bluuebunny/crossref_metadata_2025_split huggingface dataset:
SOME PROPERTIES OF ENZYMES INACTIVATING OXYTOCIN IN THE RABBIT BRAIN
Authors: Hooper K. C. , Hopkinson C. R. N. 
Published: December 2008

ABSTRACT
Some properties of enzymes inactivating oxytocin in the rabbit brain have been investigated. Enzymes acting on oxytocin and cystine di β naphthylamide were compared using enzyme inhibitors. The effect of incubation of both whole brain homogenate and supernatant fraction with deamino oxytocin and deamino carba1 oxytocin was also determined. It is concluded that oxytocin is inactivated by enzymes which are neither amino peptidases nor those which require prior reduction of the disulphide bridge. Comparison with data in the literature suggests that the molecule is probably cleaved at a C-terminal position.
The effects of the injection of oestradiol monobenzoate and of various endocrine physiological states on hypothalamic oxytocinase levels were compared with the effects produced on the levels of cystine di β naphthylamidase. The effect of dehydration on hypothalamic supernatant oxytocinase was also determined. The results suggest that there is no correlation between hypothalamic enzymes inactivating oxytocin and those hydrolyzing cystine di β naphthylamide, and that hypothalamic supernatant oxytocinase may be concerned specifically with gonadotrophin feedback control.
EFFECTS OF SYNTHETIC LH/FSH-RELEASING HORMONE (LRH) ON PLASMA LH AND FSH IN AMENORRHOEIC WOMEN
Authors: Rannevik G. , Thorell J. 
Published: December 2008

ABSTRACT
Eight amenorrhoeic women were given 100 μg synthetic LRH (Hoechst) iv and im, respectively, at an interval of 2 weeks. Four of the women received the iv injection first and four the im injection. The urinary excretion of oestrogens and pregnanediol was low and unaltered throughout the test weeks.
The effects of LRH were compared by serial measurements of the plasma LH and FSH during 8 h. The initial response of LH for up to 25 min and that of FSH for up to 60 min were equal whether LRH was given iv or im. The difference appeared later. Four hours after the injection the mean increase of LH to iv injection was 0.5 ng/ml (N. S.), while that to im injection was 1.9 ng/ml (P < 0.01). The corresponding values for FSH were 1.3 (P < 0.05) and 3.2 (P < 0.001).
The effect of LRH administration im was thus found to be larger and more prolonged.
BIOASSAY OF GROWTH HORMONE
Authors: Thorngren K.-G. , Hansson L. I. 
Published: December 2008

ABSTRACT
The longitudinal bone growth of proximal tibia determined by tetracycline in hypophysectomized rats was used for the bioassay of growth hormone. Female Sprague-Dawley rats were hypophysectomized at 60 days of age and after a post-operative control period of 15 days growth hormone (NIH-GH-B16) was given daily for 5 or 10 days followed by a 10 day period after its withdrawal.
A linear log dose-response relation was found for the two administration models with high precision. In the present investigation the longitudinal bone growth was more favourable as a growth parameter for the bioassay of growth hormone than the body weight and the width of the proximal tibial growth plate.
BIOASSAY OF GROWTH HORMONE
Authors: Thorngren K.-G. , Hansson L. I. 
Published: December 2008

ABSTRACT
The growth stimulating effect of growth hormone was determined with tetracycline as intravital marker of the longitudinal bone growth of proximal tibia in female Sprague-Dawley rats hypophysectomized at 60 days of age. After a post-operative control period of 15 days growth hormone (NIH-GH-B16) was given daily for 5 or 10 days followed by a 10 day period after its withdrawal. L-thyroxine was given in association with the growth hormone administration to potentiate the growth stimulation.
A linear log dose-response relation was found for the two administration models with a high precision. The thyroxine-treatment increased the sensitivity of the bioassay. An administration period of 5 days was found sufficient for the bioassay of growth hormone in thyroxine-treated hypophysectomized rats.
Compared with the earlier bioassay methods for growth hormone, the present bioassay is more favourable when all the factors, such as precision, sensitivity, specificity, and administration period are considered.
THE INFLUENCE OF d-TRIIODOTHYRONINE (d-T3) ON THYROTROPHIN SECRETION IN MAN
Authors: Zabransky S. , von zur Mühlen A. , Köbberling ]. 
Published: December 2008

ABSTRACT
d-Triiodothyronine (d-T3) is used in the treatment of hyperlipidaemia. To examine the influence of this kind of therapy on thyroid function the effect of various doses of d-T3 on TRH induced TSH release has been studied in 10 male euthyroid subjects. d-T3 was administered orally for 4 days; blood samples were taken on the first day 12 h after the d-T3 dose and then after an additional 12 h and after 4 days. The final sample was taken on the 5th day after 24 h without d-T3. Administration of 31.25 μg of d-T3 reduced the maximum increase of TSH in response to 200 μg TRH iv by 40%; 62.5 and 125 μg of d-T3 did not produce a significantly higher inhibition (50%; 45%). However, after 250 μg of d-T3, the response to a single dose was reduced by 68 %. After 500 μg of d-T3 TRH did not stimulate TSH at all. After 4 days regardless of d-T3 dosage the inhibition was not significantly lower than after 24 h. Prolonging the administration of 500 μg d-T3 over 3 weeks raised PBI to 150% whereas thyroxine fell to 65% of the values before d-T3 administration. In a primary hypothyroid patient the basal TSH secretion was lowered from 63 to 36 μU/ml by a daily dose of 0.5 mg d-T3 for 12 days. This study demonstrates that TSH release is inhibited by small doses of d-T3. This stresses the importance of assessing thyroid function in patients receiving d-T3.
EFFECT OF PARA-CHLOROPHENYLALANINE ON RAT THYROID FUNCTION
Authors: Coleoni Aldo H. , Masini Ana M. 
Published: December 2008

ABSTRACT
Administration of p-chlorophenylalanine (p-CPA), a brain serotonin (5-HT) depleting agent, induced a significant reduction in thyroid function as evaluated by the thyroid/serum ratio, 24 hour 131I uptake uptake and the 131I biological half-life. The iodo-amino acid composition of hydrolyzed thyroid tissue remained unchanged by the drug. The injection of thyrotrophin (TSH) to rats the endogenous TSH of which had previously been blocked with thyroxine, raised the plasma 131I and PB131I levels in both treated and control rats. The brain 5-HT concentration measured 24 hours following the last dose of p-CPA was markedly lowered by 50 mg/kg/day and 100 mg/kg/day. Cardiac 5-HT stores were only slightly depleted, while the thyroid 5-HT content remained unchanged. These results suggest a role of brain 5-HT depletion on the reduction of thyroid function caused by p-CPA. Some possible mechanisms are briefly discussed.
IN VITRO STUDIES OF TESTOSTERONE AND 5α-DIHYDROTESTOSTERONE BINDING IN BENIGN PROSTATIC HYPERTROPHY
Authors: Steins P. , Krieg M. , Hollmann H. J. , Voigt K. D. 
Published: December 2008

ABSTRACT
The cytosol fractions of prostatic adenoma and of the rectus abdominis muscle, together with the respective plasma samples were investigated in 13 patients in order to clarify whether or not there is an androgen receptor in human benign prostatic hypertrophy.
The following methods were used:
High speed ultracentrifugation in a sucrose gradient and agar gel electrophoresis at low temperature, of the 100 000 g supernatants after in vitro incubation with 3H-testosterone, 3H-5α-dihydrotestosterone, and 3H-oestradiol-17β. In parallel experiments the supernatants were heated to 45°C for 1 h before the steroid incubation. Displacement experiments with a 100–500-fold excess of various cold androgens. In the supernatants as well as in the plasma samples the total protein concentration was measured by the biuret reaction. The concentration of albumin and of immunoglobulin G (IgG) in the various biological fluids was determined by quantitative immuno diffusion. After charcoal stripping the binding of testosterone and of 5α-dihydrotestosterone was estimated quantitatively and correlated to the plasma contamination. By the methods used no physico-chemical differences in the androgen binding properties of plasma and of prostate cytosol were observed. However, in any individual cytosol a higher 5α-DHT binding than could be related to the plasma contamination was obtained. The question therefore remains open, as to whether the augmented 5α-dihydrotestosterone binding relates to a cellular increase of sex hormone binding globulin (SHBG) or to androgen receptors which do not show up clearly under the experimental conditions used.
THE INFLUENCE OF HAEMOGLOBIN-S AND G6PD DEFICIENCY ON THE ACTIVITY OF THE 17β-HYDROXYSTEROID DEHYDROGENASE OF INTACT HUMAN ERYTHROCYTES
Authors: Sogbesan A. O. , Dada O. A. , Adadevoh B. Kwaku 
Published: December 2008

ABSTRACT
The 17β-hydroxysteroid dehydrogenase activity in intact erythrocytes of Nigerian patients, in particular with regard to haemoglobin genotypes and G6PD* activity was studied. The G6PD activity of the erythrocyte did not affect the oxidative transformation of testosterone to androstenedione and of oestradiol to oestrone. The reduction (reverse transformation) was inhibited in G6PD-deficient erythrocytes but this inhibition was offset by the addition of 0.025 m glucose to the incubation medium. The per cent oxidation transformation of testosterone was higher in Hb-AA than in Hb-SS erythrocytes. It is suggested that the differences may be a result of either lower enzyme activity in the Hb-SS erythrocytes or of differences in the uptake and possibly binding of sex steroids by intact Hb-SS and Hb-AA erythrocytes.
SEX STEROIDS STIMULATE THE ACTIVITY OF HYPOTHALAMIC ARYLAMIDASES IN THE RAT
Authors: Kuhl Herbert , Rosniatowski Christian , Oen Siang-An , Taubert Hans-Dieter 
Published: December 2008

ABSTRACT
The effect of steroid treatment on the activity of hypothalamic arylamidases in male and female rats was investigated. A new and improved method for the assay of arylamidase activity utilizing L-α-amino acid-p-nitroanilides as substrates is presented. The influence of varying experimental conditions on the activity of hypothalamic arylamidases hydrolyzing the p-nitroanilides of cystine, glutamic acid, alanine, tyrosine, leucine, and phenylalanine, such as changes of substrate and enzyme concentration, temperature, incubation time, and pH, were tested. There was a sex-dependent response in the activity of hypothalamic arylamidases to treatment of the rats with sex steroids. In female rats, the injection of 7 μg of ethinyloestradiol was followed 16 hours later by a significant rise of L-cystine and L-glutamic acid arylamidase activity. In male rats, the injection of testosterone and of ethinyloestradiol respectively brought about a general stimulation of all enzyme activities. This indicates that this enzyme system of the male and female rat hypothalamus responds to steroid treatment of the animals with a sex-specific pattern.
BIOASSAY OF GROWTH HORMONE AND PROLACTIN PREPARATIONS BY DETERMINATION OF LONGITUDINAL BONE GROWTH WITH TETRACYCLINE
Authors: Thorngren K.-G. , Hansson L. I. 
Published: December 2008

ABSTRACT
The growth stimulating effect of different growth hormone and prolactin preparations on the longitudinal bone growth in thyroxine-treated hypophysectomized rats was determined by the tetracycline method. The effect of the hormone preparations was compared with that of the 1st International Standard for growth hormone.
The potency calculation showed that the tested human growth hormone preparations have a higher potency than the bovine, ovine and porcine growth hormone preparations. Also potency differences were found between hormones from the same species but prepared by different methods. The prolactin preparations have a considerably lower growth promoting activity than the growth hormone preparations.
The bioassay method used in the present investigation has a favourable mean precision (λ = 0.172) and sensitivity compared with the earlier bioassay methods. The present method increases the possibility of determining the biological effects of various growth promoting substances.
PITUITARY ADENOMA ASSOCIATED WITH INAPPROPRIATE ANTIDIURETIC HORMONE SECRETION
Authors: Greiss Kamal C. , Moses Arnold M. , Krieger Dorothy T. 
Published: December 2008

ABSTRACT
A 50 year old male with a chromophobe adenoma with suprasellar extension manifested hyponatraemia, plasma hypoosmolality, renal salt wasting and inability to excrete dilute urine after a standard water load. The patient exhibited no evidence of thyroid or adrenal insufficiency. The inability to excrete a water load was not corrected by prior cortisone administration but was partially corrected after ethanol ingestion. A measurable inappropriate amount of arginine vasopressin was excreted in the presence of sustained hydration. It is suggested that inappropriate production of antidiuretic hormone either by the adenoma, or secondary to hypothalamic involvement by the suprasellar extension of the tumour was responsible for the observed findings.
QUANTITATIVE STUDIES OF IODINE METABOLISM IN SPORADIC, NON-TOXIC GOITRE
Authors: Agerbæk H. , Jensen S. E. 
Published: December 2008

ABSTRACT
In 129 patients with non-toxic goitre and 27 normal controls, thyroid dynamic patterns were estimated in an attempt to elucidate pathogenesis. The clinically euthyroid state was confirmed by measurement of PBI, T3-sephadex uptake and BMR.
Thyroid clearance (th. cl.), plasma iodide (PII), and absolute iodine uptake (AIU) were determined and a perchlorate discharge test performed. Twenty patients (16%) had a high AIU and were thus suspected of having dyshormonogenesis; nine were thoroughly investigated and in six dyshormonogenesis was found. Both normals and non-toxic goitre patients had a low PII, but in the goitrous patients values were lowest. The thyroid clearance of iodide was significantly higher in the goitre patients, suggesting iodine deficiency to be a major aetiologic factor for goitre formation. AIU was higher in the goitre patients than in normals, suggesting a larger iodine leakage from the thyroid in these patients.
THE "EFFECTIVE THYROXINE RATIO" – NEW IN VITRO TEST OF THYROID FUNCTION AND ITS CORRELATION WITH FREE THYROXINE
Authors: Nauman Janusz , Nauman Alicja 
Published: December 2008

ABSTRACT
The effective thyroxine ratio (ETR) and absolute concentration of free thyroxine (AFT4) were estimated in the sera of 31 normal subjects, 27 hyperthyroid patients, 12 hypothyroid patients and 21 euthyroid pregnant women.
The mean ETR value in the controls was 1.0 ± 0.18, in the hyperthyroid patients 1.31 ± 0.25, in the hypothyroid patients 0.71 ± 0.21 and in normal pregnant women 0.99 ± 0.24. The mean AFT4 in the normal subjects was 3.0 ± 0.53 ng/100 ml, in the hyperthyroid patients 9.49 ± 2.44 ng/ 100 ml, in the hypothyroid patients 0.58 ± 0.15 ng/100 ml and in the pregnant women 2.84 ± 0.63 ng/100 ml, respectively. High reproducibility of ETR and a significant positive correlation between ETR and AFT4 with r = 0.96 suggest that ETR might be a suitable in vitro test for routine clinical evaluation of the thyrometabolic state.
EFFECTS OF HYPOPHYSECTOMY WITH OR WITHOUT ACTH MAINTENANCE THERAPY ON THE FINAL STEPS OF ALDOSTERONE BIOSYNTHESIS IN THE RAT
Authors: Baumann Klaus , Müller Jürg 
Published: December 2008

ABSTRACT
The effects of hypophysectomy, low-dose ACTH administration or both on aldosterone biosynthesis by incubated adrenal tissue were studied in rats during different dietary regimens. Six days after hypophysectomy without any replacement therapy, the capsular adrenals of rats receiving a complete diet converted tritiated corticosterone to aldosterone and 18-hydroxycorticosterone at a normal and at a moderately increased rate, respectively, and produced normal amounts of aldosterone from endogenous precursors. Hypophysectomy, with ACTH maintenance therapy, resulted in significant decreases in these parameters. In rats kept on a sodium-deficient diet, hypophysectomy alone did not alter the conversion rates, but led to a decreased output of endogenous aldosterone. ACTH treatment of intact as well as of hypophysectomized sodium-restricted animals was followed by a decreased incorporation of tritiated corticosterone into aldosterone and 18-hydroxycorticosterone. In rats kept on a potassium-deficient diet, hypophysectomy induced an 800 % increase in the capsular adrenal conversion of added corticosterone to aldosterone and 18-hydroxycorticosterone; this was partially prevented by ACTH treatment. Hypophysectomy with or without ACTH treatment did not impair restoration to the normal of the apparent capsular adrenal 18-hydroxylase activity in response to resumed potassium intake by potassium-restricted rats.
These results indicate that neither the maintenance nor the induction of an increased activity of the enzymes involved in the final steps of aldosterone biosynthesis due to sodium restriction or to an increased potassium intake, depend on a functioning pituitary gland. On the other hand, even small doses of exogenous ACTH, which are just sufficient for the maintenance of a normal adrenal weight in hypophysectomized animals, can cause significant decreases in the activity of these enzymes.
HORMONE AND ENZYME ASSAYS IN PREGNANCY
Authors: Christensen Arne 
Published: December 2008

ABSTRACT
The cystine-aminopeptidase (CAP)1) activity of placental origin (P-CAP) and of tissue origin (T-CAP) has been investigated in plasma from non-pregnant women, during normal pregnancy, in pregnancies complicated with severe pre-eclampsia and in plasma from the umbilical cord. In plasma from non-pregnant women the enzyme activity was significantly higher at pH 5.8 (T-CAP) than at pH 7.65 (P-CAP). During the pregnancy a gradual increase in both T-CAP and P-CAP took place. However, from about day 220 in the pregnancy the P-CAP became higher than the T-CAP.
Between normal pregnancy and pregnancies complicated with severe pre-eclampsia there was only a low significant difference in the T-CAP activity, but highly significant difference in the P-CAP activity.
The normal P-CAP pattern showed a gradual increase from about the 100th to the 270th day. A great spread in normal values was seen especially from about day 238 of gestation, due to variations in the enzyme activity of the women.
The coefficient of correlation between the P-CAP and the crude placental weight was calculated to + 0.67.
The half-life of P-CAP was calculated to 8.3 days.
In plasma from the umbilical cord the T-CAP activity was significantly higher than the P-CAP, and was simultan that in plasma from non-pregnant women.
CONTROL OF PITUITARY FSH IN MALE RATS
Authors: Steinberger Emil , Chowdhury Mridula 
Published: December 2008

ABSTRACT
The pituitary and serum FSH levels were measured in cryptorchid or orchiectomized adult rats at time intervals up to 7 days after surgery utilizing a radioimmunoassay technique. In orchiectomized rats the pituitary levels showed a decline during the first 72 hours after surgery while serum levels showed an increase during this period of time. Between the 3rd and 7th days after surgery the serum levels remained elevated and pituitary levels depressed. In cryptorchid animals the pituitary levels showed marked rise during the first 72 hours after surgery and remained elevated until the end of the experiment. The serum levels showed no change during the first 72 hours and a slight elevation by 7 days. Administration of testosterone propionate (TP) prevented the ochiectomyinduced changes in pituitary and plasma FSH levels. A dose relationship was observed between the serum FSH levels and the dose of TP. With increase in TP dose up to 0.5 mg an increase in pituitary FSH levels was observed. Further increase in TP dose caused a drop in pituitary FSH levels. The plasma levels showed a progressive drop with increasing doses of TP. The data reported in this paper and information available in literature lead the authors to the conclusion that testosterone regulates primarily FSH release rather than its synthesis.
THE IMMEDIATE RESPONSE OF THE PLASMA PROLACTIN LEVEL TO OESTROGEN AND PROGESTERONE INFUSIONS IN BULLS
Authors: Schams D. , Reinhardt V. , Karg H. 
Published: December 2008

ABSTRACT
The technique of radioimmunoassay was used to determine prolactin concentration in plasma taken from bulls during and after infusions of oestradiol-17β and progesterone. During the infusion of oestradiol-17β (0.5, 1 and 2 mg) for 1 h the concentration of prolactin in the plasma fell, but showed an immediate increase of up to 6-fold after the infusion was completed. A dose-dependent increase (up to 20-fold) in prolactin concentration was observed after the infusion for 1 h of 5, 10, 40 and 80 mg progesterone. In those experiments in which 40 and 80 mg were administered the depression normally seen during the infusion was sustained for 2–3 h and the subsequent increase during the next few hours was comparatively small.
A NEW IN VITRO METHOD FOR ASSAY OF THE BIOLOGICAL ACTIVITY OF GROWTH HORMONE
Authors: Saxena R. K. , Talwar G. P. 
Published: December 2008

ABSTRACT
An in vitro method for the assay of the biological activity of growth hormone is described. The method is based on the stimulation by the hormone of the incorporation of radioactive uridine into RNA in thymocytes from young rats. The response is dose-dependent and is linearly proportional to the concentration of growth hormone up to 16 μg/ml. Other pituitary hormones like FSH, LH, ACTH, TSH and oxytocin do not interfere with the assay system. Prolactin has some effect, which is, however, not additive to that of growth hormone. Various parameters of the procedure have been standardized. The index of precision of the method has been calculated to be about 0.05.
EFFECT OF LITHIUM ON DEIODINATING ACTIVITY OF VARIOUS RAT TISSUES IN VITRO
Authors: Männistö P. T. 
Published: December 2008

ABSTRACT
The effect of lithium chloride (LiCl) on the deiodination of iodotyrosines, on the degradation of 125I-L-thyroxine (125I-L-T4) in vitro and on the disappearance of exogenous 125I-L4 and 125I-rat-TSH in vivo was studied in rats.
Iodotyrosine deiodination was studied in vitro with three techniques. The whole thyroid lobes were not satisfactory as substrate. When a diluted mixture of prelabelled iodo-amino acids was used as substrate, thyroid homogenates deiodinated iodotyrosines. The reaction was inhibited by boiling and by 3,5-dinitro-L-tyrosine (DNT), but LiCl (2 × 10−2 m) had no effect. When 125I-3-iodo-L-tyrosine (125I-L-MIT) served as substrate, increasing concentrations of thyroid homogenates showed an increasing deicdinating activity, which was stimulated by NADP (1.5 × 10−4 m). Inhibitors of dehalogenase DNT (10−4 and 10 −3 m) and menandione (10−4 m) inhibited deiodination, but LiCl (5×10−3 − 0.1 m) was again without effect. The degradation of 125I-L-T4 by liver and kidney homogenates was inhibited by LiCl (5 × 10−3 − 0.1 m).
The disappearance of 125I-L-T4 was studied in rats treated with LiCl for 1 – 4 or 60 – 64 days in vivo. The half-lives were as follows: at 1 –4 days, the control rats 15.9 ± 1.3 h and the LiCl treated rats 19.1 ± 2.1 h (P < 0.05) and at 60 – 64 days 11.2 ± 2.0 h and 66.8 ± 12.3 h (P < respectively. The prolonged half-life in the LiCl treated rats was not due to the decreased excretion of radioactivity in the urine or faeces. The biological half-life of 125I-rat-TSH (11.4 ± 3.2 min) was not modified by LiCl treatment for 5 days.
It can be concluded that the antithyroid effect of LiCl neither originates from the inhibition of iodotyrosine deiodination nor from the change in the half-life of TSH. The half-life of thyroxine is prolonged by LiCl, an effect which is perhaps due to the decreased degradation of thyroxine by tissues.