bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECTS OF PARATHYROIDECTOMY ON THE DEVELOPMENT OF NEPHROCALCINOSIS AND CALCIUM, PHOSPHORUS AND MAGNESIUM BALANCE IN RATS
Authors: GOULDING AILSA , MALTHUS R. S. 
Published: December 2008

SUMMARY
Rats of different strains raised on a semipurified casein—sugar diet, develop a nephrocalcinosis in which deposits composed principally of calcium and phosphorus accumulate at the corticomedullary junction of the kidney. To determine whether the development of this nephrocalcinosis was in any way related to the activity of the parathyroid glands, female weanling 21-day-old rats were parathyroidectomized (PTX) or sham-operated and fed the semipurified diet for 3 weeks. Absorption, retention and excretion of Ca, P and Mg were studied during a 14-day balance period. The effects of injecting PTX rats with a small amount of parathyroid extract (15 U.S.P. units Lilly Para-thor-mone, every 12 h for 1 week) were examined.
Compared with sham-operated animals PTX rats showed: lower serum Ca and higher P concentrations; a lower urinary excretion (% intake) of Ca, P and Mg; a higher retention (% intake) of P and Mg; a higher concentration of Mg in bone (% femur ash). Administration of parathyroid extract (PTE) tended to reverse changes induced by parathyroidectomy but PTE-treated animals remained slightly hypocalcaemic. Sham-operated and PTE-treated PTX rats developed nephrocalcinosis but untreated PTX rats did not do so.
The results indicate that nephrocalcinosis did not develop in rats fed the semipurified diet in the absence of parathyroid hormone. It is postulated that although some activity of the parathyroid glands is needed for mineral deposition in the renal tubules, excessive activity is not necessarily a prerequisite to the development of this type of renal calcification.
THE METABOLISM OF STEROIDS IN THE CANINE PROSTATE AND TESTIS
Authors: HARPER M. E. , PIERREPOINT C. G. , FAHMY A. R. , GRIFFITHS K. 
Published: December 2008

SUMMARY
Prostatic tissue from young mature dogs was incubated in vitro with [4-14C]testosterone to assess androgen metabolism by this target organ. At the same time tissue from a dog previously treated with implants of oestradiol-17β and tissue from an older animal were also studied. Tissue from the oestrogen-treated dog showed considerable qualitative and quantitative differences from the normal in regard to metabolic activity. Fractionation of prostatic tissue after incubation with labelled testosterone indicated the localization of certain enzymes and products in the nucleus, and 5α-androstane-3α,17α-diol formation appeared particularly interesting. The relative activities of testicular tissue from the dogs in regard to the formation in vitro of androstenedione and testosterone from various radioactive precursors were measured.
EFFECT OF CALCITONIN ON [3H]PROLINE INCORPORATION INTO BONE HYDROXYPROLINE IN THE RAT
Authors: KALU D. N. , FOSTER G. V. 
Published: December 2008

SUMMARY
The effect of calcitonin on the incorporation of [3H]proline into bone hydroxyproline was investigated in young growing rats. The action of the hormone was studied under the following conditions: (1) acutely, in both intact and thyroparathyroidectomized rats, (2) after 20 days of daily treatment in both intact and thyroparathyroidectomized animals, (3) in thyroparathyroidectomized animals treated with parathyroid extract for 20 days, and (4) in animals fed a low calcium diet for 25 days. Calcitonin had no effect when given either acutely or long-term to intact animals. [3H]Proline incorporation into bone hydroxyproline was increased in rats fed low calcium diet, in rats treated with parathyroid extract for 20 days, and in acutely thyroparathyroidectomized rats. In each instance, calcitonin prevented or reduced this increase. The results are interpreted as evidence that, with the doses used, hydroxyproline synthesis under normal conditions is unaffected by the hormone. However, where hydroxyproline formation was increased, calcitonin reduced this increase.
EFFECTS OF PROLACTIN AND LUTEINIZING HORMONE ON THE CHOLESTEROL STORES IN THE MOUSE TESTIS
Authors: BARTKE A. 
Published: December 2008

SUMMARY
In intact adult male mice three injections, 2 h apart, of 3 μg luteinizing hormone (LH), 15 μg LH or 100 μg follicle-stimulating hormone (FSH) decreased the concentration of esterified cholesterol in the testes. Treatment with 35 μg testosterone propionate (TP)/day or 4 mg aminoglutethimide/day increased the concentration of esterified cholesterol. Single heterotopic pituitary homografts increased the concentration of esterified cholesterol; injecting 7·5 i.u. prolactin twice daily had similar effect. The concentration of free cholesterol showed little individual variation and little or no response to any of the above treatments. The concentration of testicular total cholesterol was increased in hypophysectomized mice. Administration of 10 μg LH or 50 μg TP daily for 28 days reduced the concentration of both esterified and free cholesterol in these animals to approximately the levels found in intact adult males. Prolactin (12 i.u./day) given alone or with TP had no effect, but it increased the concentration of esterified cholesterol in LH-treated animals. It is concluded that in the mouse testis the concentration of esterified, but not free, cholesterol tends to fluctuate with the apparent changes in the rate of androgen synthesis and that prolactin promotes accumulation of cholesterol esters. This could explain the synergism between prolactin and LH in stimulating spermatogenesis and the growth of androgen dependent tissues.
THE CHAMELEONIC BEHAVIOUR OF GONADOTROPHINS: A REVIEW OF RECENT RESULTS ON THEIR PHYSICOCHEMICAL PROPERTIES AND MOLECULAR STRUCTURE
Authors: HELLEMA M. J. C. 
Published: December 2008

SUMMARY
Human gonadotrophin preparations are extensively used for clinical and experimental purposes. There is a plethora of reports on the chemistry of gonadotrophins. However, the complete purification, isolation and elucidation of the structures of the follicle-stimulating hormone (FSH), the luteinizing hormone (LH) and human chorionic gonadotrophin (HCG) have not been achieved. Hindering factors are the instability of these gonadotrophins, the similarity of some of their physicochemical and immunological properties and the possibility that these hormones exist as hormone complexes rather than as single entities. These complicating factors necessitate a wide variety of sophisticated approaches to the study of the gonadotrophins. Some of the methods used and some of the structural, physicochemical and immunological characteristics of the gonadotrophins are the subject of this survey.
DIURNAL VARIATIONS OF THE ACHILLES TENDON REFLEX-TIME
Authors: ZAMRAZIL V. , NEMEC J. , VÁŇA S. 
Published: December 2008

SUMMARY
In a group of 35 patients (10 euthyroid, 9 hypothyroid and 16 thyrotoxic subjects) the diurnal variability of the Achilles tendon reflex-time (ART) was investigated. The ART was recorded by the electromagnetic method at 08.00, 12.00, 16.00 and 20.00 h, and 08.00 h on the following morning, and the contraction-time and half relaxation-time were evaluated.
In the entire group significant changes — prolongation — were found in the course of the day with a return to the initial value after 24 h. When classifying the patients into groups according to thyroid function, the changes were most marked in hypothyroid subjects and those with thyrotoxicosis partially alleviated by treatment. No significant changes were found in euthyroid subjects and those with highly active thyrotoxicosis. The significance of these findings and their implications are discussed.
IMMUNORADIOMETRIC ASSAY OF PARATHYROID HORMONE
Authors: ADDISON G. M. , HALES C. N. , WOODHEAD J. S. , O'RIORDAN J. L. H. 
Published: December 2008

SUMMARY
An immunoradiometric assay for parathyroid hormone has been developed. Antisera to bovine parathyroid hormone (BPTH) were screened for their ability to bind BPTH and human parathyroid hormone (HPTH). A BPTH-immunoadsorbent was used to extract antibodies from an antiserum which did not discriminate between BPTH and HPTH in a standard radioimmunoassay. These antibodies were labelled with 125I for use in the immunoradiometric assay. With this system as little as 5 pg BPTH and 8 pg HPTH could be detected. The serum concentration of BPTH was shown to rise in a cow rendered hypocalcaemic by an infusion of EDTA. Sera from patients with hyperparathyroidism contained high concentrations of hormone. These sera were found to dilute-out parallel to calibration curves obtained using HPTH extracted from parathyroid adenomata. The advantages of this method over the standard radioimmunoassay are discussed.
THE DEVELOPMENT OF THYROID-STIMULATING HORMONE-RELEASING FACTOR ACTIVITY IN THE NEONATAL RABBIT
Authors: ŚLEBODZIŃSKI A. , MACH Z. , MALINOWSKA W. 
Published: December 2008

SUMMARY
Nine-day chick embryos received grafts of hypothalamus, adenohypophysis, thyroid, and fat (controls) from 0-, 7-, 14- and 21-day-old rabbits to the chorio-allantois. In addition, aqueous rabbit adenohypophysial and hypothalamic extracts were given to 1-day-old chicks. Animals injected with thyrotrophin and saline served as controls. On the 5th day of incubation of treated embryos, or 24 h after the administration of the extracts, the chicks were killed and their thyroids studied histologically.
The hypothalamic grafts or extracts activated the chick thyroid gland and a similar trend was found in adenohypophysial or thyroid-stimulating hormone-treated chicks. The degree of activation of the embryo chick thyroid gland was related to the age of the donor rabbit. In general, thyroidstimulating hormone-releasing factor activity in hypothalamic heterografts or extracts appeared first in 14-day-old rabbits and was correlated with increasing thyrotrophic potency of the rabbit adenohypophysis.
THE INFLUENCE OF METHALLIBURE (ICI 33,828) ON SERUM AND PITUITARY THYROID-STIMULATING HORMONE LEVELS IN THE RAT
Authors: BOURKE J. R. , MANLEY S. W. , HAWKER R. W. 
Published: December 2008

SUMMARY
The effect of methallibure (ICI 33,828), a non-steroidal pituitary inhibitor, on serum and pituitary thyroid-stimulating hormone (TSH) levels has been investigated.
A biphasic action of the drug on serum TSH levels was observed, the greatest falls occurring with the lowest doses (2mg/day). Increasing dose and period of administration induced progressive decreases in pituitary TSH content. These results are interpreted in terms of three actions on the thyroid—pituitary system: (1) inhibition of the release of TSH from the pituitary, (2) inhibition of TSH synthesis evident only at higher doses, and (3) a thyroid-blocking action, which is also only observed at the higher dose levels, with consequent pituitary stimulation via the thyroid—pituitary feedback mechanism. Effects upon body weight and weight of endocrine organs are reported, that upon the seminal vesicles being the most marked.
CELL PROLIFERATION IN THE PREPUBERTAL MALE RAT ADRENAL CORTEX: AN AUTORADIOGRAPHIC STUDY
Authors: WRIGHT N. A. 
Published: December 2008

SUMMARY
On the basis of labelling indices measured with tritiated thymidine at intervals throughout its thickness, the adrenal cortex of prepubertal male rats has been divided into four compartments. These are called the glomerular, proliferative, fascicular and reticular compartments, respectively. Labelling indices measured for each compartment showed highest values in the glomerular and proliferative compartments, with values of 6·73% and 7·09% respectively. The fascicular compartment showed a lower index of 3·16% while the reticular compartment gave the lowest value of 1·15%. These differences are further reflected in measurements of the mitotic indices for each compartment.
The phases of the cell cycle have been measured by pulse-chase analysis in each compartment, and all phases estimated showed an increase in duration as the inner compartments were approached. The duration of interphase DNA synthesis (ts) was found to be shortest in the glomerular and proliferative compartments, with values of 7·45 and 7·73 h, respectively. The fascicular compartment showed lengthening of ts to 8·56 h, and the reticular compartment gave the highest value of 9·21 h. Similarly, the values obtained for G2 (the post-DNA synthetic interval) and tm (the duration of mitosis), and a calculated value of the cell cycle time all showed a general increase in duration from the outer to the inner compartments. The relation of these results to theories of adrenocortical cytogenesis is discussed, and it is suggested that the differences in cell cycle components can best be explained by the inward migration of cortical cells from the outer compartments.
THE EFFECT OF NEONATAL ADMINISTRATION OF SEX HORMONES ON THE TURNOVER OF HEPATIC MICROSOMAL PHOSPHOLIPID IN MALE AND FEMALE RATS
Authors: TOH Y. C. 
Published: December 2008

SUMMARY
The effect of neonatal administration of testosterone propionate and oestradiol benzoate on the metabolism of microsomal phospholipid in the liver of male and female rats was studied. Males had a greater uptake of radioactive phosphorus than females. Gonadectomy at the age of 4 weeks reduced the incorporation of 32P into the microsomal phospholipid. Administration of testosterone significantly increased 32P uptake both in the intact and ovariectomized females as well as in the castrated males, whereas oestradiol produced no effect. A sex difference of total microsomal phospholipid phosphorus was also found in the gonadectomized rats. Oestrogen caused no change in the intact animals but restored the level of phospholipid in ovariectomized female rats. On the other hand, testosterone significantly increased the total content of the phospholipid in the liver microsomes of both intact and gonadectomized male and female rats.
PRE-OVULATORY PROGESTERONE, THE ADRENAL CORTEX AND THE 'CRITICAL PERIOD' FOR LUTEINIZING HORMONE RELEASE IN RATS
Authors: FEDER H. H. , BROWN-GRANT K. , CORKER C. S. 
Published: December 2008

SUMMARY
During the day of pro-oestrus in rats showing regular 4-day oestrous cycles, the concentration of progesterone in peripheral plasma increased slowly from 09.30 to 13.30 h and more rapidly during and after the 'critical period' for luteinizing hormone (LH) release to reach a level of 24·4 ng/ml at 21.00 h. Administration of sodium pentobarbitone at 07.00 or 13.30 h (but not at 16.30) on the day of pro-oestrus delayed ovulation and also prevented the rise in progesterone concentration at 21.00 h on that day. Levels were found to be high 24 h later on the evening of the day preceding the delayed ovulation. It is concluded that the major rise during and after the 'critical period' is the result of LH stimulation of ovarian progesterone secretion.
The possibility that the gradual increase in peripheral plasma progesterone concentration that occurred before the 'critical period' was due to adrenal secretion and played some role in facilitating the onset of the ovulatory surge of LH was examined. The rise in plasma corticosterone concentration roughly paralleled that of progesterone up to the 'critical period' but the curves for the two steroids later became divergent. Suppression of adrenal activity during pro-oestrus by the administration of dexamethasone phosphate resulted in a blockade of ovulation which could be reversed by the administration of either progesterone or corticotrophin (ACTH). Conversely, blockade of ovulation followed ACTH administration at metoestrus and approximately 50% of animals adrenalectomized or sham-adrenalectomized at metoestrus or dioestrus failed to ovulate at the expected time. In adrenalectomized rats tested 12–15 days after operation, the period of pro-oestrus during which sodium pentobarbitone administration could block ovulation was more prolonged than in intact rats. The possible roles of progesterone of adrenal origin in facilitating LH release and entraining the LH release mechanism to the light—dark rhythm and of progesterone of ovarian origin in ensuring full sexual receptivity are discussed.
INFLUENCE OF INSULIN INJECTED INTO THE LATERAL VENTRICLE ON PITUITARY GROWTH-HORMONE RELEASE IN THE RAT
Authors: PECILE A. , MÜLLER E. E. , FELICI M. , NETTI C. , COCCHI D. 
Published: December 2008

SUMMARY
Injections of insulin (0·2 or 0·01 i.u./20 μl) into the lateral ventricle of the rat brain, while not changing blood glucose levels or altering the pituitary content of growth hormone (GH), blocked the release of GH from the pituitary and the decrease of growth-hormone releasing activity (GHRF) of stalk median eminence (SME) extracts in the presence of the hypoglycaemic effect on insulin (2 i.u./kg) given intraperitoneally. Intraventricular administration of insulin also impaired the GH release elicited by cold exposure (4 °C, 1 h) but not the release induced by electric shock. The possibility that insulin injected into the brain acts on glucose-sensitive GH-regulating structures is suggested.
MEASUREMENT OF PLASMA CORTISOL LEVELS IN THE EEL ANGUILLA ANGUILLA IN RELATION TO OSMOTIC ADJUSTMENTS
Authors: BALL J. N. , JONES I. CHESTER , FORSTER M. E. , HARGREAVES G. , HAWKINS E. F. , MILNE K. P. 
Published: December 2008

SUMMARY
The competitive protein-binding radioassay (CPB method) of Murphy (1967) has been adapted to determine total cortisol levels in the plasma of the eel, Anguilla anguilla L. Validation of the method for this species depended in part on the development of a chromatographic—fluorimetric technique for eel cortisol, following classical procedures and using radioactive tracers; by this means, the specificity of the CPB method for cortisol in eel plasma was established. Accuracy, precision and sensitivity of the CPB method were also investigated and were shown to be satisfactory.
Plasma total cortisol levels were determined in eels during osmotic adjustments after transfers from fresh water (FW) to sea-water (SW) and vice versa, and from FW to distilled water. Plasma osmotic pressure and/or sodium levels were monitored simultaneously, to follow the progress of osmotic regulation. In only one of the transfer situations did the plasma cortisol level change significantly, showing a marked transitory increase during the first few days after transfer from FW to SW, corresponding to the development and correction of an 'osmotic crisis'. Plasma cortisol levels were the same in eels adapted for long periods to FW and to SW. Plasma cortisol fell to extremely low levels after hypophysectomy.
These results are discussed in the light of the literature on hormonal control of osmoregulatory mechanisms in the eel, with particular emphasis on the role of adrenocorticosteroids in ionic regulation of animals in SW.
DETERMINATION OF THE DETAILED HYPOTHALAMIC ROUTE OF THE MILK-EJECTION REFLEX IN THE GUINEA-PIG
Authors: TINDAL J. S. , KNAGGS G. S. 
Published: December 2008

SUMMARY
The effect of various types of surgical damage to the forebrain on the release of oxytocin in response to electrical stimulation of the discrete ascending milk-ejection reflex pathway in the mid-brain was investigated in 99 anaesthetized lactating guinea-pigs. Oxytocin release was measured by comparison of experimental milk-ejection responses with the response to i.v. injection of known amounts of synthetic oxytocin.
Removal of the entire telencephalon, including cerebral cortex, hippocampi, amygdalae and forebrain rostral to the hypothalamus, did not affect the subsequent release of oxytocin after electrical stimulation of the pathway in the mid-brain, from which it was concluded that the reflex pathway within the forebrain is entirely diencephalic. Transection of the hypothalamus immediately rostral to the paraventricular (PV) nuclei was without effect, while transection immediately caudal to the PV nuclei blocked the release of oxytocin. Destruction of the PV nuclei by a radiofrequency lesion which spared the supraoptic (SO) nuclei blocked the release of oxytocin. Undercutting both PV nuclei so as to isolate them from the ventral hypothalamus blocked the release of oxytocin. Undercutting the PV nucleus ipsilateral to the stimulated side of the mid-brain blocked the release of oxytocin, while undercutting the contralateral PV nucleus had no effect. The PV nuclei, therefore, lie on the ascending path of the milk-ejection reflex, the SO nuclei do not, and, from the mid-brain forwards, the ascending pathway remains uncrossed.
The course of the reflex pathway was traced rostrally from the mesodiencephalic junction by making narrow transverse knife-cuts and determining which cuts reduced or blocked the release of oxytocin after mid-brain stimulation. At this level, the pathway on each side of the brain is represented by separate dorsal and ventral paths and in the present study it was found that the ventral path is more important than the dorsal path in terms of oxytocin release. The ventral path passes forward in the medial forebrain bundle, in the far-lateral hypothalamus, while the dorsal path enters the posterior hypothalamus dorsally in the periventricular region at the top of the third ventricle and impinges on the thalamic reuniens nucleus. Shortly afterwards the dorsal path swings abruptly in the lateral direction to join the ventral path in the lateral hypothalamus. The reunited pathway then moves forward in this position until it is level with the PV nuclei, where it swings dorsomedially to relay with the lateral tip of the ipsilateral PV nucleus, and in doing so intermingles with the descending neurosecretory fibres from this nucleus.
PARAVENTRICULAR—HYPOPHYSIAL NEUROSECRETORY PATHWAYS IN THE GUINEA-PIG
Authors: KNAGGS G. S. , TINDAL J. S. , TURVEY A. 
Published: December 2008

SUMMARY
The neurosecretory pathways from the paraventricular (PV) nuclei have been identified in the guinea-pig and plotted according to stereotaxic coordinates for the guinea-pig brain. The magnocellular neurosecretory neurones are concentrated in the lateral tip of the PV nucleus approximately half-way between the third ventricle and the fornix. Some neurosecretory fibres pass between the cranio-ventral extension of the PV nucleus and the supraoptic (SO) nucleus. Neurosecretory fibres leave the rostral region of the main part of the PV nucleus and pass ventral to the fornix, those from the middle region pass both ventral and dorsal to the fornix and those from the caudal region pass mainly dorsal to the fornix. After passing around the fornix, these fibres merge to form a broad band, the paraventricular—hypophysial tract, which curves ventrolaterally and then ventromedially in a gentle arc around the lateral edge of the anterior hypothalamic area and the hypothalamic ventromedial nucleus before turning caudomedially to run over the dorsal surface of the optic chiasma towards the median eminence. Neurosecretory fibres were not observed in the anterior hypothalamic area or in the ventromedial nucleus. An accessory PV nucleus was found dorsolateral to the fornix. Neurosecretory fibres pass over the fornix in both directions between the PV and the accessory PV nuclei, also fibres leave the accessory PV nucleus and pass ventrally to merge with those of the main paraventricular—hypophysial tract.