RESUMO
BACKGROUND: Adaptation of the organism to the action of certain damaging factors, including radiation, is closely related to the state of the hypothalamic-pituitary-adrenal system. The important role in its activities is played by adrenocorticocytes (ACC) - the cells of the fascicular zone of the adrenal cortex. The disturbance of the structure and function of these cells can significantly impair and limit the development of the adaptive reactions in the body. One of the most promising ways to prevent the post-radiation changes in adrenocorticocytes consists of the application of the non-pharmacological therapeutic factors, such as low-intensity electromagnetic radiation (EMR) of ultra high frequency ( UHF) and the low-frequency (LF) magnetic field (MF) of low intensity (LI) after the exposition of the cells to the action of radiation. AIM: The objective of the present study was to identify the ultrastructural regenerative - adaptive changes in ACC of the fascicular zone of the adrenal gland in response to the primary preventive action of ultra high frequency EMR, microwave oven, and low-intensity MF after the exposition of the cells to the action of radiation. MATERIAL AND METHODS: The investigations were carried using the outbred male rats (180-200 gr body weight). The experimental animals were allocated to four groups two of which had been preliminarily treated by the application of ultra high frequency EMR and low-intensity MF and were thereafter exposed to radiation. The animals of the third group were exposed to radiation alone without the treatment with the therapeutic physical factors and served as controls whereas the animals of the fourth group underwent no treatment whatever and were regarded as intact. Transmission electron microscopy was used to count light and dark adrenocorticocytes of the fascicular zone. The morphometric analysis of mitochondria included the determination of their number, the average and the total area per standard cell area, and the number of cristae per average area of mitochondria). In addition, the analysis of the lipid content and protein-synthesizing organelles was performed. RESULTS: The study has demonstrated that the primary prophylactic application of ultra high frequency EMR and the low-frequency MF caused stimulation of the cellular and intracellular regenerative-adaptive reactions and increased the resistance of the ultrastructure of ACC in the fascicular zone of the adrenal glands to the action of radiation. These changes were most pronounced in response to the application of ultra high frequency EMR. The resulting structural-adaptive rearrangements of the organelles (the enlargement of mitochondria with the simultaneous increase in the number of cristae, hyperplasia of ribosomes and smooth endoplasmic reticulum, preservation of membranes) were largely due to antioxidative and membrane-stabilizing effects of low-intensity electromagnetic radiation of ultra high frequency and were directly related to the formation of the mechanisms of ACC radioprotection. The Increased regenerative-adaptive potential of these cells prevented the development of the dystrophic processes and protected the adrenocorticocytes from aggressive radiation. CONCLUSIONS: The results of the present study suggests the necessity of the further studies on the action of the non-pharmacological therapeutic factors, especially low-intensity electromagnetic radiation (EMR) of ultra high frequency and the low-frequency magnetic field of low intensity as the tools for the prevention of post-radiation changes in the adrenocorticocytes of the fascicular zone of the adrenal cortex exposed to the action of radiation.
Assuntos
Córtex Suprarrenal/efeitos da radiação , Radiação Eletromagnética , Regeneração/efeitos da radiação , Córtex Suprarrenal/citologia , Animais , Masculino , RatosRESUMO
We observed immunorehabilitation effects of ultrahigh frequency electromagnetic fields (microwaves) in immunocompromised animals. It was shown that microwave irradiation of the thyroid gland area could abolish actinomycin D- and colchicine-induced immunosuppression and did not affect immunosuppression caused by 5-fluorouracil. These findings suggest that changes in the hormonal profile of the organism during microwave exposure can stimulate the processes of transcription and mitotic activity of lymphoid cells.
Assuntos
Córtex Suprarrenal/efeitos da radiação , Campos Eletromagnéticos , Hospedeiro Imunocomprometido/efeitos da radiação , Magnetoterapia/métodos , Glândula Tireoide/efeitos da radiação , 11-Hidroxicorticosteroides/sangue , Córtex Suprarrenal/imunologia , Córtex Suprarrenal/metabolismo , Glândulas Suprarrenais/metabolismo , Glândulas Suprarrenais/efeitos da radiação , Animais , Células Produtoras de Anticorpos/efeitos dos fármacos , Células Produtoras de Anticorpos/efeitos da radiação , Colchicina , Dactinomicina , Eritrócitos/imunologia , Eritrócitos/efeitos da radiação , Hospedeiro Imunocomprometido/imunologia , Terapia de Imunossupressão , Masculino , Micro-Ondas/uso terapêutico , Coelhos , Baço/citologia , Glândula Tireoide/imunologia , Glândula Tireoide/metabolismoRESUMO
The influence of serpistene in dose of 5 and 50 mg/kg on chronic low-dose gamma-irradiation (22.6 cGy) effects on cytogenetic (abnormal sperm cell, marrow bone micronucleus) and function and morphology (thyroid and adrenal glands) parameters of mice was estimated. The serpistene modifies effects of gamma-irradiation depends on the administration regime and a dose of the substance. The most expressive radioprotective effect on endocrine organs after serpistene prophylactic administration was found. The prophylactic dose was 5 mg/kg for adrenal gland and both doses--for thyroid gland. The most expressive radioprotective effect on marrow bone cells after serpistene therapeutic administration in a dose of 5 mg/kg was found. The most expressive antimutagenic effect on somatic and germinal cells of prophylactic and therapeutic administration in a dose of 50 mg/kg was found.
Assuntos
Asteraceae/química , Ecdisteroides/uso terapêutico , Raios gama/efeitos adversos , Lesões Experimentais por Radiação/prevenção & controle , Protetores contra Radiação/uso terapêutico , Córtex Suprarrenal/efeitos dos fármacos , Córtex Suprarrenal/efeitos da radiação , Animais , Relação Dose-Resposta a Droga , Relação Dose-Resposta à Radiação , Ecdisteroides/administração & dosagem , Ecdisteroides/isolamento & purificação , Perda do Embrião/etiologia , Perda do Embrião/prevenção & controle , Feminino , Masculino , Camundongos , Micronúcleos com Defeito Cromossômico/efeitos dos fármacos , Micronúcleos com Defeito Cromossômico/efeitos da radiação , Doses de Radiação , Protetores contra Radiação/administração & dosagem , Protetores contra Radiação/isolamento & purificação , Reprodução/efeitos dos fármacos , Reprodução/efeitos da radiação , Cabeça do Espermatozoide/efeitos dos fármacos , Cabeça do Espermatozoide/efeitos da radiação , Testículo/efeitos dos fármacos , Testículo/efeitos da radiação , Glândula Tireoide/efeitos dos fármacos , Glândula Tireoide/efeitos da radiaçãoRESUMO
We studied morphological-biochemical time-course reactions of adrenal cortex and hormonal function of testicles after combined or separate actions of external radiation exposure (1.0 Gy at 7.8 x 10(-4) Gy/sec) and prolonged (12-, 32 days) subcutaneous corticosterone injections (10 mg/kg/animal) in 2-3-month old male rats. Both variants with exogenous hormone depressed endogenous glucocorticoid production and evolved acute structure-functional adrenal gland cortex deficiency. Radiocensitivity of the gland at the experimental conditions was increased. Simultaneously the aggravation of adrenal cortex functional activity accompanied with hypogonadism and depressed reproductive potential of male rats, accessed by means of androgen status and androgenspecific (transporting and receptional) proteins characteristics as sensitive molecular markers of an animal possible fecundity.
Assuntos
Córtex Suprarrenal/fisiologia , Córtex Suprarrenal/efeitos da radiação , Androgênios/metabolismo , Raios gama , Tolerância a Radiação/fisiologia , Córtex Suprarrenal/citologia , Animais , Corticosterona/sangue , Corticosterona/farmacologia , Glucocorticoides/fisiologia , Hipogonadismo/metabolismo , Masculino , Tolerância a Radiação/efeitos dos fármacos , Ratos , Ratos Endogâmicos , Receptores Androgênicos/metabolismo , Testículo/metabolismo , Testículo/efeitos da radiação , Testosterona/sangue , Testosterona/metabolismoRESUMO
A morphological evaluation of the results of transcutaneous radiation of male mice with infra-red impulse laser beam for 10 min (10,100, 1000, 10,000 Hz) 5 min, 3 and 24 hours after the procedure has confirmed the existence of "resonance" frequencies for different types of endocrine cells and has shown that the response depends not only on the dose of infrared low-intensity laser radiation. Thus, account for resonance frequencies is one of perspective approaches to optimization of laser therapy which may raise effectiveness and safety of laser exposure.
Assuntos
Degranulação Celular/efeitos da radiação , Células Enteroendócrinas/efeitos da radiação , Raios Infravermelhos , Lasers , Terapia com Luz de Baixa Intensidade/efeitos adversos , Córtex Suprarrenal/citologia , Córtex Suprarrenal/efeitos da radiação , Animais , Relação Dose-Resposta à Radiação , Células Enteroendócrinas/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos , Pâncreas/citologia , Pâncreas/efeitos da radiação , Piloro/citologia , Piloro/efeitos da radiação , Fatores de Tempo , Irradiação Corporal TotalRESUMO
PURPOSE: To investigate the long-term effects of total-body irradiation (TBI) on kidneys in non-human primates. METHODS AND MATERIALS: The kidneys of Rhesus monkeys were histologically examined at 6-8 years after TBI with low single doses of 4.5-8.5Gy or two fractions of 5.4Gy. The kidneys of age-matched non-irradiated monkeys served as controls. Irradiation was performed on adult monkeys aged about 3 years; 6-8 years later animals were sacrificed and the kidneys removed and processed for histology. A semi-quantitative scoring system was used to evaluate overall histological damage. Glomerular changes were also morphometrically analysed according to previously published criteria. In selected dose groups (pro)thrombotic and inflammatory changes were investigated by immunostaining cryosections with antibodies against von Willebrand factor (vWF), leukocytes and macrophages. RESULTS: Histological changes were generally mild and only seen in kidneys irradiated with doses higher than 7 Gy. Glomerular changes were characterized by increased mesangial matrix and capillary dilatation. Tubulo-interstitial changes included hypercellularity, fibrosis and mild tubular atrophy. The mean glomerular area expressing vWF protein in the irradiated kidneys was not different from that in the age-matched controls. Numbers of infiltrating leukocytes were not significantly different between irradiated kidneys and controls. However, slightly increased numbers of macrophages were present in the renal cortex after irradiation. CONCLUSIONS: Renal damage after TBI of Rhesus monkeys with single doses of 4.5-8.5 Gy or two fractions of 5.4 Gy was mild, even after follow-up times of 6-8 years.
Assuntos
Rim/efeitos da radiação , Irradiação Corporal Total/efeitos adversos , Córtex Suprarrenal/efeitos da radiação , Animais , Relação Dose-Resposta à Radiação , Feminino , Processamento de Imagem Assistida por Computador , Imuno-Histoquímica , Rim/anatomia & histologia , Glomérulos Renais/efeitos da radiação , Túbulos Renais/efeitos da radiação , Macaca mulatta , Masculino , Fatores de Tempo , Raios X , Fator de von Willebrand/biossínteseRESUMO
Single whole-body gamma-irradiation of BALB/c mice at a dose of 6.0 Gy results in an immediate response of the hypothalamus and hypophysis system: an increased generation of gonadotropin, adrenocorticotropin, and thyreotropin. The response of other organs manifests itself in an increase in testosterone, corticosterone and thyroxine in the organism. The above disturbances result in depression of the testicular activity and in fertility. The deficiency of testosterone is partly compensated by the enhancement of the adrenal secretion of adrogens.
Assuntos
Córtex Suprarrenal/efeitos da radiação , Testículo/efeitos da radiação , Glândula Tireoide/efeitos da radiação , Córtex Suprarrenal/fisiologia , Animais , Raios gama , Hormônios/sangue , Hormônios/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Contagem de Espermatozoides/efeitos da radiação , Testículo/fisiologia , Glândula Tireoide/fisiologia , Fatores de Tempo , Irradiação Corporal TotalRESUMO
In recent years, some epidemiologic studies have suggested that extremely low frequency magnetic and electric fields might affect human health, and, in particular, that the incidence of certain types of cancer, depression, and miscarriage might increase among individuals living or working in environments exposed to such fields. Work in our laboratory studies whether and how changes in the electromagnetic environment might affect human health. The study presented here was designed to look for possible effects of acute exposure to 50-Hz linearly polarized magnetic fields (10 microT) on the hormones of the hypothalamic-pituitary-thyroid and hypothalamic-pituitary-adrenal axes. Thirty-two young men (20-30 years old) were divided into two groups (sham-exposed or control group, and exposed group) of 16 subjects each. All subjects participated in two 24-hour experiments to evaluate the effects of both continuous and intermittent (one hour "off" and one hour "on" with the field switched "on" and "off" every 15 seconds) exposure to linearly polarized magnetic fields. The subjects were exposed to the magnetic field (generated by three Helmholtz coils per bed) from 2300 to 0800 while recumbent. Blood samples were collected during each session at 3 hour intervals from 1100 to 2000 and hourly from 2200 to 0800. Total urine was collected every 3 hours from 0800 to 2300 and then again at 0800. No significant differences were observed between sham-exposed and exposed men for any of the parameters measured: thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, triiodothyronine, thyroxine, free triiodothyronine, free thyroxine, thyroxine-binding globulin, cortisol, 17-hydroxycorticosteroids (17-OH-CS) and TBK. These results suggest that acute exposure to either continuous or intermittent 50-Hz linearly polarized magnetic fields of 10 microT does not affect, at least under our experimental conditions, these endocrine functions or their circadian rhythmicity in healthy young men.
Assuntos
Córtex Suprarrenal/efeitos da radiação , Ritmo Circadiano , Campos Eletromagnéticos/efeitos adversos , Sistema Hipotálamo-Hipofisário/efeitos da radiação , Sistema Hipófise-Suprarrenal/efeitos da radiação , Glândula Tireoide/efeitos da radiação , 17-Hidroxicorticosteroides/urina , Córtex Suprarrenal/fisiologia , Adulto , Hormônio Foliculoestimulante/sangue , Humanos , Hidrocortisona/sangue , Sistema Hipotálamo-Hipofisário/fisiologia , Hormônio Luteinizante/sangue , Masculino , Sistema Hipófise-Suprarrenal/fisiologia , Valores de Referência , Glândula Tireoide/fisiologia , Tireotropina/sangue , Tiroxina/sangue , Proteínas de Ligação a Tiroxina/análise , Tri-Iodotironina/sangueAssuntos
Córtex Suprarrenal/efeitos da radiação , Corticosterona/metabolismo , Luz , Fotoperíodo , Seleção Genética , Córtex Suprarrenal/anatomia & histologia , Córtex Suprarrenal/metabolismo , Animais , Corticosterona/sangue , Feminino , Masculino , Tamanho do Órgão/efeitos da radiação , Ratos , Ratos Wistar , Especificidade da Espécie , Estresse Psicológico/metabolismo , Fatores de TempoRESUMO
The rat adrenal cortex activation is accompanied by inhibition of steroid metabolism in liver and vice versa at acute radiation disease caused by X-ray irradiation. A coupling of contrary changes of corticosteroid secretion and metabolism evidences that there is common regulation of these functions. The possible ACTH participation in coupling of adrenals and liver functions and the liver role in radiation hypercorticism genesis are discussed.
Assuntos
Corticosteroides/efeitos da radiação , Córtex Suprarrenal/efeitos da radiação , Fígado/efeitos da radiação , 11-Hidroxicorticosteroides/sangue , Doença Aguda , Córtex Suprarrenal/metabolismo , Corticosteroides/metabolismo , Hiperfunção Adrenocortical/etiologia , Hiperfunção Adrenocortical/metabolismo , Hormônio Adrenocorticotrópico/fisiologia , Hormônio Adrenocorticotrópico/efeitos da radiação , Animais , Relação Dose-Resposta à Radiação , Fígado/metabolismo , Masculino , Lesões Experimentais por Radiação/etiologia , Lesões Experimentais por Radiação/metabolismo , Ratos , Fatores de TempoAssuntos
Córtex Suprarrenal/efeitos da radiação , Exposição Ambiental , Centrais Elétricas , Liberação Nociva de Radioativos , Glândula Tireoide/efeitos da radiação , Adaptação Fisiológica , Córtex Suprarrenal/metabolismo , Feminino , Humanos , Hipotireoidismo/etiologia , Hipotireoidismo/fisiopatologia , Lactente , Recém-Nascido , Radioisótopos do Iodo , Hipófise/metabolismo , Hipófise/efeitos da radiação , Gravidez , Efeitos Tardios da Exposição Pré-Natal , República de Belarus , Glândula Tireoide/metabolismo , UcrâniaRESUMO
Forty-nine children who had undergone treatment with cyclophosphamide and total body irradiation before bone marrow transplantation were investigated for impaired endocrine function. Twenty-six patients received single fraction total body irradiation as a dose of 9-10 Gy, whereas 23 patients received fractionated total body irradiation as a total dose of either 12 Gy divided into six fractions or 14.4 Gy divided into eight fractions, administered over 3 or 4 days. Half of the patients in the single fraction group and nine in the fractionated group had received cranial irradiation prior to total body irradiation. Pathological changes in thyroid function were observed in 19 patients (73%) of the single fraction group (elevated thyrotrophin (58%) and decreased thyroxine levels (15%)), whereas in the fractionated group only six patients (25%) developed transient raised thyrotrophin levels: the mean observation period was 3.2 years in the single fraction group and 2.7 years in the fractionated group. The stimulated growth hormone peak concentration was influenced significantly by previous cranial irradiation and was independent of the type of total body irradiation administered. In the patients who had received cranial irradiation, the mean growth hormone peak levels were 8.4 mU/l (single fraction group) and 13.9 mU/l (fractionated group), whereas in those who received only total body irradiation they were 24.9 mU/l(single fraction group) and 28.1 mU/l (fractionated group). The basal gonadotrophin concentration in children older than 9 years showed elevated levels in nine patients (50%) of the single fraction group and in only three patients (30%) of the fractionated group.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Transplante de Medula Óssea , Glândulas Endócrinas/efeitos da radiação , Irradiação Corporal Total/efeitos adversos , Adolescente , Córtex Suprarrenal/efeitos da radiação , Criança , Pré-Escolar , Glândulas Endócrinas/metabolismo , Feminino , Gonadotropinas/sangue , Hormônio do Crescimento/sangue , Humanos , Hidrocortisona/sangue , Hipotireoidismo/etiologia , Leucemia Mieloide Aguda/cirurgia , Estudos Longitudinais , Masculino , Análise Multivariada , Hipófise/efeitos da radiação , Leucemia-Linfoma Linfoblástico de Células Precursoras/cirurgia , Puberdade/efeitos dos fármacos , Hormônios Tireóideos/sangueRESUMO
Increase of capillaries blood volume, nuclear mass and nuclear cytoplasmic relationship and decrease of lipid content and adrenocortical sizes were determined in superficial adrenocortical layers on helium-neon LAZER irradiation of uncovered left adrenal glands in white female rats. It was confirmed by corticosteroid function increase. Similar morphometric changes were identified all over adrenocortical bundles on arsenate-helium irradiation of covered left adrenal gland from the back of the animal. According to obtained results LAZER irradiation may be recommended to use for functional stimulation of adrenal cortex.
Assuntos
Córtex Suprarrenal/efeitos da radiação , Lasers , Córtex Suprarrenal/anatomia & histologia , Córtex Suprarrenal/fisiologia , Animais , Arseniatos , Feminino , Hélio , Microcirculação/efeitos da radiação , Neônio , RatosRESUMO
Wistar male rats underwent a single exposure for 20 min, 1 and 2.5 hour to a pulsed electromagnetic field of 20 mT or a single exposure for 2.5 hour and a chronic exposure for 6 hours a day during 30 days to a pulsed electromagnetic field of 0.1 mT, the pulse time and an interval between pulses being 10(-2) sec. As a result, the experimental animals showed changes in the activity of the adrenals, thyroid and sex glands as well as eosinopenia and lymphopenia. The concentration of thyroid hormones and lymphocytes remained lowered during 2 months after a single exposure to 20 mT. In some cases the exposure modified the physiological responses of rats to an acute stress-5-hour immobilization.
Assuntos
Córtex Suprarrenal/efeitos da radiação , Campos Eletromagnéticos , Fenômenos Eletromagnéticos , Linfócitos/efeitos da radiação , Testículo/efeitos da radiação , Glândula Tireoide/efeitos da radiação , Córtex Suprarrenal/metabolismo , Animais , Corticosterona/metabolismo , Corticosterona/efeitos da radiação , Linfócitos/citologia , Masculino , Ratos , Ratos Endogâmicos , Testículo/metabolismo , Testosterona/metabolismo , Testosterona/efeitos da radiação , Glândula Tireoide/metabolismo , Hormônios Tireóideos/metabolismo , Hormônios Tireóideos/efeitos da radiação , Fatores de TempoRESUMO
In rats the roentgen irradiation with lethal doses results in an essential decrease of liver capacity to metabolise corticosteroids with increasing secretion activity of adrenal cortex. That is a sign for increasing waste of reciprocal control of adrenal gland and liver, that is indispensable to maintenance of corticosteroid hemostasis.
Assuntos
Corticosteroides/metabolismo , Córtex Suprarrenal/metabolismo , Fígado/metabolismo , Lesões Experimentais por Radiação/metabolismo , Córtex Suprarrenal/efeitos da radiação , Animais , Fígado/efeitos da radiação , Masculino , RatosRESUMO
The authors presented the results of study of lymphocytic and adrenal cortical function in preoperative radiotherapy of 38 laryngeal cancer patients in different oxygen regimens: in the air and under the conditions of hyperbaric oxygenation (HBO). A method of mean dose fractionation (a single focal dose of 3.3 Gy 3 times a week up to a total dose of 33 Gy) was employed in all the patients. The total lymphocyte count in 1 microliter of the blood, the number of lymphocytes blast transformed as a result of PHA exposure, the number of lymphocytes with a positive reaction to acid phosphatase and blood 11-OCS concentration were examined. Radiation reaction like epitheliitis was shown to be less frequent in patients treated under HBO conditions, the probability of development of epitheliitis in patients with lowered lymphocytic function being higher.
Assuntos
Córtex Suprarrenal/efeitos da radiação , Neoplasias Laríngeas/radioterapia , Linfócitos/efeitos da radiação , Oxigênio/fisiologia , Córtex Suprarrenal/fisiopatologia , Idoso , Ar , Humanos , Oxigenoterapia Hiperbárica , Neoplasias Laríngeas/fisiopatologia , Linfócitos/fisiologia , Masculino , Pessoa de Meia-IdadeRESUMO
As early as 0.5-3 h after X-irradiation of rats with a lethal dose of 12 Gy glucocorticoid activity of adrenal cortex was enhanced and 11-oxycorticosteroid level in blood was increased. The increasing of the immunoreactive insulin content of blood was registered at the background of hypercorticoidism and normal function of insular apparatus during the first hours following irradiation. At later times (24-72 h), a stable hypercorticoidism developed, the ability of beta-cells to react adequately to glucose was impaired, and IRI content of blood decreased.
Assuntos
Córtex Suprarrenal/fisiopatologia , Ilhotas Pancreáticas/fisiopatologia , Lesões Experimentais por Radiação/fisiopatologia , 11-Hidroxicorticosteroides/sangue , Córtex Suprarrenal/efeitos da radiação , Animais , Insulina/sangue , Ilhotas Pancreáticas/efeitos da radiação , Masculino , Ratos , Fatores de TempoRESUMO
Six-hundred-and-one male Long-Evans rats were used to study the effect of microwaves on adrenocortical secretion. Power density ranged from 0.1 to 55 mW/cm2 (SAR 0.02 to 11 W/kg). The microwave signal was 2.45 GHz amplitude modulated at 120 Hz. Serum corticosterone (CS) concentration was used as an index of adrenocortical function. Ten different exposure protocols were used to identify confounding factors influencing the sensitivity of adrenal cortex to microwave exposure. Increases in CS concentration were proportional to power density or colonic temperature and inversely proportional to the baseline CS. Increased CS concentration was never observed without increased colonic temperature and was not persistent 24 h after exposure. Acclimation (reduction in magnitude of response) could be noted after the tenth exposure. Facilitated heat loss attenuated the magnitude of CS increases by limiting the degree of hyperthermia. Ethanol enhanced the hyperthermic response and desensitized the adrenal response to microwave hyperthermia by increased baseline CS. Ether stimulated adrenal secretion irrespective of previous microwave exposure or adrenal stimulation induced by microwaves. Minor inhibition was also noted occasionally as decreased CS concentration at lower intensity (less than 20 mW/cm2) and decreased postexposure urinary CS excretion at 40 mW/cm2. Adrenal stimulation required minimally a 20 mW/cm2 (4 W/kg) or 0.7 degrees C increase in colonic temperature. An SAR lower than 4 W/kg may stimulate adrenal secretion by potentiating the hyperthermic effect if the ambient temperature is well above 24 degrees C.