but weaker (p < 0.01) to T3 (r = -0.512), FT3I (r = 0.520) and TgAb (thyroglobulin antibodies) (r = 0.618). Thus, measurement of TSH with the highly sensitive ELISA (enzyme linked immunosorbent assay) would form a useful first line test for thyroid dysfunction in pregnancy while measurement of thyroid autoantibodies would aid in the diagnosis of autoimmune hypothyroidism.
1. Anaesthesia caused marked decreases in the plasma concentrations of triiodothyronine (T3) and thyroxine (T4) and in the body temperature of young fowl. 2. Exogenous T4 or a thyroid hormone secretagogue (somatostatin antiserum), increased endogenous T3 and T4 concentrations and body temperature in conscious birds and prevented the body temperature decline in anaesthetized fowl. 3. These results provide further evidence for a role of T3 and T4 in temperature regulation in birds, particularly during anaesthesia.
An iodinator was fitted to the existing gravity-fed water-supply of a remote village in Sarawak, Malaysia, where goitre was endemic. Within nine months, the prevalence of goitre had been reduced from 61% to 30%, with 79% of goitres showing visible reduction in size. All subjects were clinically euthyroid before and nine months after the start of iodination, although pre-treatment serum thyroid-stimulating hormone (TSH) concentrations varied from normal up to 24 mU/l. Before treatment basal serum triiodothyronine (T3) and thyroxine (T4) concentrations were typical of endemic goitre with a low mean serum T4 (80 +/- 30 [SD] nmol/l) and a slightly raised mean serum T3 (2.3 +/- 0.7 nmol/l). After iodination, circulating TSH concentration was generally undetectable (less than 0.1 mU/l), mean T3 concentration was unchanged, but the mean T4 rose significantly to 109 +/- 41 nmol/l (p less than 0.01). Urinary iodine concentrations fluctuated; this largely reflected intermittent blockage of the iodinator, but concentrations became consistent with a return to the iodine-replete state. There was no evidence of the Jod Basedow effect in the group studied. Iodinated water was more convenient to distribute than iodised salt and is less likely to cause Jod Basedow phenomenon than are injections of iodised oil. Moreover, iodination of water is effective in killing most microorganisms and this additional benefit could contribute significantly to village health.
The third and final meeting of a coordinated research programme on the diagnosis and management of thyroid disorders was held in Vienna from 15 to 17 December 1986. The participants were from Czechoslovakia, Egypt, Israel, Malaysia and Thailand. Each participant had studied between 500 and 1000 patients for thyroid function evaluation by performing T3, T4 and TSH radioimmunoassays. Each had also used the newly available supersensitive immunoradiometric (IRMA) assay in a group of patients to compare the efficiency of the new assay with that of the conventional assay. A microcomputer was provided to each participant for data analysis. Internal quality control was studied by establishing precision profiles and external quality control was on the basis of pooled standard sera in different ranges. Recommendation for the strategy suggested T4 RIA as the test of first choice in each category of thyroid function. IRMA TSH was suggested as a second test in borderline cases.
The effect of consuming large amounts of cassava leaves on thyroid function and urinary iodine was studied. Twenty volunteers were given 200 gm of boiled cassava leaves twice a day for 12 consecutive days. Thyroid hormones triiodothyronine and thyroxine were significantly lower by 9 days. Urinary iodine excretion was also significantly decreased. Cassava leaves, consumed in large amounts by aborigines, probably caused goitres by decreasing iodine absorption.
The effect of thyroid hormones on the renin-angiotensin-aldosterone system has not been fully resolved. Highly specific immunoassays for measurement of renin, aldosterone, free T4 (fT4), free T3 (fT3) and ultrasensitive TSH enables a direct and more accurate measurement of these hormones. We investigated the relationship between plasma renin, aldosterone and thyroid hormones in the basal state and after intravenous frusemide. This is a cross-sectional study involving 37 patients with thyrotoxicosis, 42 rendered euthyroid with normal fT4, fT3 and TSH levels, 17 with euthyroid levels of fT4 and fT3 but suppressed TSH, and 11 with hypothyroidism. Basal plasma renin was significantly higher in thyrotoxicosis (63.4 +/- 9.8 microU/ml, mean +/- SEM) compared to euthyroid (32.7 +/- 4.4 microU/ml) and hypothyroid (26.7 +/- 9.8 microU/ml). Basal plasma renin for euthyroid with suppressed TSH (41.0 +/- 7.4 microU/ml) was significantly higher than hypothyroid (p = 0.02). Basal plasma aldosterones were not significantly different except for suppressed TSH (157.7 +/- 13 pg/ml), which was higher than normal (109.9 +/- 10.4 pg/ml; p = 0.04). Following frusemide, plasma renin and aldosterone were significantly increased in all groups. Plasma renin was highly correlated to fT3 (r = 0.405, p < 0.001), total T3 (r = 0.359, p < 0.001), fT4 (r = 0.331, p < 0.001) and TSH (r = 0.300, p < 0.001) in the basal state, but less to total T4 (r = 0.248, p < 0.01). Plasma renin correlated poorly to serum aldosterone (r = 0.212, p < 0.03). This study clearly showed that regulation of renin was mainly influenced by fT3, and that aldosterone response to frusemide was blunted in thyrotoxicosis despite normal electrolytes.
OBJECTIVE: Overt and subclinical hypothyroidism are risk factors for atherosclerosis. It is unclear whether thyroid hormone levels within the normal range are also associated with atherosclerosis measured by coronary artery calcium (CAC).
APPROACH AND RESULTS: We conducted a cross-sectional study of 41 403 apparently healthy young and middle-aged men and women with normal thyroid hormone levels. Free thyroxin, free triiodothyronine, and thyroid-stimulating hormone levels were measured by electrochemiluminescent immunoassay. CAC score was measured by multidetector computed tomography. The multivariable adjusted CAC ratios comparing the highest versus the lowest quartile of thyroid hormones were 0.74 (95% confidence interval, 0.60-0.91; P for trend <0.001) for free thyroxin, 0.81 (0.66-1.00; P for trend=0.05) for free triiodothyronine, and 0.78 (0.64-0.95; P for trend=0.01) for thyroid-stimulating hormone. Similarly, the odds ratios for detectable CAC (CAC >0) comparing the highest versus the lowest quartiles of thyroid hormones were 0.87 (0.79-0.96; P for linear trend <0.001) for free thyroxin, 0.90 (0.82-0.99; P for linear trend=0.02) for free triiodothyronine, and 0.91 (0.83-1.00; P for linear trend=0.03) for thyroid-stimulating hormone.
CONCLUSIONS: In a large cohort of apparently healthy young and middle-aged euthyroid men and women, low-normal free thyroxin and thyroid-stimulating hormone were associated with a higher prevalence of subclinical coronary artery disease and with a greater degree of coronary calcification.
KEYWORDS: thyroid hormones; thyrotropin; thyroxine; triiodothyronine
This is a report of a cross sectional study involving 3 groups of children, moderately malnourished (BMI < 15), mildly malnourished (BMI 15-18) and well nourished (BMI > 18) to determine the differences in hormonal and biochemical parameters between the groups. The children were of age range from 7-17 years old. The children were from the same area with exposure to the same food, drinking water and environment. There were significant differences in the nutritional indices between the three groups. No differences were observed in levels of triiodothyronine (T3), thyroxine (T4) and T3:T4 ratio. Significant difference however was found in the TSH levels using highly sensitive IRMA TSH assays. Moderately malnourished children had higher TSH levels (p < 0.05) compared to mildly malnourished and well-nourished children. No difference was found between the mildly malnourished and well-nourished groups. There were no significant differences in serum cortisols done at similar times, fasting growth hormone and calcium. Serum alanine transminase (ALT) however was higher in moderately malnourished than in well-nourished children. Thus using highly sensitive IRMA TSH assays, we were able to detect differences in TSH levels even though T3, T4 and T3:T4 ratio, cortisol, growth hormone and calcium were normal, implying in moderately malnourished children, a higher TSH drive to maintain euthyroid state.
BACKGROUND: This research was performed to determine the prevalence of iodine deficiency disorder (IDD) and the effects of iodized salt supplementation on thyroid status amongst Orang Asli in Hulu Selangor, Malaysia.
METHODS: Study respondents were from three target groups, i.e. pre-school children (PSC), primary school-going children (SGC) and adult women. Each household was supplied with iodized salt fortified with iodate fortificant for a period of 12 months and the iodine levels in the salt ranged from 20 to 30 μg/L. Samples collected before and after 6 and 12 months of introduction to iodized salt were urine from all groups, as well as serum samples from adult women.
RESULTS: A total of 200 respondents were recruited; 58 (29.0%) PSC, 65 (32.5%) SGC and 77 (38.5%) adult women. The median urine-iodine concentration (mUIC) in all groups were of moderately low before the iodized salt intervention, but increased significantly in all study groups after 6 and 12 months of intervention. However, at the end of the study, there was an increase in severe iodine deficiency (mUIC <20 μg/L) from 7.5% to 12% and about 9% of PSC and SGC respondents had mUIC level of more than 300 μg/L while the adult women showed a significant increase in free triiodothyronine (fT3) levels.
CONCLUSION: The study demonstrated that iodized salt supplementation was able to show an improvement in iodine level amongst Orang Asli. However, an increase in severe iodine deficiency and iodine excess indicated that the iodized salt programme needs to be carefully monitored.