Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Small doses of iodide (2 times 3.2 mug at 12 h interval), below those capable of inducing Wolff-Chaikoff effect, were injected into rats kept on a moderately low iodine diet. By means of a 125I equilibration technique as well as by direct measurement of cold T4, it was demonstrated that the level of circulating PB125I (representing iodothyronines as confirmed by column chromatography) increased by a mean of 40% within 24 h following the first iodide injection. The serum TSH concentration (measured by radioimmunoassay) was simultaneously depressed. Thus, in stimulated thyroid glands, a biologically significant fraction of an iodide load escapes autoregulatory control of iodothyronine synthesis. A small, transient increase of hormone release is likely to represent the physiological response of a normal gland to a sudden supplement of iodide supply. The ensuing depression of TSH secretion may be necessary for final adjustment of thyroid function. It is considered to be the last step in a cascade of mechanisms whose interaction keeps the thyroidal hormone output within narrow limits in the face of a fluctuating iodide supply. Failure of one or several of these mechanisms in the goitrous human gland could conceivable explain the phenomenon of "Jod Basedow".
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PMID:A transient rise of hormone secretion: a response of the stimulated rat thyroid gland to small increments of iodide supply. 5 15

Follicular cells isolated from normal human thyroid tissue have been cultured for up to 140 h with bovine thyrotrophin (TSH) or dibutyryl cyclic AMP (DBcAMP). Both compounds induced marked reorganization of the cells into three-dimensional follicular structures, whilst non-supplemented cells assumed a monolayer form. Cultures treated initially with TSH or DBcAMP showed a greater iodide uptake capacity, in comparison with unsupplemented cultures, in which iodide uptake was markedly diminished after 24 h. The release of tri-iodothyronine (T3) and thyroxine (T4) into the medium was determined by radioimmunoassay. Both TSH- and DBcAMP-treated cells showed a significant increase in iodothyronine output compared with unsupplemented control cells. In contrast to the "classical" TSH-induced depression of the T4:T3 ratio in vivo, an increase in the ratio was observed for both TSH- and DBcAMP-supplemented cells in vitro. The ratio was also significantly greater after TSH than after DBcAMP, and possible implications of this findings are discussed.
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PMID:In-vitro studies of normal human thyroid cells: responses to thyrotrophin and dibutyryl cyclic AMP. 18 67

Erythrosine and sodium fluorescein, two colors used as a dental plaque disclosing agents, have similar chemical structures differing only in that erythrosine has four iodine atoms in the molecule while sodium fluorescein has no iodine. A comparative toxicological profile was made on both compounds employing oral dose ranges and acute oral toxicity tests in mice and rats. The results show erythrosine to be approximately twice as toxic as sodium fluorescein with LD50 values of 2558 +/- 1.35 mg/kg in mice and 2891 +/- 1.02 mg/kg in rats for erythrosine and 4738 +/- 1.23 mg/kg in mice and 6721 +/- 1.26 mg/kg in rats for sodium fluorescein. The major toxic manifestations of both compounds were those indicative of central nervous system depression.
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PMID:Acute toxicity testing of erythrosine and sodium fluorescein in mice and rats. 26 92

The effects of an altered content of dietary iodine and fat on the development of N-nitrosomethylurea-induced mammary tumors in rats were studied and correlated with thyroid and pituitary function studies. In three separate experiments, animals fed a semisynthetic diet containing 11.8% fat had an earlier time of tumor appearance and greater tumor burden than did controls maintained on a diet containing 4.6% fat. These diet-associated changes were markedly inhibited by ovariectomy, indicating that the tumor growth was hormone responsive. We examined the possibility that the diet with increased fat content enhanced tumor growth through alterations in prolactin metabolism but could find no consistent elevation in serum prolactin and no increase in pituitary prolactin synthesis in vitro. Our data further showed that rats on an iodine-deficient form of the high-fat diet had no greater tumor growth than did animals receiving an iodine-supplemented form of the same diet. We conclude from these results that iodine deficiency does not promote mammary tumorigenesis. An incidental finding of great interest was that ovariectomy led to a highly significant depression of thyroid-stimulating hormone production in vitro. This suggests that estrogens may directly influence thyroid-stimulating hormone synthesis in vivo and thus contribute to the sex-related differences in thyroid physiology.
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PMID:Effects of iodine deficiency and high-fat diet on N-nitrosomethylurea-induced mammary cancers in rats. 42 60

Recent advances in protein metabolism and in glycoprotein synthesis bring further insight into endemic goiter epidemiology. Retinol circulates in the blood stream in close parallelism with retinol-binding protein and prealbumin (RBP-PA), a protein complex whose liver secretory rate is dependent upon hormonal and nutritional status. On the other hand, normal glycosylation reaction occurs through the formation of a retinol-linked sugar complex. It is suggested that the relative drop of serum retinol levels, as a result of modified hormonal climate and/or declining protein status, might constitute a critical factor capable of inducing a defective incorporation of mannose into native thyroglobulin, leading to an early depression of the full glycoprotein production. This concept affords a comprehensive explanation of the following unresolved data recorded in goitrous areas: (1) clinical and biochemical discrepancies between subjects living in the same morbid territory, (2) persistence of endemicity in spite of appropriate iodine supplementation, (3) similar prevalence of goiter hypertrophy in male and female prepubertal children, (4) increased frequency of goiter enlargement in the four most vulnerable groups, namely preschool children of both sexes, adolescent girls, pregnant women, and elderly persons, (5) decreased impact of thyroid swelling accompanying improved socio-economic status, even without iodine addition, and (6) resurgence of goitrous hyperplasia as an effect of seasonal or sporadic deterioration of nutritional habits, even when iodine supply remains unchanged.
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PMID:Hormonal and nutritional status: critical conditions for endemic goiter epidemiology? 56 53

This study comprises 81 thyrotoxic patients with onset after the age of 60. In elderly persons, toxic multinodular goiter is the most common cause (68%) of hyperthyroidism, followed by solitary thyroid nodules (16%) and Graves' disease (16%). Cardiovascular disorders (cardiac failure, arrythmias etc.) constitute the first and often the only symptom in 62% of the cases. The other forms of appearance are both various and deceptive: depression, slight fever, asthenia or nausea. Separate analysis of the three forms of hyperthyroidism did not reveal clinical, biological or therapeutic differences between them, except an inferior rate of captation for the toxic nodules. Isolated measurement of T3 or T4 is often insufficient to confirm the diagnosis because either of these hormones may appear at a normal rate. In three cases only the free thyroxin index was pathological on first determination. The authors have established that the autonomous nodules are larger and more active after, rather than before, 60 years of age, and have attempted to define their morphological identity. The results of the treatment are analyzed and preference is expressed for radioactive iodine in every form of hyperthyroidism.
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PMID:[Hyperthyroidism in older patients]. 58 12

The effects of the oral contraceptive on the pituitary content and plasma level of luteinizing hormone (LH) and the hypothalamic LH-releasing hormone (RH) level were investigated in 16 adult female rabbits. The oral contraceptive preparation, Sophia-C (norethindrone 2 mg plus mestranol .1 mg), was administered orally by a stomach tube each day for 7 days in 8 adult female rabbits. At the end of the treatment, the rabbits were bled from the abdominal aorta into heparinized syringes and the plasma was separated. The stalk median eminences were excised. All the materials were stored in -80 degrees C until assayed. Plasma level and the pituitary content of LH and the hypothalamic LH-RH were measured by radioimmunoassy. All the dose-response curves were drawn using logit-log transformation. Radioimmunoassay procedures for LH was described in detail elsewhere. Purified rabbit LH for iodination (iodine-125) and standard were prepared by T. Makino and R.O. Greep, at Research Laboratories for Human Reproduction, Harvard Medical School, Boston. The starting B/T ratio was 25% at the final dilution of the antibody of 1/20,000. Minimal detectable quantity was about 40 pg/tube. The 50% intercepts were approximately 460 pg/tube. Radioimmunoassay procedures for LH-RH were performed according to the method described by Arimura et al. Antiserum against synthetic LH-RH was kindly supplied to us by Drs. A. Arimura and A.V. Schally, New Orleans, Louisiana. The synthetic LH-RH was kindly supplied to us by Dr. N. Yanaihara. The starting B/T ratio was 29% at the final dilution of the antibody of 1/17,500. Minimal detectable quantity was about 40 pg/tube and the 50% intercepts were 150 pg/tube. It has been assumed that oral contraceptive drugs exert their action by blocking the hypothalamic LH-RH, resulting in a depression of the plasma level of LH, because plasma level of LH returned to the normal level when LH-RH was administered (iv even while oral contraceptive steroids were given continuously. However, these findings concerning the site of action of the drugs furnished only indirect evidences. The possibility of a direct inhibitory effect of these steroids on the anterior pituitary cannot be ruled out. Administration of 2 mg of norethindrone and .1 mg of mestranol significantly depressed both the pituitary content and the plasma level of LH. On the other hand, they significantly increased the hypothalamic LH-RH level. Those findings strongly suggested the direct action of this drug on the anterior pituitary in the female adult rabbits. Detailed mechanisms on how the hypothalamic LH-RH was increased were not known in this experiment; further investigations are now in progress.
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PMID:[Effect of oral contraceptive on the pituitary and plasma L.H. levels and on the hypothalamic LH-RH level (author's transl)]. 79 81

Where necessary, women should be counselled so as to understand that a slim, elegant figure is not the prerogative of all. An inherited large frame requires a corresponding body contour, and dieting to change this situation will be in vain. All weight reducing diets must provide an adequate amount of vitamins and minerals. Women on the contraceptive pill often have diminished serum levels of folic acid and vitamin B6, and there have been suggestions that vitamin supplementation may help overcome depression and diminished libido in some women. This has been partially successful. A well-balanced diet should be recommended prior to trial of supplements. During pregnancy and lactation there is an increased need for protein, calcium, iron, iodide and fluoride. Vitamin and iron supplementation may be required where deficiencies exist due to dietary neglect. Excessive alcohol and smoking should be discouraged--especially during pregnancy. The elderly are particularly vulnerable to diseases of nutritional deficiency for various reasons. The importance of foods providing protein, calcium and vitamins should be stressed, as these are the main nutrients lacking. The consumption of meat, milk, cheese, eggs, fish, fresh fruit and vegetables should be encouraged.
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PMID:Nutrition and family practice. 86 Sep 67

The study was designed to confirm a previous, unexpected observation of a strong growth depressing effect of 1 microgram cobalt/g in rats fed lactalbumin based diets. The addition of 0.25, 0.5, and 1.0 microgram of cobalt/g to the basal diet containing 0.056 microgram/g depressed growth rates of rats progressively with increasing doses. This depression was overcome by increasing the cobalt supplement to 2 microgram/g, and additional weight gain was observed with 3 microgram/g. Higher concentrations were progressively toxic. Hemoglobin concentrations, hematocrits, and thyroid retention of intravenously injected sodium iodide all were lowest in rats fed the diet containing 1 microgram cobalt/g and increased with lower and higher concentrations of cobalt. The opposite was true for fasting serum glucose levels, which were elevated in rats fed the 1 microgram/g diet and low in rats fed the 3 microgram/g diet or control diet. This biphasic response to cobalt is consistent with the hypothesis that cobalt in low concentrations may have an essential function in the rat. However, an alternative explanation, an interaction of cobalt with a toxic constituent of the diet, has not yet been ruled out.
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PMID:A biphasic response of rats to cobalt. 88 93

Administration of 3 units of thyrotropic hormone to rabbits with autoimmune thyroiditis and hypothyroidism led to reduction of the I131 absorption by the thyroid gland and to increase in the activity of proteolytic enzymes of the gland. Apparently, in autoimmune thyroiditis disturbances at the stages of the iodide incorporation into the gland were irreversible; proteolysis depression was apparently secondary. Possibly the mentioned disturbances were associated with the circulating antithyroid antibodies.
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PMID:[The effect of thyrotropic hormone on processes mediating the cytotoxicity of antithyroid antibodies]. 93 90


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