bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE ONSET OF FIRST OESTRUS IN THE GUINEA-PIG AND THE EFFECTS OF GONADOTROPHINS AND OESTRADIOL IN THE IMMATURE ANIMAL
Authors: MILLS P. G. , REED MAY 
Published: December 2008

SUMMARY
The immature female guinea-pig approaching first oestrus and ovulation has been studied. A clear relationship between the rate of growth of the animal and the age at puberty has been found. The 'crucial period', a time just before first oestrus, when external signs of endogenous hormonal activity give an indication of the presence of ripening follicles in the ovary, has been defined. At this time premature ovulation can be regularly induced by a single injection of gonadotrophin (guinea-pig anterior pituitary homogenate, purified luteinizing hormone or follicle-stimulating hormone). Injection of oestrogen advanced vaginal opening but, in contrast to the rat, did not cause premature ovulation.
EFFECT OF CYPROHEPTADINE (PERIACTIN) ON ACCUMULATION OF [14C]5-HYDROXYTRYPTAMINE IN PREGNANT RATS
Authors: PFEIFER Y. , SADOVSKY E. , POLISHUK Z. , SULMAN F. G. 
Published: December 2008

SUMMARY
Subcutaneous injection of the 5-hydroxytryptamine (5-HT) antagonist cyproheptadine hydrochloride (Periactin) produced a significant decrease in uptake of [14C]5-HT (serotonin) in the myometrium and to a lesser degree in the ovaries, foetuses and heart of pregnant rats. This effect of cyproheptadine was considerably increased in rats pretreated with the monoamine oxidase inhibitor pargyline hydrochloride. These results suggest that the anti-abortive effect of cyproheptadine is based on specific inhibition of the contractile effect of 5-HT on the myometrium. The hypothesis is advanced that cyproheptadine competes with serotonin for its receptors and thus blocks the effect of serotonin.
RELATIONSHIP BETWEEN BLOOD LEVELS OF LUTEINIZING HORMONE AND TESTOSTERONE IN BULLS, AND THE EFFECTS OF SEXUAL STIMULATION
Authors: KATONGOLE C. B. , NAFTOLIN F. , SHORT R. V. 
Published: December 2008

SUMMARY
Luteinizing hormone (LH) and testosterone were measured in the peripheral plasma of two bulls by radioimmunoassay and competitive protein binding techniques. Samples were collected from an indwelling jugular catheter once an hour for 24 h, and then at more frequent intervals after a number of experimental procedures.
Each bull showed its own characteristic pattern of cyclic LH changes, with 5–10 peaks during 24 h that were apparently unrelated to daylight, feeding or sleep. Each LH peak was associated with a testosterone peak; the LH concentrations ranged from 5 to 50 ng/ml, and those of testosterone from 2 to 20 ng/ml.
Sexual stimulation, such as the sight of a cow, or 'teasing', or on one occasion the act of ejaculation itself, caused an immediate release of a large amount of LH. If the testosterone levels were low at the time, the LH peak was followed by a testosterone peak. But when the testosterone levels were high at the time of LH discharge, the testis seemed to be unable to respond any further. An intravenous injection of 500 i.u. human chorionic gonadotrophin was associated with LH release and caused the testosterone levels to rise to maximal values of 22 ng/ml within 1½ h.
It is concluded that the cyclical pattern of LH release is due to some inherent central rhythm, and that each transient LH peak results in transient maximal stimulation of testicular testosterone secretion.
CORRELATION OF WATER AND ELECTROLYTE DISTRIBUTION IN THE THYROID GLAND WITH ITS FUNCTIONAL STATE IN RATS AND GUINEA-PIGS
Authors: CHOW S. Y. , WOODBURY D. M. 
Published: December 2008

SUMMARY
In the thyroid gland of rats and guinea-pigs, follicular cell fluid volume was increased and luminal fluid volume was decreased after a single injection of thyroid-stimulating hormone (TSH) (1 i.u./animal) or long-term administration of propylthiouracil (PTU) (0·1% in drinking water for 2 weeks). In rats, follicular cell fluid volume was decreased and luminal fluid volume was increased after hypophysectomy. Interstitial fluid volume remained fairly constant in different functional states of the thyroid gland in both species. As a result of the decrease in luminal colloid content by TSH and PTU treatments, the Cl− concentration in the luminal compartment of the thyroid gland was increased. Luminal Cl− concentration decreased in hypophysectomized rats. In the cellular compartment of the thyroid gland, TSH and PTU treatments caused an increase in K+ and Cl− concentrations and a decrease in Na+ concentration, whereas hypophysectomy caused a decrease in K+ and Cl− and an increase in Na+ concentrations. Water and electrolytes in the thyroid gland of rats younger than 5 weeks were distributed in the same pattern as that of adult guinea-pigs and hypophysectomized adult rats; all these animals probably had lower TSH activity than intact adult rats.
RESULTS OF RADIOIMMUNOASSAYS OF RAT PITUITARY AND SERUM PROLACTIN AFTER ADRENALECTOMY AND PERPHENAZINE TREATMENT IN RATS
Authors: BEN-DAVID M. , DANON A. , BENVENISTE R. , WELLER C. P. , SULMAN F. G. 
Published: December 2008

SUMMARY
Treatment for 5 days of female rats with perphenazine (5 mg/kg/day) induced full lobulo—alveolar differentiation. Long-standing adrenalectomy (12 days) decreased this mammotrophic effect of perphenazine. The mechanism of this reaction was studied in male rats in order to avoid fluctuations of the prolactin content in the anterior pituitary. Adult male rats were adrenalectomized and injected s.c. after 12 days with perphenazine (10 mg/kg). Two hours later the rats were killed and pituitary and serum prolactin levels assayed by double antibody radioimmunoassay. In intact rats, perphenazine treatment enhanced serum prolactin up to 104 ± 4 (s.e.m.) ng/ml (± 350%). Adrenalectomy alone increased serum prolactin from 30± 5 to 47 ± 6 ng/ml (+56%), and augmented the perphenazine-induced release of prolactin from the pituitary into the blood from 104 ± 4 to 147 ± 10 ng/ml (+ 42%).
In chronically adrenalectomized adult female rats extremely high amounts of prolactin (+ 1617%) were detected in the serum at the end of 5 days' treatment with perphenazine (5 mg/kg/day).
These results indicate that removal of the adrenals in male and female rats does not interfere with the ability of the pituitary to secrete prolactin. Moreover, they also show that in adrenalectomized rats the impaired mammotrophic effect of perphenazine is not due to prolactin deficiency (since high serum levels of this hormone were present) but to the absence of corticosteroids at the target organ.
THE RELATIONSHIP BETWEEN THE α-MANNOSIDASE ACTIVITY AND THE ZINC CONTENT OF MAMMALIAN SEX ORGANS
Authors: SNAITH SYBIL M. , HAY A. J. , LEVVY G. A. 
Published: December 2008

SUMMARY
The α-mannosidase activity and the zinc content of rat epididymis increased with age and there was a positive correlation between the two parameters. After castration of rats, epididymal α-mannosidase activity and zinc content both fell; subsequent administration of testosterone caused a partial restoration in enzyme activity, but not in zinc content. In zinc-deficient rats, the epididymal α-mannosidase activity reached little more than half the normal value for adults. In sucrose homogenates of rat epididymis and liver, α-mannosidase activity was concentrated in the cytoplasmic granules, but this was not accompanied by enrichment in zinc. In ovaries from cattle, pigs and women, the very low level of α-mannosidase activity in follicular fluid was reflected in a virtual absence of zinc: the zinc content of the corpus luteum was similar to that of the remaining ovarian tissue, in spite of the greater α-mannosidase activity of the former.
THE EFFECTS OF NEUROHYPOPHYSECTOMY ON THE PATTERN OF RENAL EXCRETION IN THE DUCK (ANAS PLATYRHYNCHOS)
Authors: BRADLEY E. L. , HOLMES W. N. , WRIGHT A. 
Published: December 2008

SUMMARY
Renal excretion in intact, sham-operated and neurohypophysectomized ducks was studied. Neurohypophysectomy produced immediate and profound polydipsia and polyuria. These conditions steadily diminished during the first 2 weeks after the operation and by the 14th day they had stabilized at levels which were approximately three times higher than the corresponding values in sham-operated birds. The stabilized levels of polydipsia and polyuria persisted throughout the remainder of the 60–90 day experimental period. The rates of excretion of Na+, Cl− and total osmotically active material were also increased when compared with intact or sham-operated birds. No change in the rate of K+ excretion was observed.
The i.m. administration of vasopressin reduced the rate of urine flow to that observed in the control birds but the rates of electrolyte excretion were not restored to normal. Synthetic oxytocin had no antidiuretic effect in the neurohypophysectomized birds. Arginine vasotocin treatment restored the rates of both water and ion excretion to values very close to those observed in intact and sham-operated birds.
THE RESPONSE OF THE SEBACEOUS GLANDS OF THE HYPOPHYSECTOMIZED—CASTRATED MALE RAT TO 5α-DIHYDROTESTOSTERONE, ANDROSTENEDIONE, DEHYDROEPIANDROSTERONE AND ANDROSTERONE
Authors: EBLING F. J. , EBLING ERIKA , McCAFFERY VIRGINIA , SKINNER J. 
Published: December 2008

SUMMARY
5α-Dihydrotestosterone and androstenedione (0·2 mg/24 h for 24 days), but not testosterone, significantly increased sebum production in hypophysectomized—castrated rats. Dehydroepiandrosterone and androsterone, even in doses ten times greater, could not be shown to do so, though all the steroids increased the incidence of mitoses in the sebaceous glands. In rats with intact pituitaries, however, the greatest effect on sebaceous secretion was produced by testosterone. A significant increase was also produced by 5α-dihydrotestosterone; androstenedione was only effective at ten times the dose, and androsterone was without significant effect. Dehydroepiandrosterone was not tested.
A possible interpretation of the results is that within the sebaceous glands, either the release of testosterone from its conjugates or its conversion to an active metabolite is under pituitary control. The results also support the view that there are at least two distinct points of action of steroids on the sebaceous glands, namely mitosis and intracellular synthesis of sebum.
GENETIC VARIATION IN THE NEUROHYPOPHYSIAL HORMONES OF THE MOUSE, MUS MUSCULUS
Authors: STEWART A. D. 
Published: December 2008

SUMMARY
The possibility of genetic variation in the amino acid composition of neurohypophysial hormones of the mouse was investigated. Acetic acid extracts from acetone-dried neurohypophyses from six strains of mice were subjected to thin-layer chromatography. Extracts from two strains were tested for natriferic potency on a toad bladder preparation. Extracts from three strains of mice were purified on a carboxymethylcellulose column, and the amino acid composition determined by paper electrophoresis at pH 2.
All six strains of mice were found to elaborate an oxytocic principle with the chromatographic properties of oxytocin. All results were compatible with the view that five of the strains elaborate the usual mammalian vasopressin, [8-arginine]-vasopressin. However, chromatography, natriferic assays and analyses of amino acid composition indicated that the Peru strain of mice elaborated [8-lysine]-vasopressin. These mice would be the first mammals outside the Suina which possess this hormone, and the difference between the strains of mice is almost certainly genetic in origin. The significance of genetic variation within a species in the structure of a hormone is discussed in terms of its physiological and evolutionary consequences.
EFFECT OF A PHENOTHIAZINE TRANQUILLIZER ON PLASMA MELANOPHORE-STIMULATING ACTIVITY IN SPANISH GOATS
Authors: PEASLEE MARGARET H. , MILBURN S. E. 
Published: December 2008

SUMMARY
A phenothiazine tranquillizer was administered intravenously to Spanish goats. An increase of plasma melanophore-stimulating activity ranging from 300 to 2000% above base level was observed usually within 15 min after injection.
SEX-ATTRACTANT PROPERTIES OF ETHER EXTRACTS OF VAGINAL SECRETIONS FROM RHESUS MONKEYS
Authors: KEVERNE E. B. , MICHAEL R. P. 
Published: December 2008

SUMMARY
Vaginal secretions were collected by lavage from ovariectomized, oestrogen-treated female rhesus monkeys. Ether extracts of these secretions were applied to the sexual skin of long-ovariectomized, untreated females immediately before mating tests with males. Application of extracts resulted in an immediate and marked stimulation of the sexual activity of males which had been inactive with these females during pretreatment tests when control material was applied. Extracts caused increases in male mounting activity, in ejaculations and in male grooming times, in the apparent absence of any behavioural or genital tract signs of female receptivity. It is concluded from these and other observations that male sex-attractant pheromones, with powerful behavioural effects, are present in ether extracts of oestrogen-stimulated vaginal secretions: this will facilitate their chemical characterization.
EFFECT OF GROWTH HORMONE ON THE ALDOSTERONE SECRETORY RESPONSE TO SODIUM RESTRICTION IN CORTICOTROPHIN-MAINTAINED HYPOPHYSECTOMIZED NEPHRECTOMIZED RATS
Authors: PALKOVITS M. , STRIK J. J. T. W. A. , de JONG W. , de WIED D. 
Published: December 2008

SUMMARY
The rate of aldosterone production in vitro by adrenal glands from rats hypophysectomized 7 days previously, treated with corticotrophin (ACTH) and subjected to dietary sodium restriction for 2 weeks, was decreased 6 h after nephrectomy. However, 18 h and 48 h after nephrectomy there was a marked increase in the rate of aldosterone production in vitro. In addition there was a rise in the plasma potassium concentration. These results indicated that in order to detect whether the influence of growth hormone on aldosterone secretory response to sodium restriction in hypophysectomized rats was mediated by the kidney, studies had to be performed within 6 h after removal of the kidneys.
Since the effect of growth hormone on aldosterone production requires 2 days to develop (Palkovits, de Jong, van der Wal & de Wied, 1971), rats hypophysectomized 54 h previously were used. The kidneys were removed 6 h before decapitation. In these animals, the administration of growth hormone in the presence of ACTH restored the aldosterone secretory response to sodium deficiency.
The results suggest that growth hormone maintains the aldosterone secretory response to sodium restriction in hypophysectomized rats in the absence of the kidneys.
THE ACTION OF CLOMIPHENE IN THE FERRET
Authors: DONOVAN B. T. 
Published: December 2008

SUMMARY
In an attempt to interfere pharmacologically with the feedback action of oestrogen in the ferret, clomiphene citrate was given to anoestrous animals for 10 days, and to oestrous females for 7 or 14 days, in doses ranging from 10 μg to 1000 μg daily. With the higher doses oestrogenic effects on the uterus were observed, while arrest of follicular development in the ovaries indicated inhibition of gonadotrophin secretion. Enhancement of gonadotrophin secretion in anoestrous females was not encountered, although ovulation in oestrous females was an occasional consequence of treatment with the drug.
HORMONAL IODINE IN THE DOG
Authors: FARRAN HELEN E. A. , BUSH B. M. 
Published: December 2008

SUMMARY
The nature and rate of formation of hormonal iodine in the dog has been studied by radioactive and chemical methods. A rapid appearance of protein-bound iodine (PBI) which was not extractable with acid butanol was noted during the first few hours after the administration of 131I. The butanol-insoluble fraction of PBI was not detectable 2–3 days after the dose when the residual activity was found to consist of approximately equal amounts of thyroxine and tri-iodothyronine. This unexpectedly high proportion of circulating tri-iodothyronine was checked by saturation analysis. It is suggested that relatively high levels of tri-iodothyronine in some dogs may in part account for the low PBI levels found in normal canine sera.
DETERMINATION OF PLASMA OESTRIOL IN NORMAL PREGNANCY AND LABOUR USING GAS-LIQUID CHROMATOGRAPHY
Authors: COOPER W. , COYLE M. G. , MILLS J. A. 
Published: December 2008

SUMMARY
A method is described for estimating oestriol in 2–10 ml samples of human pregnancy peripheral plasma. It incorporates acid hydrolysis, chemical purification, methylation, chromatography on alumina columns, formation of a derivative and quantitative determination by gas chromatography. A radioactive internal standard was added to correct for procedural losses. Plasma oestriol determinations in five normal patients throughout pregnancy and delivery are reported.
EFFECTS OF STILBOESTROL ON GROWTH HORMONE SECRETION AND PITUITARY CELL PROLIFERATION IN THE MALE RAT
Authors: LLOYD H. M. , MEARES J. D. , JACOBI JOAN , THOMAS FRANCES J. 
Published: December 2008

SUMMARY
A single 12 mg dose of stilboestrol dipropionate given to 100-day-old male rats resulted in increased pituitary mitotic activity, pituitary weight and serum growth hormone; the latter rose from a mean value of 20 ng/ml to a maximum of 342 ng/ml 9 days later. Serum growth hormone and pituitary mitotic activity then gradually diminished but were still slightly increased on day 28. Serum growth hormone and pituitary weight were significantly correlated during the periods of rapidly rising and of sustained high levels of serum growth hormone. Indices of mitotic activity were correlated with serum growth hormone during the periods of rapidly rising and of falling levels of serum growth hormone.
SYNTHESIS OF ANDROGENS IN VITRO BY TESTES OF RATS ACCLIMATIZED TO A HOT ENVIRONMENT
Authors: BEDRAK E. , SAMOILOFF V. , SOD-MORIAH U. A. , GOLDBERG S. 
Published: December 2008

SUMMARY
The relative activities of enzymes participating in the biosynthesis of testosterone via the 4-ene pathway were determined in testicular homogenates of rats acclimatized to a hot environment (33–35 °C, 25–40% relative humidity). Acclimatized animals showed an increase in activity of 17α-hydroxylase, 17,20-lyase and 20α-hydroxysteroid oxidoreductase, whereas the activity of 17β-hydroxysteroid oxidoreductase was markedly decreased. Histological examination of the testes disclosed that neither the germinal epithelium nor the Leydig cells were adversely affected by the increased environmental temperature. The results are discussed in relation to the synthesis and release of the gonadotrophins.
A similar degree of acclimatization, as determined by the comparable decrease in oxygen uptake, was achieved by either of two methods: daily 4 h exposure to a high ambient temperature for 4 weeks or continuous maintenance at 35 °C. The former procedure, however, appeared to be the preferred method for acclimatization of male rats since it did not inhibit growth rate and was free of mortality.
THE EFFECT OF CORTISOL ON THE TOLERANCE TO GLUCOSE OF THYROIDECTOMIZED CALVES
Authors: EDWARDS A. V. , NATHANIELSZ P. W. , VAUGHAN N. J. A. 
Published: December 2008

SUMMARY
The results of serial glucose tolerance tests in cortisol-treated, thyroidectomized calves indicate that there is a progressive reduction in the tolerance to glucose and that this is associated with a diminution in the rise in plasma insulin concentration which normally occurs in response to hyperglycaemia. These experimental conditions also stop growth within 12–14 days. All these effects are reversed by injections of thyroxine at a dose which raises the plasma thyroxine concentration to normal values for 7 days in spite of the continued administration of cortisol.
These results suggest that, in the unweaned thyroidectomized calf, daily injections of cortisol reduce the sensitivity of the insulin release mechanism, which may provide an explanation for the severe diabetic syndrome which is known to develop under these conditions.
EFFECT OF RESERPINE ON GROWTH HORMONE RESPONSE TO INSULIN HYPOGLYCAEMIA AND TO ARGININE INFUSION IN NORMAL SUBJECTS AND HYPERTHYROID PATIENTS
Authors: CAVAGNINI F. , PERACCHI M. 
Published: December 2008

SUMMARY
The effect of reserpine on growth hormone (GH) secretion induced by insulin hypoglycaemia and by arginine infusion was studied in ten normal subjects and ten hyperthyroid patients. In both groups of subjects, oral reserpine administration resulted in a reduction of GH response to hypoglycaemia, but caused no significant change of GH release after arginine infusion. These results strongly support the theory of an adrenergic control of GH secretion and indicate that arginine stimulates GH secretion in a different way from insulin and independently of catecholamines.
EVIDENCE OF ANTAGONISM BETWEEN PROLACTIN AND GONADOTROPHIN SECRETION: EFFECT OF METHALLIBURE ON PERPHENAZINE-INDUCED PROLACTIN SECRETION IN OVARIECTOMIZED RATS
Authors: BEN-DAVID M. , DANON A. , SULMAN F. G. 
Published: December 2008

SUMMARY
Perphenazine has previously been shown to stimulate prolactin secretion in intact and to a lesser degree in ovariectomized virgin female rats. The question whether the oversecretion of gonadotrophins (follicle-stimulating hormone and luteinizing hormone) occurring in ovariectomized animals interferes with the ability of the pituitary cells to secrete prolactin was investigated in sham-operated and ovariectomized rats after separate and combined treatment with methallibure (ICI-33828, a non-steroidal gonadotrophin suppressor) and perphenazine which served as a prolactin releaser. Pituitary and serum prolactin were measured simultaneously by radioimmunoassay. Serum prolactin detected at the end of 5 days' treatment with perphenazine (5 mg/kg/day, s.c.) was found to be increased (81 ng/ml) compared with controls (29 ng/ml). Similar treatment given to ovariectomized animals increased serum prolactin levels from 13·7 ng/ml to only 27 ng/ml. Although high doses of methallibure alone (20 mg/kg/day, s.c.) given to ovariectomized rats for 17 days restored prolactin secretion to the levels occurring in intact non-treated animals, a dose of 10 mg was ineffective. However, when 10 mg methallibure were given to perphenazine-treated ovariectomized rats, serum prolactin rose again to 80·1 ng/ml.
These results provide substantial evidence that, when the pituitary is secreting high amounts of gonadotrophin, its prolactin secretion is reduced and its ability to secrete prolactin after perphenazine challenge is limited. Once the gonadotrophic oversecretion is suppressed, more prolactin is secreted and the pituitary can again secrete high amounts of prolactin when challenged by perphenazine. The results show that in rats there exists an antagonism between gonadotrophin and prolactin secretion.
THE CONTROL OF THE APOCRINE GLANDS OF THE RABBIT BY STEROID HORMONES
Authors: WALES N. A. M. , EBLING F. J. 
Published: December 2008

SUMMARY
The rabbit has specialized apocrine glands in the submandibular (chin), inguinal and anal regions. The glands enlarge at puberty and are heavier and more active in mature males than females. Prepubertal castration causes the adult male to have lighter and less active glands than intact mature animals; this effect can be reversed by administration of testosterone (0·6 mg/24 h).
Severe reduction in gland weight and activity below the level of the castrated animals was produced by administration of oestradiol (10–20 μg/24 h) either when given alone to intact males or together with testosterone to castrated males. The degree of depression by oestradiol varied between the three glandular regions.
Progesterone (0·6 mg/24 h) was unable to stimulate the glands of castrated male rabbits but did modify the suppressive action of exogenous oestradiol.
The sebaceous glands of the inguinal complex showed the same fluctuations in weight with hormone treatment as did the inguinal apocrine glands.