bluuebunny/crossref_metadata_2025_split huggingface dataset:
HORMONAL CONTROL OF ADULT REPRODUCTIVE DIAPAUSE IN THE EGYPTIAN GRASSHOPPER, ANACRIDIUM AEGYPTIUM, L.
Authors: GELDIAY S. 
Published: December 2008

SUMMARY
The histology of the cerebral neurosecretory system and the corpora allata of Anacridium aegyptium is similar to that of other locusts, except that the adult diapause of this species introduces differences during oocyte growth. In diapausing adults of Anacridium, the cerebral neurosecretory cells contain large amounts of stainable material; when diapause is broken, the cells contain very much less material as the oocytes develop, but material accumulates once more when the oocytes are fully grown. The corpora allata are small in diapausing females, enlarge considerably during oocyte growth and vitellogenesis in post-diapause insects, and again decrease in size when the oocytes are fully grown.
It is inferred from these observations that the neurosecrectory cells and the corpora allata are both inactive during diapause. But the effects upon oocyte growth of destruction of the neurosecretory cells, and of allatectomy, in diapausing females which are subsequently kept under conditions which terminate diapause in normal individuals, strongly suggest that the cerebral neurosecretory system is the primary cause of the inhibition of oocyte growth during adult diapause.
THE EFFECT OF THYROXINE ON THE MOVEMENT OF CALCIUM AND INORGANIC PHOSPHATE THROUGH THE SMALL INTESTINE OF THE RAT
Authors: NOBLE H. M. , MATTY A. J. 
Published: December 2008

SUMMARY
Young female rats were given a daily injection of 1 mg. thyroxine/kg. body weight for 7 days. They were killed on the eighth day and the small intestine used for a study of the movement of radioactive calcium and inorganic phosphate. The everted sac technique was used.
The results indicate that the passive movement of phosphate was depressed. Both the passive and active transport of calcium were also depressed. It is suggested that the transport of calcium and the transport of phosphate, whether active or passive, are related and that thyroxine affects a single site located perhaps at the basement membrane of the mucosa.
EFFECT OF OESTROGEN ON THE RESPONSIVENESS OF NEURONES IN THE HYPOTHALAMUS, SEPTUM AND PREOPTIC AREA OF RATS WITH LIGHT-INDUCED PERSISTENT OESTRUS
Authors: LINCOLN D. W. , CROSS B. A. 
Published: December 2008

SUMMARY
The responses of septal, preoptic and hypothalamic neurones to pain, cold, changes in ocular illumination and probing of the cervix were recorded in adult female rats under light urethane anaesthesia. Responses in rats with light-induced persistent oestrus were compared with those obtained after ovariectomy, and after ovariectomy with oestrogen treatment.
The majority of units in the lateral hypothalamic area were excited by pain, cold and cervical stimuli, whereas in the lateral septal area most were inhibited. The numbers of units in the anterior hypothalamic and preoptic areas that displayed excitation to these stimuli were approximately equal to those showing inhibition.
The time-course of the responses to pain, cold and cervical stimuli of most hypothalamic and septal units closely corresponded to that of the associated EEG activation (frontal cortex), suggesting that they were non-specific arousal effects. Other responses, usually of brief duration, were not correlated with EEG changes.
Endogenous and exogenous oestrogen increased the percentage of units in the lateral and anterior hypothalamic areas that were inhibited by the pain, cold and cervical stimuli, and decreased the number in the lateral septal area. Oestrogen enhanced the responsiveness of preoptic units to the cervical stimulus, but depressed their responsiveness to pain and cold.
Hypothalamic units inhibited by the pain stimulus had mean 'spontaneous' firing rates of 4–5 spikes/sec. and those which were excited had rates of 1–2/sec.
Light-sensitive units were found mainly in the lateral septal and anterior hypothalamic areas. The usual form of the response was a brief 'on-off' or 'off-on' discharge.
The results are discussed in relation to the central nervous control of ovulation.
IMMUNOFLUORESCENT LOCALIZATION OF CALCITONIN IN THE 'C' CELLS OF PIG AND DOG THYROID
Authors: BUSSOLATI G. , PEARSE A. G. E. 
Published: December 2008

SUMMARY
In the pig, the C cells of the thyroid gland, which are the counterparts of parafollicular cells of Nonidez in the thyroid of the dog, are mainly epifollicular rather than parafollicular.
Using guinea-pig anti-pig calcitonin, and an indirect ('sandwich') technique, immunofluorescence tests indicated that calcitonin in the pig thyroid is present in cells which are morphologically indistinguishable from the C cells. Calcitonin was also present in cells which resemble pericytes.
Taking advantage of cross-reactivity between canine calcitonin and anti-pig calcitonin antibody, a similar localization (C cells and pericytes) could be shown by immunofluorescence tests in the thyroid of dogs.
These results confirm previous work indicating that the parafollicular cells are responsible for the production and secretion of thyrocalcitonin. The role of the pericytes has not been established with certainty.
DETERMINATION OF FREE AND CONJUGATED OESTROGENS IN FLUID FROM HUMAN OVARIES
Authors: GIORGI ELEONORA P. 
Published: December 2008

SUMMARY
Free and conjugated oestrogens were determined in the fluid from ovarian cysts of normally menstruating women, of subjects under gonadotrophin stimulation and of patients with different gynaecological conditions. The fluid was first extracted with ether to yield free oestrogens, and then the aqueous residue was submitted to acid hydrolysis. Three samples of ovarian venous blood were assayed by the same procedure. Indirect evidence that the oestrogens measured after acid hydrolysis were originally present as chemical conjugates was obtained.
The results indicated that conjugated oestrogens were synthesized in the ovary. The amount of oestrogens in cyst fluid varied with the phase of the cycle, and was increased in patients treated with gonadotrophins, in subjects with high secretion of gonadotrophins, and in some patients with functional uterine haemorrhage. It was low in patients with the Stein-Leventhal syndrome. Conjugate concentration was low relative to the concentration of free oestrogens in fluid from follicles and cysts derived from follicles, and similar to that of free oestrogens in corpora lutea, corpus luteum cysts and in patients with irregular bleeding. The concentration of conjugated oestradiol appeared to be generally independent from that of conjugated oestrone.
The relative proportions of free and conjugated oestrogens were different in cyst fluid and in ovarian venous blood.
THE RELEASE OF BOUND CORTICOSTEROIDS FROM THE MUSCLE OF THE TOAD (XENOPUS LAEVIS)
Authors: BELLAMY D. , PHILLIPS J. G. , LEONARD RUTH A. 
Published: December 2008

SUMMARY
After the injection of cortisol into the toad Xenopus laevis, the concentration of steroid in the main circulatory system was much higher than that in the limb muscles. The concentration of corticosteroids in the blood fell at a faster rate than that in muscle. The particulate fraction of toad muscle homogenate bound added cortisol and some of it was not removed by repeated washing of the tissue with fresh medium. Bound steroid was not confined to any one subcellular fraction. The small particle fraction ('microsomes') contained the greatest proportion of steroid and the highest steroid concentration. The loss of corticosteroids from intact and washed particle preparations of toad gastrocnemius was not influenced by temperature over the range of 17–37°.
Copper, zinc and manganese (between 26 and 31 mm) inhibited the release of cortisol bound to muscle particles; p-chloromercuribenzoate (2 mm) and anoxia had no effect. A variation in pH from 2 to 10 made little difference to the rate of steroid release by muscle particles suspended in 0·15 m-KC1. The results suggest that the release of strongly bound steroids from muscle does not involve an enzymic mechanism.
THE BINDING OF CORTISOL BY OVINE PLASMA PROTEINS
Authors: PATERSON J. Y. F. , HILLS F. 
Published: December 2008

SUMMARY
Albumin was isolated from ovine plasma and its affinity for cortisol was determined by equilibrium dialysis at 37°. The value of Ka[σpa] for a 1 % (w/v) albumin solution was 0·275 which is similar to the value for human plasma albumin.
The affinity constant of transcortin in ovine plasma was determined by equilibrium dialysis of diluted plasma at several concentrations of cortisol. The value found, Kt (37°) = 0·87 x 108 l./mole, is close to that found for human plasma transcortin by Mills (1962).
The concentration of transcortin in ovine plasma, expressed as cortisolbinding capacity, was 6–49 μg. (mean 24 μg.) cortisol/l. These concentrations are much lower than those found in human plasma. The observation of Lindner (1964) that cortisol binding capacity did not increase during pregnancy in sheep has been confirmed.
In sheep which were accustomed to handling, the mean concentration of cortisol in plasma was 17·8 μg./l. and of this amount 59% was bound to transcortin, 19 % to albumin and 22 % was not bound to protein.
STUDIES ON THE EXPERIMENTAL ALTERATION OF WATER AND ELECTROLYTE COMPOSITION OF THE EEL (ANGUILLA ANGUILLA L.)
Authors: CHAN D. K. O. , JONES I. CHESTER , HENDERSON I. W. , RANKIN J. C. 
Published: December 2008

SUMMARY
The distribution of water, electrolyte composition (Na, K, Ca, Mg, PO4, Cl) and extracellular fluid volume of eels (Anguilla anguilla L.) were investigated under different experimental conditions.
Adrenalectomy of the freshwater eel was followed by an increase in body weight, a fall in the amount and concentration of sodium in serum and muscle and a shift of water into the cells. The concentration of serum potassium remained within the normal range. Adrenalectomy of the sea-water eel was followed by a decrease in body weight and an increase in the concentration of extra- and intracellular sodium. The concentration of serum calcium also increased, that of potassium remained within the normal range but the actual content diminished.
Removal of the corpuscles of Stannius from the freshwater eel gave some effects similar to adrenalectomy. There was, however, no significant increase in body weight but the concentrations of serum potassium and calcium rose. Removal of the corpuscles from the sea-water eel brought about changes similar to, but less pronounced than those after adrenalectomy. The results of the injection of mammalian corticotrophin, cortisol, aldosterone and anti-aldosterone compounds are given. They are discussed in the light of the possible roles of the adrenal cortex and the corpuscles of Stannius in the maintenance of homeostasis of the eel in different environments.
ENDOCRINE INFLUENCES ON THE NET EXTRARENAL FLUXES OF SODIUM AND POTASSIUM IN THE EUROPEAN EEL (ANGUILLA ANGUILLA L.)
Authors: HENDERSON I. W. , JONES I. CHESTER 
Published: December 2008

SUMMARY
By use of the 'eel tube', it was shown in the freshwater eel that there was a regular net influx (gain) of sodium and a net outflux (loss) of potassium in quiescent animals with steady and normal respiration. Adaptation of eels to distilled water for periods of up to 6 weeks resulted in an increased net extrarenal (gills) uptake of sodium and an increased net loss of potassium when the head of the animal was placed in tap water made up to 600 μmoles Na+.
Stress, injection of cortisol, metyrapone, metyrapone plus betamethasone and aldactone reduced or abolished net sodium gain and had variable effects on net potassium loss. The injection of aldosterone or a potassium chloride solution, but not that of a sodium chloride solution, produced an increased net gain of sodium.
Removal of the corpuscles of Stannius was without demonstrable effect on net sodium and potassium fluxes; they remained within the normal range. Hypophysectomy reduced net sodium gain. Adrenalectomy markedly diminished or abolished net sodium gain with increased potassium loss. Net sodium gain was restored to normal values by injection of aldosterone.
These results are discussed with regard to the homeostatic mechanisms in the euryhaline teleosts.
THE EFFECT OF VARYING TEMPERATURES ON THYROID ACTIVITY AND THE SURVIVAL OF RATS EXPOSED TO COLD AND TREATED WITH l-THYROXINE OR CORTICOSTERONE
Authors: BAUMAN T. R. , TURNER C. W. 
Published: December 2008

SUMMARY
Rates of thyroid secretion (TSR) were determined in female Sprague-Dawley-Rolfsmeyer and male Holtzman rats at varying temperatures. When exposed to cold, TSR reached the highest value within the first 20 days after exposure, with a gradual increase up to 90 days. When rats reared in the cold were exposed to warm temperatures, TSR declined slightly at first, but 35–40 days were required to produce a significant decrease.
Treatment before and after exposure to cold with l-thyroxine (T4), corticosterone and T4 plus corticosterone significantly increased survival at 4·5°. Corticosterone plus T4 was most effective, T4 alone was next best and corticosterone alone had the poorest effect.
EFFECTS OF A GLUCOCORTICOID (DEXAMETHASONE) ON THE EOSINOPHILS OF THE RAT
Authors: BLENKINSOPP EVELYN C. , BLENKINSOPP W. K. 
Published: December 2008

SUMMARY
The effects of single and continuous administrations of a synthetic gluco-corticoid (dexamethasone) on eosinophil numbers and distribution have been studied. Absolute blood eosinophil counts were made, and the turnover of the eosinophils was examined by continuous infusion of tritiated thymidine to label the deoxyribonucleic acid of all newly formed cells.
Dexamethasone equivalent to less than 200 μg. cortisone/100 g. rat/day produced disappearance of eosinophils from the blood and the normal output of glucocorticoids is therefore probably less than this.
Single administrations of dexamethasone produced a blood eosinopenia within 2 hr. due to removal and destruction of eosinophils by the reticulo-endothelial system. Continuous dexamethasone administration reduced the number of proliferating eosinophil cells in the marrow, with a consequent reduction in the number of eosinophils in the tissues.
EXPERIMENTAL PROTEIN-CALORIE DEFICIENCY: HISTOPATHOLOGICAL CHANGES IN THE ENDOCRINE GLANDS OF PIGS
Authors: PLATT B. S. , STEWART R. J. C. 
Published: December 2008

SUMMARY
The endocrine glands of the protein-calorie deficient animals were smaller than those of pigs of the same age normally fed. However, relative to body weight, the adrenals were large, the hypophysis within the normal range, the thymus small and the pancreas and thyroid showed wide variations attributable to different degrees of oedema.
In the tissues of the endocrine glands of the protein-calorie deficient animals the cells exhibited a loss of cytoplasm and, when normally present, of secretory granules, the severity of the change varying widely between the different organs of the same animal. Thus the exocrine portion of the pancreas was more severely affected than the islet tissue; within the latter β cells showed greater changes than did α cells. The cells of the thyroid gland were flattened and epithelioid in shape and those of the hypophysis were small, with many partially or wholly degranulated chromophiles. The zona fasciculata of the adrenal cortex was usually less severely affected, with, at some stages, a relatively excessive activity which contributed to the precarious endocrine balance. Since most of the animals were killed before sexual maturity less attention was given to the gonads. Testes, however, appeared to be affected by the deficiency to a greater extent than did ovaries.
The relationships between protein-calorie deficiency, hypophysectomy and an excess of corticosteroids are discussed. It is suggested that in protein-calorie deficiency, an adequate supply of protein for anabolic purposes is the primary factor with a subsequent alteration in hormonal secretions playing an important, but secondary, role.
A QUANTITATIVE STUDY OF THE EFFECTS OF PROGESTERONE AND RELATED STEROIDS ON THE UTERUS:PLASMA CONCENTRATION RATIO FOR RADIOACTIVE IODIDE IN THE RAT
Authors: BROWN-GRANT K. 
Published: December 2008

SUMMARY
Optimal conditions for determining the quantitative effect of a single subcutaneous injection of progesterone in oil on the uterus:plasma concentration ratio for radioactive iodide were found to be measurement of this ratio 24 hr. after the injection of steroid in rats ovariectomized 7–10 days previously. Under these conditions there is a linear regression of response on log dose over the range of 156–2500 μg. progesterone.
Reduction of the 20-ketone group or the 4–5 double bond, introduction of 17α- or 21-hydroxyl groups or of an 11-oxo group into the molecule reduces the activity in this test. Steroids with predominantly glucocorticoid, androgenic or oestrogenic activity do not produce this response. The relative potencies of a variety of synthetic steroids derived from progesterone or 19-nortestosterone have been assessed. The results obtained in this test appear to be more closely related to the ability to maintain pregnancy than are those obtained in the usual assays for progestational activity. It is suggested that the uterus:plasma 131I ratio response could be made the basis of an accurate and potentially useful assay method for steroids with progestational properties.
THE FEEDBACK ACTION OF OVARIAN HORMONES IN THE FERRET
Authors: DONOVAN B. T. 
Published: December 2008

SUMMARY
The operation of an ovarian feedback mechanism in the control of pituitary function in the ferret has been tested in anoestrous and in oestrous animals by removing one gonad to determine whether compensatory hypertrophy of the remaining organ occurred, and by the administration of gonadal steroids.
Compensatory ovarian hypertrophy was found after 10 days in both anoestrous and oestrous ferrets. Oestradiol or oestradiol benzoate occasionally caused ovulation after injection into oestrous females, and inhibition of follicular development occurred after s.c. implantation of a tablet of oestradiol. Ovulation also took place in two out of three ferrets injected with oestradiol benzoate (100 μg.) together with progesterone (2 mg.); one out of five animals given 2 mg. progesterone alone ovulated.
These experiments show that release of gonadotrophin by the ferret hypophysis can be modified by gonadal steroids.
EFFECTS OF CASTRATION AND OF PROGESTERONE IMPLANTATION ON MUSCLE COMPOSITION IN THE FERRET
Authors: HAMMOND J. , LAWRIE R. A. 
Published: December 2008

SUMMARY
Longissimus dorsi muscles from intact and castrated male ferrets were investigated at the time of maximum body weight in winter, and muscles from control and progesterone-treated animals in summer. The animals had free access to food throughout. The seasonal decrease in body weight was accompanied by decreased fat concentration in the muscle and by reduction of the subcutaneous and mesenteric fat depots.
Implantation of progesterone pellets increased the body and muscle weights of intact males (but not of castrated animals) and also increased intramuscular fat. It may have reversed the seasonal pattern of changes in that the fat in the muscle became more unsaturated. The water content of the muscle decreased only reciprocally in relation to the increased fat content. Progesterone had no obvious effect on the composition of muscle in castrated ferrets.
In summer the castrated animals had more intramuscular fat than the intact males at this time; moreover, despite the higher concentration, its degree of unsaturation was greater.
BODY WEIGHT AND FOOD CONSUMPTION OF LACTATING RATS: EFFECTS OF OVARIECTOMY AND OF ARREST AND RESUMPTION OF SUCKLING
Authors: ÔTA K. , YOKOYAMA A. 
Published: December 2008

SUMMARY
In order to assess the role of the suckling stimulus in the regulatory mechanism of body weight and food consumption of lactating rats, changes in body weight and food intake under various conditions were investigated.
The results of the changes in food intake during the oestrous cycle, pregnancy and lactation, and after weaning were consistent with those reported by previous workers. The rate of increase in body weight was similar during dioestrus, early pregnancy, early lactation and after ovariectomy. Food consumption of mother rats was maintained at the lactating level for 24 hr. after the removal of suckling pups on the 12th day of lactation, then it rapidly decreased. Resumption of suckling by foster litters, 5 days after removal of the original litters, caused increase in body weight and food intake as well as the restoration of lactation in both normal and ovariectomized animals. The rate of increase in body weight arising from the resumption of suckling was similar to that observed in the ovariectomized rats that were not resuckled after removal of the litters. The increase in body weight in the resuckled rats was not necessarily associated with the enhanced food intake. In spite of vigorous suckling by pups, food intake of the resuckled animals did not show a progressive increase as in normal lactating mothers until the function of mammary glands was restored and sufficient milk was produced to increase the weight of the foster litters. After restoration of lactation food consumption of the resuckled mothers increased progressively, the increase being closely related to increased milk secretion.
The greater food intake in the resuckled rats than in the non-resuckled animals, even before restoration of milk secretion, seems to indicate a direct stimulating effect of the suckling stimulus on appetite; consumption of energy associated with milk secretion is also considered to be one of the main factors in inducing the enhanced food intake in lactating rats. A further possibility that the suckling stimulus participates in the regulation of body weight and food consumption in lactating animals by changing the ovarian function is discussed.
AN AUTOMATED METHOD FOR THE DETERMINATION OF URINARY 17-HYDROXYCORTICOSTEROIDS
Authors: CAISEY J. D. , CHILD K. J. 
Published: December 2008

SUMMARY
An automated method for measuring urinary 17-hydroxycorticosteroids is described. The preliminary borohydride reduction of pre-existing 17-oxo-steroids is performed manually and the reduced urine transferred to the sample cups of an Auto-Analyzer. The urine is submitted to periodate oxidation, mild alkaline hydrolysis and then extracted with dichloromethane. The dichloromethane extract is mixed with an aqueous solution of m-dinitrobenzene in hyamine and the mixture passed through a 'solvent exchanger' at 75° to evaporate the dichloromethane. Alkali is added and the Zimmermann reaction performed at 55°. After extraction of the reaction products into n-hexanol their light absorption is measured at 510 mμ. The method has been evaluated for accuracy, precision, sensitivity and validity. Urine samples can be assayed in duplicate at the rate of 5/hr. with adequate accuracy. Passage time through the automated procedure is 36 min.; thus 30 to 40 samples can easily be assayed in a normal working day. Details are given of the recovery of cortisone from urine and of comparison between the results obtained with the automated method and with a manual method. The choice of cortisone as the standard, and the role of the temperature and the pH maintained during periodate oxidation are discussed.