bluuebunny/crossref_metadata_2025_split huggingface dataset:
Urinary excretion of androgen metabolites, comparison with excretion of radioactive metabolites after injection of [4-14C]testosterone. Influence of age
Authors: Deslypere J. P. , Wiers P. W. , Sayed A. , Vermeulen A. 
Published: December 2008

Abstract.
The influence of age on the metabolic pattern of [4-14C]testosterone was studied in 20 young and 8 elderly males and compared to the metabolic pattern of endogenous androgens; the latter was also studied in 16 young and 8 elderly women. In both young and elderly males, androsterone and aetiocholanolone glucuronide represent 65% of [4-14C]testosterone metabolites; together with their sulphoconjugates as well as with 5α- and 5β-androstane-3α,17β-diol they represent even more than 75% of total urinary metabolites. The 5α/5β ratio of metabolites of [4-14C]testosterone was significantly (P < 0.01) correlated with the 5α/5β ratio of the metabolites of the endogenous androgens, mainly dehydroepiandrosterone and androstenedione. The 5α/5β ratio of [4-14C]testosterone metabolites was generally higher than the ratio of metabolites of endogenous androgens, suggesting that the transformation of T to ring A saturated metabolites occurs at least partially in another compartment than the transformation of DHEA to these metabolites.
For both [4-14C]testosterone and endogenous androgen metabolites we observed a statistically significant reduction of the 5α/5β ratio with age, a general phenomenon in both males and females. This reduction concerns also 11-OH-androst-4-ene-3,17-dione metabolism. Neither sex hormone levels, nor specific binding seems to determine this age dependent shift; neither is there convincing evidence for latent hypothyroidism or liver dysfunction in the elderly. An age associated primary decrease of the 5α-reductase activity seems the most likely explanation.
Effects of oestradiol benzoate (OeB) and human chorionic gonadotrophin (hCG) on the testes and accessory sex glands of the rat
Authors: Chowdhury Mridula , Tcholakian Robert , Steinberger Emil 
Published: December 2008

Abstract.
It has been suggested that treatment of intact male rats with oestradiol benzoate (OeB) causes an interference with testosterone (T) production by the testes by a direct inhibitory effect on steroidogenesis. To test this hypothesis, different doses (5, 10 or 25 IU) of hCG were administered concomitantly with 50 μg of OeB to adult intact or hypophysectomized male rats. The testicular and plasma testosterone, and serum hCG levels were determined. The sex accessory weights were recorded. In the intact OeB-treated group of animals, hCG stimulated both the secondary sex organs and plasma testosterone levels above the intact control group. However, in hypophysectomized animals, although plasma testosterone levels increased above that of intact controls, their secondary sex organ weights did not. Moreover, inspite of high circulating hCG levels, the testicular testosterone content and concentration remained suppressed in OeB-treated animals. The reason for such dichotomy of hCG action on OeB-treated animals is not clear at present.
Dose- and age-dependent effects of clomiphene citrate administered to prepubertal female rats on development of anovulatory sterility and pyosalpinx
Authors: Morishita Hajime , Nakago Kichijiro , Ii Kunio , Hashimoto Tadashi , Mitani Hiroshi , Tomioka Michio , Kuroiwa Shunichiro , Nishiuchi Ken , Okada Akira 
Published: December 2008

Abstract.
The influences of dose of clomiphene and age at clomiphene treatment in prepubertal female rats on development of anovulatory sterility and pyosalpinx were investigated. By varying the amount of clomiphene administered, it was found that 50 μg is the minimal dose of clomiphene which will produce anovulatory sterility and pyosalpinx in a majority of female rats treated at 5 days of age. By varying the age of rats at clomiphene treatment, it was observed that the period of clomiphene sensitivity in female rats is within the first 10 days of life, in which administration of 500 μg clomiphene will result in subsequent anovulatory sterility and pyosalpinx. These results demonstrate that the induction of anovulatory sterility and pyosalpinx is dependent upon the dose of clomiphene and the age of rats at clomiphene injection.
An investigation into the origin of the pro-oestrus/oestrus change in pituitary responsiveness to LRH of the pseudopregnant rat
Authors: Schuiling G. A. , Pols-Valkhof N. , Koiter T. R. 
Published: December 2008

Abstract.
LH-secretory responses, induced by (standard) infusion of LRH in the pro-oestrous rat, are much greater than in the oestrous rat. In the present investigation the factors which accomplish the transition from the pro-oestrus to the oestrus state of responsiveness to LRH of the pituitary were studied in the pro-oestrous pseudo-pregnant (PSP) rat. It was considered that the change in responsiveness might be caused by either the cyclic release of LRH by the hypothalamus (which results in a depletion of pituitary LH content and an altered state to further stimulation), the peri-ovulatory changes in the endocrine milieu, or some combination of these factors.
It was observed that LH-secretory responses induced 24 h after ovariectomy (OVX) on pro-oestrus, take an intermediate position between the pro-oestrus and the oestrus responses. However, when treated with oestradiol benzoate (OeB), such animals maintain the pro-oestrus state of responsiveness.
Regardless of the presence of OeB or of the ovaries, following the simulation of a 'pre-ovulatory' LH-surge by a 3 h lasting infusion of LRH, the pituitary gland passes into the oestrus state of responsiveness to LRH. When, however, ovulation was induced by hCG, the pituitary passed into the same state of responsiveness as after OVX, i.e. the intermediate position.
It is concluded that the transition from the pro-oestrus to the oestrus state of responsiveness of the pituitary results from the exposure of the gland to the pro-oestrous LRH-surge.
Aldosterone response to sodium deprivation and angiotensin II in patients with hypopituitarism
Authors: Seifert Cornelia , Oelkers Wolfgang 
Published: December 2008

Abstract.
Unknown pituitary factor(s) apart from ACTH may participate in the regulation of aldosterone (aldo) secretion in man. We investigated whether the 'sensitization' of the zona glomerulosa against angiotensin II (A II) by sodium deficiency was mediated by the pituitary gland. A II was infused in stepwise increasing doses (2, 4, 8 ng/kg/min) into 5 normal subjects (N) and into 8 patients with hypopituitarism (H) before and after 4 days on a low sodium diet. Mean cumulative sodium balance after the low sodium diet was − 145 mm in N and − 165mm in H. Plasma-aldo and aldo-exretion rate on the normal sodium diet were slightly lower in H than in N but rose less than normal during sodium depletion in H. Plasma A II and renin activity on normal sodium were slightly higher in H than in N, but the increase on the low sodium diet was blunted in H. The stimulation of plasmaaldo by A II infusion was similar in both groups on the normal sodium diet. In both groups, the response of P-aldo to A II infusion was greater in the sodium deplete than in the replete state, although 'sensitization' was slightly less marked in H than in N. This may be due to the blunted rise of plasma-A II after sodium loss in H, which may also account for abnormalities in the blood pressure response in the H group. Altogether, the results speak against a direct involvement of the pituitary gland in 'sensitization', but an indirect influence through unexplained abnormalities in renin secretion is possible.
An autoradiographic study of follicle growth in the ovaries of cyclic rats
Authors: Groen-Klevant A. C. 
Published: December 2008

Abstract.
Follicle growth in the ovaries of cyclic rats was studied by autoradiography after pulse labelling with [3H]thymidine: growth rates and numbers were determined for follicles of the types 3b to 6 (type 3b: follicles with 1 –2 layers of granulosa cells; type 6: follicles with a diameter of 200 μm and usually with a single antrum). The data indicate a total time of follicle development, from type 3b to ovulation, of 22 days. Growth of follicles of the types 3b to 6 in these cyclic rats was roughly similar to that in late prepubertal animals, previously studied. However, some changes of the growth of these types of follicles, related to the stages of the cycle, could be noted.
A quantitative test for oestrogenic activity using rat endometrium lactate dehydrogenase
Authors: Jelínková Marta , Jelínek J. , de Visser J. , van der Vies J. 
Published: December 2008

Abstract.
In ovariectomized rats treatment with ethinyloestradiol (EOe) po started 1 week after castration and given for 4 days resulted in an increase of endometrial lactate dehydrogenase per DNA (LDH/DNA).
The λ of the dose-response curve was 0.178. In subsequent experiments EOe was used as a standard and the oestrogenic activity of four steroids given po was compared. The effect of testosterone was studied using oestradiol as a standard.
If the activity of EOe is 1, the relative oestrogenic potencies of oestriol succinate, oestradiol decanoate, 11β-methoxymethyl-17α-ethinyl-Δ1,3,5(10)-oestratriene-3,17β-diol and 11β-methoxymethyl-Δ1,3,5(10)-oestratriene-3,16α,17β-triol were 0.074, 0.7, 12.5 and 32, respectively.
The results of the test were compared with the relative potencies of these four compounds in two biological tests, viz. the vaginal cornification in ovariectomized adult rats and stimulation of the uterine growth in immature intact rats. The relative oestrogenic potencies as measured by an increase in the endometrial LDH/DNA were in better agreement with those found in the vaginal cornification assay than with those in the uterine growth stimulation test. Testosterone caused no significant changes of LDH/ DNA. We conclude that the increase in LDH/DNA in the endometrium of ovariectomized rats can be used as a quantitative assay for oestrogenic potency.
Plasma concentrations of progesterone, oestrogens and prostaglandin F in maternal blood and corticosteroids and oestrogens in foetal blood of cows during dexamethasone-induced deliveries
Authors: Fairclough R. J. , Hunter J. T. , Peterson A. J. , Welch R. A. S. 
Published: December 2008

Abstract.
Infusing dexamethasone at rates of 0.1, 1.0 or 10 mg/day into 6 foetal calves at day 240 of gestation (2 calves per infusion rate), induced premature calving in a mean 12, 9 and 3 days respectively. Maternal plasma concentrations of progesterone, oestrone, oestradiol- 17β and prostaglandin F or 13, 14-dihydro- 15-keto-prostaglandin F, and foetal plasma concentrations of oestrone, oestradiol-17β and corticosteroids were monitored until calving.
The maternal hormone changes observed for all cows were a decline in progesterone, and a rise in both oestrogen and prostaglandin F concentrations before calving. Dexamethasone infused at a rate of 1.0 and 10.0 mg/day suppressed plasma corticosteroids in the foetus; however at 0.1 mg/day, foetal corticosteroids increased tenfold during the last 3 days before calving. At the lowest rate of infusion, dexamethasone had no effect on foetal oestrogen levels, but at rates of 1.0 and 10.0 mg/day there was a marked rise in foetal plasma levels of oestrogen.
Distribution study of a synthetic ACTH analogue in rat tissue
Authors: Hirata Masaharu , Futaguchi Shinya , Odaguchi Kunihiro , Inouye Ken , Tanaka Akira 
Published: December 2008

Abstract.
Tissue distribution of {Aib1, Lys17,18,19}-corticotrophin-(1-19)-nonadecapeptide amide (690024-S), iv injected to hypophysectomized rats, were surveyed by bioassay. Among the tissues examined, the largest amount of 690024-S was found in the liver during 3 h of search for the injection, while a higher concentration of the peptide per tissue weight was found in kidney. Though a small amount of 690024-S was detected in spleen, heart and lung at an early stage, it was not detectable in other tissues such as brain, stomach, small intestine, thigh muscle, fat or foetus. The peptide was found to be excreted into bile for the duration of about 2 h. It was also found that the elimination of 690024-S in blood followed biphasic first order kinetics.
Foetal and maternal plasma adrenaline and noradrenaline concentrations in the late pregnant rat: effects of intra-uterine isotonic saline or uterine handling
Authors: Legrand C. , Maltier J. P. 
Published: December 2008

Abstract.
The catecholamines adrenaline (A) and nor-adrenaline (NA) were determined in plasma samples of late pregnant rats and rat foetuses using a radioenzymatic procedure.
In maternal plasma of control rats, values of A were stable during the last three days of gestation (between 5.64 and 6.90 ng/ml) whereas NA values increased just before parturition (+ 70%) and on day 23 post-coitum NA was the main plasma catecholamine.
In foetal plasma of control rats, values of A and NA were constant during the last three days of gestation and A was always higher than NA. For both catecholamines, values in foetal plasma were lower than in maternal plasma.
Blood of rats injected with isotonic saline into the uterus on day 21 of gestation contained 24 h and 48 h later about 2–3 times more A, and no more NA, than blood of control rats.
In foetal plasma the levels of both catecholamines especially of NA were greatly increased after the handling of the uterus or the intra-uterine isotonic saline injection. Both treatments had the same prolonged effect upon A and NA values in foetal plasma. There is no increase of A and NA in maternal and foetal plasma after sham-operation.
Although the values of plasma A and NA were high in control rats because blood sampling was carried out under stressful conditions, these results showed that handling of the uterus or injection of intrauterine isotonic saline was a severe aggression for the mother and foetus.
Rat embryo development in vitro
Authors: Roy S. K. , Sengupta Jayasree , Manchanda S. K. 
Published: December 2008

Abstract.
We report the first successful culture of 8-cell/morula stage rat embryos in a fully synthetic medium supplemented with 3% crystalline bovine serum albumin. Eighty-four per cent of morulae developed to blastocysts, showing that this is a highly efficient culture medium for in vitro studies on rat pre-implantation embryos. Blastocyst formation was severely inhibited by antioestrogen (nafoxidine 3 μg/ml) but no further reversal was obtained by giving oestrogen to culture medium containing this antagonist.
Somatomedin A levels in patients with Cushing's disease
Authors: Thorén Marja , Hall Kerstin , Rähn Tiit 
Published: December 2008

Abstract.
The serum levels of immunoreactive somatomedin A (SMA) in 23 patients with Cushing's disease, aged 6–61 years, were within the range of healthy subjects for their ages. No correlation was found between SMA and the excretion of cortisol. After im administration of hGH (8 IU = 4 mg) daily for 3 days there was a significant rise in SMA, both determined by radioimmunoassay and radioreceptor assay. Thus no impairment was found in the GH-dependent SMA levels or the ability of hGH to generate somatomedin, which indicates that the growth retarding effect of cortisol is most likely due to a direct effect on the tissue. After treatment with stereotactic radiation to the hypophysis there was a significant decrease in cortisol excretion without any change in SMA levels, indicating the possibility to achieve a selective impairment of the ACTH-cortisol axis.
DDAVP treatment of diabetes insipidus during pregnancy and the post-partum period
Authors: Burrow G. N. , Wassenaar W. , Robertson G. L. , Sehl H. 
Published: December 2008

Abstract.
A 23 year old woman with diabetes insipidus who had previously been treated with pitressin, pituitary snuff and chlorpropamide, was treated with DDAVP during pregnancy. DDAVP concentrations immunoassayed as vasopressin were determined in maternal serum and breast milk. Oxytocin antibodies were also determined in maternal serum.
Effect of calcium and potassium on basal and gonadotrophin-releasing hormone (GnRH) stimulated release of luteinizing hormone (LH)
Authors: Zolman Joseph C. , Valenta Lubomir J. 
Published: December 2008

Abstract.
LH release from the anterior pituitary was studied by the method of an in vitro superfusion of bovine anterior pituitary tissue slices. LH release was stimulated by increased potassium concentration (23 and 59 mm) and by synthetic GnRH (1 and 4 ng/ml). While the potassium effect was completely dependent on extracellular calcium, that of GnRH was only partially dependent. Additive effect was observed when GnRH followed enhanced potassium infusion but not vice versa. This suggested that the mechanism responding to potassium may be contained within the stimulatory pathway of GnRH. There was a difference in the dynamics of the LH response: maximum response was attained in about 10 min of potassium infusion while infusion of GnRH resulted mostly in multiphasic stepwise release of LH reaching a plateau in 60 to 90 min only. It is speculated that the potassium effect involves the K+, Na+ dependent ATPase.
Triiodothyronine binding to lymphocyte nuclei and plasma cyclic AMP response to intravenous glucagon in patients with peripheral resistance to thyroid hormones
Authors: Elewaut A. , De Baets M. , Vermeulen A. 
Published: December 2008

Abstract.
In vitro studies of nuclear binding of triiodothyronine (T3) in lymphocytes were performed in three members of a family with hereditary peripheral resistance to thyroid hormone action. Ficoll-Hypaque® purified lymphocytes were used; the binding characteristics were analyzed by Scatchard's methods.
In 5 euthyroid subjects the apparent mean equilibrium association constant (Ka) was 6.1 × 109 1/mol and the mean maximal binding capacity (Cap) 14.4 × 10−15 mol/ 100 μg DNA. In the 3 members of the family one single set of saturable T3 nuclear binding sites with affinity constants similar to those in the controls (mean Ka = 3.2 × 109 1/mol; mean Cap = 17.4 × 10−15 mol/100 μg DNA) were found.
The glucagon stimulated increase in plasma cyclic AMP was studied in 6 healthy subjects and the four members of the family. The plasma cyclic AMP levels of the patients with hormone resistance were generally within the normal range.
These observations demonstrate that in these patients with peripheral resistance to thyroid hormone binding of T3 to the receptor in the nucleus of lymphocytes is normal; in relation to the high circulating thyroid hormone levels, the thyroid hormone mediated cyclic AMP response is disturbed, suggesting that the defect is at the post-receptor effector level.
Activation of membrane-bound adenylcyclase by thyroid stimulating antibodies
Authors: Karlsson F. Anders , Dahlberg Per Anders , Wålinder Olov 
Published: December 2008

Abstract.
Human thyroid plasma membranes isolated from thyroids from patients with Graves' disease or non-toxic nodular goitres produced, under basal conditions, about 100 pmol cAMP per mg membrane protein in 30 min at 37°C. TSH increased the membrane response from a Graves' thyroid by up to 11-fold. cAMP production with immunoglobulins from patients with Graves' disease was four times that from normal immunoglobulins. The onset of action of thyroid stimulating antibodies (TSAb) was rapid and persisted for 30 min of incubation. A change of incubation buffer from 20 mm to 200 mm Tris-HCl reduced the degree and altered the pattern of immunoglobulin stimulation, whereas maximal TSH stimulation was unchanged. The in vitro interaction between the TSH receptor system and TSAb or TSH will differ according to the conditions used.
The synthesis and release of TSH in the thyroidectomized rat: c) the effect of T3 on hypothyroidism of varying duration
Authors: Spira Ofra , Gross Jack , Gordon Amirav 
Published: December 2008

Abstract.
The effect of thyroid hormones on TSH synthesis and release from the anterior pituitary of the rat, at the various stages of hypothyroidism was studied by injecting L-Triiodothyronine (T3) iv (1.5 μg/100 g b.w.) to rats 5 days and 3 months post thyroidectomy (Tx-5d and Tx-3m rats). The changes in plasma and pituitary TSH levels, as well as in the metabolic clearance rate (MCR) of the TSH were followed for 3 days after the T3 injection. From these data TSH synthesis and release rates were determined. TSH release was inhibited in both experimental groups between 3 and 24 h after the injection. TSH synthesis was suppressed in the Tx-5d group to 35% of the initial value. However in the Tx-3m group it was stimulated to approximately 270%, 24 h after the T3. The data suggest that thyroid hormones may affect the synthesis of TSH in two opposite pathways, the first through the stimulation of protein synthesis and the second, inhibitory, as part of the feedback mechanism. Under short-term hypothyroidism, when protein synthesis is not yet diminished, the administration of thyroid hormones results in the inhibition of both TSH synthesis and release through the feedback regulation. In prolonged hypothyroidism, however, when protein synthesis is depressed, the effect of thyroid hormones on the stimulation of TSH synthesis predominates.
Thyroid hormone-catecholamine interrelationships during exposure to cold
Authors: Storm H. , van Hardeveld C. , Kassenaar A. A. H. 
Published: December 2008

Abstract.
Basal plasma levels for adrenalin (A), noradrenalin (NA), l-triiodothyronine (T3), and l-thyroxine (T4) were determined in rats with a chronically inserted catheter. The experiments described in this report were started 3 days after the surgical procedure when T3 and T4 levels had returned to normal. Basal levels for the catecholamines were reached already 4 h after the operation.
The T3/T4 ratio in plasma was significantly increased after 3, 7, and 14 days in rats kept at 4°C and the same holds for the iodide in the 24-h urine after 7 and 14 days at 4°C. The venous NA plasma concentration was increased 6- to 12-fold during the same period of exposure to cold, whereas the A concentration remained at the basal level.
During infusion of NA at 23°C the T3/T4 ratio in plasma was significantly increased after 7 days compared to pair-fed controls, and the same holds for the iodide excretion in the 24-h urine. This paper presents further evidence for a role of the sympathetic nervous system on T4 metabolism in rats at resting conditions.
The TSH response to TRH is exaggerated in primary testicular failure and normal in the male castrate
Authors: LeRoith D. , Liel Y. , Sack J. , Livshin Y. , Laufer N. , Schenker J. , Spitz I. M. 
Published: December 2008

Abstract.
Basal TSH levels and the TSH response to TRH have been evaluated in 26 males aged 20–48 years with primary testicular failure, and 6 males aged 58–69 years who had been orchidectomised for prostatic carcinoma. The patients with testicular failure were sequentially challenged at 30 min intervals with iv LRH (100 μg), TRH (200 μg) and the dopaminergic antagonist, metoclopramide (10 mg). The castrates received a bolus of LRH and TRH given together. The responses in the 2 patient groups were compared to a group of 28 healthy male controls aged 20–40 years, who received the sequential protocol and 8 elderly controls aged 65–79 years, who were given the LRH, TRH bolus.
Mean ± SD basal TSH levels were 3.0 ± 1.2 μU/ml in primary testicular failure and significantly greater than both control and castrate groups. The peak TSH response to TRH was 18.4 ± 7.4 μU/ml in testicular failure and significantly greater than in the young controls, where it was 11.5 ± 5.0 μU/ml. The peak levels in the castrates and in the elderly controls were similar to the young male controls. Total T4 and T3, as well as FTI, were similar in all groups, although the subjects with primary testicular failure had a reduction in their T3 resin uptake. The normal TSH profile in the castrates indicates that a testicular factor produces the exaggerated responses in primary testicular failure.