bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endothelin-like immunoreactivity in rat models of diabetes mellitus
Authors: Takahashi K. , Suda K. , Lam H.-C. , Ghatei M. A. , Bloom S. R. 
Published: December 2008

ABSTRACT
The factors associated with high concentrations of circulating plasma immunoreactive endothelin in patients with diabetes mellitus are unknown. Plasma and tissue (lung and kidney) immunoreactive endothelin levels were therefore measured by radioimmunoassay in three animal models of diabetes mellitus: dexamethasone-treated rats (2 mg/kg per day for 12 days), streptozotocin-treated rats (100 mg/kg, 4 days before being killed) and rats treated with both dexamethasone and streptozotocin. Plasma concentrations of immunoreactive endothelin in the dexamethasone-treated rats (3·13±0·28 pmol/l, mean ± s.e.m., n = 15) were significantly (P < 0·005) higher than those in controls (1·33±0·18 pmol/l, n = 15), while plasma concentrations of immunoreactive endothelin in streptozotocin-treated rats (n = 8) and rats treated with both dexamethasone and streptozotocin (n= 14) were undetectable (< 0·5 pmol/l). Fast protein liquid chromatographic analysis of the plasma immunoreactive endothelin of dexamethasone-treated rats showed four peaks: one in the void volume, one eluting before endothelin-3, one eluting after endothelin-3 and before endothelin-1 and one eluting in a position identical with that of endothelin-1. Pulmonary concentrations of immunoreactive endothelin in the three groups of rats with diabetes mellitus were lower (P < 0·005) but no significant change was found in renal immunoreactive endothelin. These findings indicate that short-term dexamethasone treatment increases plasma levels of immunoreactive endothelin while streptozotocin treatment decreases them. Thus, multiple factors may influence plasma concentrations of immunoreactive endothelin in diabetes mellitus.
Journal of Endocrinology (1991) 130, 123–127
In-vivo inhibition of the preovulatory LH surge by substance P and in-vitro modulation of gonadotrophin-releasing hormone-induced LH release by substance P, oestradiol and progesterone in the female rat
Authors: Battmann T. , Parsadaniantz S. Mélik , Jeanjean B. , Kerdelhué B. 
Published: December 2008

ABSTRACT
The effects of substance P (SP) on the preovulatory surge of LH and on the inhibitory and stimulatory effects of oestradiol-17β and progesterone on gonadotrophin-releasing hormone (GnRH)-induced LH release were investigated in vivo and in vitro in the rat. A single s.c. injection of 100 μg SP at 12.00 h on the day of pro-oestrus significantly decreased the preovulatory surge of LH. In vitro, the inhibitory effect of oestradiol-17β on GnRH-induced LH release was not modified by treatment with SP. The stimulatory effect of progesterone on GnRH-induced LH release was reduced by treatment with SP. It is concluded that SP may play a modulatory role in the neuroendocrine control of the preovulatory LH surge.
Journal of Endocrinology (1991) 130, 169–175
Avidin and ovalbumin induction by progesterone in chicken oviduct detected by sensitive immunoenzymometric assays
Authors: Joensuu T. , Tuohimaa P. , Vilja P. 
Published: December 2008

ABSTRACT
This study describes sensitive immunoenzymometric assays (IEMAs) for chicken avidin and ovalbumin, markers of cytodifferentiation and action of progesterone and oestrogen in the oviduct magnum mucosa. The determination range was 0·5–100 ng/ml and the detection limit 0·1 ng/ml in both IEMAs. The intra- and interassay coefficients of variation, measured from chicken tissue supernatants, averaged below 6 and 10% respectively. IEMAs correlated well with the radioimmunoassays for avidin and ovalbumin previously developed in our laboratory, and with the widely used [14C]biotin-binding method for avidin. Using an IEMA, we found avidin induction with low concentrations of progesterone in the differentiated oviduct of oestrogen-pretreated chicks. The induction has not been detected previously by less sensitive methods. Avidin was induced by all given doses of progesterone (0·2–200 mg/kg in vivo for 24 h after a short oestrogen treatment), the response being dose-dependent at doses of 0·2–20 mg progesterone/kg body weight, the maximum avidin production being about 70 μg/g tissue. Ovalbumin was induced at doses of 2–200 mg progesterone/kg body weight without variations in the responses, being about 35 mg/g. The mean content of avidin in the oviduct of laying hens was 58·1 μg/g, and of ovalbumin 74·9 mg/g. Minimal traces of avidin and ovalbumin were found in the oviduct after hatching (0·3 and 5 μg/g respectively); however, progesterone did not have an effect on this expression. Sensitivity, rapidity and practicability, together with non-radioactivity, are the main advantages of the present IEMAs for chicken avidin and ovalbumin.
Journal of Endocrinology (1991) 130, 191–197
Separation and characterization of Leydig cells and macrophages from rat testes
Authors: Dirami G. , Poulter L. W. , Cooke B. A. 
Published: December 2008

ABSTRACT
A method involving centrifugal elutriation followed by density gradient centrifugation and incubation with a macrophage monoclonal antibody has been investigated to separate and characterize Leydig cells and macrophages from adult rat testes. After dispersion of the testes with collagenase, the isolated interstitial cells were found to contain 18% Leydig cells and 12% macrophages. These cells were then separated by centrifugal elutriation into eight fractions (F1–F8) (9 to 74 ml/min at 386 g). Each of these fractions was then further purified by density gradient centrifugation on 0–90% Percoll gradients. After centrifugal elutriation, the macrophages were mainly eluted in the first three fractions (F1–F3), whereas the Leydig cell percentage increased in each fraction with increasing flow rate. After further purification of each fraction on Percoll gradients, high percentages of macrophages (11–20%) were found in fractions F1–F3 (average density 1·045 g/ml), containing 11–37% Leydig cells. Less than 3% of the cells in fraction F4–F8 (average density 1 ·075 g/ml) were macrophages and more than 95% were Leydig cells. Heterogeneity of Leydig cells with respect to sedimentation velocities and function was found. Leydig cells from elutriated-and Percoll-purified fractions F4–F8 were heterogeneous with respect to testosterone and cyclic AMP (cAMP) production but showed a similar binding capacity for 125I-labelled human chorionic gonadotrophin. Leydig cells with the highest sedimentation velocity (35·7 mm/h-g) from fractions F7 and F8 were approximately twofold more responsive to LH (3·3 nmol/l) with respect to testosterone and cAMP production compared with Leydig cells with the lowest sedimentation velocity (20·7 mm/h-g).
The elutriated and Percoll-purified cells (corresponding to fractions F4–F8) were further purified by incubation with magnetic beads coated with a macrophage monoclonal antibody; this yielded very pure Leydig cells containing <0·3% macrophages. The incubation temperature (room temperature or 4 °C) during the purification with magnetic beads did not affect the degree of purity or the responsiveness of the Leydig cells to LH. The removal of the remaining macrophages with magnetic beads did not have any significant effect on the Leydig cell responsiveness to LH.
It was concluded that Leydig cells purified by elutriation and density gradient centrifugation are heterogeneous with respect to their sedimentation velocities and responses to LH; the higher the sedimentation velocity, the higher is their capacity to respond to LH. Leydig cells free from macrophages can be prepared by further purification using magnetic beads coated with a macrophage monoclonal antibody.
Journal of Endocrinology (1991) 130, 357–365
The influence of reproductive status on vasopressin release in the rat
Authors: Forsling M. L. , Kelestimur H. , Windle R. 
Published: December 2008

ABSTRACT
It has been shown that surgical ovariectomy of the rat results in a fall in plasma vasopressin concentrations suggesting that ovarian steroids may influence hormone release. To determine whether a similar fall is found on suppression of the oestrous cycle, vasopressin concentrations were monitored after treatment with the antioestrogen preparation tamoxifen or a long-acting analogue of LH-releasing hormone (LHRH) which suppresses ovarian function. Treatment with either agent was found to result in a fall in circulating vasopressin concentrations, with little effect on fluid balance. To determine whether the ovary could influence the vasopressin release in response to known stimuli, hormone concentrations were measured in ovariectomized animals during extracellular fluid hypertonicity produced by an i.p. injection of hypertonic saline and hypovolaemia produced by an i.p. injection of polyethylene glycol. It was found that after ovariectomy or treatment with tamoxifen, the response to hypertonicity was unaffected but that to hypovolaemia was attenuated. Treatment with LHRH affected the response to both hypovolaemia and hypertonicity.
Journal of Endocrinology (1991) 130, 387–393
Administration of insulin-like growth factor-I, but not growth hormone, increases maternal weight gain in late pregnancy without affecting fetal or placental growth
Authors: Gargosky S. E. , Owens J. A. , Walton P. E. , Owens P. C. , Wallace J. C. , Ballard F. J. 
Published: December 2008

ABSTRACT
During late pregnancy in the rat, circulating levels of insulin-like growth factor-I (IGF-I) and some IGF-binding proteins (IGFBP) decline. The aim of the present study was to determine the relationship of GH to circulating IGF and IGFBP in the late-pregnant rat and to examine the effects on maternal, fetal and placental growth of preventing the decline in serum IGF and IGFBP concentrations. During the first 9 days of pregnancy, IGF-I concentrations increased from 340 to 500 μg/l. Recombinant human (rh) GH at 2·4 mg/kg per day and rhIGF-I at 1·4 mg/kg per day were infused into pregnant rats via osmotic mini pumps during the second half of pregnancy. After pump implantation on day 11 of pregnancy, only IGF-I infusion significantly increased circulating IGF-I. A maximum IGF-I concentration of 907 μg/l was measured on day 14 during treatment with IGF-I, after which the serum concentration decreased to 510 μg/l by day 20 of pregnancy. The serum IGFBPs were examined using a Western ligand blot technique. Infusion of neither GH nor IGF-I returned the IGFBPs to non-pregnant levels. Administration of IGF-I slightly increased IGFBP-3 and a smaller 32 kDa IGFBP at days 17 and 20 of pregnancy.
Neither fetal nor placental weight was significantly different between treatment groups. However, administration of IGF-I significantly increased maternal weight gain during the 10-day treatment period. Thus, pregnant rats infused with IGF-I gained 99±4 g (mean ± s.e.m., n = 10) compared with rats treated with GH or vehicle which gained 72±4 g (n = 9) and 77±4 g (n = 10) respectively. The increase in maternal weight after administration of IGF-I was not due to increased litter size, fetal or placental weight. The increased maternal weight gain after IGF administration, without affecting fetal and placental weights, suggests a modification in the mode of maternal nutrient repartitioning during late pregnancy.
Journal of Endocrinology (1991) 130, 395–400
Pharmacological characterization of a novel oestrogen antagonist, ZK 119010, in rats and mice
Authors: Nishino Y. , Schneider M. R. , Michna H. , von Angerer E. 
Published: December 2008

ABSTRACT
The oestrogenic and antioestrogenic effects of a new non-steroidal compound ZK 119010(2-(4-hydroxyphenyl)-3-methyl-1-[6-(1-pyrrolidinyl)-hexyl]-indol-5-ol) were evaluated and compared with those of tamoxifen and ICI 164384.
In immature mice, ZK 119010 administered once daily for 3 days (s.c.) inhibited the uterotrophic and vaginotrophic effect of oestradiol in a dose-dependent manner and was distinctly more potent than tamoxifen or ICI 164384 in exerting antioestrogenic effects.
When antioestrogens in combination with oestradiol were administered once daily for 5 days to ovariectomized adult rats, ZK 119010 at lower doses (≤ 1 mg/kg) was slightly less effective than tamoxifen in inhibiting the uterotrophic effect of oestradiol. At the higher doses, however, ZK 119010 was strongly antioestrogenic, and ICI 164384 was less effective than ZK 119010 or tamoxifen. ZK 119010 at 10 mg/kg, like ICI 164384 at 30 mg/kg, caused an almost complete inhibition of the oestradiol-induced uterine growth in rats. The antioestrogenic effect of tamoxifen in rats was also limited by its inherent oestrogenic property. The oestrogenic activity of ZK 119010 was much below that of tamoxifen, whereas ICI 164384 did not show oestrogenicity. The present results indicate that ZK 119010 is a novel type of non-steroidal antioestrogen which has only a marginal oestrogenic effect in rats and mice. Such an antioestrogen may be useful for the treatment of oestrogen-sensitive diseases in man.
Journal of Endocrinology (1991) 130, 409–414
Long-term effects of recombinant human growth hormone treatment on skeletal maturation and growth in female rhesus monkeys with normal pituitary function
Authors: Wilson M. E. , Tanner J. M. 
Published: December 2008

ABSTRACT
Female rhesus monkeys (n = 5), having normal pituitary function, were treated for 50 months with recombinant human growth hormone (rhGH; 250 μg/kg) 3 days/week (Monday, Wednesday and Friday) and rates of growth were compared with a group of age-matched untreated females (n = 6). Treatment was initiated at 20 months of age, approximately 10 months before the expected age of menarche. Long-term treatment with rhGH accelerated bone maturation and increased the velocity of increase in crown–rump length, tibia length and body weight. The period of acceleration occurred coincident with the occurrence of spontaneous puberty. Body measurements remained larger in the treated females until growth ceased. Long-term rhGH treatment increased final adult crown–rump length by some 3%, with a slight increase in tibia length and body weight, without having any untoward effects on reproductive capacity or health. One treated animal exhibited higher estimates of antibodies to rhGH throughout the study period, and this female also had a smaller increment in crown–rump length than the other treated females. These data suggest that long-term treatment of normal-pituitary females with rhGH augments crown–rump growth without any untoward effects of health.
Journal of Endocrinology (1991) 130, 435–441
Protein glycation: its role in the changes induced by diabetes in the properties of the serum insulin-like growth factor-I binding proteins
Authors: Cortizo A. M. , Gagliardino J. J. 
Published: December 2008

ABSTRACT
The purpose of this work was to study the effect of diabetes on 125I-labelled insulin-like growth factor (IGF) binding to specific serum binding proteins (IGFBPs) and the possible role of protein glycation in such an effect. Accordingly, ligand blotting and fructosamine assays were performed in serum samples from diabetic and non-diabetic eSS rats as well as in samples of normal rat serum previously incubated with different concentrations of glucose.
IGFBPs with molecular weights of 24, 30 and 40 kDa were identified in samples from diabetic and non-diabetic rats. 125I-Labelled IGF-I binding to each of these fractions increased significantly in the serum of diabetic rats. IGF-I binding to IGFBP-40 increased significantly as a function of the degree of glycation of serum proteins. Conversely, the increased binding of IGFBP-24 and IGFBP-30 was related only to the glucose concentration attained at 120 min during the oral glucose tolerance test.
Glycation of proteins of normal serum and the binding of labelled IGF-I increased as a function of glucose concentration in the incubation media. In these in-vitro glycated normal sera, only the binding to IGFBP-40 increased significantly; this increase was closely related to the amount of protein glycation. No clear and reproducible changes occurred with the binding of 125I-labelled IGF-I to IGFBP-24 and IGFBP-30 fractions.
These results confirm the increase in the binding capacity of IGFBPs reported in diabetic animals. They also show that the increase in IGF-I binding to each IGFBP fraction is regulated by a different mechanism; whereas protein glycation induces changes in IGFBP-40, this mechanism does not affect the binding properties of the other two IGFBPs.
The increased binding of IGFBP might affect the availability of free IGF-I, and the consequent alterations in IGF-I-dependent metabolic processes could explain the role of this growth factor in the pathogenesis of chronic complications of diabetes.
Journal of Endocrinology (1991) 131, 33–38
Uptake of nicotinamide by rat pancreatic β cells with regard to streptozotocin action
Authors: Sofue M. , Yoshimura Y. , Nishida M. , Kawada J. 
Published: December 2008

ABSTRACT
Exposure of rat pancreatic β cells in monolayer culture to 2 mmol streptozotocin (STZ)/1 for 1 h followed by thorough washing inhibited their uptake of [14C]nicotinamide and [3H]2-deoxyglucose ([2H]2-DG) to about 50% and also reduced the intracellular ATP concentration to 50% of that in control cells. These changes were not due to a lethal cytotoxic effect of STZ, because cell viability, as estimated by succinic dehydrogenase activity, was 90% of that of control cells. Oligomycin and carbonylcyanide-m-chlorophenylhydrazone (CCCP), an uncoupler of oxidative phosphorylation, caused a dose-dependent decrease in intracellular ATP concentration while maintaining high cell viability. These ATP-depleted cells showed a decrease in insulin release and an inhibition of the uptake of [14C]nicotinamide and [3H]2-DG in a dose-dependent manner. Therefore oligomycin and CCCP reproduced the same effects as those found in β cells treated with STZ. These results suggest that the uptake of nicotinamide and 2-DG by β cells might be regulated by their intracellular ATP concentration. The decreased uptake of nicotinamide in ATP-depleted β cells caused by STZ might explain the lack of protective effect of nicotinamide against STZ cytotoxicity when administered after the latter. Furthermore, the radiotracer experiments demonstrated that the transport of nicotinamide by intact β cells was inhibited in a dose-dependent manner by 2-DG and vice versa, i.e. the transport of 2-DG was inhibited by nicotinamide. These findings suggest the existence of a common transport mechanism in β cells responsible for the uptake of nicotinamide and 2-DG, the transport of which is known to occur by facilitated diffusion.
Journal of Endocrinology (1991) 131, 135–138
Parathyroiditis in the non-obese diabetic mouse – a new finding
Authors: Krug J. , Williams A. J. K. , Beales P. E. , Doniach I. , Gale E. A. M. , Pozzilli P. 
Published: December 2008

ABSTRACT
Autoimmune reactions to parathyroid cells have been observed in human autoimmune polyendocrinopathy, but such findings have not been described in animal models of polyendocrine autoimmunity. We report here three cases of lymphocytic infiltrations in 12 parathyroid glands identified in a total of 18 thyroid glands studied in the non-obese diabetic (NOD) mouse.
The majority of parathyroid-infiltrating lymphocytes possessed the helper/inducer phenotype as defined by the L3T4 monoclonal antibody. Parathyroiditis was accompanied by lymphocytic thyroiditis only on one occasion, whereas in other cases of thyroiditis, lymphocytic infiltration of the parathyroid was undetectable. We conclude that parathyroiditis in the NOD mouse is part of the wide spectrum of autoimmunity observed in this animal model of diabetes.
Journal of Endocrinology (1991) 131, 193–196
Oestradiol-17β induces the major vitelline envelope proteins in both sexes in teleosts
Authors: Hyllner S. J. , Oppen-Berntsen D. O. , Helvik J. V. , Walther B. T. , Haux C. 
Published: December 2008

ABSTRACT
During growth of the ovarian follicle, the teleost oocyte becomes surrounded by an acellular coat, the vitelline envelope. The nature, origin and number of the vitelline envelope proteins in fish appear to vary with species. In this work, polyclonal antibodies directed against vitelline envelope proteins from rainbow trout, brown trout and turbot were used to show that oestradiol-17β induces the major vitelline envelope proteins in juveniles, both males and females, from different species. The fact that males can synthesize vitelline envelope constituents shows that the origin of these proteins is not confined to the ovary. The vitelline envelope of rainbow trout eggs consists of three major proteins, designated α (60 kDa), β (55 kDa) and γ (50 kDa). The amino acid composition of each of the three proteins indicated that the three proteins are alike and the suggestion that these proteins represent a separate class of structural proteins is sustained.
Journal of Endocrinology (1991) 131, 229–236
Effect of cell density on growth hormone release from, cyclic AMP levels in and peptide α-amidation activity of primary cultured rat anterior pituitary cells
Authors: Sugimoto H. , Suzuki M. , Takeuchi T. , Ishikawa K. 
Published: December 2008

ABSTRACT
To investigate the effect of cell density on rat somatotrophs, dispersed adult rat anterior pituitary cells were plated at several densities (0·6, 1·2, 2·4 and 6·0 × 105 cells/cm2) or at two densities (6·07 × 105 and 1·21 × 105 cells/cm2) as high and low densities respectively. A static incubation system was used to study the release of GH and peptidyl glycine α-amidating enzyme (PAM; a component of secretory granules) and the cellular concentration of cyclic AMP (cAMP) in basal and stimulated cells. In addition, a perifusion system was used to characterize the sensitivity to GH-releasing factor (GRF) at both high and low densities. The high density of cells in both the static incubation and perifusion systems caused a low basal secretion rate of GH and PAM. When the cultured cells were stimulated with human GRF (hGRF) in perifusion, GH secretion from cells at high density was markedly higher than that from cells at low density. The cAMP content in the static incubation system showed a similar tendency to that observed for basal and stimulated GH secretion; that is, the basal cAMP content was increased as the cell density decreased. The cellular concentration of cAMP was increased by about threefold by 1 nmol hGFR/1 and by more than tenfold by 10 nmol hGRF/1. When the medium from cells cultured at low density was replaced by that from the cells at high density, there was no change in the basal cellular cAMP content of the cells at low density. These data suggest that cell-to-cell contact in dispersed pituitary cells seems to be important in the maintenance of their cellular integrity to secrete GH.
Journal of Endocrinology (1991) 131, 237–244