bluuebunny/crossref_metadata_2025 huggingface dataset:
RATES OF INCORPORATION OF [3H]LEUCINE INTO PROTEIN OF THE PARS INTERMEDIA OF THE PITUITARY IN THE AMPHIBIAN XENOPUS LAEVIS AFTER CHANGE OF BACKGROUND COLOUR
Authors: WHUR P. , WEATHERHEAD B.
Published: December 2008

Xenopus were kept on, and transferred between, black or white back-grounds before incubating the pars intermedia and sometimes other parts of the pituitary with [3H]leucine. The rates of incorporation of label were assessed either by liquid scintillation counting of trichloroacetic acid precipitates or quantitative analysis of autoradiographs. Inhibition of incorporation of label was achieved after incubation with puromycin, showing that the label was associated with newly synthesized peptide material. The rates of incorporation of label into pars distalis and pars nervosa were not significantly different in animals from black or white back-grounds. However, pars intermedia from animals on a black background incorporated label at three to six times the rate of animals from a white background. In animals kept for some days on a white background and then transferred to a black background the rate of incorporation began to rise within a few minutes and reached the new higher level after several hours. In animals transferred from a black to a white background, however, no decline in rate was detected until 2 days after the transfer, but by 3 days the rate had returned to the white background level. The timing of these changes bears no relationship to the timing of changes, reported elsewhere, in the ultrastructure of pars intermedia cells after changes in background colour. They are, on the other hand, similar to the timing of changes in the melanocyte-stimulating hormone content of pars intermedia and also to changes in the melanophore index.
METABOLISM OF PREGNENOLONE AND DEHYDROEPIANDROSTERONE BY HOMOGENIZED TISSUE FROM THE SEPARATED ZONES AND WHOLE ADRENAL GLANDS FROM NEWBORN ANENCEPHALIC INFANTS
Authors: COOKE B. A. , SHIRLEY I. M. , DOBBIE J. , TAYLOR PATRICIA D.
Published: December 2008

The metabolism of [3H]pregnenolone and [3H]dehydroepiandrosterone ([3H]DHA) by tissue from the separated zones and whole adrenal glands from newborn anencephalic infants was investigated.

Pregnenolone was metabolized by the whole gland homogenates mainly to pregnenolone sulphate and unconjugated 17α-hydroxypregnenolone and also to small amounts of DHA and dehydroepiandrosterone sulphate (DHAS). DHA was metabolized by the whole gland homogenates mainly to androstenedione and DHAS and small amounts of 11β-hydroxyandrostenedione.

Adrenal gland tissue from a 42-week-old anencephalic infant containing three histologically distinct zones in the adult cortex in addition to residual foetal zone had sulphokinase, 17α-hydroxylase, 17–20 lyase and 3β-hydroxy-steroid dehydrogenase/Δ4,5 unsaturated isomerase activity in each of these zones. These enzymes were also present in the adrenal adult zone of another anencephalic infant.

Omission of ATP from the incubation medium greatly reduced the conversion of DHA to DHAS in the homogenates and separated zones.

These results are discussed in relation to oestrogen biosynthesis in anencephaly and to foetal 4-en-3-oxosteroid synthesis in utero.
EFFECTS OF OESTROGEN AND PROGESTERONE ON THE DEVELOPMENT, OVIDUCTAL TRANSPORT AND UTERINE RETENTION OF EGGS IN HYPOPHYSECTOMIZED PREGNANT RATS
Authors: WU J. T. , DICKMANN Z. , JOHNSON D. C.
Published: December 2008

Hypophysectomy of rats on day 1 of pregnancy resulted in expulsion of most eggs from the uterus between days 5 and 6, delayed entry of eggs into the uterus, and retarded development of eggs.

Expulsion of eggs was prevented with daily injections of 2 mg progesterone. Other regimes of progesterone administration were also beneficial, but not as effective as daily injections.

Daily injections of 2 or 4 mg progesterone, or of progesterone plus oestrone, restored egg transport to normal, whereas a single injection of progesterone did not. Daily injections of small amounts of oestrone caused total disappearance of eggs from the reproductive tract.

The development of eggs was significantly improved with daily injections of progesterone plus oestrone, but not with progesterone alone.

Combined treatment with progesterone and oestrone caused premature shedding of the zona pellucida in mature blastocysts, young blastocysts, and morulae.
FEMALE SEXUAL BEHAVIOUR IN MALE GOLDEN HAMSTERS
Authors: TIEFER LEONORE , JOHNSON W. A.
Published: December 2008

Four groups of adult male hamsters were castrated and injected with either 6 μg oestradiol benzoate (OB), 100 μg OB, 6 μg OB plus 0·5 mg progesterone or 100 μg OB plus 0·5 mg progesterone. In repeated tests with virile males, all the injected males showed lordosis behaviour similar, but quantitatively inferior, to that of female hamsters. Uninjected controls showed no lordosis. There was no dose—response relationship between the two doses of oestrogen. Progesterone significantly facilitated the quantity and quality of lordosis behaviour shown. This is in contrast with previous reports of the absence of facilitation by progesterone in male rats. After cessation of hormone injections the animals continued to display the lordosis response for several weeks.
RECOVERY FROM LETHAL X-RAY DAMAGE DURING DELAYED IMPLANTATION IN THE RAT
Authors: WARD W. F. , MEYER R. K. , WOLF R. C.
Published: December 2008

Rats were exposed to either 300 or 500 röntgen (R) acute whole-body X-irradiation on the 5th day of delayed pregnancy induced by ovariectomy. From 0 to 8 days after irradiation, implantation was induced by the administration of oestrogen. Foetal survival to the 20th day of development was used as an index of radiation effect.

If oestrogen was given immediately after exposure to 300 R, or 12 h later, only 30–35% of the embryos survived, significantly less (P < 0·01) than the non-irradiated control values of 74–79%. When implantation was postponed for 24 h or more, embryonic survival ranged from 57 to 64% and was not significantly different from that of controls.

After exposure to 500 R X-irradiation, embryonic survival increased linearly from 2% to a maximum of 41% as the interval between irradiation and oestrogen administration increased from 0 to 48 h. Embryonic survival never reached control levels after 500 R, regardless of the interval between irradiation and implantation. The irradiation regimens also induced developmental abnormalities, doubled the incidence of dead foetuses (death at a late stage of development), and significantly reduced foetal and placental weights at autopsy.

The results confirm that recovery from potentially lethal X-irradiation damage can occur during delayed implantation, and demonstrate that both the extent and the rate of recovery are functions of the radiation dose.
THE ROLE OF GASTRIN AS A CALCITONIN SECRETAGOGUE
Authors: CARE A. D. , BATES R. F. L. , SWAMINATHAN R. , GANGULI P. C.
Published: December 2008

Our earlier observation that pentagastrin is a calcitonin (CT) secretagogue was confirmed and extended to include both synthetic human gastrin I and pure porcine gastrin II. The latter hormone was shown to stimulate the secretion rate of CT from thyroid preparations perfused in situ in anaesthetized pigs at concentrations (0·5 nmol/l) similar to those found after stimulation of gastrin production by a meat extract placed in the stomach (0·2 nmol/1). These concentrations of plasma gastrin are considerably less than those found in man in both pernicious anaemia and the Zollinger—Ellison syndrome, whereas the mean fasting plasma gastrin concentrations in normal human beings and pigs are similar. It is suggested that the comparatively high incidence of parathyroid hyperactivity in association with the Zollinger—Ellison syndrome may be a consequence of an increased CT secretion rate induced by hypergastrinaemia. Furthermore, the existence of a gastrointestinal—thyroid C cell system is proposed as an integral part of postprandial calcium homeostasis.
STEROID METABOLIC PATHWAYS IN THE OVARY OF THE CHINCHILLA (CHINCHILLA LANIGER)
Authors: TAM W. H.
Published: December 2008

The ovarian tissue components of the pregnant chinchilla were incubated with equimolar amounts of [7α-3H]pregnenolone and [4-14C]progesterone. The greater contribution by [7α-3H]pregnenolone than by [4-14C]progesterone towards the formation of 17α-hydroxyprogesterone and androstenedione, and the relatively high yields of 17α-hydroxypregnenolone and dehydroepiandrosterone showed that both the 4-ene and 5-ene pathways of steroid metabolism were used in the interstitial tissue. No significant amount of 17α-hydroxylation was observed in the primary and accessory corpora lutea. The results of kinetic investigations using [7α-3H]pregnenolone as substrate also demonstrated a precursor—product relationship between dehydroepiandrosterone and androstenedione in the interstitial tissue, but this was not apparent in the luteal tissue. The results indicated that the interstitial tissue was capable of synthesizing progesterone and oestrogens as major products, and that the lack of 17α-hydroxylation in the luteal tissue was a controlling factor ensuring the synthesis of progesterone as its principal hormonal product. A small amount of [4-14C]dehydroepiandrosterone was always isolated with a much larger amount of the tritiated compound. This implied the conversion of 14C-labelled 4-en-3-oxosteroids into 5-ene-3β-hydroxysteroids which has generally been regarded as impossible. The isolation of this product, which may be an artifact, and the possibility that progesterone and oestrogens may be synthesized by different cells (granulosa and theca lutein cells) in the corpus luteum, or that there may be a third pathway for oestrogen synthesis, as suggested by the results of the kinetic experiments, are discussed.
THE EFFECT OF DIAZEPAM ON PITUITARY FUNCTION IN MAN
Authors: HAVARD C. W. H. , SALDANHA V. F. , BIRD R. , GARDNER R.
Published: December 2008

The integrity of pituitary—adrenal function and growth hormone production was determined in 15 patients before and after treatment with diazepam (30 mg daily). There was no evidence of impairment; nor was the urinary excretion of catecholamines significantly altered. The reproducibility of the plasma corticosteroid response to insulin-induced hypoglycaemia was separately assessed and both the degree of fall in blood sugar and the rise in plasma corticosteroid level were found to be similar.
EXCRETION OF 15α-HYDROXYOESTRIOL AND OESTRIOL IN URINE OF NEWBORN INFANTS AND IN MATERNAL URINE BEFORE AND AFTER DELIVERY
Authors: HEIKKILÄ JORMA
Published: December 2008

The amounts of oestriol and 15α-hydroxyoestriol (oestetrol) were determined in 24-h urine samples collected from pregnant women before and after delivery. In addition, the concentrations of these oestrogens were estimated in the urine of the newborn infants born to these mothers. The excretion of both these oestrogens decreased exponentially in maternal urine after delivery, the rate of decrease being significantly slower for oestetrol. The concentration of oestriol and oestetrol in the urine of the newborn infants also fell rapidly after delivery, the reduction being a linear function of time. The concentration of oestetrol in the urine of the newborn infant was relatively high in comparison to that of oestriol, and during the first day of life was the same as in maternal urine before delivery.
LOCALIZATION OF FOLLICLE-STIMULATING AND LUTEINIZING HORMONES IN THE RAT TESTIS USING IMMUNOHISTOLOGICAL TESTS
Authors: CASTRO A. E. , ALONSO A. , MANCINI R. E.
Published: December 2008

Rabbit antisera to ovine follicle-stimulating (FSH) and luteinizing (LH) hormones were used in the indirect fluorescent antibody technique on sections of rat testis to detect intravenously injected FSH or LH. A direct method using ferritin-labelled rabbit anti-LH globulins was also performed on sections of testis from LH-injected rats. Follicle-stimulating hormone was localized in the Sertoli cells while LH appeared mainly in the interstitial and peritubular cells. These results agree with previous observations on the cellular distribution of both gonadotrophins in the rat testis.
THE BLOOD LEVELS OF OXYTOCIN DURING SUCKLING AND HAND-MILKING IN THE GOAT WITH SOME OBSERVATIONS ON THE PATTERN OF HORMONE RELEASE
Authors: McNEILLY A. S.
Published: December 2008

Thirty-six series of serial jugular blood samples were collected from 12 goats during suckling during the first 3 weeks of lactation and the transient appearance of oxytocin (5–86 μu./ml plasma) was detected in 24 of the series. Blood oxytocin was assayed on the lactating guinea-pig mammary gland. Forty series of serial blood samples were also collected from 12 goats during hand-milking over the first 6 weeks of lactation and the transient appearance of oxytocin (5–160 μu./ml plasma) was observed in 25 of these.

The results indicated that: (1) oxytocin may be released at any time during the suckling or milking process; (2) in only 16% of experiments where oxytocin was released and 5·6% of all experiments investigated could a conditioned release of oxytocin be induced in goats before suckling and in no case before hand-milking despite a vigorous and prolonged conditioning period; (3) there is a large degree of variability in the pattern of oxytocin release between animals and between individual suckling and milking episodes in the same animal; (4) suckling and hand-milking are equally effective in causing the release of oxytocin; (5) stimuli arising during various stages of the suckling and hand-milking routines may be assigned a figure indicative of the relative effectiveness of these stimuli in terms of percentage probability in causing oxytocin release; (6) there is a greater probability of oxytocin release occurring before suckling than before hand-milking; (7) there is a very marked similarity in the pattern of oxytocin release both during and after teat stimulation in response to suckling and milking stimuli; (8) there is a greater probability of oxytocin being released in response to hand-milking during early lactation than during late lactation; (9) the milk-ejection reflex in the goat does not appear to be important for the achievement of normal milk yields during suckling or hand-milking.
INACTIVATION OF LONG-ACTING THYROID STIMULATOR IN VIVO
Authors: SMITH B. R. , MUNRO D. S.
Published: December 2008

The prolonged action of long-acting thyroid stimulator (LATS) in the McKenzie assay could be related to the slow clearance of LATS from the blood of assay mice.

Injection of soluble thyroid extracts before or after LATS reduced the assay response. This corresponded with the inactivation of circulating LATS activity by the formation of a complex which was then rapidly removed from the blood.
EFFECT OF SOME ANTI-OESTROGENIC RING METHYL-SUBSTITUTED STILBOESTROLS ON THE UPTAKE OF TRITIATED OESTRADIOL BY THE MOUSE VAGINA
Authors: CLARK E. R. , McCRACKEN ANNA M.
Published: December 2008

Intravaginal administration to ovariectomized mice of 2·5 μg of either 3,3′,5,5′,α,α′-hexamethylstilboestrol (structure V) or 3,3′,5,5′-tetramethyl-α,α′-diethylstilboestrol (structure VI) significantly depressed the retention by vaginal tissue of concomitantly administered [6,7-3H]oestradiol-17β (0·75 × 10−4 μg), but did not affect the absorption of oestradiol from the vaginal lumen. The antagonism was shown by subcellular fractionation studies on vaginal homogenates to occur in the nuclear fraction.
THE ACCUMULATION, RETENTION AND INTERACTION OF OESTRADIOL AND OESTRONE IN CENTRAL NEURAL AND PERIPHERAL TISSUES OF GONADECTOMIZED FEMALE RATS
Authors: LUTTGE W. G. , WHALEN R. E.
Published: December 2008

Adult female rats which had been ovariectomized and hysterectomized were given tritiated oestradiol or tritiated oestrone and killed 1, 2 or 4 h later. Several brain samples were taken including anterior hypothalamus, posterior hypothalamus, 'cerebral peduncle' and cerebral cortex. Pituitary and blood plasma samples were also taken. [3H]Oestradiol and [3H]oestrone showed different patterns of retention in basal brain structures. After [3H]oestradiol administration the anterior hypothalamus retained more radioactivity than the posterior hypothalamus, which in turn retained more radioactivity than the cerebral peduncle. With [3H]oestrone, samples from the cerebral peduncle and posterior hypothalamus retained more radioactivity than samples from the anterior hypothalamus. The cerebral peduncle and posterior hypothalamus did not differ from one another in this respect. After administration of either hormone, all basal brain structures retained more radioactivity than cerebral cortex and plasma. The pituitary retained six times more radioactivity after administration of [3H]oestradiol than after [3H]oestrone.

For ovariectomized females killed 2 h after the injection of [3H]oestradiol, pretreatment with oestradiol for 30 min reduced the radioactivity retained in the pituitary and anterior hypothalamus, while pretreatment with oestradiol for 24 h produced no changes in uptake except in the uterus where radioactivity levels were nearly doubled. The increased uterine uptake was independent of increases in uterine weight. Oestrone pretreatment failed to produce consistent effects except at high doses where it reduced [3H]oestradiol uptake in the pituitary and hypothalamus. Pretreatment with either oestrone or oestradiol had no effect on uptake by neural tissues after [3H]oestrone injection.

It is concluded that there are at least four kinds of oestrogen uptake mechanisms in the female rat. The uterus contains a limited capacity 'receptor system' which selectively accumulates oestradiol and which permits displacement of oestradiol by oestrogen post-treatment, and stimulation of oestradiol uptake by oestrogen pretreatment. In the pituitary, oestradiol is selectively accumulated by a limited capacity receptor system which permits oestradiol displacement, but not oestradiol uptake stimulation. The brain contains two receptor systems: a regionally localized limited capacity receptor system for the non-displaceable selective accumulation of oestradiol, and a regionally localized comparatively unlimited capacity receptor system for the selective accumulation of oestrone.
ELIMINATION OF RADIOIODINE BY THE SHEEP PAROTID GLAND AFTER [131I]l-TRI-IODOTHYRONINE ADMINISTRATION
Authors: ŚLEBODZIŃSKI A.
Published: December 2008

A study was made of the metabolism of [131I]l-tri-iodothyronine ([131I]T3), in sheep with a unilateral fistula of the parotid gland. After [131I]T3 injection a constant rise in radioactivity in the saliva and a decline in the radioactivity of the serum were found; detectable amounts of radioiodine reentered the circulation from the metabolized hormone after 1 h. Gel filtration showed that the radioactivity in the collected saliva was due to inorganic [131I]iodide. Such an effect might be caused by deiodination [131I]T3 which occurs in sheep parotid glands in vitro. The presence of tracer amounts of hormonal radioiodine in individual sheep could not be excluded.

Non-specific deiodinating enzymes may exist in sheep parotid salivary glands.
CHANGES IN GONADOTROPHINS, OVARIAN STEROIDS AND FOLLICULAR MORPHOLOGY IN SHEEP AT OESTRUS
Authors: BJERSING L. , HAY MARY F. , KANN G. , MOOR R. M. , NAFTOLIN F. , SCARAMUZZI R. J. , SHORT R. V. , YOUNGLAI E. V.
Published: December 2008

The concentrations of progesterone, oestrogen and luteinizing hormone (LH) in ovarian venous plasma, and of progesterone, follicle-stimulating hormone, LH and prolactin in peripheral plasma were measured in 47 Welsh Mountain sheep at accurately timed stages around oestrus. The histology and ultrastructure of the pre-ovulatory and newly ruptured follicles in these animals were also examined.

The highest ovarian vein levels of oestrogen were invariably obtained from the ovary containing the largest non-atretic follicle. A significant amount of oestrogen was already being secreted by day 13, when both the peripheral and ovarian venous blood progesterone levels were still high.

On day 15 the corpus luteum stopped secreting progesterone; coincident with this decline there was a maximal increase in oestrogen secretion from the largest non-atretic follicle. The thecal cells of this follicle enlarged concomitantly with the rise in oestrogen, and maximal development of the smooth endoplasmic reticulum was observed at or after the oestrogen peak.

By 6 h after the onset of oestrus, progesterone concentration was still very low, and oestrogen values had fallen in most animals, while LH showed a pronounced increase. The maximal level of prolactin was also found at this time.

By 15 h after the onset of oestrus, both progesterone and oestrogen values were low and LH had returned to baseline levels except in a few animals. Ovulation had occurred in 11 out of 12 animals by 30 h after the onset of oestrus and the recently ruptured follicle was just beginning to secrete a little progesterone. Luteinizing hormone and oestrogen values were very low.
INCREASED CHROMATIN ACID LABILITY AND ACTINOMYCIN-D BINDING IN ENDOMETRIAL CELLS UNDER THE ACTION OF SEX STEROIDS
Authors: LEROY F. , PREUMONT A. M. , GALAND P. , BRACHET J.
Published: December 2008

Modifications of chromatin activity, induced by sex steroids, were studied in rat endometrial tissues by the following semi-quantitative cytochemical methods: 'staining' of fixed uteri by [3H]actinomycin-D followed by radioautography and cytophotometric evaluation of Feulgen reaction kinetics in isolated endometrial nuclei. The following hormonal treatments were applied to groups of animals: oestradiol-17β (10 μg); progesterone (2 mg); progesterone (2 mg daily for 4 days) with oestradiol-17β (0·05 μg on the 4th day). With both cytochemical methods, different hormonal treatments were found to induce different patterns of response in endometrial cell types. In luminal epithelium and endometrial stroma, hormonal treatment increased the binding of actinomycin-D in a variable manner as judged from autoradiographic grain counts. Sex steroids also induced an overall increased DNA acid-lability as estimated by cytophotometric evaluation of Feulgen staining intensity. Hormonal treatments induced different hydrolysis curve patterns in both endometrial nuclear types.
CORTICOTROPHIN-INDUCED DIFFERENTIATION OF MITOCHONDRIA IN RAT ADRENAL CORTICAL CELLS GROWN IN PRIMARY TISSUE CULTURE: EFFECTS OF ETHIDIUM BROMIDE
Authors: MILNER A. JOSEPHINE
Published: December 2008

Foetal rat adrenals were grown in primary tissue culture. The effects of ethidium bromide on the adrenocorticotrophin (ACTH)-induced differentiation of the mitochondria of the cortical cells were examined. Ethidium bromide (1 μg/ml/day for 4 days) inhibited the morphological transformation of the mitochondria normally induced by ACTH. At the same time the steroid 11β-hydroxylating activity, which is associated with the inner mitochondrial membrane, was either partially or completely blocked. The ethidium bromide-treated cells contained mitochondria of varying sizes and with poorly developed inner membranes. The biochemical and morphological effects of ethidium bromide on the cortical cell mitochondria were only partially reversible.
THYROID-STIMULATING AND LIPOLYTIC ACTIVITIES OF PURIFIED PREPARATIONS OF HUMAN THYROID-STIMULATING HORMONE
Authors: HARTREE ANNE STOCKELL , THOMAS MARJORIE , FURNIVAL BRIDGET E. , BURNS T. W. , LANGLEY P.
Published: December 2008

A partially purified fraction of human thyroid-stimulating hormone (DEAE-II) was further purified by ion-exchange chromatography on IRC-50, gel-filtration on Sephadex G-100 and finally chromatography on DEAE-cellulose. Two fractions were obtained which were high in thyroid-stimulating activity (8·3 and 7·3 units human Research Standard A/mg) and were comparable in potency to other preparations of the human hormone reported in the literature. They were also electrophoretically heterogeneous as were the preparations of other workers. Lipolytic activity toward cells obtained from human or rat adipose tissue was demonstrated for all fractions containing thyroid-stimulating activity, the two activities being roughly parallel. It is concluded that both thyroid-stimulating and lipolytic activities are probably present in the same protein molecule, but it is unlikely that the latter activity is of physiological significance.
RELATIONSHIP BETWEEN THE THYROID HORMONE AND MINERAL METABOLISM IN THE RAT
Authors: HUMPHRAY H. P. , HEATON F. W.
Published: December 2008

The effect of thyroid activity on the distribution of magnesium, potassium and calcium between plasma, soft tissues and bone was investigated in adolescent rats. Administration of thyroxine or propylthiouracil produced variable effects on their concentrations in tissues, but the total amounts of all three metals in the complete liver and a single femur showed consistent changes that were similar to changes in the nitrogen content of the liver and the dry weight of bone. It is concluded that the influence of thyroid hormone on mineral metabolism is secondary to its action on tissue anabolism and catabolism.

Magnesium deficiency decreased thyroid activity, and loading with magnesium salts increased the activity of the gland, a very close relationship being observed between the plasma magnesium concentration and the activity of the thyroid. Deficiency or loading with potassium salts produced changes that were qualitatively similar to those with magnesium, but less well-defined, and it appears that potassium may have an indirect effect on the gland. A hypothesis is advanced to explain how, in the absence of a homeostatic relationship, the availability of magnesium could modulate thyroid activity.
ESTIMATION OF MARSUPIAL RENIN USING MARSUPIAL RENIN-SUBSTRATE
Authors: SIMPSON PAMELA A. , BLAIR-WEST J. R.
Published: December 2008

Bilateral nephrectomy of an Eastern Grey kangaroo (Macropus giganteus) increased plasma renin-substrate concentration approximately tenfold when compared with intact kangaroos. A preparation made from this plasma had a renin-substrate concentration of 3000 ng/ml. A pH profile of rate of reaction with pig renin had an optimum at pH 5·39. By comparison, the pH optimum of sheep renin-substrate was pH 6·15. Estimates of plasma renin concentration for kangaroos, wombats and wallabies, using kangaroo renin-substrate or sheep renin-substrate were highly correlated. Results from incubation with sheep renin-substrate were greater and hence indicate the advantage in using this substrate for marsupial renin estimation.

The consistently large difference between sheep and kangaroo renin-substrate when incubated with renin from marsupial and eutherian species appears to be due to a structural difference between the two substrates, probably near the C-terminal end of the angiotensin I molecule.
STANDARDIZATION AND EVALUATION OF A SENSITIVE AND CONVENIENT ASSAY FOR MELANOCYTE-STIMULATING HORMONE USING ANOLIS SKIN IN VITRO
Authors: BJÖRKLUND A. , MEURLING P. , NILSSON G. , NOBIN A.
Published: December 2008

A method is described for the quantitative bioassay of melanocytestimulating hormone (MSH) activity using the skin of the lizard Anolis carolinensis in vitro. The colour changes were registered photoelectrically as changes in reflexion of green monochromatic light. Synthetic α-MSH (CIBA-Geigy Ltd) was used as standard. The method can detect MSH activity at a concentration down to 0·01–0·05 ng α-MSH/ml, and allows the detection of MSH activity in normal rat plasma. The mean precision of the assay λ is about 0·13. This assay thus combines high sensitivity with good precision, and is also comparatively rapid, easy to handle and inexpensive.
ACUTE DEPLETION OF THE HORMONAL-IODINE STORES FROM THE THYROID GLAND AFTER BIRTH IN LAMBS
Authors: ŚLEBODZIŃSKI A.
Published: December 2008

Hormonal iodine metabolism was studied in newborn lambs born to sheep which had been injected with 131I 3–11 days earlier. A rapid outflow of the pre-formed foetal hormone occurred immediately after birth causing a loss of 41% of the pre-formed hormone within 15 min and a loss of 60% of iodine pre-accumulated in thyroglobulin 5 h later (as revealed by histochemistry). Postnatal hypersecretion was followed by a short-lived rise in serum protein-bound iodine and free thyroxine (measured indirectly).

Assuming that thyrotrophin (TSH) is a major stimulator of the thyroid secretory activity in the newborn lamb, the sequence of events indicates that the enhanced TSH and thyroxine release begins as a result of the stress of parturition rather than as a result of body-cooling thereafter.
EFFECTS OF PINEALECTOMY, CONSTANT LIGHT AND DARKNESS ON GROWTH HORMONE LEVELS IN THE PITUITARY AND PLASMA OF THE RAT
Authors: RELKIN R.
Published: December 2008

The effects of constant light, constant darkness, and diurnal lighting, in combination with pinealectomy or sham pinealectomy, on pituitary and plasma concentrations of radio-immunoassayable growth hormone (GH) were investigated in 23- to 24-day-old male rats. In addition, the effects on pituitary, accessory sex organ, testes, adrenal and body weights, as well as tail length, were measured. Three days after operation random groups of pinealectomized and sham-pinealectomized animals were placed in either continuous light, continuous darkness or diurnal light, and killed 28–29 days later. Analysis of the results revealed that the sham-pinealectomized group exposed to constant darkness differed from the other five groups by showing lower pituitary and plasma GH concentrations, body weight, tail length and accessory sex organ weight relative to body weight and testes weight. No statistically significant differences were found in pituitary or adrenal weights. It is concluded that increased pineal function occurring in darkness probably inhibits secretion of GH releasing factor, decreasing pituitary synthesis and release of GH.
STIMULATION BY OVINE PROLACTIN OF FLUID TRANSFER IN EVERTED SACS OF RAT SMALL INTESTINE
Authors: RAMSEY D. H. , BERN H. A.
Published: December 2008

Ovine prolactin injected subcutaneously for 2 days stimulated an increase in fluid uptake in vitro by everted gut sacs from male Sprague—Dawley rats. Four intestinal segments from each rat were incubated, but only two of the four segments tested showed a prolactin-stimulated increase in fluid transfer in intact rats. In adrenalectomized—nephrectomized rats all four sacs showed an increased fluid transfer after prolactin treatment. Sacs incubated for 1 h in glucose—Ringer solution containing 0·1 mg ovine prolactin/ml did not show an increased water transfer as compared with controls incubated in medium containing albumin. Dietary changes seemed to alter the sensitivity of the gut to prolactin.
METABOLISM OF PORCINE, HUMAN AND SALMON CALCITONIN IN THE RAT
Authors: de LUISE M. , MARTIN T. J. , GREENBERG P. B. , MICHELANGELI V.
Published: December 2008

Whereas the liver is the major site of accumulation of 125I-labelled porcine calcitonin soon after injection in the rat, both human and salmon calcitonin were rapidly taken up in rat kidney, with relatively insignificant amounts found in the liver.

In-vitro studies of degradation of 125I-labelled calcitonins showed that human calcitonin was readily degraded by most rat tissues but the major activity was found in a kidney microsomal fraction, whereas the liver supernatant was most active towards pig calcitonin. Salmon calcitonin was resistant to breakdown by all tissues and fractions except the kidney microsomal fraction, which rapidly degraded it to trichloroacetic acid-soluble fragments. Liver homogenates from a number of mammalian and non-mammalian species degraded pig calcitonin but had little effect on salmon calcitonin.

The results show that the kidney is the most important organ in the metabolism of human and salmon calcitonin in the rat, while confirming that the liver is mainly responsible for the metabolism of porcine calcitonin.
RNA SYNTHESIS IN THE MOUSE OVIDUCT AND UTERUS: VARIATIONS BEFORE, DURING AND AFTER ZYGOTE TRANSPORT
Authors: BRONSON F. H. , HAMILTON T. H.
Published: December 2008

Two experiments were performed to examine variations in whole-organ concentrations of RNA, DNA and protein, and specific activities of RNA in vivo in the mouse oviduct and uterus during the oestrous cycle and early pregnancy. Concentrations of DNA did not vary in the oviduct at any stage of the reproductive cycle in either study. In the first experiment with Yale Swiss mice, the concentration of RNA in the oviduct was highest at pro-oestrus, somewhat lower at mid-day of oestrus, and lowest on days 2, 4 and 12 after insemination. Concentrations of RNA were essentially identical in the oviducts of inseminated and non-inseminated females at mid-day of the day following ovulation. The second experiment, using CF-1 mice, confirmed these results, and, in addition, examined oviducal and uterine uptake and incorporation of [3H]uridine. Incorporation of the radioactive precursor into RNA was highest in the oviduct at mid-day of pro-oestrus, was markedly decreased before ovulation, and remained relatively low during the period of egg transport in both inseminated and non-inseminated mice. Most of the RNA necessary for appropriate oviducal function during zygote transport, therefore, is synthesized well before ovulation, and relatively little is formed during the 3 days of tubal residence. The general pattern of incorporation of [3H]uridine into RNA in the uterus appeared basically similar to that shown by the oviduct, except at mid-pregnancy when transcriptional activity of the oviduct genome was relatively low. The two organs also differed markedly in the magnitude of the pro-oestrous surge in RNA synthesis and accumulation, with the uterus showing a greater increase.
THE EFFECT OF AGE, SEX, PREGNANCY, OESTROGEN AND PROGESTOGEN ON RAT SERUM PROTEINS
Authors: HORNE C. H. W. , FERGUSON J.
Published: December 2008

Using a radial immunodiffusion technique the levels of four serum proteins, albumin, transferrin, slow α1-globulin and γ2-globulin, were measured in normal rats to determine the effects on these proteins of age, sex, pregnancy and of the administration of oestrogen (mestranol) and progestogen (ethynodiol diacetate). Significant increases in albumin, slow α1-globulin and γ2-globulin were found with increasing age, and highly significant differences in albumin and slow α1-globulin occurred between male and female rats. During pregnancy significant increases in slow α1-globulin and transferrin were found but albumin and γ2-globulin concentrations fell. Oestrogen administration resulted in significant increases in slow α1-globulin and transferrin, but albumin and γ2-globulin were unaltered. In the progestogen-treated group the concentrations of all four proteins were unchanged.
THE EFFECTS OF FOETAL THYROIDECTOMY ON THE DEVELOPMENT OF THE OVINE FOETUS
Authors: HOPKINS P. S. , THORBURN G. D.
Published: December 2008

Thyroid glands were surgically ablated from foetal sheep between 81 and 96 days of gestation in order to study the role of the thyroid gland in foetal development. Gestation of ewes bearing thyroidectomized foetuses was prolonged by about 5 days, and athyroid lambs failed to survive more than 24 h. Athyroid foetuses delivered by Caesarian section 1 week before term were characterized by low body weight, low thymus gland weight, and shortened limbs. Foetal thyroidectomy markedly retarded both the maturation and growth of wool follicles and osseous tissue.

Plasma concentrations of growth hormone, calcium and phosphorus were normal in the athyroid foetuses, but cholesterol levels were increased. The absence of thyroxine in the foetal circulation agrees with previous findings that the ovine placenta is impermeable to maternal thyroxine.
THE EFFECT OF OESTROGENS ON THE RESPONSE OF BONE TO PARATHYROID HORMONE IN VITRO
Authors: ATKINS D. , ZANELLI JOAN M. , PEACOCK M. , NORDIN B. E. C.
Published: December 2008

An organ culture system was used to examine the effects of oestrogens on the response of 5-day-old mouse calvaria to parathyroid hormone (PTH). Parathyroid hormone released calcium and phosphate from the bone and this was associated with an increase in glucose consumption, an accumulation of citric acid and an inhibition of citrate oxidation. Oestradiol, oestriol, oestrone and ethinyl oestradiol all inhibited the PTH-induced release of calcium. The accumulation of citrate was prevented without the PTH-induced block on citrate oxidation being removed, and this was explained in terms of a reduction in glycolysis. Oestradiol, oestriol and oestrone appeared to be of equal potency. However, ethinyl oestradiol was active at much lower doses but appeared to be toxic at higher levels.
SECRETION OF PROLACTIN AND LUTEINIZING HORMONE AT OESTRUS IN THE EWE
Authors: CUMMING I. A. , BROWN JOAN M. , GODING J. R. , BRYANT GILLIAN D. , GREENWOOD F. C.
Published: December 2008

Studies of the effect of mating on the release of prolactin over a 47-h period from the onset of oestrus in the ewe are presented. Surges of prolactin occurred around the time of pre-ovulatory luteinizing hormone release, and in some instances copulation appeared to result in an additional surge of prolactin secretion.
THE INFLUENCE OF SERUM ON UPTAKE, CONVERSION AND ACTION OF TESTOSTERONE IN RAT PROSTATE GLANDS IN ORGAN CULTURE
Authors: LASNITZKI ILSE , FRANKLIN HILARY R.
Published: December 2008

Explants of ventral rat prostates were incubated with [1,2-3H]testosterone in media (1) without serum, (2) with horse or calf serum, and (3) with human male or human pregnancy serum. With all sera the uptake of testosterone fell with rising serum content. At the same concentration, the uptake of testosterone and the amounts of dihydrotestosterone and androstanediol formed were significantly lower in explants incubated with pregnancy serum than in those incubated with male serum. Since testosterone binding is markedly higher in pregnancy than in male serum it was concluded that only the free unbound form of the hormone may be available to the target tissue. This was supported by findings that the degree of maintenance by testosterone in prostatic explants grown for 6 days without serum, or in the presence of either male or pregnancy serum, was closely related to the uptake and metabolism of testosterone under these three conditions.

The results suggest that the degree of testosterone binding regulates the supply of hormone to the target organ and, thus, influences its biological action.
STUDIES ON THE MECHANISM OF ACTION OF ANGIOTENSIN ON FLUID TRANSPORT BY THE MUCOSA OF RAT DISTAL COLON
Authors: DAVIES N. T. , MUNDAY K. A. , PARSONS B. J.
Published: December 2008

A study was made of the effects of cyclic AMP, theophylline, cycloheximide, puromycin and actinomycin D on the stimulation by angiotensin of fluid transport by sacs of rat colon mucosa.

Cyclic AMP and theophylline, added together or separately, had no effect on fluid transport by colon sacs, suggesting that the stimulation of fluid transport after the application of angiotensin is not mediated through cyclic AMP. Cycloheximide and puromycin (used at concentrations which block colon protein synthesis by 50–90%) had no effect on fluid transport by control colon sacs, but completely blocked the stimulatory response of the colon to angiotensin. In contrast, actinomycin D (at a concentration which significantly inhibits RNA synthesis) did not affect fluid transport in control or angiotensin-stimulated colon sacs. The results are discussed in relation to the possibility that protein synthesis, at the stage of translation, is involved in the action of angiotensin on fluid transport by the colon.
GLUCAGON RELEASE FROM THE PANCREAS OF THE NEWBORN RAT
Authors: EDWARDS J. C. , ASPLUND K. , LUNDQVIST G.
Published: December 2008

A solid phase radioimmunoassay for glucagon was specially modified in order to overcome the problems involved in the measurement of glucagon release from incubated pieces of pancreas. The modified immunoassay procedure was used to study glucagon release from pieces of pancreas taken from newborn rats aged from 1 to 20 days. The glucagon content of rat pancreas was also measured during this period.

It was found that glucagon release from rat pancreas was stimulated by arginine and inhibited by octanoic acid at 1 and 2 days of age. However, glucagon release at 3 days of age was low, and between 3 and 7 days of age glucagon release could not be inhibited by octanoic acid or stimulated by arginine. At 10 and 20 days of age, the stimulatory action of arginine and the inhibitory action of octanoic acid were again noted. Glucagon release, measured at several ages, was not significantly affected by changes in glucose concentration. The glucagon content of the rat pancreas rose to a maximum at 5 days of age and then decreased gradually over a period of 90 days.

It is suggested that the low rate of glucagon release between 3 and 7 days of age may be a result of the high levels of blood fatty acids and ketone bodies found in the rat during this period.
THE OLFACTORY RESPONSE OF MICE TO URINE AND EFFECTS OF GONADECTOMY
Authors: DAVIES V. JANE , BELLAMY D.
Published: December 2008

Using a standard arena technique, the reactions of groups of albino mice were noted in response to traps baited with urine. The response was measured in terms of latency, duration of investigatory visit, total investigation time and number of visits.

Because of a high level of variability between individuals, many of the results were not significant, but it was demonstrated that urine contained olfactory attractants and there was a suggestion that it might also contain repellents. Animals showed a positive response to traps baited with urine from the opposite sex and where there was a difference in response to urine produced during the night and urine produced during the day, 'night' urine generally elicited a stronger response than 'day' urine. Males reacted negatively to male urine, whereas females were more strongly attracted to female urine than to male urine. The attractiveness of female urine to male mice, as measured by duration of investigatory visit, was increased twofold during pregnancy and threefold during oestrus. Oestrous urine tended to be more effective than dioestrous urine. Female urine stored at −10 °C was more attractive to male mice than fresh female urine. After prepubertal castration, males showed no preference for oestrous urine over dioestrous urine. Both normal and prepubertally castrated males, however, spent less time sniffing urine from spayed females than urine from females in oestrus or from non-oestrous females. There was evidence that intact male mice spent more time investigating female urine odours than did castrated mice, but this did not apply to dioestrous urine.
ADRENAL AND TESTICULAR CONTRIBUTION TO PLASMA OESTROGENS
Authors: SAEZ JOSÉ M. , MORERA ANNE M. , DAZORD ALICE , BERTRAND JEAN
Published: December 2008

The concentration of oestrone (E1) and oestradiol (E2) in plasma was measured by a radioimmunological method. In five premenopausal women, ovariectomy provoked a significant fall in the concentrations of E1 and E2. In 11 subjects of both sexes with cancer, dexamethasone (20 μg/kg/day) caused a significant fall in the levels of cortisol (84 ± 9·5%) and E1 (55 ± 16%), but not in E2 (2 ± 18%). Ninety minutes after administration of tetracosactrin, the increase in concentration of cortisol (80 ± 30%) and of E1 (70 ± 49%) was highly significant: that of E2 (5 ± 12%) was not. Similar results were observed in four subjects during infusion of corticotrophin. In six subjects, plasma concentration of E1, androstenedione and dehydroepiandrosterone was higher in the adrenal vein than in a peripheral vein, but the concentration of E2 and of testosterone was similar in the two samples. In two men, the concentration of androgens and oestrogens was measured in plasma from a peripheral vein and in plasma of mixed origin from the renal and the spermatic vein. The level of E2 was higher in plasma from the renal—spermatic mixture than in that from the peripheral vein, but the concentration of E1 was similar. All these results suggest that: (1) the adrenal secretes only 17-oxo androgens and oestrogens whereas in the testicular secretion, 17β-hydroxylated compounds predominate; (2) in men, nearly all of the E2 is secreted directly or indirectly by the testes, but the main source of E1 is the adrenal; (3) in postmenopausal women, most of the E1 also derives from the adrenal gland.
THE ZONA GLOMERULOSA AND CORTICOTROPHIN: A GENETIC STUDY IN MICE
Authors: SHIRE J. G. M. , STEWART J.
Published: December 2008

CBA/FaCam mice have adrenals with a well-developed zona glomerulosa. This zone is poorly developed in mice of the Peru strain, although the production of aldosterone is similar in the two strains. The zona glomerulosa was considerably reduced in CBA mice treated with synthetic corticotrophin (ACTH). In these mice degeneration of the adrenal X zone took the form typical of Peru mice. Treating Peru mice with dexamethasone resulted in the appearance of a wide zona glomerulosa, presumably as a consequence of lowered levels of ACTH in plasma. The hypothesis of relatively high levels of ACTH in Peru mice also received support from the relatively small spleens and large adrenals found in mice of this genotype. A significant negative correlation existed between the width of the zona glomerulosa and the weight of cortical tissue for the two strains and their F1 hybrid. This correlation did not, however, hold for mice of the genetically heterogeneous backcross generations. Thus the variation in the histological appearance of the subcapsular tissue was not causally related to differences in the mass of steroidogenic tissue.

The relationships between the visibly differentiated zona glomerulosa, the cells that produce aldosterone, and their control systems are discussed in the light of theories about the relationship between structure and function in the adrenal glands.
EFFECT OF GLUCAGON ON BONE COLLAGEN METABOLISM IN THE RAT
Authors: KALU D. N. , HILLYARD CARMEL , FOSTER G. V.
Published: December 2008

The effect of glucagon on bone was studied in rats. Urinary hydroxyproline excretion and incorporation of [3H]proline into bone hydroxyproline were used as indices of bone collagen breakdown and formation respectively. Parathyroid extract (15 USP units/rat/h, i.v.), infused into thyroparathyroidectomized animals, increased urinary hydroxyproline excretion. This increase was nullified by simultaneous administration of glucagon (50 μg/rat/h, i.v.). Rats treated with glucagon for 12 days (30 μg/100 g/day, s.c.) excreted slightly less hydroxyproline in their urine than controls. In both intact and thyroparathyroidectomized rats, glucagon (10 μg/100 g/h, s.c.) decreased incorporation of [3H]proline into bone. Similar results were obtained in nephrectomized rats, evidence that changes produced by glucagon were not solely due to alterations in proline pool size caused by increased renal excretion. From these data it is concluded that: (1) glucagon can inhibit bone resorption (the effect being slight in normal rats, but easily demonstrable in parathyroid hormone-treated thyroparathyroidectomized rats), (2) release of endogenous calcitonin is not required to produce this effect, (3) parathyroid hormone and glucagon may act on the same target cell in bone, (4) inhibition of skeletal resorption may contribute to glucagon-induced hypocalcaemia, and (5) the hormone possibly decreases bone formation. Since pharmacological doses of glucagon were used in our studies, the relationship of the observations made to the physiological role of glucagon is unknown.