THYROTROPHIN RELEASING FACTOR (TRF) IN CEREBROSPINAL FLUID OF THE 3RD VENTRICLE OF RAT

1974 ◽  
Vol 76 (2) ◽  
pp. 209-213 ◽  
Author(s):  
K. M. Knigge ◽  
S. A. Joseph
Keyword(s):  
Cerebrospinal Fluid ◽  
Drinking Water ◽  
Median Eminence ◽  
Cold Exposure ◽  
Male Rats ◽  
Assay Method ◽  
Normal Male ◽  
3Rd Ventricle ◽  
Pooled Samples

ABSTRACT The concentration of TRF in cerebrospinal fluid (CSF) of the 3rd ventricle and content of TRF in median eminence of the rat was examined. CSF (0.3–0.5 μl per animal) was collected from the 3rd ventricle by a microcannula technique and pooled samples from 10–15 animals were examined for TRF using an in vitro pituitary assay method. TRF concentration in 3rd ventricle CSF of normal male rats was 18.5 ± 4.2 pg/μl; median eminence contained 115 ± 12 pg. Cold exposure (4°C) for 16–18 h and thyroxine treatment (2.5 μg/day) for 5 days markedly reduced TRF concentration in CSF and content in the median eminence. Treatment with the anti-thyroid drug methimazole (0.01 % in the drinking water) for 5 days did not notably affect TRF in CSF or median eminence.

DER EINFLUSS VON RESERPIN AUF DIE ANTITHYREOIDALE WIRKUNG VON KALIUMPERCHLORAT

1962 ◽  
Vol 39 (3) ◽  
pp. 423-430
Author(s):  
H. L. Krüskemper ◽  
F. J. Kessler ◽  
E. Steinkrüger
Keyword(s):  
Thyroid Gland ◽  
Male Rats ◽  
Normal Male ◽  
Tissue Respiration ◽  
List Type ◽  
Morphological Alterations ◽  
Hormone Synthesis ◽  
Stimulation Of

ABSTRACT 1. Reserpine does not inhibit the tissue respiration of liver in normal male rats (in vitro). 2. The decrease of tissue respiration of the liver with simultaneous morphological stimulation of the thyroid gland after long administration of reserpine is due to a minute inhibition of the hormone synthesis in the thyroid gland. 3. The morphological alterations of the thyroid in experimental hypothyroidism due to perchlorate can not be prevented with reserpine.

Effect of streptozotocin-induced diabetes on bile acid sulfation in male rat liver

1984 ◽  
Vol 247 (3) ◽  
pp. G226-G230
Author(s):  
R. B. Kirkpatrick ◽  
B. G. Kraft
Keyword(s):  
Bile Acid ◽  
Specific Activity ◽  
Male Rats ◽  
Male Rat ◽  
Estrogen Metabolism ◽  
Normal Male ◽  
Activity Levels ◽  
Receptor Kinetics ◽  
Streptozotocin Induced Diabetes

The sulfation of bile acids is hormone dependent, being increased in females and ethynylestradiol (EE)-treated males compared with normal males. Diabetes causes significant alterations in estrogen metabolism and uterine estrogen receptor kinetics. Male rats were given streptozotocin (90 mg/kg) and diabetes was verified. An increase in hepatic bile acid sulfotransferase (BAST) activity was significant by 6 days and continued to increase to 29 days. This increase was prevented by insulin replacement. Administration of EE (6.0-600 micrograms X kg-1 X day-1) to normal male rats resulted in a significant increase in hepatic BAST activity; however, administration of similar doses of EE to diabetic males failed to further increase activity levels over the already-elevated levels in the diabetic controls. This increase in in vitro specific activity was accompanied by an increase in the biliary excretion of lithocholate 3-sulfate and taurolithocholate 3-sulfate in 21-day-diabetic animals. Bile flow and total bile acid excretion were also markedly increased in the diabetic animals. The data indicate that streptozotocin-induced diabetes causes a significant increase in hepatic BAST activity. These findings are consistent with an alteration in hepatic estrogen action in streptozotocin-induced diabetes.

Thermogenic and metabolic consequences of thyroid hormone treatment in brown and white adipose tissue

1985 ◽  
Vol 5 (2) ◽  
pp. 175-184 ◽  
Author(s):  
Christine M. Williams ◽  
Rodney Ellis
Keyword(s):  
Drinking Water ◽  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Hormone Treatment ◽  
Male Rats ◽  
Fat Pad ◽  
Brown Adipose ◽  
Glucose Incorporation ◽  
White Fat

Male rats were treated with triiodothyronine in the drinking water for 12 days. In vitro rates of isoprenaline stimulated lipolysis were significantly greater in brown but not white adipose tissue. Rates of [14C]glucose incorporation into triacylglycerols were significantly reduced in BAT (brown adipose tissue) and WAT (white adipose tissue) under basal and isoprenaline stimulated conditions, in a second experiment, hyperthyroid animals showed impaired weight gain, despite increased food intake during t9 days' treatment. Energy expenditure on days 5 and 12, and BAT core temperature differences (TBAT – TCORE) on day 19, were significantly greater than in control animals. Epididymal white fat pad weight was reduced and interscapular brown fat pad weight increased by triiodothyronine treatment.

scholarly journals Inhibition of Androgen Synthesis in Human Testicular and Prostatic Microsomes and in Male Rats by Novel Steroidal Compounds*

Endocrinology ◽  
1999 ◽  
Vol 140 (6) ◽  
pp. 2891-2897 ◽  
Author(s):  
Ivo P. Nnane ◽  
Katsuya Kato ◽  
Yang Liu ◽  
Brian J. Long ◽  
Qing Lu ◽  
...  
Keyword(s):  
Male Rats ◽  
Normal Male ◽  
Rat Tissues ◽  
The Novel ◽  
Androgen Synthesis ◽  
Potent Inhibition ◽  
Ic50 Value ◽  
Ic50 Values ◽  
Wet Weight

Abstract The C17,20-lyase and 5α-reductase are key enzymes in the biosynthesis of androgens. The effects of novel steroidal compounds were evaluated as inhibitors against both human C17,20-lyase and 5α-reductase in vitro. The concentrations of testosterone (T) and dihydrotestosterone (DHT) in the prostate, testis and serum and changes in the tissue weights were also determined in rats treated with the novel inhibitors. L-12 and L-26 showed potent inhibition of human testicular C17,20-lyase with IC50 values of 50 and 25 nm, respectively. L-12, L-38, and I-47 showed moderate inhibition of human testicular C17,20-lyase with IC50 values of 75, 108, and 70 nm, respectively similar to ketoconazole (78 nm). Interestingly, L-6, L-26, and L-38 also showed some inhibitory activity against 5α-reductase with IC50 values of 75, 125, and 377 nm, respectively. Finasteride, an inhibitor of 5α-reductase had an IC50 value of 33 nm. However, ketoconazole did not inhibit 5α-reductase nor did finasteride inhibit C17,20-lyase. Treatment of normal male rats with several of these novel inhibitors (50 mg/kg·day, sc, for 14 consecutive days) caused about 45–91% decrease in serum, testicular and prostatic T concentration. Similarly, serum and prostatic DHT concentration were significantly decreased in rats treated with these novel compounds by 50–90% compared with controls. Surgical castration caused almost complete elimination of circulating T and DHT concentration in rat tissues. L-6 and L-12 were the most effective and reduced the wet weight of the prostate by 50%. Although future improvements in their bioavailability are necessary, these novel steroidal compounds show promise as potential agents for reducing T and DHT levels in patients with androgen dependent diseases.

scholarly journals Assessment of the Central Effects of Natural UraniumviaBehavioural Performances and the Cerebrospinal Fluid Metabolome

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
P. Lestaevel ◽  
S. Grison ◽  
G. Favé ◽  
C. Elie ◽  
B. Dhieux ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Drinking Water ◽  
Locomotor Activity ◽  
Brain Function ◽  
Spatial Working Memory ◽  
Natural Uranium ◽  
Female Rats ◽  
Male Rats ◽  
The Central Nervous System ◽  
And Control

Natural uranium (NU), a component of the earth’s crust, is not only a heavy metal but also an alpha particle emitter, with chemical and radiological toxicity. Populations may therefore be chronically exposed to NU through drinking water and food. Since the central nervous system is known to be sensitive to pollutants during its development, we assessed the effects on the behaviour and the cerebrospinal fluid (CSF) metabolome of rats exposed for 9 months from birth to NUvialactation and drinking water (1.5, 10, or 40 mg·L−1for male rats and 40 mg·L−1for female rats). Medium-term memory decreased in comparison to controls in male rats exposed to 1.5, 10, or 40 mg·L−1NU. In male rats, spatial working memory and anxiety- and depressive-like behaviour were only altered by exposure to 40 mg·L−1NU and any significant effect was observed on locomotor activity. In female rats exposed to NU, only locomotor activity was significantly increased in comparison with controls. LC-MS metabolomics of CSF discriminated the fingerprints of the male and/or female NU-exposed and control groups. This study suggests that exposure to environmental doses of NU from development to adulthood can have an impact on rat brain function.

scholarly journals Hypersecretion of corticotrophin-releasing hormone and arginine vasopressin in hypothyroid male rats as estimated with push-pull perfusion

1998 ◽  
Vol 156 (2) ◽  
pp. 395-400 ◽  
Author(s):  
A Tohei ◽  
G Watanabe ◽  
K Taya
Keyword(s):  
Drinking Water ◽  
Median Eminence ◽  
Arginine Vasopressin ◽  
Plasma Concentrations ◽  
Male Rats ◽  
Releasing Hormone ◽  
In Vivo Release ◽  
The Relationship ◽  
Acth Release

The relationship between hypothyroidism and disturbance of the hypothalamo-hypophysial-adrenal axis was investigated using adult male rats. Hypothyroidism was produced by administration of 4-methyl-2-thiouracil (thiouracil) in the drinking water for 2 weeks. Hypothyroidism decreased adrenal weights to 57% of controls and plasma concentrations of corticosterone to 48% of controls. The changes in the weight of adrenals recovered to control levels by administration of thyroxine. The pituitary responsiveness to corticotrophin-releasing hormone (CRH) and arginine vasopressin (AVP) for ACTH release markedly increased in hypothyroid rats as compared with euthyroid rats. In vivo release of CRH and AVP in median eminence significantly increased in hypothyroid rats as compared with euthyroid rats. There were no significant differences in hypothalamic concentrations of CRH and AVP. These results indicate that hypothyroidism causes adrenal dysfunction directly and results in hypersecretion of ACTH mediated by increases in synthesis of CRH and AVP in the hypothalamus.

Effects of hypophysectomy and GH administration on bovine and human GH binding to rat liver membranes

1985 ◽  
Vol 249 (1) ◽  
pp. E56-E62
Author(s):  
J. L. Messina ◽  
S. Eden ◽  
J. L. Kostyo
Keyword(s):  
Binding Sites ◽  
Plasma Membranes ◽  
Specific Binding ◽  
Human Growth ◽  
Male Rats ◽  
Normal Male ◽  
Number Of Binding Sites ◽  
Liver Membranes ◽  
Isolated Liver

Experiments were conducted to investigate the specific binding of highly purified bovine and human growth hormones (bGH and hGH) to purified liver plasma membranes of male rats at various times after hypophysectomy and after the acute intravenous administration of bGH. Liver membranes prepared from hypophysectomized male rats showed a two- to threefold increase in the specific binding of either [125I]iodo-bGH or [125I]iodo-hGH, when compared with membranes prepared from the livers of age-matched normal male rats. The increase in GH binding was apparent within 3 days after hypophysectomy and persisted for a number of weeks after the operation. The increase in GH binding produced by hypophysectomy appeared to be due to an increase in the number of binding sites present on the membranes. The intravenous injection of 200 micrograms of bGH into hypophysectomized male rats 5-60 min before they were killed markedly reduced the ability of liver membranes prepared from these animals to bind [125I]iodo-bGH specifically. This decrease in GH binding seen after the injection of bGH may have been due to the development of a slowly dissociating hormone-binding site complex, which thereby reduced the number of available binding sites. This conclusion is supported by the finding that bGH, which is bound in vitro to isolated liver membranes, dissociates slowly and incompletely in the presence of an excess of unlabeled hormone. Moreover, the degree to which the bound hormone can dissociate appears to depend on the length of time that association is allowed to occur.(ABSTRACT TRUNCATED AT 250 WORDS)

EFFECT OF VARIOUS PUTATIVE NEUROTRANSMITTERS ON THE SECRETION OF CORTICOTROPHIN-RELEASING HORMONE FROM THE RAT HYPOTHALAMUS IN VITRO – A MODEL OF THE NEUROTRANSMITTERS INVOLVED

1976 ◽  
Vol 69 (1) ◽  
pp. 1-10 ◽  
Author(s):  
M. T. JONES ◽  
E. W. HILLHOUSE ◽  
JANET BURDEN
Keyword(s):  
Median Eminence ◽  
Incubation Medium ◽  
Direct Action ◽  
Aminobutyric Acid ◽  
Male Rats ◽  
Releasing Hormone ◽  
Inhibitory Neurotransmitters ◽  
Basal Release ◽  
Dose Dependent

SUMMARY The effect of incubating the hypothalamus of adult male rats with various neurotransmitters upon the release of corticotrophin-releasing hormone (CRH) was studied. The CRH activity in the incubation medium was assayed in 48 h median eminence-lesioned rats and the corticosteroidogenesis of excised adrenals in vitro was used as the end-point. 5-Hydroxytryptamine (100 pg/ml–10 ng/ml) caused a dose-dependent release of CRH which was antagonized by methysergide (30–100 ng/ml). The response to 5-hydroxytryptamine was also inhibited by hexamethonium and atropine which indicated that it was acting through a cholinergic interneurone. Melatonin (10 ng) did not alter the basal release of CRH but inhibited the action of both 5-hydroxytryptamine (10 ng) and acetylcholine (3 pg). Thus it appears that both 5-hydroxytryptamine and melatonin play a role in the control of CRH release. Noradrenaline blocked the release of CRH induced by both acetylcholine and 5-hydroxytryptamine and presumably this inhibition was caused by direct action on the CRH neurone. γ-Aminobutyric acid (GABA) also inhibited the release of CRH and may also be involved in the regulation of CRH secretion. The inhibitory neurotransmitters, noradrenaline, GABA and melatonin, act via independent receptor mechanisms. A model based on the above data is presented.

Benzodiazepine receptors and cerebrospinal fluid formation

1990 ◽  
Vol 72 (5) ◽  
pp. 759-762 ◽  
Author(s):  
Gregg L. Williams ◽  
Michael Pollay ◽  
Thomas Seale ◽  
Brent Hisey ◽  
P. Alex Roberts
Keyword(s):  
Cerebrospinal Fluid ◽  
Choroid Plexus ◽  
Binding Sites ◽  
Benzodiazepine Receptors ◽  
Secretory Activity ◽  
Assay Method ◽  
Content Type ◽  
High Affinity ◽  
Fluid Formation

✓ There is autoradiographic evidence that peripheral-type benzodiazepine ligands bind with high affinity to the membranes of choroid plexus tissue. In this study, the binding of a 4′-chloro analog of diazepam (Ro 5-4864) to rabbit choroid plexus and cerebral cortex was accomplished utilizing an in vitro radioactive assay method. A kinetic analysis of this binding revealed a relatively high affinity of this ligand (KD) for peripheral binding sites in plexus tissue (KD = 16.1 nM/mg protein). There was a 4.6-fold greater density of binding sites (total receptor density (Bmax) = 2.3 pmol/mg) in choroidal membrane as compared to cortical tissue (Bmax = 0.5 pmol/mg). In 40 rabbits in which a ventricular perfusion system was used, the rate of cerebrospinal fluid (CSF) formation was observed to decrease some 48% in the presence of 10−4 M Ro 5-4864, although some inhibition of secretory activity was still noted at a CSF concentration of 10−8 M. The choroid plexus tissue levels of adenosine 3′,5′cyclic monophosphate (cAMP) and adenosine triphosphatase (ATPase) were not affected by 10−4 M Ro 5-4864. The results of this study support the notion that the specific benzodiazepine peripheral binding sites in choroid plexus serve to modulate CSF formation. The mechanism of action is poorly understood but does not involve the transport ATPase system or the second messenger cAMP.

Sign in / Sign up

Export Citation Format

Share Document