bluuebunny/crossref_metadata_2025_split huggingface dataset:
IMPAIRMENT OF INDUCTION OF GLYCOLYTIC ENZYMES AND DEVELOPMENT OF INSULIN RESISTANCE IN RATS AS A RESULT OF CONTINUOUS INSULIN TREATMENT
Authors: Salganik R. I. , Mertvetsov N. P. , Gordienko O. E. , Chesnokov V. N. , Semenova L. A. 
Published: December 2008

ABSTRACT
It has been established that the administration of insulin to rats for 10 days results in a considerable increase of RNA synthesis as well as in the activity of hexokinase and pyruvate kinase in liver cells. Electron microscopic studies have shown that on the 6th day of insulin treatment the size of hepatocytes nucleoli and the number of free ribosomes increase. Moreover on the 10th day of treatment the glycogen content is changed in the liver cells. Following long-term insulin treatment (16–20 days) the liver cells lose their capacity to respond by enhanced RNA synthesis and by the induction of hexokinase and pyruvate kinase.
It has also been demonstrated that insulin administration for 10–15 days significantly decreases blood sugar. However, continuous insulin treatment (up to 25-27 days) elevates blood sugar to values surpassing even the normal value on day 27 of treatment.
The administration of insulin to rats for 25–27 days leads to a decreased tolerance to glucose load. The content of immunoreactive insulin in the blood plasma increases considerably on day 10 of insulin injection and continues to rise more sharply on subsequent days of treatment.
CONTROL OF RAT TESTICULAR MONOAMINE OXIDASE (MAO) ACTIVITY: HYPOPHYSECTOMY, ADRENALECTOMY, FSH, LH. PROLACTIN, HCG AND TESTOSTERONE
Authors: Urry Ronald L. , Frehn John L. , Ellis LeGrande C. 
Published: December 2008

ABSTRACT
Testicular monoamine oxidase activity (MAO) was measured in rats subjected to adrenalectomy, hypophysectomy, or hypophysectomy and treatment with either HCG, FSH, LH, prolactin, or a combination of FSH, LH, and prolactin. Total testicular MAO activity was reduced by hypophysectomy, but unchanged by adrenalectomy. The specific activity of MAO, expressed as units of activity per mg of tissue, increased after hypophysectomy, suggesting that this enzyme is located in a non-germinal-type cell in the testis. In the mature animals total MAO activity decreased during the first 4 weeks and then increased to near normal levels 2 weeks later. Specific activity of MAO increased the first 7 weeks after surgery in immature animals and for 6 weeks for mature animals. In immature animals the specific activity of MAO had regressed to the control level by 15 weeks after surgery. FSH was more effective in increasing total MAO activity, but LH in high concentrations may be capable of increasing it. Additions of 2 or 5 IU of FSH to seminiferous tubules in organ culture also increased MAO activity. Treatment of hypophysectomized animals with HCG or a combination of FSH, LH, and prolactin increased testicular weights and androgen synthesis, but depressed specific MAO activity. Thus, androgens do not appear to increase total MAO activity, but could depress it especially at high concentrations. Injections of pargyline, a MAO inhibitor, significantly increased endogenous serotonin concentrations in rat testes.
THE EFFECT OF NANDROLONE PHENYLPROPIONATE ON 14C-LEUCINE INCORPORATION INTO MUSCLE PROTEIN IN THE RAT AND RABBIT IN VIVO
Authors: Bresloff P. , Fox P. K. , Sim A. W. , der Vies J. van 
Published: December 2008

ABSTRACT
Investigations have been carried out into the incorporation of 14C-leucine into muscle protein of rats and rabbits and its modification by various treatments. Significant decreases in the rate of incorporation of 14C-leucine into protein of the gastrocnemius and levator ani muscles of rats have been observed following hypophysectomy, fasting or treatment with a corticosteroid. In these situations, treatment with an anabolic steroid, nandrolone phenylpropionate, always prevented or reversed the decrease in 14C-leucine incorporation in the levator ani muscle but never in the gastrocnemius muscle.
In contrast to the situation in the rat, the decreased incorporation of 14C-leucine in the gastrocnemius muscle of the rabbit following corticosteroid administration could be partially reversed by the anabolic steroid.
The results demonstrate that 14C-leucine incorporation into muscle protein in vivo following various experimental treatments may vary markedly not only from one species to another but also from one muscle to another. Great care should be taken in interpreting the effect, or lack of effect, of androgenic/anabolic steroids on the basis of the response of a single muscle.
EFFECT OF SYNTHETIC LUTEINIZING HORMONE RELEASING HORMONE ON OVULATION DURING THE OESTROUS CYCLE IN THE RAT
Authors: Morishita H. , Mitani H. , Masuda Y. , Higuchi K. , Tomioka M. , Nagamachi N. , Kawamoto M. , Ozasa T. , Adachi H. 
Published: December 2008

ABSTRACT
The effect of synthetic luteinizing hormone releasing hormone (LH-RH) on ovulation has been studied during the oestrous cycle in adult female rats. Ovulation could be induced by the administration of 1 μg synthetic LH-RH at 1:00 a. m. on the day of dioestrus II (lights on from 10:00 p.m. to 10:00 a.m.). At 1:00 a.m. on the day of dioestrus II, the average volume of the largest follicles reached a volume of 83 × 106 μm3 and was three fifth of the volume of that at 6:00 a. m. on the day of pro-oestrus (critical period). These findings suggest that the luteinizing hormone (LH) content in the pituitary gland during the early period of dioestrus II is sufficient to induce ovulation and that the follicles that reach to three fifth of the volume at the critical period are capable of ovulating providing endogenous ovulatory LH released.
SOME ANTIGONADOTROPHIC EFFECTS OF MELATONIN-FREE BOVINE PINEAL EXTRACTS IN RATS
Authors: Orts Richard J. , Benson Bryant , Cook Byron F. 
Published: December 2008

ABSTRACT
Studies were made to determine if a substance other than melatonin was present in bovine pineal gland extracts which possessed properties inhibitory to some gonadotrophin-dependent reproductive parameters in rats. Bovine pineal extracts were partially purified by organic solvent extraction or by ultrafiltration and gel-filtration to exclude melatonin. When administered to rats, the extracts inhibited compensatory ovarian hypertrophy, delayed vaginal opening time and reduced the incidence of constant oestrus. Either of the melatonin-free extracts reduced significantly the concentration of serum luteinizing hormone (LH) in long-term castrate male rats. The data suggest that some substance other than melatonin present in bovine pineal glands has a modifying effect on the reproductive parameters observed probably due to its inhibitory effect on LH.
CALCIUM AND STIMULUS-SECRETION COUPLING IN THE NEUROHYPOPHYSIS
Authors: Russell J. T. , Thorn N. A. 
Published: December 2008

ABSTRACT
Slices of bovine neurohypophyses (wet weight approximately 50 mg), were used as an in vitro model for studying stimulus-secretion coupling for antidiuretic hormone. Release of hormone could be stimulated repeatedly for a period of at least 140 min by a 56 mm K+ medium or in an electrical field. Varying the current caused release of varied amounts of hormone.
Several methods were used in an attempt at demonstrating intra-axonal calcium uptake during stimulated release. Stimulation with a 56 mm potassium medium did not cause any significant increase in the influx of 45Ca2+ measured by conventional technique or in total tissue calcium. Kinetic analyses of 45Ca2+ "desaturation" curves showed that incubation in a 56 mm potassium medium for 30 min did increase the 45Ca2+ in a slowly washed out compartment (presumably intracellular). However, the rate of washout of 45Ca2+ was decreased. Electrical field stimulation caused release of hormone in comparable amounts, but this stimulation did not cause any significant increase in 45Ca2+ in the slowly washed out compartment. Application of the "lanthanum method" of van Breemen and coworkers for studying changes in a calcium compartment that is presumably intracellular, gave the same results as the studies of desaturation curves without lanthanum.
It is suggested that increased 45Ca2+ "uptake" found during stimulation in a 56 mm K+ medium is a phenomenon which cannot be used as evidence that a calcium uptake is essential for release.
Even using these more detailed methods of study, it could thus not be demonstrated that hormone release is always associated with a measurable uptake to the cell interior of calcium. If calcium uptake is obligatory for secretion, it would appear that it is very small. Uptake of a very small amount would, however, be in agreement with recent findings using very special techniques in squid axons. A very small uptake would also agree with recent experiments done in our laboratory in which Ca2+ conductance inhibitors were applied on neurohypophyseal tissue.
DOWN'S SYNDROME. STUDY OF CARBOHYDRATE METABOLISM
Authors: Raiti Salvatore , Lifschitz Fima , Trias Estrellita , Sigman Bernice 
Published: December 2008

ABSTRACT
Eight adolescent patients with Down's syndrome and short stature were studied. Three of the 8 patients had inadequate plasma insulin response to glucose or to arginine stimulation. The glucose disappearance rate in one of them followed a diabetic pattern. Exogenous insulin disappeared with a mean t½ of 13 min, and the Kt for glucose was 2.276. We conclude that the abnormalities in insulin production and glucose disappearance in a few of the patients suggests a possible diabetic tendency. The short stature and delayed puberty were not due to pituitary deficiency of growth hormone or of gonadotrophins.
NOCTURNAL PLASMA INSULIN LEVELS IN COWS WITH VARYING LEVELS OF PLASMA KETONE BODIES; RELATIONS TO PLASMA SUGAR AND ACETOACETATE
Authors: Hove Knut 
Published: December 2008

ABSTRACT
The interrelations of plasma values of insulin, sugar and acetoacetate (AcAc) have been investigated on nocturnal blood samples from 544 dairy cows at different stages of lactation. A wide range of plasma levels was observed (plasma sugar 42–106 mg/100 ml, insulin 0.3–2.2 ng/ml, AcAc 0.05–27 mg/100 ml). Nocturnal samples were taken to exclude as much as possible variations in plasma components induced by feeding.
The following correlations were found: sugar/insulin r = 0.45, P < 0.001; insulin/AcAc r=–0.23 (P <0.001); sugar/AcAc r=–0.61 (P <0.001). The partial correlation between insulin and AcAc was not significant (r = 0.07) when glucose was eliminated. A simultaneous decrease in plasma insulin and sugar was found, hypoglycaemic cows having the lowest insulin levels. It is concluded that this decreased insulin level is probably of importance in facilitating lipolysis during hypoglycaemia, thus being a prerequisite for the development of ketosis.
Ten cows were sampled twice, one sample being taken before partus and the other during the 45 first days of lactation. After the onset of lactation indications of a more diabetic metabolism was found. The mean plasma insulin level was reduced from 1.3 to 0.6 ng/ml; a significant fall in plasma sugar and a rise in AcAc was also observed.
Nine samples from cows developing ketosis and 23 with elevated AcAc levels, but without clinical symptoms, were compared to 26 samples of cows with low AcAc levels from the same herds and in the same stage of lactation. The mean insulin levels were 0.42, 0.52 and 0.71 ng/ml, and sugar 50.5, 59.5 and 73.6 mg/100 ml, respectively. It is concluded that the low insulin values found in the samples from the ketotic cows were due to reduced glucose stimulation of the pancreatic β-cells.
A NEW APPROACH FOR INVESTIGATING HYPOTHALAMO-PITUITARY-GONADAL AND ADRENAL FEEDBACK CONTROL MECHANISMS: ACTIVE IMMUNIZATION WITH STEROIDS
Authors: Nieschlag E. , Usadel K. H. , Kley H. K. , Schwedes U. , Schöffling K. , Krüskemper H. L. 
Published: December 2008

ABSTRACT
A new method for the investigation of hypothalamo-pituitary-gonadal and adrenal feedback control mechanisms based on the biological neutralization of gonadal and adrenal steroids by active immunization is proposed. The regulatory influence of a given steroid in the feedback control is proved when reduction of the free, biologically active fraction of this steroid caused by antibody binding induces a positive response of the pituitary, thus effecting gonadal or adrenal hypertrophy and hyperfunction. The advantages and limitations of the new model are demonstrated by the effects of active immunization of rabbits with cortisol (F), aldosterone (Aldo), dehydroepiandrosterone (DHA), androstenedione (Δ4-A), testosterone (T), 5α-dihydrotestosterone (5α-DHT), 5β-DHT and oestradiol (E2). In the immunized animals and in a control group serum concentrations of total corticosteroids (TC), DHA, T, Δ4-A, E1, E2, LH and FSH, the percentage of binding of steroids in serum and the specificity of the antisera are determined. The testes are evaluated by histometry and the nuclear volume of the adrenocortical and Leydig cells is measured.
CHARACTERISTICS OF THE NUCLEAR AND MICROSOMAL STEROID Δ4-5α-HYDROGENASE OF THE RAT PROSTATE
Authors: Nozu Kaoru , Tamaoki Bun-ichi 
Published: December 2008

ABSTRACT
Steroid Δ4-5α-hydrogenase was intracellularly localized in the nuclear and microsomal fractions of the rat ventral prostate (Nozu Sc Tamaoki 1973). The nuclear Δ4-5α-hydrogenase was found to have the following enzymatic properties essentially similar to the microsomal Δ4-5α-hydrogenase, with regard to the metabolism of [4-14C] testosterone in the presence of NADPH: The optimum pH of the enzymes in the two fractions was around 7.0 and the maximal conversion rates were obtained at a temperature of 35 to 40°C. The apparent Km values of the nuclear and microsomal Δ4-5α-hydrogenases were estimated respectively as 1.05 and 0.90 μmol/l, while the Km value of the hepatic microsomal Δ4-5α-hydrogenase was simultaneously estimated as 154 μmol/l. Among steroids, the most potent inhibitor group on the enzymatic 5α-hydrogenation of testosterone was Δ 4-3-oxo-C-21 steroids such as progesterone and 17α-hydroxyprogesterone, which were competitively converted into their 5α-hydrogenated metabolites in the highest rates. Among some anti-androgens, cyproterone and its acetate hardly inhibited the activities of the nuclear and microsomal enzymes, whereas etienic acid (4-androsten-3-one-17β-carboxylic acid), oestradiol-17β and diethylstilboestrol markedly inhibited both prostatic enzymes in a competitive manner. The Ki values of etienic acid, oestradiol-17β and diethylstilboestrol for the nuclear Δ4-5α-hydrogenase were respectively 1.50, 0.49 and 1.02 μmol/l, indicating similar affinities of these for the nuclear enzyme to that of testosterone.
BIOASSAY OF ANTIGONADOTROPHIC SERA
Authors: Romaní P. , Robyn C. , Petrusz P. , Diczfalusy E. 
Published: December 2008

ABSTRACT
Data are presented on the reliability of the previously described bioassay of gonadotrophin neutralizing potency of antisera raised against HCG preparations. The sensitivity of the method may be defined as the smallest detectable neutralizing activity expressed in anti-units (AU). This depends partly on the bioassay system used, and partly on the intended percentage of neutralization. In the HCG bioassay used in the present study, and around 50 % neutralization, the smallest detectable neutralizing activity is about 1.0 AU. The sensitivity decreases with increasing levels of neutralization: it is about 9 AU around 90% neutralization. The precision as given by the mean index of precision (λ) was 0.12 in 52 assays. The 95 % fiducial limits expressed as a percentage of the mean potency estimate ranged from 65.8 % to 125.7% in 52 assays conducted at 50 % and from 89.1% to 105.3% in 25 assays conducted at 90% intended neutralization. Reproducibility: eighteen antisera raised in 18 rabbits against 9 HCG preparations were assayed at 50% intended neutralization repeatedly (at least twice each antiserum) in 52 assays. Only one antiserum showed significant heterogeneity among repeated estimates by a χ2 test. The achieved neutralization ranged from 36 % to 79 % with a mean of 50 %.
The neutralizing potency estimates of 19 antisera raised in 19 rabbits against 10 HCG preparations in 45 assays at 50% intended neutralization and in 25 assays at 90 % intended neutralization were also compared. These potency estimates were in close agreement with each other at both levels of neutralization (except for one antiserum) as evidenced by the results of χ2 test and the value of the correlation coefficient obtained (r = 0.99). It is concluded that "the principle of simple additivity" is a satisfactory approximation to represent the antigen - antibody reaction involved in the neutralization of the biological activity of HCG preparations.
METABOLISM OF [4-14C]CHOLESTEROL BY HUMAN ADRENAL GLANDS IN VITRO AND ITS INHIBITION BY METYRAPONE
Authors: Carballeira Andres , Cheng Su Chiau , Fishman Lawrence M. 
Published: December 2008

ABSTRACT
The in vitro conversion of [4-14C] cholesterol1) to steroid hormones was studied in 1 normal, 1 adenomatous and 2 hyperplastic, surgically resected, human adrenals. The degree of overall conversion per gram of tissue was similar (4.4–5.6 %) in NADPH-supplemented homogenates from normal or moderately hyperactive adrenals; a 2-fold increase was found in a markedly hyperfunctioning gland. Only labelled cortisol, corticosterone, 11-deoxycortisol, 11-deoxycorticosterone and androstenedione were isolated from incubations with [4-14C] cholesterol, but cortisol accounted for slightly more than 50 % of overall substrate conversion in the normal adrenal, while 11-deoxycortisol and androstenedione predominated in the abnormal glands. "Apparent 11β-hydroxylase activity" was considerably lower in the abnormal glands than in normal tissue when assessed using [4-14C] cholesterol as substrate, but this deficit was not observed in comparable incubations with 14C-labelled pregnenolone, progesterone or 11-deoxycorticosterone. [4-14C] Cholesterol was a more efficient precursor of androstenedione than either [4-14C] pregnenolone or [4-14C] progesterone.
In parallel studies, metyrapone (1.0 mm) depressed the formation of both 11-oxy and 11-deoxymetabolies from [4-14C] cholesterol, overall inhibition ranging from 66 to 86%. The conversion of [4-14C] 11-deoxycorticosterone to corticosterone was inhibited by 93 % under identical conditions. Metyrapone did not, however, impair the overall transformation of either [4-14C]pregnenolone or [4-14C]progesterone, since the inhibition of cortisol and corticosterone biosynthesis was associated with an increment in 11-deoxycortisol (with [4-14C] pregnenolone) or 11-deoxycorticosterone (with [4-14C]progesterone). From these studies it appears likely that the additional site of metyrapone inhibition of steroid biosynthesis suggested by others on the basis of clinical observations involves the rate-limiting, ACTH-regulated conversion of cholesterol to pregnenolone.
PITUITARY-THYROID FUNCTION AFTER TOTAL ADRENALECTOMY IN PATIENTS WITH CUSHING'S DISEASE
Authors: Blichert-Toft Mogens , Hummer Lotte , Dige-Petersen Harriet 
Published: December 2008

ABSTRACT
In patients with untreated Cushing's disease decreased thyroid function has been demonstrated by several investigators. An inhibiting effect of glucocorticosteroids on the release of thyrotrophin seems to be the cause. In the treated patient with remission of the disease the pituitary-thyroid function has not been studied in detail. The question is, if the hypofunction proved in the untreated state might persist in the treated patient. This might be anticipated from both clinical and experimental studies.
In the present study the pituitary-thyroid function has been determined after total adrenalectomy followed by remission in 14 patients with Cushing's disease. All patients were replaced adequately with cortisone acetate post-operatively as estimated by excretion of cortisol in urine. Levels of serum thyroxine, thyroxine-binding globulin, and serum thyrotrophin were measured. In addition, tracer studies were performed. The 131I-uptake in the thyroid gland and plasma protein-bound radioiodine were determined. After thyrotrophin-stimulation test, the thyroxine reserve and the rise in 131I-uptake in the gland were measured. TRH-stimulation test was performed to determine the TSH-reserve. A normal pituitary-thyroid function and a normal pituitary and thyroid reserve were demonstrated.
In the conclusion it can be said that decreased pituitary-thyroid function or reserve has not been found in the Cushing-patient subjected to adrenalectomy followed by remission. Thus, thyroid replacement therapy has not to be considered, when an adequate replacement therapy is planned after total adrenalectomy.
THE INTERACTION OF DIHYDROTESTOSTERONE AND OESTRADIOL-17β WITH MACROMOLECULES IN HUMAN HYPERPLASTIC PROSTATE TISSUE
Authors: Fraser H. M. , Mitchell Angela J. H. , Anderson C. K. , Oakey R. E. 
Published: December 2008

ABSTRACT
During incubation of minced human hyperplastic prostate tissue with [3H]5α-dihydrotestosterone (27 nm), 3H became firmly bound to macromolecules in both cytosol and nucleus. The binding to the cytosol fraction was inhibited when oestradiol-17β (0.3 μm), oestrone sulphate, ethinyl-oestradiol-17β or diethylstilboestrol (10 μm) was included in the incubation. Binding to the nuclei was inhibited by incubation with oestradiol-17β (1 μm) or cyproterone acetate (6.5 μm), a potent anti-androgen, but not by incubation with cortisol (30 μm).
CIRCULATING LUTEINIZING HORMONE AND TESTOSTERONE RESPONSE IN RAMS AFTER LUTEINIZING HORMONE RELEASING HORMONE TREATMENT
Authors: Galloway D. B. , Cotta Y. , Pelletier J. , Terqui M. 
Published: December 2008

ABSTRACT
The relationship between the secretions of LH and testosterone after LH-RH administration was tested in entire rams. Three groups of two rams received, intravenously, 100 μg; 800 μg LH-RH in single injection; or 100 μg × 7 injections at half-hour intervals respectively and samples were collected every 10 or 20 min for 6 hours. Plasma LH and testosterone were assayed by radioimmunoassay. The quantity of LH released following 800 μg LH-RH was higher than released after 100 μg LH-RH and there was a positive correlation between the total amount of LH released after LH-RH and the amount of testosterone released. It seems probable that the pre-injection level of testosterone regulates in a quantitative manner the effect of a given dose of LH-RH. In the case of successive injections of LH-RH, the plasma LH rose to a plateau but the last two treatments failed to prevent the decline in the level of LH. This suggests that testosterone, still high at the time, directly blocked the effect of LH-RH at the level of the pituitary.
PEPTIDASE ACTIVITY IN DIFFERENT AREAS OF THE RAT HYPOTHALAMUS
Authors: Griffiths E. C. , Hooper K. C. 
Published: December 2008

ABSTRACT
To provide further information on the function of peptidases present in the rat hypothalamus which are capable of inactivating oxytocin, these enzymes' activity was investigated in anterior, middle and posterior hypothalamic areas of normal male and female rats, gonadectomized rats and rats gonadectomized and injected with gonadal steroids (oestradiol in female animals, testosterone in males). Peptidase activity in the supernatant fraction was distributed unevenly through the hypothalamus with the majority of activity in the anterior and middle areas from both sexes; particulate peptidase activity occurred principally in the middle and posterior areas. Gonadectomy selectively decreased supernatant activity in the anterior and middle areas, whereas steroid treatment reversed this effect, but neither caused any change in particulate activity from female rats and only small changes in male animals. These results are interpreted as indicating a selective distribution of supernatant peptidase activity in those hypothalamic areas responsible for luteinizing hormone – releasing factor (LRF) synthesis and release, and confirming previous findings that this fraction may be involved in LRF metabolism. They may also suggest the sites of gonadal steroid feedback at the hypothalamic level.