bluuebunny/crossref_metadata_2025_split huggingface dataset:
ADRENOCORTICAL FUNCTION IN A PROTOTHERIAN MAMMAL, TACHYGLOSSUS ACULEATUS (SHAW)
Authors: SERNIA C. , McDONALD I. R. 
Published: December 2008

SUMMARY
The peripheral plasma concentrations and production rates of corticosterone and cortisol were measured in the conscious, unrestrained echidna (Tachyglossus aculeatus) under basal conditions and during maximal ACTH stimulation.
Using Sephadex LH-20 column chromatography and radioligand assay, only cortisol and corticosterone could be detected in the peripheral blood plasma at very low concentrations of 0·07 ± 0·03 (s.e.m.) μg/100 ml and 0·14 ± 0·07 μg/100 ml respectively. Two-hourly sampling over periods of 36–48 h disclosed a diurnal periodicity in the combined plasma concentration of these corticosteroids, the high concentrations corresponding to periods of behavioural activity. Marked, short-term fluctuations in plasma corticosteroid concentration were also observed during periods of more frequent (20 min) sampling. Constant rate i.v. infusion of synthetic ACTH increased the plasma concentrations of both steroids to maximal values of 0·42 ± 0·23 μg cortisol/100 ml and 1·06 ± 0·56 μg corticosterone/100 ml at infusion rates of 1 i.u. ACTH/kg/h. This is approximately 1/160 of the potency of this ACTH in man.
The production rates of corticosterone and cortisol, measured by isotope dilution during constant rate i.v. infusion of 3H-labelled tracers, were only 0·35 ± 0·21 and 0·56 ± 0·26 μg/kg/h respectively during saline infusion, and increased to 2·86 ± 3·47 and 2·74 ± 2·07 μg/kg/h during the infusion of 1 i.u. ACTH/kg/h. The metabolic clearance rate of cortisol was greater than that of corticosterone and both were depressed by ACTH.
Plasma corticosteroid concentrations were increased after surgery during ether anaesthesia and in sick animals with heavy worm infestation. It is concluded that the adrenal cortex of echidnas responds to ACTH stimulation and stress in a similar way to eutherians, but the level of activity is much lower.
TEMPORAL RELATIONSHIPS BETWEEN THE DIURNAL RHYTHM OF HYPOTHALAMIC CORTICOTROPHIN RELEASING FACTOR, PITUITARY CORTICOTROPHIN AND PLASMA CORTICOSTERONE IN THE RAT
Authors: IXART GUY , SZAFARCZYK ALAIN , BELUGOU JEAN-LUC , ASSENMACHER IVAN 
Published: December 2008

SUMMARY
Plasma corticosterone (fluorometric assay), pituitary ACTH (bioassay using isolated adrenal cells) and hypothalamic corticotrophin releasing factor (CRF) (bioassay using isolated pituitary cells) were measured singly in groups of six female rats which were killed at 11.00, 15.00, 19.00, 21.00, 23.00, 01.00, 03.00, 05.00, 07.00 and 11.00 h, after 5 weeks of adaptation to a photoperiod of 12 h light:12 h darkness. Locomotor activity was recorded continuously, using actographic cages, and the waking/sleep pattern was recorded by electroencephalography from chronically implanted control rats during the first hours of the light span.
The three hormones measured fluctuated with a 24 h rhythmicity, with extreme values ranging between 4·12 ± 1·42 and 31·78 ± 194 (s.e.m.) μg/100 ml for corticosterone, 4486 ± 269 and 16629 ± 882μu./mg pituitary for ACTH, and 439 ± 20 and 1270 ± 39μu. ACTH production/hypothalamus/105 pituitary cells.
The onset of the ascending phase of the rhythm started during the first 2 h of light for CRF, 2 h later for ACTH, and again 2 h later for corticosterone. Similarly, the estimated acrophase of the rhythms occurred respectively, 9·4 (CRF), 10·3 (ACTH) and 14·4 h (corticosterone) after onset of light. These phase relationships point to a central origin of the adrenal rhythm.
The diurnal activation of CRF at the very beginning of the light phase was concomitant with an almost immediate reduction of the locomotor activity and onset of sleep. These correlations favour the hypothesis of a common temporal control of both the adrenal and the sleep/waking rhythms.
HYPOTHALAMIC LUTEINIZING HORMONE RELEASING FACTOR AND CORTICOTROPHIN RELEASING ACTIVITY IN RELATION TO PITUITARY AND PLASMA HORMONE LEVELS IN MALE AND FEMALE RATS
Authors: CHIAPPA SHARON A. , FINK G. 
Published: December 2008

SUMMARY
Hypothalamic corticotrophin releasing (CR) activity and LH-releasing factor (RF) content, and pituitary and plasma LH, FSH and ACTH were measured in adult male and female Wistar rats maintained under 14 h light per day. Hypothalamic LH-RF and pituitary and plasma hormones were estimated by radioimmunoassay while CR-activity was assessed by the amount of ACTH released from hemipituitaries in vitro. Two experiments were carried out on male animals. In the first, some of the animals were kept in a room, distant from the animal house, in which the lighting was reversed with respect to the external environment. In animals exposed to the reversed lighting régime, hypothalamic LH-RF content and pituitary gonadotrophin concentrations were significantly lower than the values in male rats kept in the animal house where they were in close proximity to female rats. In the second experiment, which was carried out on animals which had all been kept in the animal house, there were no significant differences between the LH-RF contents measured at 3–4 h intervals throughout the day. Pituitary LH and FSH contents, but not concentrations, were significantly increased at 12.00 h. There was little difference between the experiments in CR-activity, plasma ACTH concentrations and profiles of pituitary ACTH content and concentration. As expected there was a diurnal rhythm in plasma corticosterone concentrations (determined by competitive protein-binding assay) with the peak occurring between 15.00 and 18.00 h. The profiles of plasma and pituitary ACTH were similar to that of plasma corticosterone. Corticotrophin releasing activity dropped significantly between 12.00 and 16.00 h, but remained steady at the other times.
CHANGES IN THE CONCENTRATION OF ADRENOCORTICOTROPHIN AND CORTICOSTEROID IN THE PLASMA OF FOETAL SHEEP IN THE LATTER HALF OF PREGNANCY AND DURING LABOUR
Authors: JONES C. T. , BODDY K. , ROBINSON J. S. 
Published: December 2008

SUMMARY
The changes in plasma ACTH concentration of pregnant sheep and their foetuses during the latter half of pregnancy and during labour were studied. Before 140 days of gestation the mean concentration in foetal arterial plasma was 117 ± 19 (s.e.m.) pg/ml which rose to a mean of 286 ± 63 pg/ml. The rise in ACTH occurred at about the same time as, but not before, the rise in corticosteroid concentration in foetal plasma. The maternal plasma ACTH concentration did not change during the latter half of pregnancy and had a mean concentration of 64 ± 9 pg/ml. During labour there was a progressive rise in the ACTH concentration in foetal plasma which was not associated with any corticosteroid changes. Ethanol did not suppress labour but reduced the ACTH concentration in foetal plasma.
INFLUENCE OF OXYGEN TENSION ON SOMATOMEDIN ACTIVITY IN VITRO
Authors: DEHNEL JENNIFER M. , HAMBLEN D. L. 
Published: December 2008

SUMMARY
Somatomedins are the intermediaries through which growth hormone acts on the epiphyseal growth plate to effect linear skeletal growth.
Rat epiphyseal chondrocytes were isolated and cultured in vitro in the presence of somatomedin. Two sources of somatomedin were used, foetal calf serum and rat liver perfusates. The chondrocytes proliferated and synthesized sulphated glycosaminoglycans when grown in the presence of somatomedin from either source, but were not metabolically active in chemically defined medium alone. Some differences in the growth patterns in response to serum or liver somatomedins are reported and discussed.
Chondrocyte metabolic activity in the presence of somatomedin in vitro showed a graded response to alterations in the atmospheric oxygen, being greatest at low oxygen pressure, and almost completely inhibited at 95% oxygen. A gradient of local oxygen tension has been reported to exist across the epiphyseal plate in vivo. The effects of somatomedin combined with changing oxygen levels may help to explain the divergence of cell proliferation and matrix synthesis seen in the various regions of the growth plate.
PLASMA LEVELS OF HUMAN CHORIONIC SOMATOMAMMOTROPHIN, PROGESTERONE, UNCONJUGATED OESTRADIOL AND OESTRIOL, AND α-FOETOPROTEIN IN PATIENTS WITH HYDATIDIFORM MOLES
Authors: MIYAKAWA I. , YAGI K. , NAKAYAMA M. , MATSUO I. , MAEYAMA M. 
Published: December 2008

SUMMARY
Human chorionic somatomammotrophin (HCS), progesterone, and unconjugated oestradiol and oestriol were measured in the plasma of 13 patients with intact hydatidiform moles from week 9 to 19 of pregnancy and in 89 normal women from week 5 to 20 of pregnancy. Plasma α-foetoprotein (AFP) was also measured in 9 out of 13 patients and in 23 of the normal women from week 13 to 20 of pregnancy. All the compounds were measured by radioimmunoassay. The plasma HCS concentration in 35 samples from 13 patients with hydatidiform moles ranged from 10 to 910 ng/ml; this was lower than that in normal pregnancy of corresponding duration in eight patients, within the normal range in four patients and high in one patient. The plasma progesterone concentration ranged from 17·5 to 79·2 ng/ ml: it was higher than that in normal pregnancy in eight patients and within the normal range in five patients. The plasma unconjugated oestradiol concentration ranged from 1·82 to 8·10 ng/ml: it was higher than normal in six patients and within the normal range in seven patients. The plasma unconjugated oestriol concentration ranged from 0·168 to 1·37 ng/ml, the levels at 15–19 weeks of gestation being significantly lower than those in normal pregnancy at this time (P < 0·005). Plasma AFP was not detectable in the nine patients (< 10 ng/ml) whereas it ranged from 10 to 80 ng/ml in 18 out of 23 women in week 13–20 of normal pregnancy. The present results suggest that both plasma oestriol and AFP could be helpful in the diagnosis of hydatidiform mole at about 12–14 weeks though diagnosis could not be made with absolute certainty.
SIMULTANEOUS INFUSION OF PROSTAGLANDIN E2 ANTAGONIZES THE LUTEOLYTIC ACTION OF PROSTAGLANDIN F2α IN VIVO
Authors: HENDERSON K. M. , SCARAMUZZI R. J. , BAIRD D. T. 
Published: December 2008

SUMMARY
Corpora lutea of ewes bearing ovarian autotransplants were infused for 4 h with prostaglandin F2α (PGF2α) (10 μg/h), PGF2α + PGE2 (10 μg/h of each), PGE2 (10 μg/h) or saline on day 10 of the cycle. Ovarian venous blood obtained before, during, and up to 12 h after the infusion period, was assayed for progesterone. Prostaglandin F2α produced an immediate, rapid and sustained decline in progesterone secretion, but infusion of PGE2 together with PGF2α prevented the decline until after the infusion. Progesterone secretion was unaffected by infusion of PGE2 alone. Oestrous behaviour was observed in four out of seven animals infused with PGF2α but in only one out of six infused with PGF2α + PGE2. None of the animals infused with PGE2 alone or saline only came into heat.
EFFECT OF SEX AND AGE AT GONADECTOMY ON THE SEBACEOUS RESPONSE TO PROGESTERONE
Authors: SHUSTER SAM , HINKS WENDY M. , THODY A. J. 
Published: December 2008

SUMMARY
The effect of progesterone on the rate of sebum secretion was examined in intact and gonadectomized rats. In intact, adult, male rats, progesterone administered for 3 weeks decreased sebum secretion; after castration of adult males, progesterone increased sebum secretion and an even greater response occurred in males castrated at 21 days of age. In intact, adult, female rats progesterone slightly increased sebum production. As in the male, the response was affected by the time of gonadectomy, a greater response occurring after spaying at 21 days compared with 10 weeks of age. Thus, the response to progesterone in the adult rat differs in intact males and females and is affected by changes in the endocrine environment induced by gonadectomy, especially near the time of puberty.
DIFFERENCES BETWEEN IN-VITRO AND IN-VIVO POTENCIES OF CORTICOTROPHINS: AN INTERPRETATION IN TERMS OF METABOLIC STABILITY
Authors: McMARTIN COLIN , PURDON GILLIAN E. E. , SCHENKEL LOTTE , DESAULLES PIERRE-A. , MAIER RENÉ , BRUGGER MAX , RITTEL WERNER , SIEBER PETER 
Published: December 2008

SUMMARY
Relative activities of a series of corticotrophin analogues have been measured by means of five different bioassays using the rat.
Similarities in the relative potencies of various ACTH analogues determined using lipolysis or steroidogenesis in vivo and for the lipolytic and steroidogenic responses of fat pads and adrenal slices in vitro emerged and support the concept of a close structural relationship between the ACTH receptors in adipose and adrenal tissues in the rat.
Potencies based on the steroidogenic response of isolated adrenal cells, adrenal slices or in-vivo experiments differed markedly from each other. Inactivation of peptides did not occur in the isolated cell assay, so it is likely that this assay estimates potency at the receptor level. A number of arguments suggest that the difference between the isolated cell assay and the other steroidogenic assays lies solely in the effects of peptide inactivation in the latter, and this allows the relative metabolic stabilities for the peptide analogues in these assays to be calculated. In this way it can be shown that:
(1) Replacement of l-Ser by d-Ser in amino acid position 1 markedly increases the metabolic stability of the peptide and has only a slight effect on receptor properties.
(2) Shortening at the NH2-terminus reduces the activity of peptides at the receptor level by several orders of magnitude, but increases their relative metabolic stability.
(3) Introduction of amide groups at the CO2H-terminus markedly increases receptor potency of (1–16), (1–17) and (1–18) ACTH without affecting their metabolic stability in vivo. However, amidation of the CO2H-terminus does have a large effect on metabolic stability in the adrenal slice assay.
(4) Replacement of Arg by Lys in positions 17 and 18 of (1–18) ACTH increases potency at the receptor level (adrenal cells) but has little effect on metabolic stability.
The comparison of potencies obtained in the various assays, therefore, throws light on the significance of each assay. In addition, the effects of structural modification of analogues can be separately evaluated with respect to the metabolic stability of a peptide and its potency at the receptor level.
CIRCADIAN RHYTHM OF PINEAL UPTAKE OF 32P IN DOMESTIC FOWL
Authors: SACKMAN J. W. 
Published: December 2008

SUMMARY
The uptake of radioactive phosphorus by the pineal gland in White Leghorn cockerels (Gallus domesticus) showed a diurnal variation with maxima in the light phase and minima in the dark phase of the light:dark cycle. Constant light caused the rhythm to disappear while constant dark had no effect other than lowering the amplitude of the variations. These data indicate that the rhythm in pineal uptake of 32P is circadian.
CONCENTRATION OF PROSTAGLANDIN F2α AND STEROIDS IN THE HUMAN CORPUS LUTEUM
Authors: SWANSTON I. A. , McNATTY K. P. , BAIRD D. T. 
Published: December 2008

SUMMARY
The concentration of prostaglandin F2α (PGF2α), progesterone, pregnenolone, oestradiol-17β, oestrone, androstenedione and testosterone was measured in corpora lutea obtained from 40 women at various stages of the menstrual cycle. The concentration of PGF2α was significantly higher in corpora lutea immediately after ovulation (26·7 ± 3·9 (s.e.m.) ng/g, P < 0·005) and in corpora albicantia (16·3 ± 3·3 ng/g, P < 0·005) than at any other time during the luteal phase. There was no correlation between the concentration of PGF2α and that of any steroid. The progesterone concentration was highest in corpora lutea just after ovulation (24·9 ± 6·7 μg/g) and in early luteal groups (25·7 ± 6·8 μg/g) but declined significantly (P < 0·05) to its lowest level in corpora albicantia (1·82 ± 0·66 μg/g). The concentration of oestradiol-17β in the corpus luteum and luteal weight were significantly greater during the mid-luteal phase than at any other stage (concentration 282 ± 43 ng/g, P < 0·05; weight 1·86 ± 0·18 g, P < 0·005).
The results indicate that regression of the human corpus luteum is not caused by a rise in the ovarian concentration of PGF2α in the late luteal phase of the cycle.
SITE OF MODULATORY ACTION OF OESTROGEN AND PROGESTERONE ON GONADOTROPHIN RESPONSE TO LUTEINIZING HORMONE RELEASING FACTOR
Authors: FINK G. , HENDERSON S. R. 
Published: December 2008

SUMMARY
The effect of oestrogen and progesterone on the spontaneous release of gonadotrophins and on the gonadotrophin response to luteinizing hormone releasing factor has been examined in female rats subjected to hypothalamic deafferentation or pituitary stalk section. The results indicate that both steroids act at the level of the medial basal hypothalamus as well as the anterior pituitary gland; progesterone, for its full effect, also requires the integrity of connexions of the hypothalamus with other areas of the brain.
IMMATURE RAT PITUITARY GLANDS IN VITRO: AGE- AND SEX-RELATED CHANGES IN LUTEINIZING HORMONE RELEASING HORMONE-STIMULATED GONADOTROPHIN RELEASE
Authors: DULLAART J. 
Published: December 2008

SUMMARY
Pituitary glands from immature female and male rats aged between 5 and 30 days were incubated in vitro and the effect of LH releasing hormone (RH) on the release of LH and FSH was studied. Pituitary gonadotrophin contents were also measured.
Gonadotrophin release showed changes with age as well as sex differences: after LH-RH stimulation the female pattern of release of LH and FSH (expressed per mg pituitary tissue) showed a peak at day 15; the male pattern of LH release was characterized by a steady increase with age, whereas FSH release stayed more or less constant from day 10 onwards. In both sexes the LH:FSH ratio increased with age, both in pituitary gonadotrophin content and in the mixture of gonadotrophins released. It is discussed, that the prepubertal development of pituitary gonadotrophic function might be determined on the one hand by rather autonomous growth processes (more or less similar in female and male hypophyses) and on the other hand by modulating influences of sex steroid hormones, which are different in female and male animals.
RAT FOETAL ENDOCRINE PANCREAS IN EXPERIMENTAL DIABETES
Authors: AERTS L. , VAN ASSCHE F. A. 
Published: December 2008

SUMMARY
The endocrine pancreas of foetuses and newborn rats of experimental diabetic mothers showed morphological and ultrastructural changes. Islet hypertrophy and β cell hyperplasia were constantly present, but the β cells of foetuses of severely diabetic mothers were degranulated. The ultrastructural changes indicated hyperfunction in the β cells of foetuses of experimental diabetic mothers. The morphological changes mentioned were similar to those seen in human diabetic pregnancy.
STEROIDS IN THE AMNIOTIC FLUID OF THE RHESUS MONKEY (MACACA MULATTA)
Authors: CHALLIS J. R. G. , HARTLEY PHILLIDA , JOHNSON P. , PATRICK J. E. , ROBINSON J. S. , THORBURN G. D. 
Published: December 2008

SUMMARY
Representative C21, C19 and C18 steroids have been measured in the amniotic fluid and maternal femoral plasma of rhesus monkeys during the last 50 days of pregnancy. The concentrations of cortisol, progesterone, androstenedione, oestrone and oestrone sulphate all increased in amniotic fluid before spontaneous parturition. In contrast, amniotic fluid oestradiol levels remained low and unchanged, and were always less than the concentrations in the maternal plasma. The changes in progesterone, cortisol and oestrone concentrations in amniotic fluid occurred independently of significant changes in the concentration of these steroids in the maternal plasma.
Betamethasone administered to monkeys after day 150 of pregnancy suppressed amniotic fluid and maternal plasma cortisol. This treatment markedly suppressed the concentration of progesterone in amniotic fluid, but did not alter its concentration in maternal plasma. It is concluded that during late pregnancy in the rhesus monkey there is an increase in the concentration of some steroids in amniotic fluid independent of alterations in their concentrations in maternal plasma. These changes could reflect an increase in foetal adrenal steroid secretion.
BIOLOGICAL ACTIONS OF HUMAN SOMATOTROPHIN AND ITS DERIVATIVES ON MOUSE MAMMARY GLAND AND TELEOST URINARY BLADDER
Authors: DONEEN B. A. , BERN H. A. , HAO LI CHOH 
Published: December 2008

SUMMARY
These studies are concerned with the structural and functional evolution of the ancestrally related pituitary prolactins and somatotrophins. Prolactin-like biological activities of human somatotrophin (hGH) and its peptide fragments were bioassayed in vitro on the mouse mammary gland and the teleost urinary bladder. Plasmin modified-hGH was as active as hGH in both bioassays. The NH2-terminal 134-residue fragment possessed about 10% of the lactogenic and urinary bladder potency of hGH, whereas the CO2H-terminal 51-residue fragment was inactive at the concentrations observed. These results suggest that the same regions of primary structure are responsible for the prolactin-like actions of hGH on the target organs of lower and higher vertebrates. Alteration of the tertiary structure of hGH, human chorionic somatomammotrophin, and ovine prolactin by performic acid oxidation destroys the mammary gland activities of these hormones.
TEMPORAL CHANGES IN OVARIAN ORNITHINE DECARBOXYLASE AND CYCLIC AMP IN IMMATURE RATS STIMULATED BY EXOGENOUS OR ENDOGENOUS GONADOTROPHINS
Authors: JOHNSON D. C. , SASHIDA TATSURO 
Published: December 2008

SUMMARY
Pregnant mare serum gonadotrophin given intravenously to immature rats caused a maximal (×70) increase in ornithine decarboxylase activity (ODC) at 3 h; enzyme activity declined to about ten times the control level by 9 h and a second rise began after about 20 h. Anti-PMSG given 30 min after PMSG reduced the peak response by 70%. Actinomycin D, or cycloheximide, completely prevented an increase in ODC when given with PMSG, but only cycloheximide lowered the enzyme activity when given 18 h later.
Ovine FSH plus LH also produced a peak in ODC at 3 h but the activity decreased quickly and by 9 h it was at the control level. Secretion of endogenous FSH and LH, induced by hourly injections of LH releasing hormone (LH-RH) increased ODC to the same extent as did the exogenous hormones; ODC was still higher than in the controls 4 h after the last dose of LH-RH.
Increased endogenous levels of FSH and LH did not consistently raise ovarian cyclic AMP content and the increases found were much less than those obtained after injection of PMSG or FSH + LH.
The results indicate that increased ODC is induced and maintained by the continual presence of gonadotrophin. The dependence of increased ODC upon increased cyclic AMP cannot be unequivocally determined because of important differences in the timing of the responses and the difficulty in determining biologically significant changes in cyclic AMP.