bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alterations in hepatic nuclear binding of triiodothyronine in experimental diabetes mellitus in rats
Authors: Wiersinga Wilmar M. , Frank Harrison J. L. , Chopra Inder J. , Solomon David H. 
Published: December 2008

Abstract.
The interrelationship between hepatic nuclear T3 receptors and glucose metabolism was studied in 8 diabetic rats and 8 paired control animals.
Serum glucose (mean ± sem, normal vs. diabetic, 167 ± 11 vs. 470 ± 41 mg/100 ml, P < 0.001) and plasma glucagon (183 ± 8.5 vs. 370 ± 29 pg/ml, P < 0.001) were higher in diabetic animals than in controls; serum insulin was lower but not significantly (59 ± 19 vs. 24 ± 12 μU/ml). Serum T4 (4.1 ± 0.53 vs. 0.8 ± 0.27 μg/100 ml, P < 0.005) and T3 (77.3 ± 3.2 vs. 41.7 ± 12.1 ng/100 ml, P < 0.05) were lower in diabetic rats than in controls. Hepatic concentration of non-protein sulfhydryl-groups was also moderately (∼ 19%) lower in diabetic rats than in controls (4.62 ± 0.11 vs. 3.75 ± 0.24 μmol/g, P < 0.02).
The maximal binding capacity (MBC) of the binding of [125I]T3 to isolated rat liver nuclei was significantly decreased in the diabetic rats (368 ± 37 vs. 232 ± 36 fmol/mg DNA, P < 0.01; mean decrease 38%); the affinity constant Ka) was also lower but not significantly (1.60 ± 0.13 vs. 1.25 ± 0.13 109 L/M, 0.05 < P < 0.1). Addition of 1 mm dithiothreitol (DTT) enhanced the Ka of nuclear binding of T3 similarly in the controls and the diabetics. However, it did not restore the decreased MBC of nuclear binding of T3 in diabetic rats to the level of the controls.
The decrease in MBC of hepatic nuclei for T3 did not correlate (P < 0.05) with the decrease in serum T3, serum T4, or hepatic non-protein sulfhydryl-groups. There was, however, a significant negative correlation of MBC of T3 with serum glucose and with plasma glucagon. These data suggest a regulatory role of glucose metabolism (or glucagon) in modulation of binding of T3 by hepatic nuclear T3 receptors.
Effects of insulin on wound healing in diabetic mice
Authors: Weringer Elora J. , Kelso John M. , Tamai Irene Y. , Arquilla Edward R. 
Published: December 2008

Abstract.
In the present study wound healing was examined in normal C57B1/6 male mice, diabetic mice, non-treated; and in diabetic mice treated with insulin. Small dermal wounds were made in the ears of the mice 40 h after the initial injection of insulin or vehicle alone. All animals were biopsied 8 h later. The wounds were examined by light and electron microscopy and wound components (capillaries, fibroblasts, PMN's, oedema, collagen) were quantitated by lineal point analysis. The non-treated, diabetic mice demonstrated an inability to heal wounds when compared to controls; whereas, diabetic mice given a multidose insulin regimen demonstrated a response similar to controls. Insulin treatment of diabetic mice reduced the mean level of hyperglycaemia when compared to the non-treated diabetic mice. There was no detectable difference in the healing response with duration of diabetes in either the insulin-treated or nontreated diabetic mice. Although there was a mild reduction in hyperglycaemia, these data support the hypotheses that insulin is a necessary component of an adequate wound healing response.
Short-term kinetics of LRH-induced LH-release in the long-term ovariectomized rat
Authors: Koiter T. R. , Pols-Valkhof N. , Schuiling G. A. 
Published: December 2008

Abstract.
In a first series of experiments plasma concentrations of luteinizing hormone (LH) were measured at 10 min intervals during 2 h of constant rate infusion of luteinizing hormone-releasing hormone (LRH; 104 ng/ h) in phenobarbitone-anaesthetized long-term ovariectomized (OVX) rats, treated with oil or oestradiol-benzoate (OeB). From these data the mean LH secretion rates during the sampling intervals were calculated using a one-compartment model for the elimination of LH from the plasma. It was found in the OeB-primed OVX rats that during the initial 30–40 min of infusion the LH release is high but constant. Thereafter it shows a further increase. In the oil-treated OVX rats a similar biphasic LH release pattern was found, but in these animals it was preceded by an initial phase of very high LH release, lasting a few minutes.
In another series of experiments a second LRH infusion (again 104 ng/h) was given to OeB-primed OVX rats, starting 1.5 h after the discontinuation of a first LRH infusion lasting either 1, 3.5 or 20 h. The resulting secondary LH responses were smaller the longer the first infusion had lasted, but the LH secretion pattern was similar with all three time schedules and resembled the triphasic pattern observed during the first experiment in the oil-treated OVX rats, rather than the biphasic pattern of the OeB-primed OVX rats.
These results indicate that the LH response to LRH of OVX rats (either treated with OeB or oil), like that of the cyclic rats, exhibits a phase of constant LH release. It is generally assumed that during this period conditions, necessary for the subsequent further increase of the LH secretion, are generated. It is concluded that these conditions largely disappear during a 1.5 h non-stimulus period. It is also concluded that the short initial phase of very high LH secretion is due to recent exposure of the LH-secretory system to stimulatory amounts of LRH.
Long-lasting desensitizing effect of short-term LRH exposure on the pituitary responsiveness to LRH in the ovariectomized rat
Authors: Koiter T. R. , Pols-Valkhof N. , Schuiling G. A. 
Published: December 2008

Abstract.
The influence of short-term exposure to LRH on the responsiveness to LRH and on the LH content of the pituitary gland was studied in the 2-weeks ovariectomized rat. Rats were infused with LRH at the rate of either 208 or 1040 ng/h from 12.00 h to 15.00 h on day 0, and injected with 3 μg of oestradiol-benzoate (OeB) or oil at 09.00 h on either day 1 or day 3. LH-responses were induced by a 21-h lasting infusion of LRH at the rate of 104 ng/h, starting at 12.00 h on the day after the OeB/oil treatment. Control rats received only one LRH treatment: they were injected with OeB or oil on day—1 and LH-responses were induced on day 0.
Results were evaluated on the basis of two parameters: total amounts of LH released during exposure to LRH (1) and release efficiency, i.e. total amounts of LH released in relation to pituitary LH content (2). The findings obtained indicate that exposure to relatively low LRH concentrations causes a greater loss of release efficiency than exposure to relatively high ones. Loss of release efficiency may even increase long after the blood has been cleared of the releasing hormone. From the present experiments it can thus be inferred that exposure of the pituitary gland to LRH leads to either a marked loss of release efficiency and a relatively small LH depletion (1), or a smaller loss of release efficiency and a relatively large LH depletion (2). The two variables both influence the state of responsiveness of the pituitary gland and the present results indicate that only in situation 2 the LH-responsiveness recovers effectively. However, when after exposure to LRH rats are treated with OeB, the consequences, in terms of total amounts of LH released, of differences in degrees of loss of release efficiency and in depletion of LH are eliminated. It is suggested that during the ovulatory cycle this effect of oestrogen plays an important role in the process of recovery of the pituitary gland from diminished responsiveness to LRH induced by LRH.
Activation and clearance of a hormonogen, triglycyl-oxytocin, in the conscious dog
Authors: Stevenson Ralph W. , Robinson Iain C. A. F. , Parsons John A. 
Published: December 2008

Abstract.
Triglycyl-oxytocin (TGOT) and oxytocin (OT) were administered iv and sc to conscious dogs and the plasma concentrations of these peptides determined simultaneously by RIA and bioassay. Constant iv infusions (1 h) at 23 pmol/kg/min produced plateau levels of 1.1 and 1.6 pmol/ml plasma for OT and TGOT respectively. Whilst the distribution space was similar for each peptide, TGOT persisted longer in the circulation (t½, for TGOT 6.6 min; for OT 4.2 min). Bioactive values for OT followed RIA values whether this peptide was given iv or sc. Although very little bioactivity was generated by iv infusions of TGOT, considerable amounts of bioactive OT were found in plasma after injection of TGOT subcutaneously. The hormonogen proved relatively resistant to oxytocinase, an enzyme that destroys OT rapidly. Our results indicate that TGOT is converted to OT in vivo and that its action as a hormonogen is more pronounced after sc than iv administration.
Oxytocin determination by radioimmunoassay in cattle
Authors: Schams D. , Baumann G. , Leidl W. 
Published: December 2008

Abstract.
Oxytocin concentration in jugular vein blood was measured radioimmunologically with a detection limit of 3 pg/ml plasma in male and female cattle.
Five bulls were tested; during mating a cow in oestrus with intromission and ejaculation, during mounting a dummy or another bull with ejaculation into an artificial vagina or during false mounts. No increase in oxytocin concentrations could be observed, but stimulation with an electro-ejaculator caused an increase ranging from 5–84 pg/ml after a latent period of 3–5 min. A similar response was observed in two cows following the same procedure.
The contact with a bull, false mount or mating with intromission and ejaculation was not followed by a measurable oxytocin release in 5 test cows.
The following stimulation techniques, massage of vulva and clitoris, massage of cervix and uterus per rectum, artificial insemination, introduction of a speculum into the vagina or insufflation of air into the vagina were performed with 5 cows and 5 heifers.
Insufflation of air into the vagina was the most effective stimulus, eleciting an oxytocin release up to 588 pg/ml. All 5 heifers responded positively, as well as 4 cows in oestrus. The other manipulations caused an oxytocin response mainly in heifers (whether in oestrus or dioestrus), whereas only one cow in oestrus responded with an oxytocin release. In general, oxytocin concentrations increase about 30–90 s after the start of the stimulus.
Temporal and seasonal relationships between LH, testosterone and antlers in fawn and adult male roe deer
Authors: Sempéré A. J. , Lacroix A. 
Published: December 2008

Abstract.
Plasma LH and testosterone patterns, testis and antler growth and rutting period were determined in the roe deer from birth to 4 years of age. In adults, a typical annual cycle was observed for these endocrine growth and behaviour events. The greatest testosterone levels (9.65 ng/ml) and testis size (13.13 cm3) were recorded for an average period of one month, from July 15th to August 15th, and coincided with the rutting period. At this time antler size was maximal (from 12.70 to 21.35 cm according to age). Plasma testosterone levels and testis size decreased rapidly from September until December (0.23 ng/ml and 3.48 cm3, respectively) and casting occurred at the same time as the decrease of testosterone. It was concluded that testosterone release is an important factor which is correlated with testis growth, antler maintenance and rutting behaviour. Plasma LH levels showed large fluctuations throughout the year and an annual cycle was demonstrated. The lowest plasma LH concentrations were recorded in December (1.36 ng/ml) while higher values were recorded in February (3.25 ng/ml). This suggests that an increase of pituitary gonadotrophic activity appears in spring and is responsible for the testicular reactivation. In the roe deer as in other seasonally breeding species it may be inferred that gonadotrophic activity is controlled by daylength. The present findings show that sexual activity is initiated by increasing daylength and that the roe buck is the only cervidae whose breeding period is early summer.
In fawns, a low plasma testosterone level (1.27 ng/ml), a small testis size (2.96 cm3) and antler growth ('buttons') were observed a few months after birth in autumn and high plasma LH levels (4.08 ng/ml) were recorded before this, as early as the first month of age. It is suggested that interrelationships between LH, testosterone, testis and antler growth begin to appear at this time and that the precocious LH release induces the first pubertal testicular activity. This first increase of gonadotrophic activity which appears in summer can not be related to the photoperiod as in adults and would be under central endogenous control for the onset of the pubertal maturation process. From this pubertal state (3 months of age) to the following testicular initiation where potential sexual maturity is probably reached (7-9 months of age), complex temporal interrelationships occur between daylength, gonadotrophic and testicular factors.
Δ5-androstenediol: kinetics of metabolism and binding to plasma proteins in normal post-menopausal women
Authors: Bird Charles E. , Tremblay John , Masters Valerie , Clark Albert F. 
Published: December 2008

Abstract.
Δ5-androstenediol (Δ5-diol) while having minimal androgenic activity is of potential biological importance because it binds to oestrogen receptors and has oestrogenic activity in several systems. We have examined Δ5-diol metabolism in post-menopausal women utilizing the constant infusion technique. The metabolic clearance rate for 11 subjects was 763 ± 50 1/24 h or 467 ± 30 1/m2/24 h. Labelled dehydroepiandrosterone, testosterone, Δ4-androstenedione, androsterone and the sulphates of Δ5-diol, dehydroepiandrosterone and androsterone were found in the plasma. Of all the kinetic parameters only the conversion ratio for dehydroepiandrosterone sulphate was different from that for young women (4.958 ± 0.410 for young women vs 3.084 ± 0.220 for older women). The plasma concentration of Δ5-diol was 0.94 ± 0.19 ng/ml and the calculated blood production rate was 686 ± 80 μg/24 h. The per cent free plasma Δ5-diol was 4.6 ± 0.25. These values are slightly lower but not significantly different from those previously reported for normal young women.
Plasma levels of medroxyprogesterone acetate (MPA), sex-hormone binding globulin, gonadal steroids, gonadotrophins and prolactin in women during long-term use of depo-MPA (Depo-Provera®) as a contraceptive agent
Authors: Jeppsson Sten , Gershagen Sten , Johansson Elof D. B. , Rannevik Gunnar 
Published: December 2008

Abstract.
The aim of the study was to evaluate the functional state of the hypothalamo-pituitary-gonadal axis and to assess the concentrations of MPA in the peripheral blood during very long-term use of depomedroxyprogesterone acetate (DMPA) as a contraceptive agent.
The concentrations of MPA, sex-hormone binding globulin (SHBG) and the different pituitary and gonadal hormones in the peripheral blood were measured in nine 26–41 year old women. They had for 4.4–10.6 years (mean 8.9 years) been receiving DMPA im in a dose of 150 mg every 12th week as a contraceptive. Blood samples were obtained immediately before an injection of DMPA, 2 weeks later, and again immediately before the next injection. SHBG was measured by radio-electroimmunoassay; MPA, gonadal and pituitary hormones by RIA.
The investigation showed that the oestradiol levels — even after very long-term use of DMPA — were still within the normal range for the early follicular phase. Gonadotrophins and prolactin were within the normal range for eumenorrhoeic women as well as the concentration of SHBG. MPA did not accumulate in the plasma. The changes in the plasma levels of oestradiol, MPA and SHBG after each injection disappeared within 12 weeks. The study appears to warrant the conclusion that even up to 10 years' use of DMPA in a dose of 150mg im every 12th week as a contraceptive agent, does not induce hormonal changes different from those seen after the very first injection.
Thyrotrophin and prolactin responses to thyrotrophin-releasing hormone in patients with Parkinson's disease
Authors: Martinez-Campos Abraham , Giovannini Paolo , Novelli Antonello , Cocchi Daniela , Caraceni Tommaso , Müller Eugenio E. 
Published: December 2008

Abstract.
The thyrotrophin (TSH) and prolactin (Prl)-releasing effects of TSH-releasing hormone (TRH) were investigated in 20 subjects with Parkinson's disease (PD), unmedicated, on chronic treatment with a combination levodopa-benserazide (Madopar) or levodopa-carbidopa (Sinemet) or withdrawn from therapy. Administration of TRH (200 μg iv) induced in unmedicated patients TSH and Prl responses significantly lower than those of sex-and age-matched controls. In patients on Madopar therapy the TSH and Prl responses to TRH were greater than in unmedicated patients and comparable to those of controls, while in patients on Sinemet therapy the pituitary responses were undistinguishable from those of unmedicated subjects. Withdrawal of Madopar therapy resulted in a marked diminution of the TSH response but did not affect the Prl response to TRH. Withdrawal of Sinemet therapy did not alter the TSH and Prl responses to TRH. Concomitant evaluation of growth hormone (GH) levels, in none of the subjects evidenced non-specific changes in plasma GH following TRH.
Since TSH and Prl responses to TRH are inhibited by an enhancement of the dopaminergic tone, it would appear that the latter is preserved in the tuberoinfundibular system of unmedicated subjects and subjects on chronic Sinemet therapy, but is defective in subjects on chronic Madopar therapy.
ACTH-producing pituitary adenomas in Addison's disease: two cases treated by transsphenoidal microsurgery
Authors: Krautli Barbara , Müller J. , Landolt A. M. , von Schulthess F. 
Published: December 2008

Abstract.
In 2 women with known Addison's disease, progressive hyperpigmentation reappeared years after an initial remission under conventional substitution therapy with cortisone. Excessively elevated plasma ACTH concentrations and radiological evidence of sella turcica deformation led to the diagnosis of ACTH-producing adenomas and prompted their removal by transsphenoidal microsurgery.
In one patient, a large Crooke's cell adenoma with extensive extrasellar expansion had caused severe and irreversible bilateral defects of the visual fields and unilateral optic atrophy. Surgical removal of the tumour and radiotherapy brought about a permanent disappearance of the hyperpigmentation, but eventually led to secondary hypothyroidism. In the second patient, the selective removal of a small intrasellar eosinophilic adenoma consisting of ACTH-producing cells did not alleviate the hyperpigmentation and did not lower the plasma ACTH concentration. However, hyperpigmentation regressed markedly within a year of treatment with a higher dose of cortisone.
The rarity of similar cases in the literature seems to indicate that insufficient feedback suppression of ACTH-producing cells in treated Addison's disease does not by itself induce the development of a pituitary adenoma, but might promote the growth of an independently and coincidentally occurring microadenoma, which would have caused Cushing's disease in a person with intact adrenal glands.
A case of ectopic ACTH syndrome: diagnostic difficulties caused by intermittent hormone secretion
Authors: Thorner Michael O. , Martin William H. , Ragan Gary E. , MacLeod Robert M. , Feldman Philip S. , Bruni Carlo , Williamson Brian R. J. , Orth David N. 
Published: December 2008

Abstract.
A patient with a thymic carcinoid tumour causing ectopic ACTH syndrome is presented. The case illustrates the rapid development of the clinical and laboratory findings often associated with ectopic secretion of ACTH, including severe proximal myopathy, emotional lability, and hypokalaemic alkalosis. Interpretation of conventional tests of pituitary-adrenal function was complicated by intermittent secretion of ACTH by the tumour. The results of selective venous sampling for ACTH ruled out pituitary ACTH hypersecretion and were suggestive of a thymic source; computerized tomography of the chest localized the tumour. In vivo and in vitro investigations confirmed excessive ACTH production by the tumour, and surgical resection plus radiotherapy has resulted in resolution of the syndrome.
The diagnostic problems created by intermittent secretion of ACTH by these tumours and the pre-operative and post-operative medical management of these patients are discussed.
Testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH) in plasma of rabbit from birth to adulthood. Correlation with sexual and behavioural development
Authors: Berger M. , Jean-Faucher Ch. , de Turckheim M. , Veyssiere G. , Blanc M. R. , Poirier J. C. , Jean Cl. 
Published: December 2008

Abstract.
Plasma testosterone, LH and FSH levels were determined and correlated with reproductive organs growth, testicular differentiation, fighting and mounting behaviour in maturing rabbit.
An infantile phase of development extends from birth to 40 days, characterized by low testosterone and FSH levels, decreasing LH levels (until 20 days) and by a slow growth of testis and seminal vesicle. The peripubertal phase starts abruptly around day 40. It is marked by simultaneous events: the appearance of mature Leydig cells in the testis, a striking increase in testosterone and FSH levels, a small rise in LH levels and an acceleration of testicular growth. The phase of rapid growth of seminal vesicle and the first meiotic divisions start around day 70, in presence of high circulating levels of FSH and testosterone. Fighting (3 months) and mounting behaviour (146 ± 13 days) occur lately after a long period of high circulating testosterone levels.
Mineralocorticoid escape in man: role of renal prostaglandins
Authors: Dürr J. , Favre L. , Gaillard R. , Riondel A. M. , Vallotton M. B. 
Published: December 2008

Abstract.
The role of renal prostaglandins (PGE2 and PGF2α) and kallikrein in the renal escape from excess mineralocorticoid has been evaluated in 10 normal volunteers on a high sodium diet. Escape from 9-α-fluorohydrocortisone (9-α-FF) administered for 12 days (0.6 mg daily) occurred within 4–5 days when 345 ± 50 mmol sodium had accumulated. Indomethacin, a cyclooxygenase inhibitor, was then administered for 3 days while maintaining 9-α-FF. This was followed by a further cumulative gain of 105 ± 28 mmol sodium after which escape resumed. Potassium balance remained negative throughout the study. Both PGE2 and PGF2α excretion increased significantly under 9-α-FF from respective control values of 220 ± 50 and 818 ± 86 ng/24 h, to 610 ± 317 and 1213 ± 132 ng/24 h at the time of escape. Concomitantly urinary kallikrein increased from 1.1 ± 0.2 to 2.5 ± 0.3 units/24 h. Creatinine clearance increased from a mean baseline value of 111 ± 4 to 123 ± 4 ml/min during the same period. Indomethacin produced an inhibition of prostaglandin excretion without significant alteration of kallikrein excretion. Overall these results and particularly the transient sodium retention induced by indomethacin at the time of mineralocorticoid escape, suggest that prostaglandins may contribute to the escape phenomenon, whereas the role of kallikrein does not appear to be determinant.