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1.
Arch Intern Med ; 146(10): 1985-7, 1986 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-3767543

RESUMEN

Papillary-follicular thyroid carcinoma usually remains localized to the thyroid bed and, in cases of metastasis, almost always involves the lung, bone, or liver. The two patients described here presented with papillary carcinoma and neurologic dysfunction. Total body iodine 131 scans disclosed cerebral uptake, and cerebral masses were confirmed by computed tomographic scan. Both patients presented diagnostic and therapeutic dilemmas, and ultimately underwent craniotomy. One patient's cerebral metastasis recurred and was treated by a second craniotomy. The other patient received postoperative external cerebral radiotherapy and a novel intraoperative treatment: implantation of 22 iodine 125 seeds in the tumor bed, estimated to yield 16,000 rad (160 Gy) in one year. To date, cerebral metastases have not recurred in the latter patient, although tumor has reappeared in other sites. There is little reported in the medical literature concerning cerebral metastases of thyroid carcinoma, and the present report reviews this experience and discusses treatment alternatives.


Asunto(s)
Adenocarcinoma/secundario , Neoplasias Encefálicas/secundario , Neoplasias de la Tiroides/patología , Adenocarcinoma/diagnóstico , Adenocarcinoma/terapia , Anciano , Braquiterapia , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/terapia , Terapia Combinada , Craneotomía , Humanos , Radioisótopos de Yodo/uso terapéutico , Masculino , Enfermedades del Sistema Nervioso/diagnóstico
2.
Arch Intern Med ; 145(8): 1507-9, 1985 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-3896182

RESUMEN

While papillary and follicular thyroid carcinomas are frequently mixed, this is a case of a medullary, papillary, follicular, and undifferentiated carcinoma of the same gland. In addition, all four tumor types were metastatic to regional lymph nodes. The patient described herein did not demonstrate features of the multiple endocrine neoplasia type 2 syndrome. Immunoperoxidase staining for calcitonin and thyroglobulin was positive in the follicular and medullary areas of tumor. Because the embryologic origin of the thyroidal follicular cells is from the endoderm and the origin of the parafollicular cells of the medullary carcinoma is from the ectodermal neural crest, this case seems noteworthy for demonstrating mixed metastatic tumor of composite embryologic origin. Alternatively, this case may represent an extension of what has recently been termed differentiated thyroid carcinoma, intermediate type by Ljungberg and co-workers.


Asunto(s)
Carcinoma/patología , Neoplasias de la Tiroides/patología , Calcitonina/análisis , Carcinoma/metabolismo , Carcinoma/cirugía , Terapia Combinada , Histocitoquímica , Humanos , Técnicas para Inmunoenzimas , Escisión del Ganglio Linfático , Metástasis Linfática , Masculino , Persona de Mediana Edad , Disección del Cuello , Tiroglobulina/análisis , Neoplasias de la Tiroides/metabolismo , Neoplasias de la Tiroides/cirugía
3.
Arch Intern Med ; 142(9): 1749-51, 1982 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-6896806

RESUMEN

The differential diagnosis of the condition of a patient with acral thickening and normal bone roentgenograms but without obvious signs of Graves' disease may be perplexing. A patient was seen with this disorder, in which the early diagnosis of thyroid acropachy could not be made roentgenographically but was accomplished by bone-scanning techniques. To our knowledge, this is the first demonstration of the evolution of thyroid acropachy, as temporally proved by serial roentgenograms and bone radiographs. The patient complained of severe swelling and decreased finger mobility. His hands were treated in a novel manner, using fluorinated topical steroids under an occlusive dressing, because of the failure of previously described localized medical therapeutic regimens. Treatment, using one hand as a control, resulted in a substantial decrease in hand circumference and volume, as well as increased finger mobility.


Asunto(s)
Enfermedad de Graves/complicaciones , Mixedema/etiología , Osteoartropatía Hipertrófica Secundaria/etiología , Administración Tópica , Diagnóstico Diferencial , Dedos , Fluocinonida/administración & dosificación , Enfermedad de Graves/diagnóstico , Humanos , Masculino , Persona de Mediana Edad , Mixedema/terapia
4.
Endocrinology ; 113(6): 2092-6, 1983 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-6641627

RESUMEN

An approximately 60,000 mol wt glycopeptide has been isolated from acetone-dried human pituitary glands which stimulates production of the adrenal androgen dehydroepiandrosterone, but not cortisol, in acute suspensions of collagenase-dispersed dog adrenal cells. Adrenal androgen secretion has generally been considered, like cortisol, to be under the control of ACTH. This new pituitary glycopeptide, with a molecular weight greater than that of proopiocortin, ACTH, PRL, or LH, may help explain instances during adrenarche, puberty, aging, and stress in which cortisol and adrenal androgen metabolism diverge.


Asunto(s)
Glándulas Suprarrenales/metabolismo , Androsterona/metabolismo , Glicopéptidos/farmacología , Hipófisis/análisis , Glándulas Suprarrenales/efectos de los fármacos , Animales , Bioensayo , Perros , Humanos , Hidrocortisona/metabolismo , Masculino , Peso Molecular , Hormonas Adenohipofisarias/farmacología
5.
J Clin Endocrinol Metab ; 47(3): 600-2, 1978 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-162516

RESUMEN

Dehydroepiandrosterone (DHA), in large part a measure of adrenal androgen secretion, previously has been measured in urine after hydrolysis or solvolysis of the glucuronide and sulfate conjugates. These procedures are time consuming; they often require several days and variable recoveries are a source of error. A method is presented here for determination of unconjugated DHA in 24-h urine specimens which requires less time, labor, and sample volume than necessary for the assay of DHA derived from conjugates. In 76 men and women, age 20-96 yr, total 24-h urinary unconjugated DHA showed no sex differences. However, the mean unconjugated DHA excretion decreased, which may indicate decreased zona reticularis function with respect to relatively constant zona fasiculata function in advancing age.


Asunto(s)
Glándulas Suprarrenales/metabolismo , Andrógenos/biosíntesis , Deshidroepiandrosterona/orina , Dexametasona , Glándulas Suprarrenales/efectos de los fármacos , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Radioinmunoensayo/métodos
6.
J Clin Endocrinol Metab ; 60(5): 947-52, 1985 May.
Artículo en Inglés | MEDLINE | ID: mdl-3156871

RESUMEN

During serious illness, there are characteristic increases in serum cortisol concentrations and urinary cortisol excretion. In the present studies, we investigated these changes in glucocorticoid metabolism in relation to adrenal androgen metabolism, as measured by RIA of dehydroepiandrosterone (DHA) and DHA sulfate (DHAS). A group of 23 seriously ill men with various disorders, ill for a week or longer, was age-matched to a control group of 25 men, and the following changes were found: 1) basal serum cortisol concentrations were elevated in the ill group (P less than 0.001), 2) basal serum DHA and DHAS concentrations tended to be lower in the ill group (P less than 0.1); 3) basal serum DHA to cortisol and DHAS to cortisol ratios were decreased in the ill group by 80.3% and 77.2%, respectively (P less than 0.001); 4) ACTH-stimulated serum cortisol concentrations increased by the same absolute amount in both groups, whereas the increase in stimulated DHA concentrations in the ill group was 57.2% less (P less than 0.05), indicating a defect in ACTH-stimulated DHA reserve in serious illness; 5) basal daily unconjugated DHA excretion was lower in the ill group (P less than 0.05); (6) basal daily cortisol excretion was higher in the ill group (P less than 0.05); and 7) the basal daily urinary unconjugated DHA to cortisol ratio was 85.4% lower in the ill group (P less than 0.001). Recently, Zipser et al. described the entity of hyperreninemic hypoaldosteronism in the seriously ill. Their findings combined with our own indicate a relative shift in the metabolism of adrenal pregnenolone in serious illness away from mineralocorticoids and adrenal androgens and toward glucocorticoids. The cause of this change is unknown. We speculate that this shift of relative biochemical pathway predominance may be a factor necessary for survival during chronic severe stress.


Asunto(s)
Adaptación Fisiológica , Corteza Suprarrenal/fisiopatología , Enfermedad Crónica/fisiopatología , Estrés Fisiológico/metabolismo , Adulto , Anciano , Cuidados Críticos , Deshidroepiandrosterona/análogos & derivados , Deshidroepiandrosterona/metabolismo , Sulfato de Deshidroepiandrosterona , Humanos , Hidrocortisona/metabolismo , Masculino , Persona de Mediana Edad , Radioinmunoensayo , Estrés Fisiológico/sangre , Estrés Fisiológico/orina
7.
Am J Psychiatry ; 150(5): 806-9, 1993 May.
Artículo en Inglés | MEDLINE | ID: mdl-8386908

RESUMEN

Nine depressed subjects and nine comparison subjects completed a study of abnormalities in adrenal androgen and cortisol metabolism. Serum levels of cortisol and dehydroepiandrosterone (DHA) at 8:00 a.m. and 4:00 p.m. revealed hypercortisolemia and loss of diurnal DHA variation but not cortisol variation in the depressed group. These findings suggest that in depression, adrenal androgens, in contrast to cortisol, are partially regulated by mechanisms independent of ACTH.


Asunto(s)
Deshidroepiandrosterona/sangre , Trastorno Depresivo/diagnóstico , Hidrocortisona/sangre , Hormona Adrenocorticotrópica/fisiología , Adulto , Ritmo Circadiano , Deshidroepiandrosterona/fisiología , Trastorno Depresivo/sangre , Trastorno Depresivo/fisiopatología , Dexametasona , Humanos , Hidrocortisona/fisiología , Masculino , Escalas de Valoración Psiquiátrica
8.
Am J Clin Nutr ; 29(8): 832-5, 1976 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-941864

RESUMEN

Twenty-four subjects ranging from 5 to 33% above ideal weight were weighted during a 3-week control period, and then treated for the successive 9 weeks with acupuncture therapy given in three different loci, and in random order for 3-week periods. The acupuncture needles were placed in unilateral loci used by oriental acupuncturists for weight loss, in the same loci bilaterally, and in unilateral loci not used by acupuncturists for weight loss. No undesirable effects were noted. No treatment was associated with weight reduction significant at the 0.05 confidence level. A study involving guinea pigs was run parallel with the above clinical protocol and also demonstrated no effect of ear acupuncture on weight loss.


Asunto(s)
Terapia por Acupuntura , Oído Externo , Obesidad/terapia , Animales , Oído Externo/anatomía & histología , Estudios de Evaluación como Asunto , Femenino , Cobayas , Humanos , Masculino , Especificidad de la Especie
9.
Endocrinol Metab Clin North Am ; 20(1): 71-83, 1991 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-2029889

RESUMEN

Between 6 and 8 years of age, while cortisol concentrations and production rates remain constant, urinary excretion and circulating concentrations of DHA, DHAS, and other adrenal androgens increase progressively. These hormonal changes, which constitute the adrenarche, are accompanied by the appearance of axillary and pubic hair and a transient acceleration of linear growth and bone maturation. Increased adrenarchal concentrations of adrenal androgens may also contribute to the observed developmental decrease in concentration of SHBG and increase in bioavailable testosterone that occur in preadolescent boys. It is not known if extraadrenal factors, intraadrenal factors, or a combination of both are responsible for the occurrence of adrenarche. However, known hormones, such as ACTH, prolactin, gonadotropins, and estrogens, do not appear to cause the adrenarche. During adolescence, ACTH and cortisol concentrations remain constant, but concentrations of adrenal androgens continue to increase. The existence of a relationship between adrenarche and puberty has been suggested, partly because increased concentrations of adrenal androgens in undertreated congenital adrenal hyperplasia have been associated with cases of true precocious puberty in boys. However, there is evidence against a causal relationship, including the observation that children with treated primary adrenal insufficiency have been found to enter puberty normally. Adrenarche may cause a transient acceleration of growth and serve as a permissive factor in male puberty but does not appear to be necessary for the initiation of puberty.


Asunto(s)
Glándulas Suprarrenales/metabolismo , Andrógenos/metabolismo , Corticoesteroides/metabolismo , Glándulas Suprarrenales/crecimiento & desarrollo , Niño , Femenino , Humanos , Masculino , Pubertad/fisiología
10.
Endocrinol Metab Clin North Am ; 20(2): 401-21, 1991 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-1652437

RESUMEN

The human adrenal gland secretes large amounts of androgens and androgenic precursors as compared with the adrenal glands of other species. In part, this pattern of secretion is regulated by ACTH, analogous to the control of cortisol. However, in many instances, including adrenarche, puberty, aging, and severe illness, secretion of adrenal androgens and cortisol diverge for reasons which are not clear. Factors endogenous to the adrenal gland may have a role in the modulation of adrenal androgen secretion. These include the centripetal blood supply of the adrenal gland, availability of cofactors of steroidogenic enzymes, and intrinsic properties of adrenal cells or enzymes. However, these mechanisms may, in turn, be modified by factors exogenous to the adrenal gland. Possible evidence for a regulatory role for such known substances as growth hormone, IGF-1, gonadotropins, estrogens, angiotensins, prostaglandins, insulin, EGF, and POMC-related peptides is discussed. Furthermore, pituitary or extrapituitary substances, in addition to known hormones, may have a role in the control of adrenal androgen secretion. Several lines of evidence include the inability of ACTH to maintain a normal adrenal androgen/cortisol ratio in adrenally suppressed patients, or experimentally, in hypophysectomized chimpanzees. Evidence for such factors derived from fetal and adult human pituitary gland is discussed.


Asunto(s)
Glándulas Suprarrenales/metabolismo , Andrógenos/metabolismo , Homeostasis , Glándulas Suprarrenales/embriología , Glándulas Suprarrenales/crecimiento & desarrollo , Hormona Adrenocorticotrópica/fisiología , Envejecimiento/metabolismo , Andrógenos/biosíntesis , Andrógenos/genética , Enfermedad , Femenino , Humanos , Masculino
11.
J Nucl Med ; 32(6): 1266-9, 1991 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-2045945

RESUMEN

Hürthle cell carcinoma is a relatively uncommon type of well-differentiated thyroid carcinoma. Its diagnosis has been controversial due to the difficulty in separating Hürthle cell adenoma from Hürthle cell carcinoma, thus the term Hürthle cell tumor is often used to describe both lesions. The present case of anaplastic giant-cell carcinoma in an 81-yr-old woman arose in a Hürthle cell tumor. This case illustrates the propensity of Hürthle cell tumor to undergo "malignant transformation" and argues for a more aggressive approach to such tumors.


Asunto(s)
Adenoma/patología , Carcinoma/patología , Neoplasias de la Tiroides/patología , Adenoma/diagnóstico por imagen , Anciano , Anciano de 80 o más Años , Carcinoma/diagnóstico por imagen , Femenino , Humanos , Radioisótopos de Yodo , Cintigrafía , Neoplasias de la Tiroides/diagnóstico por imagen
12.
J Nucl Med ; 25(11): 1204-9, 1984 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-6092568

RESUMEN

This is a case of striking radioiodine and [99mTc]pertechnetate uptake by disseminated nonthyroidal (gastric) adenocarcinoma. A 65-yr-old man was euthyroid and serum thyroglobulin concentration was normal at 11 ng/ml. Bone-marrow biopsy showed that the metastatic tumor cells were negative for thyroglobulin on immunoperoxidase stain and the secretory product was mucicarmine-positive. We estimate that radioiodine uptake in the normal thyroid gland was less than 10% of total tumor uptake. At autopsy, the stomach was the site of the primary tumor, which had the same cellular and histochemical characteristics as the metastatic lesions in bone and liver. It is emphasized that the use of pertechnetate for screening patients with gastric adenocarcinoma may be clinically useful in the early detection of metastatic lesions.


Asunto(s)
Adenocarcinoma Mucinoso/secundario , Radioisótopos de Yodo , Neoplasias Gástricas , Adenocarcinoma Mucinoso/diagnóstico por imagen , Anciano , Neoplasias Óseas/diagnóstico por imagen , Neoplasias Óseas/secundario , Femenino , Humanos , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/secundario , Cintigrafía , Pertecnetato de Sodio Tc 99m , Neoplasias de la Tiroides/diagnóstico por imagen
13.
Immunol Lett ; 45(1-2): 143-8, 1995 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-7542625

RESUMEN

Cultured murine bone marrow macrophages specifically bound 125I-labeled beta-endorphin. Binding was displaceable by 100 times molar excess of full-length beta-endorphin but was insensitive to the opioid receptor antagonist, naloxone. Binding was inhibited by beta-endorphin's C-terminal tetrapeptide, lys-lys-gly-glu, but not by the truncated N-terminal 27 amino acid fragment, indicating that binding of beta-endorphin to this receptor is dependent on its C-terminus. Macrophages incubated for 24 h with 10(-8)-10(-5) M prostaglandin E2 showed a dose-dependent increase in beta-endorphin binding, implying receptor up-regulation. This was also observed in response to the phosphodiesterase inhibitor, isobutylmethylxanthine, indicating that regulation of these receptors may be mediated through a cAMP-dependent process. This is the first demonstration that beta-endorphin receptor expression can be positively regulated.


Asunto(s)
Dinoprostona/farmacología , Macrófagos/efectos de los fármacos , Receptores Opioides/biosíntesis , Regulación hacia Arriba/efectos de los fármacos , 1-Metil-3-Isobutilxantina/farmacología , Secuencia de Aminoácidos , Animales , Unión Competitiva , Células de la Médula Ósea , Células Cultivadas , Ratones , Ratones Endogámicos DBA , Datos de Secuencia Molecular , Naloxona/farmacología , Fragmentos de Péptidos/metabolismo , Unión Proteica , Receptores Opioides/genética , Receptores Opioides/metabolismo , betaendorfina/análogos & derivados , betaendorfina/metabolismo
14.
Metabolism ; 31(3): 269-73, 1982 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-6281615

RESUMEN

A common endocrine defect in uremia is gonadal dysfunction with decreased testosterone production. Since gonadal and adrenal tissues share androgen biosynthetic pathways, we studied the stimulated adrenal androgen response in uremic patients. In contrast to the delayed or subnormal gonadal response to hCG reported by others, the adrenal response of androgens, as well as cortisol and aldosterone, to cosyntropin stimulation was unimpaired. In summary, the secretory reserve capacity of the adrenal gland for androgen, glucocorticoids and mineralocorticoids in uremia was studied with cosyntropin stimulation and found to be wall preserved.


Asunto(s)
Glándulas Suprarrenales/fisiopatología , Andrógenos/metabolismo , Fallo Renal Crónico/fisiopatología , Hormona Adrenocorticotrópica , Adulto , Aldosterona/metabolismo , Androstenodiona/metabolismo , Deshidroepiandrosterona/análogos & derivados , Deshidroepiandrosterona/metabolismo , Sulfato de Deshidroepiandrosterona , Humanos , Hidrocortisona/metabolismo , Masculino , Persona de Mediana Edad , Diálisis Renal , Factores de Tiempo
15.
Metabolism ; 35(8): 705-8, 1986 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-3526085

RESUMEN

Benign asymptomatic or painful enlargement of the male breast is a common problem, postulated to be due to an increased estrogen/testosterone ration or due to increased estrogenic or decreased androgenic stimulation via estrogen or androgen receptor interactions. Treatment at present consists of analgesic medication or surgery. However, treatment directed against the preponderance of estrogenic stimulation would seem to represent a more specific form of therapy. In the present double-blind crossover study, one-month courses of a placebo or the antiestrogen tamoxifen (10 mg given orally bid) were compared in random order. Seven of ten patients experienced a decrease in the size of their gynecomastia due to tamoxifen (P less than 0.005). Overall, the decrease for gynecomastia for the whole group was significant (P less than 0.01). There was no beneficial effect of placebo (P greater than 0.1). Additionally, all four patients with painful gynecomastia experienced symptomatic relief. There was no toxicity. The reduction of breast size was partial and may indicate the need for a longer course of therapy. A followup examination was performed in eight out of ten patients nine months to one year after discontinuing placebo and tamoxifen. There were no significant changes from the end of the initial study period except for one tamoxifen responder who developed a recurrence of breast tenderness after six months, and one nonresponder who demonstrated an increase in breast size and a new onset of tenderness after ten months. Therefore, antiestrogenic treatment with tamoxifen may represent a safe and effective mode of treatment for selected cases of cosmetically disturbing or painful gynecomastia.


Asunto(s)
Ginecomastia/tratamiento farmacológico , Tamoxifeno/uso terapéutico , Administración Oral , Anciano , Ensayos Clínicos como Asunto , Método Doble Ciego , Humanos , Masculino , Persona de Mediana Edad , Distribución Aleatoria
16.
Metabolism ; 34(8): 731-6, 1985 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-3160911

RESUMEN

Previous studies have shown wide variation in the normal range of serum concentrations of adrenal androgens, including dehydroepiandrosterone (DHA), and DHA sulfate (DHAS). Much of this variability has been shown to be due to the marked variation of the concentrations of these hormones with age. In a search for other sources of this variation, we examined the distribution of DHAS levels in 178 individuals drawn from 26 families. DHAS was chosen because of its relatively high serum concentration, long half-life, and lack of pulsatile variation. As expected, we observed a large age effect, such that it accounted for 68% of the overall variability. In addition, however, when age was factored out by appropriate polynomial regression, there was a significant genetic component to the residual variation, with a heritability of 65%. Thus there appeared to be a significant genetic determination to DHAS serum levels. The results are in accord with previous studies suggesting a genetic component to the variation in testosterone and sex hormone globulin concentrations, and the known correlation of DHAS and testosterone levels. Thus there appears to be significant genetic control of androgen concentrations in humans.


Asunto(s)
Deshidroepiandrosterona/análogos & derivados , Adolescente , Adulto , Anciano , Envejecimiento , Análisis de Varianza , Niño , Preescolar , Deshidroepiandrosterona/sangre , Deshidroepiandrosterona/genética , Sulfato de Deshidroepiandrosterona , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fenotipo , Radioinmunoensayo , Análisis de Regresión
17.
Steroids ; 29(6): 715-24, 1977 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-910247

RESUMEN

A radioimmunoassay using an antiserum produced against 6beta-hydroxy-4-androstene-3,17-dione-6-succinyl-BSA conjugate is described which permits the rapid determination of 4-androstene-3,17-dione in multiple serum samples that are purified by column chromatography on neutral alumina. Steroids which reacted significantly with the antiserum were found to be 5alpha-androstane-3,17-dione, 5beta-androstane-3,17-dione, and 6beta-hydroxy-4-androstene-3,17-dione. After column chromatography on alumina, however, the only significantly cross-reacting steroids were the 5alpha and 5beta-androstane-3,17-diones, while cross-reactivity from other steroids was reduced to less than 1%.


Asunto(s)
Androstenodiona/sangre , Adulto , Dexametasona , Humanos , Metirapona , Radioinmunoensayo/métodos
18.
Am J Med Sci ; 299(1): 21-5, 1990 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-2296994

RESUMEN

In order to study the effect of starvation on brown adipose tissue (BAT) type II 5'-monodeiodinating activity (5'MDI), type II 5'MDI was measured in vitro in the presence of 20 mM dithiothreitol, 1 mM propylthiouracil, 2 nM thyroxine (T4) and appropriate amounts of 600 X g infranatant of BAT from fed control or 3 day fasted mice, with or without daily T4 replacement (1.2 micrograms/100 g bw) during starvation. I- released from 125I-T4 was measured by ion-exchange column chromatography. Activity of BAT 5'MDI was markedly elevated in the 3 day fasted group (133 +/- 28 fmol I-/h per mg protein vs. 26 +/- 6.4; p less than 0.05). Kinetic studies using BAT infranatant suggested that fasting-induced activity is associated with a similar change in the Vmax, but no demonstrable change in apparent Km of T4 monodeiodination. T4 replacement during fasting, which normalized both serum T4 and T3 in fed and 3 day fasted groups, did not stop the increase of BAT 5'MDI in the fasted group (p less than 0.01). The data suggest that: (1) the fasting-induced increase in BAT 5'MDI is due mainly to the changes in capacity rather than the affinity of the enzyme, and (2) the fasting-induced increase in BAT 5'MDI is not mediated entirely through changes in serum thyroid hormone concentration.


Asunto(s)
Tejido Adiposo/enzimología , Ayuno/fisiología , Yoduro Peroxidasa/biosíntesis , Animales , Ditiotreitol/farmacología , Inducción Enzimática/efectos de los fármacos , Femenino , Cinética , Ratones , Propiltiouracilo/farmacología , Tiroxina/sangre , Tiroxina/farmacología , Triyodotironina/sangre
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