Effect of lithium chloride on the thyroid gland of white rats]

The morphological and functional changes in the thyroid tissue of white rats injected lithium chloride at doses 0.5 mekv/kg and 1.0 mekv/kg (groups 1 and 2, respectively) during three weeks were studied by the radiometric, histological and biochemical methods. The radiometric, histological and biochemical methods. The inhibitory action of lithium chloride on hormonogenesis in the thyroid gland and secretion of thyroid hormones into the blood was proved to be directly related to the lithium dose and concentration in the blood. The data of intravital radiometric and morphological analysis of the organs of the 1st group animals suggest some activization of the gland function, with the secretion of the hormones into the blood being suppressed. Increased concentration of the drug inhibits hormonogenesis and secretion of thyroid hormones into the blood.     

Effect of pineal peptides on the adrenal gland cortex glucocorticoid function and behavior in rats orally immunized with ovalbumin

The influence of intraperitoneal injections of pineal peptides (5 mg/100 g of body mass during first five days of three weeks' oral immunization by ovalbumin) on the rats' behavior in the "open field" tests and on the blood corticosterone level, was investigated. It was found out that rats' oral immunization resulted in increasing of secretion activity of Peyer's patches antibody-producing cells, in decreasing of blood leukocyte cytokine-producing activity, in depression of the searching behavior and locomotor activity and in a significant (p < 0.05) lowering of the blood corticosterone level after 15 minutes in the "open field" tests. The pineal peptide injections caused an intensification of humoral immune response, a more obvious suppression of locomotor activity and searching behavior, and a significant decrease of the corticosterone level compared to the animals intraperitoneally injected by physiological solution. These data indicate that immuno-stimulative effect of pineal peptides combines with their ability to decrease glucocorticoid hormone secretion during stress-reaction.     

Sex dimorphism in the thyroid gland. I. Morphometric studies on the thyroid gland of intact adult male and female rats

Morphometric studies were performed on thyroid glands of intact adult male and female rats. Thyroid follicular cells are markedly higher in the male rats than in the females during estrus. The volume fraction of the epithelium is larger but the fraction of colloid is less in males than in females. Also epithelium/colloid ratio is higher in male than in female rats.     

Effect of arginine-vasopressin on the rat thyroid gland in vitro

The response of the rat thyroid gland to arginine-vasopressin in vitro was studied to clear a possibility of a direct regulation of this gland by hypothalamic nonapeptide neurohormones. The function of the thyroid gland was estimated by thyrocyte height and quantity of the autoradiographs on a thyrocyte. AVP makes more active hormone synthesis in thyrocytes after 30 min of incubation and it stimulates both synthesis and secretion of the thyroid hormones in 2 hours of incubation. The higher concentrations of AVP activate the thyroid hormone synthesis but not the secretion.     

慢性不可预见性应激对大鼠恐惧条件反射和躯体感觉诱发电位的影响

目的:探讨慢性不可预见性应激对大鼠恐惧条件反射以及体感诱发电位的影响并分析可能的神经电生理机制。方法:26只雄性SD大鼠(190~200 g)随机分成两组(n=13):对照组和模型组。用慢性不可预见性应激刺激模型组大鼠,用恐惧条件反射实验检测两组大鼠的恐惧反应,用躯体感觉诱发电位检测大鼠脑电活动。结果:与对照组相比,模型组大鼠在恐惧记忆阶段不动时间百分比减小(56.64%±13.78%vs69.72%±18.10%,P<0.05),躯体感觉诱发电位的第二个正向波(P2)潜伏期也明显缩短(70.54±10.13 msvs78.46±7.80 ms,P<0.05)。相关性分析显示大鼠恐惧条件反射的不动时间与躯体感觉诱发电位潜伏期存在正相关(r=0.507,P<0.05)。结论:慢性不可预见性应激抑制大鼠恐惧反应,并缩短体表感觉诱发电位的潜伏期,恐惧反应行为与体感诱发电位潜伏期存在正相关,提示大鼠恐惧反应与体表感觉诱发电位可能有共同的神经递质机制。     

Effect of antioxidants on internucleosomal DNA fragmentation in thyroid tissue of patients with various thyroid pathology

The in vitro effects of a-tocopherol and melatonin on the intensity of DNA internucleosomal fragmentation in tissue and neoplastic tissue of patients with thyroid pathology was studied. alpha-Tocopherol at a concentration of 10(-7) M and melatonin at a concentration of 10(-3) M were shown to inhibit internucleosomal DNA fragmentation in unchanged thyroid tissue, while in pathologically changed tissue and neoplastic tissue the effect of antioxidants was either absent, or those effects of preparations were prevailing, which were aimed at an increase in the intensity of internucleosomal DNA fragmentation. Some peculiarities of changes in the content of certain oligonucleosome fractions depending on the preparation, its dose, and thyroid disorder have been identified. The possible mechanisms of the effect of antioxidants on internucleosomal DNA fragmentation in normal thyroid tissue and in the presence of thyroid pathology are discussed.     

Effect of thyrotropic hormone on the membrane potential of thyroid gland cells and thyroid hormone secretion with aging

Effect of thyrotropic hormone (TTH) on membrane potential (MP) of thyroid cells and thyroid hormone secretion was studied in experiments on male rats of two age groups (7--12- and 27--32-month-old animals). It was found that during the first 3 hours after TTH administration (5 U/100 g i. v.) the depolarization of secretory cell membranes of adult rats was done pronounced and developed more rapidly than in old ones and that an increase in free thyroxin (T4) correlation with MP changes with time. In a dose of 0.5 U/100 g TTH caused a significant rise in T4 secretion only in old rats. The cAMP level in the thyroid gland declined with aging. In a dose of 5 U/100 g TTH provoked a significant increase in the cAMP content in adult rats and had no effect on its content in old ones. A relationship between the MP level of thyroid secretory cells and thyroid hormone secretion is discussed.