bluuebunny/crossref_metadata_2025_split huggingface dataset:
THYROTROPHIN CONCENTRATIONS IN THE PLASMA OF CATTLE, SHEEP AND FOETAL LAMBS AS MEASURED BY RADIOIMMUNOASSAY
Authors: HOPKINS P. S. , WALLACE A. L. C. , THORBURN G. D. 
Published: December 2008

SUMMARY
A radioimmunoassay technique for measuring the thyrotrophin (TSH) concentration of sheep and cattle plasma is described. The sensitivity of the assay allowed the measurement of 1–50 ng TSH/ml unextracted plasma. Cross-reaction with ovine luteinizing hormone, prolactin and growth hormone was very low. The average recovery of added TSH was 103 ± 4·1 (s.e.m.)% and the between-assay coefficient of variation was 13·8%.
The normal plasma TSH levels of sheep and cattle were approximately 2·5 ng/ml (5 mu. bovine TSH/100 ml). Foetal sheep had plasma TSH concentrations of approximately 3·2 ng/ml during the last 20 days of gestation. Levels of TSH in the circulation decreased abruptly after hypophysectomy of the foetal lamb and a decline in the plasma thyroxine (T4) concentrations was also apparent within 24 h of the operation. However, thyroidectomy of adult and foetal sheep did not increase plasma TSH concentrations until almost all the T4 had been cleared from the circulation.
The injection of T4 into thyroidectomized sheep rapidly reduced plasma TSH concentrations to normal values. However, the continued injection of T4 did not further reduce TSH concentration. The injection of T4 or triiodothyronine into normal sheep was also without effect on plasma TSH concentrations.
HYPOPHYSECTOMY OF THE TAMMAR WALLABY, MACROPUS EUGENII: SURGICAL APPROACH AND GENERAL EFFECTS
Authors: HEARN J. P. 
Published: December 2008

SUMMARY
A technique of hypophysectomy and regimes of pre- and post-operative care were developed for the tammar wallaby, Macropus eugenii, to a stage when animals can survive the operation with little apparent stress.
Thyroid and adrenal gland weights declined after hypophysectomy, especially within the first 20–30 days. Changes in the adrenal cortex after hypophysectomy suggested that this region may have a zonal organization different from that in eutherian mammals. The reproductive tracts of males and females lost weight rapidly after hypophysectomy.
Eleven plasma parameters were studied for the effects of hypophysectomy. There was a reduction in sodium and chloride and a tendency to higher potassium levels, reflecting inadequate adrenal cortical function. Calcium and total protein values remained unaffected, but inorganic phosphate, glucose and cholesterol were depleted, and a less significant depletion in blood urea, nitrogen and uric acid was evident.
GEL FILTRATION OF HUMAN URINARY IMMUNOREACTIVE LUTEINIZING HORMONE
Authors: YOUNG J. L. , HARSOULIS P. , KUKU S. F. , FRASER T. R. 
Published: December 2008

SUMMARY
In human urinary concentrates and also in a urinary gonadotrophin standard (2nd IRP-HMG), gel-filtration analysis revealed three main peaks of immunoassayable luteinizing hormone (LH). A similar analysis of LH extracted from human pituitaries showed most of the activity in a peak of larger molecular weight, and only minor fractions in the positions of the urinary peaks. In an extract of normal human serum, analysis showed only one similar peak of large molecular weight, which also emerged before the urinary peaks.
During an i.v. infusion of pituitary LH into normal men, the urinary LH activity increased but was still found only in the same three peaks on gel filtration, and all were of a molecular weight smaller than that of the infused material; but a higher proportion of the urinary LH was found in the earliest of these peaks compared with that found before infusion. Conversely, 20–35 h after the i.v. infusion, there was a slightly higher proportion of LH activity in the third peak of smallest molecular weight.
These findings suggest that the urinary immunoassayable LH, which is found in three peaks of different molecular weights, is derived from the pituitary or serum LH of higher molecular weight. The changes in the proportions of larger or smaller molecular weight fractions in the urine during and after LH infusion suggest that the earliest peak may be disaggregated serum LH, while the last or smallest molecular weight peak may comprise metabolites of LH.
EFFECTS OF OVARIAN STEROID HORMONES ON ESTERASES IN THE RAT ENDOMETRIUM
Authors: BOSHIER D. P. , KATZ JUNE M. 
Published: December 2008

SUMMARY
A technique in which uterine luminal epithelium is separated from the remainder of the endometrium by rapidly vibrating everted uterine cornua in a 3·5 mm solution of EDTA has been developed. Examination of the hormonal sensitivities and physiological roles of the tissue components of the endometrium is thus facilitated.
Biochemical and histochemical studies of epithelial, stromal and endometrial esterases have shown that the rate of hydrolysis of α-naphthyl acetate is significantly higher in epithelial and endometrial tissue extracts during pro-oestrus than at any other stage of the oestrous cycle. In ovariectomized animals, oestradiol-17β caused a 60% increase in the rate of esterase activity over that of control animals, whereas medroxyprogesterone acetate had no effect. These findings suggest that the variations in the levels of neutral lipids in the uterine luminal epithelium of non-pregnant mature female rats result from the periodic stimulation of the epithelial esterases by the cyclically increased levels of plasma oestrogens.
THE EFFECT OF DAYLENGTH AND LEVEL OF FEEDING ON SERUM PROLACTIN IN GROWING LAMBS
Authors: FORBES J. M. , DRIVER P. M. , EL SHAHAT A. A. , BOAZ T. G. , SCANES C. G. 
Published: December 2008

SUMMARY
Twenty-four castrated male lambs initially maintained on a photoperiod of 12 h light: 12 h dark were allocated to a factorial experiment with two daylengths 8 h L: 16 h D or 16 h L: 8 h D) and two levels of feeding (restricted or ad libitum). Blood samples were taken every 4 h for 24 h during the introductory period and after 24, 51 and 79 days of treatment.
There were highly significant positive effects of daylength and level of feeding on serum prolactin: mean concentrations increased from a mean of 38 ± 1 ng/ml during the introductory period until at day 79 they were: 8L:16D (restricted diet), 81 ng/ml; (food ad libitum), 167 ng/ml; 16L:8D (restricted diet), 262 ng/ml; (food ad libitum), 262 ng/ml (s.e. of treatment mean ± 4). Long daylength and feeding ad libitum also significantly increased growth rate.
HORMONAL REGULATION OF LOBULO-ALVEOLAR GROWTH, FUNCTIONAL DIFFERENTIATION AND REGRESSION OF WHOLE MOUSE MAMMARY GLAND IN ORGAN CULTURE
Authors: WOOD BONNIE G. , WASHBURN LINDA L. , MUKHERJEE A. S. , BANERJEE M. R. 
Published: December 2008

SUMMARY
The entire second thoracic mammary glands of 4-week-old BALB/c female mice primed with oestradiol plus progesterone were cultivated in organ culture medium containing the 'growth-promoting' hormone combinations: insulin, prolactin, growth hormone, oestradiol, progesterone and aldosterone or insulin, prolactin and aldosterone. Full lobulo-alveolar development was induced after 5–6 days of incubation and could be maintained for 15–16 days in organ culture in medium containing either hormone combination. After the initial 5–6 days in the 'growth-promoting' medium, subsequent cultivation of the glands in a medium with the 'lactogenic hormones', insulin, prolactin plus cortisol, led to accumulation of 'milk-like' secretory material in the ductal and alveolar lumina. Incubation of the lobulo-alveolar gland in medium with insulin alone for 7–9 days resulted in complete regression of the alveoli leaving only a ductal parenchyma. Incubation in insulin, prolactin, growth hormone or insulin plus the steroid hormones for 7–9 days led to considerable alveolar degeneration without a complete regression. The results indicate that both pituitary and steroid hormones are essential for development and maintenance of mammary alveoli; insulin can only sustain the basal ductal structure.
RATE OF THYROXINE SECRETION BY MALE AND LAYING JAPANESE QUAIL: IDENTIFICATION OF THE RADIOACTIVE THYROXINE DEGRADATION COMPONENT OF THE MULTIPHASIC 131I CURVE
Authors: ROBINSON G. A. , TAM K. H. 
Published: December 2008

SUMMARY
Counting of radioactivity in Japanese quail in vivo showed a rapid loss of 131I from the body 12–24 h after the i.v. injection of [131I]thyroxine (T4), followed by a period of slow decrease in counting rates to 96 h. From comparison of these [131I]T4 curves with curves for 131iodide-injected birds and from counts on serum and other tissues in vitro it was concluded that, for Japanese quail, the T4 secretion rate should be calculated using serum samples taken during the first 12 h. Using this time period, the parameters measured were: T4 distribution space, laying hens 45·7 and mature cocks 26·3 ml/100 g body weight; fractional degradation rate for T4, hens 5·73 and cocks 3·12/day; serum T4 concentration (Tetrasorb125 method), hens 1·20 ± 0.07 and cocks 1·34 ± 0.05 (s.e.m.)μg/100 ml (n= 16); T4 secretion rate, hens 3·14 and cocks 1·10 μg/100 g/day.
STEROID ENTRY INTO RETE TESTIS FLUID AND THE BLOOD-TESTIS BARRIER
Authors: COOPER T. G. , WAITES G. M. H. 
Published: December 2008

SUMMARY
Evidence that steroids enter rete testis fluid (RTF) from the blood at varying rates was obtained during i.v. infusions into rats. Testosterone and dehydroepiandrosterone were readily transferred into the fluid, whereas cholesterol was excluded. Between these extremes, the appearance of radioactivity in the RTF suggested the following order of entry rate: progesterone > pregnenolone > 5α-reduced androgens > oestrogens > corticosteroids.
Preliminary identification of metabolites in RTF and blood suggested that testosterone and dehydroepiandrosterone were transferred largely unchanged. Androstenedione and progesterone, however, were largely metabolized during transfer into the RTF, the former being transformed to testosterone.
The results are used to discuss the nature of the blood-testis barrier to steroids and the source of androgens in the RTF.
METABOLIC EFFECTS OF TESTOSTERONE IN THE CHEQUERED WATER-SNAKE, NATRIX PISCATOR
Authors: THAPLIYAL J. P. , GUPTA S. C. , GARG R. K. 
Published: December 2008

SUMMARY
In the water-snake, Natrix piscator, the following are depressed by orchidectomy and restored to normal by testosterone treatment: glucose, free and esterified fatty acids and triglycerides in plasma, hepatic triglycerides, and total esterified fatty acids.
The increase in hepatic free fatty acids and muscle glycogen was also reduced to the level found in intact snakes. Moreover, although castration had no effect, testosterone caused a significant increase in liver weight and plasma protein, and a significant decrease in free plasma cholesterol. Except for an increase in triglyceride content by high doses of the hormone, neither castration nor the administration of 5 mg testosterone had any significant effect on the free fatty acid and triglyceride content of the adipose tissue of the snakes.
A COMPARISON OF CHANGES IN THE PERIPHERAL PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE AND FOLLICLESTIMULATING HORMONE IN THE RAT
Authors: BROWN-GRANT K. , GREIG FENELLA 
Published: December 2008

SUMMARY
Plasma FSH concentrations in rats have been determined by radioimmunoassay under a variety of experimental conditions to see whether any evidence could be obtained of an acute divergence in LH and FSH secretion rates which would support the idea of separate, specific hypothalamic releasing factors for these two hormones.
During the normal ovarian cycle and after the administration of progesterone to female rats on the morning of the day of pro-oestrus increased secretion of both LH and FSH began simultaneously but FSH concentrations were later maintained or increased slightly while LH concentrations were falling. During early pregnancy FSH concentrations were higher than at the corresponding stage of the cycle at a time when LH concentrations had been shown to be lower. Progesterone injected at the dioestrous stage of the cycle reduced both LH and FSH concentrations though the effect on LH was more marked. After ovariectomy at any stage of the oestrous cycle or on day 4 of pregnancy there was a rapid and significant increase in plasma FSH concentration which was quite different from the delayed increase in LH concentration observed in these animals. In contrast, the early increase in FSH concentration in male rats after castration was less than the increase in LH concentration. The final FSH concentration in castrated males was only about four times the basal level in contrast to the 10- to 15-fold increase in LH in males and both LH and FSH in females. Anovulatory adult females that had received 1·25 mg of testosterone propionate on day 4 of postnatal life showed the rapid and sustained increase in plasma FSH after ovariectomy that was seen in normal females.
None of these results strongly support the idea that separate and specific hypothalamic releasing factors for LH or FSH are secreted in the rat although the differences in the early response to gonadectomy could be explained on this basis.
STEROIDOGENESIS IN CEREBRAL METASTATIC CHORIONEPITHELIOMA TISSUE IN VITRO
Authors: MAEYAMA M. , IFUKU M. , NAKAHARA K. 
Published: December 2008

SUMMARY
Homogenates of cerebral metastatic chorionepithelioma tissue were incubated with labelled dehydroepiandrosterone, pregnenolone or 20α-hydroxypregn-4-en-3-one. The metabolites of dehydroepiandrosterone which were isolated and identified were androstenedione, testosterone, oestrone and oestradiol; no oestriol was detected. The only metabolite of pregnenolone and 20α-hydroxypregn-4-en-3-one isolated and identified was progesterone. No conversion of C-21 to C-19 steroids occurred in the metastatic chorionepithelioma tissue.
GONADOTROPHIC STIMULATION OF OESTROGEN SYNTHESIS BY CULTURED IMMATURE MOUSE OVARIES
Authors: RYLE MARGARET , COURT JENNIFER , SMITH TERESA , MORRIS R. 
Published: December 2008

SUMMARY
The amount of oestrogen produced by immature mouse ovaries cultured with purified gonadotrophins was measured by means of a radioimmunoassay. Small quantities were released in response to FSH or LH alone, but when both were provided production was greatly enhanced after an initial lag phase of 2–3 days. The lowest concentrations required to produce this synergistic effect were between 0·02 and 0·13 i.u. FSH/ml and between 0·01 and 0·1 i.u. LH/ml. After prolonged exposure to 0·4 i.u. FSH/ml plus 1·0 i.u. LH/ml, oestrogen output continued to rise until, on the ninth day of culture, it reached 2·6–7·3 ng/ ovary/day. Pre-treatment with 0·4 i.u. FSH/ml for 3 days enhanced the subsequent response to combined gonadotrophins but the simultaneous presence of FSH and LH was essential for inducing the delayed synergistic effect. Although both gonadotrophins also stimulated follicle growth there was no evidence suggesting any simple correlation between that response and oestrogen synthesis. Maximal oestrogen production coincided with very low follicular mitotic activity.
HYSTERECTOMY OF THE NEWBORN GUINEA-PIG, SUBSEQUENT EFFECTS ON THE OESTROUS CYCLE AND LIFE SPAN OF THE CORPORA LUTEA
Authors: BUÑO W. , CARLEVARO E. , RIBONI L. , D'ALBORA H. , DE LOS REYES L. , ZIPITRIA D. , DOMÍNGUEZ R. 
Published: December 2008

SUMMARY
Longer oestrous cycles result from neonatal hysterectomy than from hysterectomy in adult life. Section and cauterization of the utero-vaginal union also prolonged the vaginal closure period up to an average of 55 days. The destruction of the mesometrium did not lengthen the oestrous cycle.
Uterine autografts in hysterectomized newborn guinea-pigs did not prevent the long cycles.
SERUM LUTEINIZING HORMONE, FOLLICLE-STIMULATING HORMONE, PROLACTIN AND PROGESTERONE CONCENTRATIONS AND FOLLICULAR DEVELOPMENT IN THE PSEUDOPREGNANT RAT AFTER UNILATERAL OVARIECTOMY
Authors: DE GREEF W. J. , DULLAART J. , ZEILMAKER G. H. 
Published: December 2008

SUMMARY
Serum LH, FSH, prolactin and progesterone concentrations and follicular size were measured in rats during pseudopregnancy after unilateral ovariectomy (ULO) on day 1. This operation did not affect the duration of pseudopregnancy. Following pseudopregnancy compensatory ovulation occurred.
After ULO progesterone concentrations remained low as compared with control values but the progesterone secretion per ovary was increased slightly. After ULO, LH concentrations were significantly increased on days 3 and 4 of pseudopregnancy. FSH concentrations were increased 5 h after the operation and again on days 4–7 of pseudopregnancy when compared with sham-operated control animals. During pseudopregnancy prolactin secretion increased each night. Increased prolactin levels were observed 18 and 36 h after ULO. The number of medium-sized follicles had increased 24 h after ULO.
From the present study it is concluded that progesterone secretion by the corpora lutea can be increased to a limited degree by the increased release of gonadotrophins. Furthermore, it is concluded that a rapid increase in FSH concentrations after ULO is responsible for the initiation of the compensatory follicular growth.
REGION-SPECIFIC IMMUNOASSAYS FOR PARATHYROID HORMONE
Authors: BARLING P. M. , HENDY G. N. , EVANS M. C. , O'RIORDAN J. L. H. 
Published: December 2008

SUMMARY
Immunoassays specific for limited regions of bovine parathyroid hormone were developed in four ways.
With the heterogeneous antisera produced by immunizing with intact bovine parathyroid hormone (BPTH 1–84), the specificity of radioimmunoassays could be enhanced by presaturating either with an amino-terminal (BPTH 1–34) or carboxy-terminal (BPTH 53–84) fragment. Then, the antibodies which had not been neutralized reacted exclusively with the opposite end of the molecule, even using [125I]BPTH 1–84 as tracer. With some antisera, the appropriate fragment and intact hormone reacted identically. However, with other antisera, the fragment reacted less well than the intact hormone, possibly because these antisera contain antibodies reacting with the middle of the molecule.
Using the labelled fragment ([125I]BPTH 1–34) as tracer, with heterogeneous antisera, radioimmunoassays specific for the amino-terminal region were obtained. With one antiserum, BPTH 1–34 reacted identically with the intact hormone, but with another antiserum, the fragment was more reactive than the intact molecule.
A region-specific radioimmunoassay was also developed using antibodies produced by immunization with a fragment of the hormone. An antiserum raised against BPTH 1–34 had high affinity for the amino-terminal fragment, but reacted less well with the intact hormone.
Immunoradiometric assays, specific for the amino- or carboxy-terminal regions, were developed by using immunoadsorbents consisting of a fragment (either BPTH 1–34 or BPTH 53–84) coupled to cellulose. These were used to fractionate 125I-labelled antibodies. With some of these selected antibodies, the appropriate fragment was of lower reactivity than the intact hormone. This may have been due to the presence of an incomplete antigenic site on the fragment, or to conformational differences between the fragment and the corresponding region of the intact hormone. With other selected antibodies the fragment and the intact molecule reacted identically.
Careful selection of antisera and of technique is necessary to obtain an assay in which a fragment and the intact hormone behave identically.
CHANGES IN THE CONCENTRATION OF CALCITONIN IN THE PLASMA OF CHICK EMBRYOS DURING INCUBATION
Authors: TAYLOR T. G. , BALDERSTONE OLWEN , LEWIS PAMELA E. 
Published: December 2008

SUMMARY
Calcitonin (CT) was assayed in the plasma of chick embryos at eight stages of development from day 17 of incubation to day 1 after hatching by a rat bioassay. The concentration of CT rose steadily from 1060 mu./l on day 17 to 4700 mu./l at the stage when pulmonary respiration was initiated on day 20. Nine hours later, when the embryos 'pipped' the shells, the concentration of the hormone more than doubled to reach a peak of 11000 mu./l. At hatching the level had fallen to 1400 mu./l and 24 h later it was undetectable (< 500 mu./l). The physiological significance of these changes is discussed in relation to the development of the embryo.
EFFECTS OF HYPOTHALAMIC DEAFFERENTATION ON BASAL AND STRESS-INDUCED ADRENOCORTICAL ACTIVITY IN THE PIGEON
Authors: BOUILLE C. , HERBUTÉ S. , BAYLÉ J. D. 
Published: December 2008

SUMMARY
Partial and complete deafferentation of the hypothalamus of the pigeon was performed using a modified Halasz-Pupp microknife. After complete neural isolation the plasma corticosterone level stabilized at a point intermediate between the morning and evening levels found in intact pigeons. No diurnal rhythm was observed and the response to neurogenic stimulus (restraint) was suppressed. Ether stress, however, induced a rise in plasma corticosterone. Posterior deafferentation had no effect on the diurnal corticosterone rhythm but did block the rise normally found after restraint. Anterior deafferentation did not suppress the stress-induced response but provided the cuts were large enough they inhibited the diurnal corticosterone rhythm.
It is suggested therefore that the neural afferents to the hypothalamus which are necessary for diurnal fluctuations in pituitary-adrenal function pass through a sector located anteriorly between 45° and 60° on either side of the mid-line while stress-induced adrenocortical activation is triggered through posterior connexions.
VASOTOCIN-LIKE ACTIVITY IN THE PLASMA OF THE EURYHALINE FROG (RANA CANCRIVORA) AFTER TRANSFER FROM FRESH WATER TO SALINE
Authors: ELLIOTT ANNIE B. , CHEW MIOW-MIOW 
Published: December 2008

SUMMARY
When Rana cancrivora were collected from fresh water and dehydrated (weight loss 4–10%) by exposure to saline, the plasma titre of hydro-osmotic activity, measured by amphibian bladder assay, was increased three- to fourfold. This activity, which was abolished by thioglycollate and by incubation with tyrosinase or trypsin, was ascribed to vasotocin. The plasma vasotocin activities (hydrated and dehydrated frogs respectively) were estimated to be 0·03–0·05 and 0·15–0·25 μg/1; if referred to oxytocin as a standard the equivalent values were 10 and 30–60 mu./ml. Assuming that the increase represented released pituitary hormone, the amount of vasotocin released by osmotic dehydration was calculated to be of the order of 1 ng.
Pituitary glands of hydrated and dehydrated frogs were estimated to have 0·15 and 0·18 μg vasotocin/gland respectively.
The possible physiological function of released vasotocin in promoting reabsorption of urea from the urinary bladder is discussed in relation to the euryhaline ability of R. cancrivora.
CHANGES IN INSULIN CONTENT OF, AND INSULIN AND RNA SYNTHESIS IN, ISOLATED RAT ISLETS OF LANGERHANS AFTER HYPOPHYSECTOMY AND SHORT-TERM GROWTH HORMONE REPLACEMENT
Authors: PARMAN A. Ü. 
Published: December 2008

SUMMARY
Three to four weeks after hypophysectomy, the insulin content and glucose-stimulated insulin or total RNA synthesis in the pancreatic islets were estimated. The ratio of the glucose-stimulated insulin release to the islet insulin content was lowered. After shortterm GH replacement, insulin release and insulin content were slightly increased such that the ratio of release to content remained virtually unaltered. Glucose-stimulated insulin synthesis was also depressed but improved slightly after GH replacement. However, there was no significant change in the incorporation of [5-3H]uridine into islet total RNA after hypophysectomy or subsequent GH replacement.