Effect of thyroxin on accumulation of radioactive iodine in the thyroid glands of hemithyroidectomized rats of different ages

In experiments on hemithyroidectomized male rats aged from 2 to 20 months administration of thyroxin in a dose of 1 g/100 g body weight led to a significantly greater inhibition of accumulation of radioactive iodine in the residual lobe of the thyroid gland on the 5th day of the experiment in rats aged 16–20 months than in animals aged 2–2.5 months. The results confirm the earlier conclusion that the hypothalamic-hypophyseal threshold for homeostatic inhibition by thyroxin falls with age.Laboratory of Endocrinology and Roentgenodiagnostic Division, N. N. Petrov Research Institute of Oncology, Ministry of Health of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR A. I. Serebrov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 5, pp. 539–541, May, 1978.     

Dependence of androgenization on differentiation of the hypothalamic centers

Dependence of the sterilizing action of androgens on the level of differentiation of the hypothalamic centers in the postnatal period of development was studied in female rats. Asynchronous development of the arcuate nucleus (AN; the tonic center) and the suprachiasmatic nucleus (SCN; the cyclic center) was found. Neurons of AN begin to produce granules of secretion in 20-day embryos. The first neurons with granules of secretion are found in SCN in rats aged 5–7 days. Injection of testosterone propionate induces an anovulatory cycle in females during the first 7 days after birth, on account of inhibition of development of the hypothalamic cyclic center.Laboratory of Mechanisms of Action of Antitumor Preparations, Oncologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. N. Blokhin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 2, pp. 207–209, February, 1978.     

Changes in the level of epidermal G2 chalone and mitotic activity in the vaginal epithelium of rats

The content of epidermal inhibitor of mitosis (G₂ chalone) at different stages of the estrous cycle in rats was determined by the radial immunodiffusion method. The chalone level correlates with the mitotic index of the vaginal mucous membrane and is minimal in proestrus and maximal in estrus. In aging (14–16 months) rats with regular cycles the content of G₂ chalone in the vaginal mucous membrane at all phases of the estrous cycle was significantly lower than in young (3–4 months) rats with a regular cycle. In castrated rats the mitotic index begins to rise 18 h after a single injection of estradiol benzoate (1 g/100 g body weight). This increase is preceded by a significant decrease in the concentration of G₂ chalone 12 h after injection of the estrogen.Laboratory of Experimental Tumors and Laboratory of Endocrinology, N. N. Petrov Research Institute of Oncology, Ministry of Health of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR A. I. Serebrov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 4 pp. 349–351, April, 1979.     

Effect of an atherogenic diet on age differences in cholesterol biosynthesis in the rat liver

After intraperitoneal injection of radioactive sodium acetate into rats of two age groups (6–8 and 28–32 months) the dynamics of cholesterol biosynthesis in the liver was observed to be slower in the older animals. The specific liver cholesterol activity of the older rats was lower at the maximum of uptake of the label than in the younger rats. An atherogenic diet for 20 days (0.25 g cholesterol/100 g body weight) led to an increase in the total cholesterol content but to inhibition of its biosynthesis in the liver, and this effect was most marked in the younger rats. Continued administration of cholesterol depressed its biosynthesis still more, especially in the older animals.Laboratory of Pathophysiology, Institute of Gerontology, Academy of Medical Sciences of the USSR, Kiev. (Presented by Academician of the Academy of Medical Sciences of the USSR N. N. Gorev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 2, pp. 150–151, February, 1977.     

Effect of estrogens on growth and differentiation of the salivary glands of albino rats in organ culture

Salivary glands of albino rats in organ culture were investigated after the addition of 17-estradiol to the medium. After addition of estrogens characteristic glandular tubes with secretion containing acid and neutral mucopolysaccharides were found in the zone of growth. Necrobiotic changes occurred in explants of the control group in the early stages of culture and no marked differentiation of the epithelium was observed. Addition of estrogens in a physiological dose led to differentiation of the epithelium of the salivary glands with the formation of the specific secretion and it improved the changes of survival of the cultured tissue.I. P. Pavlov First Leningrad Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Kraevskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 79, No. 2, pp. 97–100, February, 1975.     

Comparison of compensatory hypertrophy of the kidney after unilateral nephrectomy on adult and senile rats

One kidney was removed from rats weighing 35–900 g. The animals were killed 2, 14, 30, and 60 days after the operation. The degree of compensatory hypertrophy of the remaining kidney varied considerably in the animals of different ages, although it was not reduced in old age. The weight of the hypertrophied kidney of the old rats 60 days after the operation was 55–92% of the combined weight of both kidneys in the control. Hypertrophy of the kidney at all ages was accompanied by increased proliferation of cells of the tubules, especially the proximal tubules. An increase in the size of the renal corpuscles during hypertrophy of the kidney was characteristic of rats of both age groups. However, with an increase in age this process developed faster and was more pronounced. At all times of investigation the hypertrophied kidney of rats of both ages contained 1. 5–2 times more open renal glomeruli than the kidney of the intact animal.Laboratory of Growth and Development, Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 11, pp. 1394–1397, November, 1976.     

Mitoses in hypertrophied smooth muscle tissue of the rat posterior vena cava

Injection of colchicine into rats revealed mitotically dividing leiomyocytes in the hypertrophied muscle tissue of the posterior vena cava of rats. The frequency of dividing cells under these conditions did not exceed 11000–110,000. Many of these smooth muscle cells were in prophase.Laboratory of Experimental Pathomorphology and Ultrastructural Characteristics of Pathological Processes, Institute of General Pathology and Pathophysiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR, N. A. Kraevskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 4, pp. 485–487, April, 1976.     

Inhibition of compensatory hypertrophy of the thyroid gland by thyroxine in rats of different ages

It was shown in male rats aged 2–2.5, 8–10, and 14–16 months that the inhibitory effect of the same dose (expressed per unit of body weight) of thyroxine on compensatory hypertrophy of the thyroid gland increases with age. It is postulated that the threshold of sensitivity of the hypothalamic-pituitary-thyroid system to homeostatic inhibition decreases with age.Presented by Academician of the Academy of Medical Sciences of the USSR A. I. Serebrov.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 80, No. 8, pp. 31–33, August, 1975.     

Effect of immunization against rabies on γ-aminobutyric metabolism in the animal brain

Subcutaneous injection of fixed rabies virus into albino rats weighing 100–120 g is followed by a decrease in the-aminobytyric acid (GABA) concentration in the animals' brains. An increase in the activity of GABA--ketoglutarate transaminase also is observed in the brain tissue of animals vaccinated against rabies.Laboratory of Immunopathology, D. I. Ivanovskii Institute of Virology. Laboratory of Biochemistry, N. N. Burdenko Institute of Neurosurgery, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician V. D. Timakov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 2, pp. 184–185, February, 1976.     

Dynamics of reactivity of mesenteric microvessels in rats with experimental renal and hormonal hypertension

Reactivity of mesenteric arterioles 10–30 in diameter to application of histamine (100–500 g) adrenalin, and noradrenalin (1–10 g) was studied in rats with experimental renal and hormonal hypertension. The sensitivity of the microvessels to the vasoactive substances was shown to vary with the stage of development of experimental hypertension.Laboratory of General Pathophysiology and Experimental Therapy, Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 2, pp. 150–152, February, 1976.     

Analysis of the mechanism of change in amplitude of the receptor potential of pacinian corpuscles in Ca++-Deficient solution

The causes of the rise in amplitude of the receptor potential (RP) of Pacinian corpuscles in Ca⁺⁺-free solution were investigated by the external perfusion method. In Ca⁺⁺-free solution the amplitude of RP was shown to increase, but this increase was blocked by the addition of 10–20 mM tetraethylammonium to the solution. A temporary increase in the amplitude of RP was observed in solution with 0.2 mM 2,4-dinitrophenol. The sensitivity of the receptor membrane to mechanical stimuli was unchanged in Ca⁺⁺-free solution. It is suggested that there are no negative charges near the mechanically sensitive ionic channel of the receptor membrane of Pacinian corpuscles which could affect the state of the gating system of the mechanically sensitive channel.Laboratory of General Physiology of Reception, I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR, V. N. Chernigovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 12, pp. 643–645, December, 1979.     

Biosynthesis of renal prostaglandins in spontaneously hypertensive rats

The biosynthesis of prostaglandins (PG) E₂ and F₂ from [¹⁴C]arachidonic acid by renal medullary tissue of rats with spontaneous hypertension and of normotensive Wistar rats was investigated at different ages (1.5 and 3.5 months). In animals with spontaneous hypertension the synthesis of PG E₂ from arachidonic acid was at a much lower level than in Wistar rats. The biosynthesis of PG F₂ in these animals was virtually indistinguishable from normal. No age differences were found in PG formation by the kidneys of rats with spontaneous hypertension, whereas in Wistar rats PG E₂ biosynthesis was depressed at the age of 3.5 months.Laboratory of Pathophysiology, Institute of Pediatrics, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 6, pp. 659–661, June, 1977     

Proof of existence of the human Le(c+) blood group obtained with goat immune serum

Diagnostic anti-Le^c sera with incomplete antibodies in titers of 18–116 have been prepared from the serum of a goat immunized over a period of 18 months with 210 ml of boiled saliva of the OLe(a ^–b^–) nonsecretor group. The sera have been tested by Race, Sanger, and Tippett in London.Serum Laboratory, Research Institute of Forensic Medicine, Ministry of Health of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR P. N. Kosyakov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 2, pp. 208–209, February, 1976.     

Role of the incretory function of the pancreatic islets in the mechanisms of development of hypothalamic obesity

Administration of alloxan, which injures the cells and depresses insulin secretion, to animals with experimental hypothalamic obesity prevented any further increase in body weight despite an excessive food intake by the animals. It is concluded that the most important mechanism of development of obesity following injury to the ventromedial hypothalamic nuclei is the hypersecretion of insulin caused by such injury.Department of Pathological Physiology, Karaganda Medical Institute. Department of Medical Radiology, Central Postgraduate Medical Institute, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR P. D. Gorizontov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 10, pp. 1185–1187, October, 1976.     

Effect of the enterotropic carcinogen 1,2-dimethylhydrazine on the hypothalamic biogenic amine level in rats

Subcutaneous injection of 1,2-dimethylhydrazine (DMH) in a dose of 21 mg/kg into male rats is followed after 24 h by a substantial fall in the hypothalamic levels of noradrenalin (NA), dopamine (DA), serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA). During the first 3–12 h after injection of DMH the NA level was lowered and the intensity of 5-HT metabolism increased in the hypothalamus. The hypothalamic histamine level rose only 30 min after injection of the carcinogen. No significant change took place in the biogenic amine levels in the brain stem and cerebral hemispheres under the influence of DMH. It is suggested that an essential link in the mechanism of the carcinogenic action of DMH in rats is the hormonal metabolic disturbances caused by the selective action of DMH at the level of the hypothalamic biogenic amines.Group for the Study of Mechanisms of Aging and Department of Human Neurophysiology, Institute of Experimental Medicine, Academy of Medical Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR N. P. Bekhtereva.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 11, pp. 1359–1361, November, 1976.     

Functional and morphological characteristics of the endocrine system in the progeny of adrenalectomized rats

Signs of premature maturation and activation of the pituitary-adrenocortical system were observed in the early postnatal period (70–90 h) in the progeny of rats adrenolectomized 1–3 and 7–9 days before parturition. The stronger response to stressor action than in the control (progeny of rats undergoing mock adrenalectomy and intact rats) was evidence of premature maturation of their suprahypophyseal regulatory mechanism also. Signs of functional exhaustion in the pituitary-adrenocortical system and also in the thyroid gland were found in sexually mature (6–10 months) rats obtained from adrenalectomized females.Deceased.Research Institute of Forensic Medicine, Ministry of Health of the USSR. Research Center, N. I. Pirogov Second Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR Yu. M. Lopukhin.) Trarnslated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 4, pp. 400–403, April, 1978.     

Changes in content of cytochromes c and a (a3) in liver mitochondria of hyperthyroid rats

Male Wistar rats aged 1, 3, 12, and 24 months were given thyroxine in a dose of 250 g/100 g body weight daily. After 9 days the content of cytochromes c and a (a₃) was considerably increased. An appreciable increase in the cytochrome c content was observed as early as after 24 h, whereas the content of cytochromes a (a₃) did not exceed normal even after 2 days. The content of cytochromes a (a₃) in rats aged 3, 12, and 24 months was little lower after 24 h than normally. A significant temporary increase in the ratio c/a (a₃) after 1–2 days was observed only in rats aged 12 and 24 months. An increase in the ratio c/a (a₃) with age also was demonstrated. The prospects for the use of thyroid hormones in the study of regulation of biogenesis of the mitochondria are suggested.Department of Biochemistry of Ontogeny, Research Institute of Biology, Khar'kov University. (Presented by Academician of the Academy of Medical Sciences of the USSR S. E. Severin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 2, pp. 174–176, February, 1980.     

β-Adrenorecptors on the surface membranes of lymphocytes and macrophages

The effect of -adrenergic stimulators adrenalin and isoproterenol and of the -adrenergic blocker propranolol on lymphocytosis and on the macrophage adhesion inhibition reaction was studied in vivo and in vitro on sensitized and intact guinea pigs and Wistar rats. Adrenalin and isoproterenol were shown to inhibit the reaction of the antigen with both sensitized and intact cells. Propranolol abolishes the protective effect of adrenalin and isoproterenol and restores the sensitivity of the cells to antigen.Research Laboratory of Experimental Immunology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. N. Zhukov-Verezhnikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 6, pp. 723–725, June, 1978.     

Sex ratio in mouse embryos in the postimplantation period of development

The sex ratio of CBA mouse embryos was studied on the 10th and 18th days of development in order to discover any connection between the sex of the embryos and their mortality. The spontaneous embryonic mortality rate was found to increase until the 18th day of development; however, the rate was unconnected with the sex of the embryos and the distribution of embryos by sex at different stages of embryogenesis did not deviate from 11.Department of Embryology, Institute of Experimental Medicine, Academy of Medical Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR M. A. Petrov-Maslakov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 2, pp. 234–235, February, 1976.     

Biosynthesis and production of specific β1-globulin in rats during pregnancy

Specific ₁-globulin of pregnancy was found in the blood serum of rats on the 6th–7th day of pregnancy. Its concentration reached a maximum toward the end of pregnancy. It was no longer detected on the 3rd–4th postnatal day. The site of synthesis of this globulin is the placenta. Other organs of pregnant rats were unable to incorporate radioactive amino acids into this protein in vitro.Department of Biochemistry and Laboratory for Problems of the Immunochemistry of Malignant and Embryonic Tissues, N. I. Pirogov Second Moscow Medical Institute. N. K. Kol'tsov Institute of Development Biology, Academy of Sciences of the USSR. (Presented by Academician of the Academy of the Medical Sciences of the USSR Yu. M. Lopukhin.) Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 88, No. 7, pp. 51–53, July, 1979.