bluuebunny/crossref_metadata_2025 huggingface dataset:
PHOTOPERIODIC CONTROL OF SEASONAL BREEDING IN THE RAM: PARTICIPATION OF THE CRANIAL SYMPATHETIC NERVOUS SYSTEM
Authors: LINCOLN G. A.
Published: December 2008

Four mature Soay rams, cranially sympathectomized by removal of the superior cervical ganglia, were housed alongside four normal rams in controlled lighting conditions of alternating 16 week periods of short days of 8 h light: 16 h darkness (8L: 16D) and long days (16L: 8D). The changes in the concentration of FSH, LH, prolactin and testosterone in the plasma, the size of the testes, the intensity of the sexual flush and the sexual and aggressive behaviour of the animals were recorded.

While the control rams were able to respond to the artificial lighting conditions with synchronized cycles of reproductive activity, the ganglionectomized animals failed to respond. The treated rams had well-developed testes and relatively high levels of gonadotrophins and testosterone in the blood throughout the experiment. It is concluded that the cranial sympathetic nervous system is involved in the photoperiodic control of seasonal breeding in the ram, probably through its role in the innervation of the pineal gland.
ROLE OF THE MESENCHYME IN THE INDUCTION OF THE RAT PROSTATE GLAND BY ANDROGENS IN ORGAN CULTURE
Authors: LASNITZKI ILSE , MIZUNO TAKEO
Published: December 2008

Rat prostate glands are induced de novo by androgens in 16·5-day-old male and female urogenital sinuses in vitro as epithelial buds projecting into the surrounding mesenchyme. The role of the mesenchyme in this process has been investigated in various epithelial-mesenchymal recombinations in organ culture.

Isolated epithelium did not form buds but required the presence of the mesenchyme to do so. This requirement seemed to be specific; in the presence of testosterone or dihydrotestosterone only urogenital mesenchyme increased cell division in the urogenital epithelium and stimulated prostatic bud formation. In contrast, heterotypic mesenchyme did not affect epithelial mitosis and failed to induce buds while heterotypic epithelia did not respond to urogenital mesenchyme.

In recombinants of urogenital mesenchyme pretreated with androgen and untreated urogenital epithelium, grown in androgen-free medium, the majority of explants developed prostatic buds while only a few buds were formed from epithelium pretreated with androgen when it was recombined with untreated mesenchyme.

The role of the mesenchyme in the loss of androgen responsiveness of the older female sinuses was examined in heterochronic recombinants. It was found that the old female mesenchyme failed to induce buds in young epithelium while young male or female mesenchymes induced them in the old female epithelium.

The results suggest that the urogenital mesenchyme is essential for the initiation of the foetal rat prostate gland and that it may be a target for androgens and complement or mediate their effect on the epithelium.
EFFECTS OF SURGICAL STRESS AND CORTICOTROPHIN ON THE PERIPHERAL METABOLISM OF THYROID HORMONES IN RABBITS
Authors: RAMSDEN D. B. , SMITH T. J. , BURR W. A. , BLACK E. G. , LEE J. M. , HOFFENBERG R.
Published: December 2008

The effect of surgical stress and ACTH injection on the peripheral monodeiodination of thyroxine (T4) was studied in the rabbit. These stimuli resulted in a switch from the peripheral formation of tri-iodothyronine (T3) to reverse T3 in normal rabbits and in rabbits whose thyroidal secretion was suppressed by administration of T4. This is analogous to the situation in man. These changes were not due to alterations in the serum binding capacity for thyroid hormones.
EFFECTS OF AROMATIZABLE ANDROGENS ON AGGRESSIVE BEHAVIOUR AMONG RATS (RATTUS NORVEGICUS)
Authors: CHRISTIE MARJORIE H. , BARFIELD R. J.
Published: December 2008

Three experiments were used to test the applicability of the aromatization hypothesis of androgen action to aggressive behaviour among Norway rats. In Expt 1, administration of testosterone propionate was highly effective in restoring aggressive behaviour to castrated rats while 17β-hydroxy-5α-androstan-3-one was of intermediate effectiveness. Of the steroids tested in Expt 2, androstenedione and testosterone were highly effective, 17β, 19-dihydroxyandrost-4-en-3-one was of intermediate effectiveness and cholesterol was ineffective. The results of Expt 3 indicated that treatment with testosterone or oestradiol both resulted in increased aggression while treatment with (5α, 17β)-17, 19-bis(acetyloxy)-andostan-3-one diacetate (5α-19-hydroxytestosterone) was without effect. Androgens which were aromatizable and could be 5α reduced, i.e. testosterone, testosterone propionate and androstenedione, were highly effective in restoring aggressive behaviour; however, two other steroids, 5α, 19-hydroxytestosterone which is 5α reduced, and 19-hydroxytestosterone, which can be aromatized, were respectively of low or medium effectiveness on behaviour. However, oestradiol, which did not maintain sexual development of accessory glands, was highly effective in the restoration of aggressive behaviour. Since the behaviourally active steroids in the present experiments were not only those predicted by the aromatization hypothesis, it is proposed that several steroids are capable of activating aggressive behaviour and that the aromatization hypothesis does not adequately explain the hormonal basis of aggressive behaviour among Norway rats.
SERUM PROLACTIN IN THE MALE MOUSE FROM BIRTH TO MATURITY
Authors: BARKLEY M. S.
Published: December 2008

The pattern of prolactin secretion was determined throughout the development of the male mouse. Levels of prolactin were at their lowest from birth to 20 days of age. A dramatic increase in serum prolactin occurred during pubertal maturation coincident with rapid growth of the accessory organ system. These events preceded the pubertal rise in the level of serum testosterone that is characteristic of this species.
CHANGES IN CORTICOTROPHIN RELEASING FACTOR OF THE STALK MEDIAN EMINENCE IN RATS WITH VARIOUS CUTS AROUND THE MEDIAL BASAL HYPOTHALAMUS
Authors: MAKARA G. B. , STARK E. , RAPPAY G. , KÁRTESZI M. , PALKOVITS M.
Published: December 2008

The activity of corticotrophin releasing factor (CRF) in extracts of the stalk median eminence (SME) complex proper (average protein content, 30·6 μg) of male rats was assayed by monolayer cultures of anterior pituitary cells using the release of immunoreactive ACTH. Extracts which were equivalent to 0·025 SME of control rats usually had detectable CRF activity, while there was no detectable activity in extracts of 0·4 SME equiv. taken 8 days after complete surgical isolation of the medial basal hypothalamus (MBH). The activity of CRF in extracts from rats with an anterolateral cut around the MBH was at least ten times less than that in the control rats. One day after placing an anterolateral cut around the MBH the ACTH releasing activity of the SME was not significantly different from that of the control animals but activity decreased significantly 3 days after the operation and was at least ten times less than in the control animals on day 7 after the operation.

It is suggested that most of the CRF activity of the SME is contained in nerve fibres entering the neurohaemal region from outside the MBH and that transection of these fibres produced the fall in CRF content of the SME in rats with partial or total surgical isolation of the MBH.
EFFECT OF NEONATAL ADMINISTRATION OF THYROXINE ON THE RATE OF SEBUM PRODUCTION IN RATS
Authors: TOH YEE CHU
Published: December 2008

Newborn Sprague–Dawley rats of both sexes were treated with 28 μg thyroxine (T4) daily for the first week of life. At the age of 80 days, the secretion rate of sebum was measured from the amount of skin-surface lipids extractable by acetone and which had been produced during 2 days. Treatment with such excess amounts of T4 during the early postnatal period significantly reduced the production of sebum in both male and female rats when compared with control rats and with rats deprived of food early in life. The thyroid, the pituitary gland, the testes and the seminal vesicles were significantly smaller but the weights of the ovaries and uteri remained relatively unaffected. There was a similar ratio of sex difference in the rate of sebum secretion irrespective of treatment. It is suggested that a reduction of sebaceous response in rats made thyrotoxic with large doses of T4 early in life was probably due to a decreased secretion of thyroid hormone which is required to maintain normal activity of the sebaceous glands.
BIOLOGICAL AND BINDING ACTIVITIES OF EQUINE PITUITARY GONADOTROPHINS AND PREGNANT MARE SERUM GONADOTROPHIN
Authors: LICHT PAUL , GALLO ANTONELLA BONA , AGGARWAL B. B. , FARMER SUSAN W. , CASTELINO J. B. , PARKOFF HAROLD
Published: December 2008

The biological and binding activities of pregnant mare serum gonadotrophin (PMSG) were compared with those of highly purified FSH and LH from the pituitary gland of the same species. Pregnant mare serum gonadotrophin showed activity in bioassays considered to be specific for both FSH (e.g. the Steelman–Pohley ovarian augmentation test and cyclic AMP production by rat seminiferous tubules) and LH (androgen production by rat Leydig cells), as well as activity in a variety of radioreceptor assay systems previously considered to be specific for one of the two types of gonadotrophin. The potency of PMSG was high compared with that of purified ovine FSH or LH standards in all assays but PMSG was considerably less active than equine FSH and LH in vitro. In radioreceptor assays employing rat, pig and horse tissues, the activity of PMSG was equivalent to only 1–5% of equine FSH in competing for FSH-binding sites and only 3–35 % of equine LH in competing for LH-binding sites. Pregnant mare serum gonadotrophin was least active in homologous binding assays with horse testis and equine LH as radioligand. In the rat Leydig cell bioassay, the activity of PMSG was only 2·0% that of equine LH. Furthermore, in some assays equine LH was found to resemble PMSG in exhibiting a high degree of FSH-like activity that could not be accounted for by cross-contamination. The FSH immunoactivity of equine LH was less than 0·5% that of equine FSH, but equine LH was up to 63% as potent as equine FSH in competition for FSH-binding sites and it was 20% as active in the Steelman–Pohley ovarian augmentation bioassay. Equine LH did not, however, show the expected activity in the cyclic AMP production bioassay. Thus, the FSH-binding sites and physiological receptors may not be identical. Overall, comparison of PMSG with pituitary gonadotrophins from homologous species shows that the apparent dual activity of PMSG may not be a unique feature of this pregnancy hormone since equine LH also exhibits some FSH activities. The chemical resemblance between PMSG and equine LH is noteworthy in this regard.
DETERMINATION OF TAMOXIFEN AND AN HYDROXYLATED METABOLITE IN PLASMA FROM PATIENTS WITH ADVANCED BREAST CANCER USING GAS CHROMATOGRAPHY–MASS SPECTROMETRY
Authors: DANIEL C. P. , GASKELL S. J. , BISHOP H. , NICHOLSON R. I.
Published: December 2008

An assay has been established for the selective measurement of tamoxifen and its monohydroxy derivative, metabolite B, in human plasma. The assay was used to examine the concentrations of these compounds, relative to oestradiol-17β, in the plasma of patients undergoing tamoxifen therapy for advanced breast cancer. Oral administration of the drug (20 mg twice a day) raised the level of tamoxifen in plasma to approximately 200 ng/ml 20 days after the commencement of treatment. This level was 3000-fold higher than the corresponding concentration of oestradiol which remained within the range for post-menopausal women. Metabolite B was present in plasma at a much lower concentration than tamoxifen although in considerable excess over oestradiol.

The overall results are discussed in relation to the possible mechanism of action of the drug.
PRESENCE OF FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE IN BULL SEMINAL PLASMA
Authors: SAIRAM M. R. , RANGANATHAN M. R. , LAMOTHE P.
Published: December 2008

Levels of FSH and LH were estimated in a crude powder of seminal plasma pooled from bulls. The FSH concentration in the seminal plasma was approximately 100 times greater than that in the circulation. The receptor-binding activity of LH in the seminal plasma was very low compared with that in blood. The FSH in bull seminal plasma was partially purified and found to be identical to ovine pituitary FSH in its ability to bind to bull testicular receptor, in its immunological reactivity and also in its chromatographic and electrophoretic properties. The partially purified LH in bull seminal plasma was more acidic than ovine pituitary LH as shown by disc electrophoresis. It showed low binding characteristics that were not parallel to pituitary LH in the specific radioreceptor assay. The significance of the inverse relationship between the levels of FSH and LH in seminal and blood plasma is unknown.
MEASUREMENT OF TAMOXIFEN IN SERUM BY THIN-LAYER DENSITOMETRY
Authors: ADAM H. K. , GAY M. A. , MOORE R. H.
Published: December 2008

A method is described for the determination of tamoxifen in serum. The drug was extracted from the serum and separated from its metabolites by thin-layer chromatography. Irradiation of the thin-layer plate with ultra-violet light after development converted tamoxifen to a fluorescent product which could be estimated in situ by densitometry. The fluorescent product was identified as a substituted phenanthrene by thin-layer chromatography, and gas chromatography–mass spectrometry. The method allowed concentrations as low as 6·8 nmol/l serum to be measured.

After an oral dose of tamoxifen (10 mg) to a female patient the maximum serum concentration (66·2 nmol/l) was achieved in 3 h. When 10 mg tamoxifen were taken twice daily for 21 days by the same patient serum concentrations of about 500 nmol/l were achieved.
ACTIVATION INDUCED BY LUTEINIZING HORMONE OF TYPE II PROTEIN KINASE DEPENDENT ON CYCLIC ADENOSINE MONOPHOSPHATE AND PHOSPHORYLATION OF SOLUBLE PROTEINS IN PORCINE GRANULOSA CELLS
Authors: HALPREN-RUDER D. H. , JUNGMANN R. A. , GEORGE W. J. , JETER J. R.
Published: December 2008

The present experiments were designed to study whether exogenous LH could elicit acute cyclic AMP-mediated activation of cyclic AMP-dependent protein kinase and phosphorylation of cellular protein in intact porcine granulosa cells.

Incubation of porcine granulosa cells (from 3 to 5 mm diameter follicles) with 2 μg luteinizing hormone/ml (LH) caused a significant rise of cellular cyclic AMP content within 2 min of the addition of LH. The increase was dose-dependent and occurred between doses of 0·2 and 2·0 μg LH/ml. Luteinizing hormone also caused a time- and dose-dependent dissociation of the type II cyclic AMP-dependent protein kinase isozyme in porcine granulosa cells. Luteinizing hormone (0·05–2 μg/ml) significantly dissociated the cyclic AMP-dependent protein kinase between 2 and 30 min after stimulation. The protein kinase dissociation was a specific effect of LH and was not elicited by either adrenocorticotrophic hormone or prolactin. During the period of LH-induced protein kinase activation, several soluble granulosa cell proteins, ranging in molecular weights from about 43 000 to 99 000, became phosphorylated in a time-dependent and hormone-specific manner.

The results suggest that cyclic AMP-mediated activation of granulosa cell type II cyclic AMP-dependent protein kinase may be a prerequisite in the short-term molecular action of LH leading to LH-specific phosphorylation of several soluble granulosa cell proteins of an as yet unidentified function.
INTERNATIONAL REFERENCE PREPARATION OF HUMAN CHORIONIC GONADOTROPHIN FOR IMMUNOASSAY: POTENCY ESTIMATES IN VARIOUS BIOASSAY AND PROTEIN BINDING ASSAY SYSTEMS; AND INTERNATIONAL REFERENCE PREPARATIONS OF THE α AND β SUBUNITS OF HUMAN CHORIONIC GONADOTROPHIN FOR IMMUNOASSAY
Authors: STORRING P. L. , GAINES-DAS ROSE E. , BANGHAM D. R.
Published: December 2008

The preparation and nature of the International Reference Preparation of Human Chorionic Gonadotrophin (HCG) for Immunoassay (IRP), as well as that of a second batch of ampoules (HCG 75/589) prepared identically from the same HCG preparation, are described.

A collaborative study of these materials was carried out by 11 laboratories in eight countries, using different bioassay and immunoassay methods. Using the various in-vivo and in-vitro bioassays and receptor assays, the mean log potency estimates for each method within each laboratory of the HCG content of ampoules of the IRP, in terms of the Second International Standard of Human Chorionic Gonadotrophin for Bioassay (IS), were homogeneous and gave an overall weighted geometric mean (95% confidence limits) of 650 (632–669) International Units (i.u.)/ampoule.

There was considerable heterogeneity of potency estimates of the IRP in terms of the IS both within and between many of the immunoassay systems (reflecting the impurity of the IS), and hence attempts to calibrate the IRP with immunoassay systems of different specificities were invalid.

Immunoassay estimates of the HCG content of preparations of serum and urine, in terms of the IRP, showed considerable heterogeneity between assay systems (although the degree of this heterogeneity was no greater than that observed using the IS as standard), but the ranking order between preparations was consistent.

Confirmation was obtained that contamination of the IRP with HCG-α and HCG-β subunits was insignificant. Accelerated degradation studies of the IRP stored at increased temperatures suggested that its stability under normal storage conditions would be satisfactory.

It was agreed that the IRP was suitable to serve as an international reference preparation for immunoassay, and it was assigned a unitage of 650 i.u./ampoule on the basis of bioassay calibration.

Since the ampoules of HCG (75/589) did not differ significantly from the IRP in any of the assay systems studied, it appeared to be equally suitable as a reference preparation.

The International Reference Preparations of the α and β Subunits of Human Chorionic Gonadotrophin for Immunoassay are also described.
EFFECT OF OVINE LUTEINIZING HORMONE AND PROLACTIN ON PROGESTERONE SECRETION BY GOAT GRANULOSA CELLS IN CULTURE
Authors: MOHINI PREM , RAJ B. J. , CHAPEKAR T. N.
Published: December 2008

Effects of LH and prolactin on cultures of granulosa cells from the goat were analysed in terms of the secretion of progesterone. The cultures were maintained for 120 h during which time they were treated at 24 and 72 h after explantation with LH and prolactin. Progesterone secreted in the culture medium was determined by radioimmunoassay. The secretion of progesterone by the cultures in response to LH and prolactin was significantly increased (P<0·01) compared with that by control cultures. The pattern of steroid secretion in the two cases (LH-treated and prolactin-treated cultures) was, however, different. The secretion dropped appreciably when the concentration of hormones was increased to 100 mu./ml.
INHIBITION BY INDOMETHACIN OF OVULATION INDUCED BY HUMAN CHORIONIC GONADOTROPHIN IN IMMATURE RATS PRIMED WITH PREGNANT MARE SERUM GONADOTROPHIN
Authors: MORI TAKAHIDE , KOHDA HEIGO , KINOSHITA YASUSHI , EZAKI YOJIRO , MORIMOTO NORIHIKO , NISHIMURA TOSHIO
Published: December 2008

Treatment of immature rats with pregnant mare serum gonadotrophin followed by human chorionic gonadotrophin (HCG) caused an acute and temporary increase in concentrations of progesterone, testosterone and oestradiol in plasma with maximum levels 3 h after the administration of HCG.

Concurrent injection of indomethacin and HCG reduced, in a dose-dependent manner, the mean number of ova shed and this was accompanied by a dose-dependent decrease in concentrations of plasma progesterone and testosterone but not of oestradiol when they were measured 3 h after the injection of HCG. The minimum effective dose that blocked ovulation completely at 0 h abolished the acute increase of progesterone and testosterone, suggesting that prostaglandins act on ovulation by stimulating steroidogenesis at an early stage in the preovulatory process. The anti-ovulatory action of the minimum effective dose at 0 h became progressively less potent as the time between injection of HCG and administration of indomethacin was increased, although plasma concentrations of progesterone and testosterone measured at autopsy 18 h after treatment with HCG had not changed appreciably. When indomethacin was administered 10 h after HCG, the relationship between the dose of indomethacin and the mean number of ova differed from that observed when simultaneous injections of indomethacin and HCG were given, and the minimum effective dose that prevented ovulation was much higher than that at 0 h, suggesting that prostaglandins act differently on ovulation in the later stage of the preovulatory process.

It was concluded that prostaglandins may mediate the action of HCG on ovulation through two mechanisms which operate at different stages of the preovulatory process.
ALTERATIONS IN GRANULOSA CELL AROMATASE ACTIVITY ACCOMPANYING PREOVULATORY FOLLICULAR DEVELOPMENT IN THE RAT OVARY WITH EVIDENCE THAT 5α-REDUCED C19 STEROIDS INHIBIT THE AROMATASE REACTION IN VITRO
Authors: HILLIER S. G. , VAN DEN BOOGAARD AGNES M. J. , REICHERT L. E. , VAN HALL E. V.
Published: December 2008

Locally produced androgens and oestrogens are thought to be important factors in the hormonal regulation of follicular development. In the present study the relationship between follicular maturity and granulosa cell aromatase activity has been examined in vitro. Granulosa cells harvested from the largest antral follicles in adult rat ovaries produced negligible amounts of immunoreactive oestradiol when incubated for 3 h in vitro irrespective of the day of the oestrous cycle upon which they were obtained. However, the addition of aromatizable C19 steroid substrate (testosterone, androstenedione or 19-hydroxyandrostenedione) to the incubation medium resulted in time- and concentration-dependent increases in oestradiol production which were related to the level of follicular maturity attained in vivo. By measuring oestradiol production using testosterone (10−7 mol/l) as substrate, the aromatase activity of granulosa cells obtained on the first day of vaginal dioestrus was shown to be only a fraction (less than 5%) of that observed for cells obtained on the morning of pro-oestrus. Cells obtained on the second day of dioestrus displayed an intermediate level of activity which remained approximately five times lower than that of granulosa cells at pro-oestrus. These observations, therefore, establish the induction or activation of granulosa cell aromatase activity as a correlate of normal preovulatory follicular development. However, intrafollicular androgen/oestrogen ratios may also be influenced by quantitative and/or qualitative alterations in the C19 steroidal substrate available for the aromatase reaction. Thus, the naturally occurring non-aromatizable 5α-reduced androgen metabolites, 5α-dihydrotestosterone and 5α-androstanedione, proved to be potent competitive inhibitors of the granulosa cell aromatase reaction in vitro. In this respect each of these biologically active androgens was more effective than 1-enetestololactone, an established C19 steroidal aromatase inhibitor. Since C19 steroid 5α-reductase is known to be an ovarian enzyme, it is suggested that by affecting the androgenic/oestrogenic composition of the hormonal milieu, local alterations in the activity of this enzyme may be an additional determinant of preovulatory follicular development and function.
SUPPRESSION OF THE LUTEINIZING HORMONE RELEASING EFFECT OF LUTEINIZING HORMONE RELEASING HORMONE BY ARGININE-VASOTOCIN IN IMMATURE MALE DOGS
Authors: YAMASHITA K. , MIENO M. , YAMASHITA ER.
Published: December 2008

Arginine-vasotocin (0·1 or 10 ng/kg body wt) was administered into the carotid artery of anaesthetized immature male dogs 3 h before the administration of a standard dose of luteinizing hormone releasing hormone (LH-RH, 5 μg/kg body wt) into the same vessel. The rate of secretion of 17-oxosteroids by the testes in vivo served as an index of luteinizing hormone (LH) secretion. The administration of LH-RH into the carotid artery of control dogs which had been injected with isotonic saline caused a slight but definite increase in the secretion of testicular 17-oxosteroids. This effect of LH-RH on the testicular secretion of steroids was markedly reduced by pretreatment with arginine-vasotocin. However, the testicular response to the i.v. administration of human chorionic gonadotrophin (5 i.u./kg body wt) was unaffected by pretreatment with arginine-vasotocin (10 ng/kg body wt). These results indicate that in immature male dogs, arginine-vasotocin is able to inhibit the action of LH-RH by acting directly on the anterior pituitary gland.
BASAL BONE RESORPTION IN THE RAT FETUS RELATED TO THE HORMONAL STATUS OF THE MOTHER
Authors: GAREL JEAN-MICHEL , REBUT-BONNETON CHARLYNE , DELBARRE FLORIAN
Published: December 2008

Fetal bone resorption was measured by an organ culture technique using fetuses from thyroparathyroidectomized (TPTX) pregnant rats to investigate the roles of fetal and maternal hormones in the regulation of basal bone resorption in utero. Thyroparathyroidectomized female rats were treated with thyroxine and/or metabolites of vitamin D3. Basal bone resorption was greatly increased in fetuses from TPTX mothers. Administration of 1,25-dihydroxycholecalciferol or 1,24,25-trihydroxycholecalciferol to TPTX female rats normalized the basal bone resorption of the fetus whereas injection of 24,25-dihydroxycholecalciferol was without effect. Treatment of the TPTX mothers with thyroxine was also shown to normalize basal bone resorption in the fetus.
FAILURE OF INFUSION OF PROSTAGLANDIN A2 TO RESTORE THE RESPONSE TO ANTIDIURETIC HORMONE IN RATS WITH POLYURIA INDUCED BY LITHIUM
Authors: CHRISTENSEN STEN
Published: December 2008

Male Wistar rats were fed a lithium diet for 2–3 months producing marked polyuria (> 75 ml/100 g in 24 h) and a plasma Li concentration of 0·7 mmol/l. In acute experiments animals were anaesthetized with 5-ethyl-5-(1-methylpropyl)-2-thiobarbituric acid and infused with hypotonic glucose–saline (15 ml/h). Addition of prostaglandin A2 (PGA2; 0·2 ng/min) for 180 min to the infusate did not restore the impaired antidiuretic response to arginine-vasopressin (AVP) whether this agent was infused continuously (150 μu./min) or given as bolus injections (2500 μu.). In long-term experiments animals were kept in metabolism cages and Alzet osmotic minipumps were implanted for intravenous infusion of drugs at 1 μl/h. Again, PGA2 infusion at 0·2 ng/min failed to restore the impaired antidiuretic response to AVP (150 μu./min). It was therefore concluded that in rats with severe polyuria induced by long-term administration of lithium, infusion of PGA2 at 0·2 ng/min cannot restore the impaired response to antidiuretic hormone as has been reported by others.
REGULATION OF THE METABOLISM OF PITUITARY NUCLEIC ACIDS IN FEMALE RATS
Authors: BÍRÓ J.
Published: December 2008

Ovariectomy caused an increase in the metabolism of pituitary nucleic acids. This effect was reversed in vivo by a biphasic action of oestradiol-17β which first facilitated RNA metabolism after 8 h and then inhibited it 16 h after intraperitoneal injection. To analyse the origin of this biphasic effect the roles of LH releasing hormone (LH-RH) and hysterectomy were examined.

Incorporation of uridine into the RNA of the anterior pituitary gland of female rats was inhibited both in vivo and in vitro by LH-RH. Hysterectomy augmented the increase in the RNA metabolism caused by ovariectomy whereas steroid-free uterine extracts inhibited the increase significantly.

We have concluded that extrapituitary factors may be involved in the effects of oestrogen on the metabolism of pituitary nucleic acids.
CONCENTRATIONS OF PLACENTAL LACTOGEN IN CHRONICALLY CATHETERIZED EWES AND FETUSES IN LATE PREGNANCY
Authors: TAYLOR M. J. , JENKIN G. , ROBINSON J. S. , THORBURN G. D. , FRIESEN H. , CHAN J. S. D.
Published: December 2008

The concentration of ovine placental lactogen (oPL) was measured by radioimmunoassay in plasma samples from chronically catheterized ewes and their fetuses from day 110 of gestation to term (about day 145).

Concentrations of oPL in the plasma of the mother and fetus were raised after surgery, and remained raised for 3–5 days after the operation. Concentrations of oPL were greatest in the fetus at days 120–124 of gestation, and then declined until delivery. Mean concentrations of oPL in the fetus in late pregnancy for single, twin and triplet pregnancies were 101±6 (s.e.m.), 100±11 and 117±59 ng/ml respectively and were not significantly different.

Mean concentrations of oPL in the mother in late pregnancy for single, twin and triplet pregnancies were 718±227, 1387±160 and 1510±459 ng/ml respectively; the difference between these means was significant (P <0·05). Peak concentrations were noted at days 130–139 of gestation after which concentrations fell and were significantly lower on the day of delivery (P <0·01). Concentrations of oPL in the mother showed no circadian rhythm. The mean concentrations of oPL in maternal plasma during late pregnancy was significantly correlated to the combined fetal weight at birth (r = 0·624, P <0·01).
INHIBITION BY CALCITONIN OF HYPERCALCAEMIA INDUCED BY 1,25-DIHYDROXYCHOLECALCIFEROL
Authors: BARLET J.-P.
Published: December 2008

The influence of injections of calcitonin on the hypercalcaemia and hyperphosphataemia induced by 1α-hydroxycholecalciferol (1α-OHD3) and 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) was studied in growing lambs and lactating cows respectively.

In lambs, the hypercalcaemic and hyperphosphataemic effect of 0·1 μg 1α-OHD3/kg body weight (i.v.) was completely inhibited by 20 units calcitonin/kg body weight, injected subcutaneously in four equal doses at intervals of 12 h, the first injection of calcitonin occurring immediately after injection of 1α-OHD3. Moreover, the same dose of calcitonin partly inhibited the hypercalcaemia and hyperphosphataemia observed after injection of 0·25 μg 1α-OHD3/kg body weight.

In lactating cows, four injections of calcitonin (5 u./kg body weight each, at intervals of 12 h) prevented the rise of plasma calcium and phosphate levels occurring after injection of 1,25-(OH)2D3 (0·01 μg/kg body weight).

The results indicated that high plasma calcitonin levels can inhibit the hypercalcaemic and hyperphosphataemic effects of 1,25-(OH)2D3 in ruminants. Thus, hypocalcaemia might occur in parturient cows in spite of raised concentrations of 1,25-(OH)2D3 in plasma.
EFFECTS OF VAGAL STIMULATION, VAGOTOMY AND ADRENALECTOMY ON RELEASE OF INSULIN IN THE RAT
Authors: SAKAGUCHI TAKEO , YAMAGUCHI KEN'ICHI
Published: December 2008

To evaluate the physiological role of the vagus nerve in the secretion of insulin in the rat, changes in plasma levels of insulin and sugar were examined after vagotomy with and without adrenalectomy. Male rats, fasted for 22 h, weighing about 300 g and anaesthetized with pentobarbitone sodium were used. Thirty minutes after unilateral or bilateral adrenalectomy, the first blood sample was taken just before pancreatic vagotomy and a second sample was taken 15 min after vagotomy. Pancreatic vagotomy significantly decreased levels of plasma insulin in bilaterally adrenalectomized rats. It was also confirmed that electrical stimulation of the pancreatic vagus nerve provoked an increase in levels of insulin associated with a reduction of carbohydrates in the blood. These observations support the theory that there is a vagal mechanism which modulates the secretion of insulin and suggest that the vagal mechanism is a potent factor although such a mechanism may be masked by the activity of the adrenal gland.
DEVELOPMENT OF HOMOLOGOUS IMMUNOLOGICAL ASSAYS FOR HUMAN PARATHYROID HORMONE
Authors: MANNING R. M. , HENDY G. N. , PAPAPOULOS S. E. , O'RIORDAN J. L. H.
Published: December 2008

Antisera to a trichloroacetic-acid precipitate of human parathyroid hormone (PTH) were produced in goats. Two of these antisera (G36 and G31) were of high affinity, and the bovine and porcine hormones were less reactive. Synthetic peptides containing the amino-terminal region of human PTH reacted with both antisera; the 1–34 peptide (PTH-(1–34)), with the sequence proposed by Niall, Sauer, Jacobs, Keutmann, Segre, O'Riordan, Aurbach & Potts in 1974, was more reactive than that having the sequence proposed by Brewer, Fairwell, Ronan, Sizemore & Arnaud in 1972. The antisera were further characterized with a number of other native and synthetic fragments of human PTH and reacted poorly with fragments from the carboxy-terminal region of the molecule. Since the amino-terminal fragments did not account for all the immunoreactivity, it is assumed that the antisera had some recognition sites for the central part of the molecule.

Highly purified human PTH-(1–84) was labelled with 125I and radioimmunoassays were developed using this tracer and antiserum G36. To avoid the problems associated with labelling human PTH with 125I, a labelled antibody assay was developed with G36 and an immunoadsorbent consisting of human PTH-(1–34) (sequence of Niall et al.) coupled to cellulose. A sensitive homologous amino-terminal specific assay was developed in this way.
INCORPORATION OF [U-14C]GLUCOSE IN VITRO BY THE VARIOUS PARTS OF THE FALLOPIAN TUBE AND UTERUS OF THE RABBIT DURING OVUM TRANSPORT
Authors: PURI R. K. , ROY S. K.
Published: December 2008

Incorporation of [U-14C]glucose in vitro was determined in ampullary, ampullary–isthmic junction and isthmic segments of the Fallopian tube and uterus of intact (oestrous) rabbits and also at various times after mating. In the oestrous animals, incorporation was slightly higher in the ampullary segment compared with the isthmic and the ampullary–isthmic junction and finally the uterus. The pattern changed significantly in the pregnant animals. At 14 and 24 h post coitum, the pattern of incorporation was similar to that found at oestrus except for an increase in uterine incorporation. However, at 48 and 72 h post coitum, incorporation by the isthmic segment and the uterus was significantly increased compared with corresponding values at oestrus, and 14 and 24 h post coitum.

The implication of these changes during egg transport through the Fallopian tube is discussed.
EFFECT OF THYROID HORMONES ON GONADOTROPHIN RELEASE AND BIOSYNTHESIS USING RAT PITUITARY CELL CULTURES
Authors: KHAR ASHOK , TAVERNY-BENNARDO T. , JUTISZ MARIAN
Published: December 2008

The effect of thyroid hormones, tri-iodothyronine (T3) and thyroxine (T4) on the gonadotrophin releasing hormone (GnRH)-induced release of LH and FSH has been studied using dispersed rat pituitary cell cultures. Both T3 and T4 significantly inhibited the release of gonadotrophins in the presence of GnRH. Actinomycin D and cycloheximide also inhibited synergistically the release of LH and FSH. The incorporation of labelled amino acids and glucosamine into LH and FSH which was stimulated by GnRH was also inhibited by T3 and T4. Gonadotrophin releasing hormone had no effect on the incorporation of labelled amino acids and glucosamine into total proteins but this incorporation was also significantly inhibited by T3 and T4, the former being the more potent.
CONVERSION OF TRIGLYCYLVASOPRESSIN TO LYSINE-VASOPRESSIN IN MAN
Authors: FORSLING MARY L. , AZIZ LEEDY A. , MILLER M. , DAVIES R. , DONOVAN B.
Published: December 2008

The concentrations in plasma of triglycyl-8-lysine-vasopressin (TGLVP), determined by radioimmunoassay, and lysine-vasopressin, determined by bioassay, have been monitored in five subjects after intravenous (7·5 μg/kg) or intranasal (5 mg) administration of TGLVP. The level of excretion in urine was also measured. The TGLVP concentration in plasma fell rapidly after the intravenous injection, the mean half-time of disappearance being 24·2±1·9 (s.e.m.) min (d.f. 4). Biologically active lysine-vasopressin reached a peak between 60 and 120 min. A similar pattern was seen following intranasal instillation but only a small proportion of the administered dose appeared in the plasma and the concentration of lysine-vasopressin was relatively higher. Less than 1% of the TGLVP injected appeared in the urine. Intravenous TGLVP had no effect on systolic blood pressure but produced an increase in diastolic blood pressure of 1·7 ± 0·19 kPa (d.f. 4) and a fall in heart rate of 9 ± 2·3 beats/min. Creatinine clearance and sodium excretion remained relatively constant in all subjects throughout the study but intravenous injection of TGLVP resulted in an antidiuresis which was evident within the first hour of observation and was maintained for a further 4 h. It was concluded that TGLVP is converted to lysine-vasopressin in man and after an intravenous injection of 7·5 μg/kg sufficiently high concentrations of lysine-vasopressin may be maintained for 2 h to produce sustained vasoconstriction. Triglycylvasopressin may therefore be of value in controlling haemorrhage.
EFFECT OF EQUOL ON OESTROGEN RECEPTORS AND ON SYNTHESIS OF DNA AND PROTEIN IN THE IMMATURE RAT UTERUS
Authors: TANG B. Y. , ADAMS N. R.
Published: December 2008

In immature, 3-week-old female rats, 5 mg equol given by subcutaneous injection increased uterine wet weight 24 h later to the same degree as did 5 μg oestradiol-17β. At this dose there was more receptor complex binding to the nucleus in the equol-injected rats than in the rats injected with oestradiol-17β even after 6 h. However, the equol–receptor complex that bound to the nucleus was more extractable with 0·3 m-KC1.

In the equol-injected rats the duration of uterine growth was shorter and there was less receptor replenishment and synthesis of protein and DNA than in the rats injected with oestradiol-17β 30 h after either injection.

It was concluded that equol is a weakly oestrogenic compound which is antagonistic to oestradiol-17β by competing with oestradiol–receptor complex for nuclear binding and yet fails to initiate the replenishment of oestrogen receptors effectively in the cytoplasm.
EFFECTS OF ENDOCRINE MANIPULATIONS ON OESTROGEN BINDING IN CYTOSOLS FROM RAT SKELETAL AND PERINEAL MUSCLES
Authors: DIONNE F. T. , DUBÉ J. Y. , FRENETTE G. , TREMBLAY R. R.
Published: December 2008

Hormonal regulation of cytosolic oestradiol-binding sites in the levator ani bulbocavernosus (LA/BC) muscles of male rats and in thigh muscles from male and female rats was investigated. Twenty-four hours after gonadectomy and/or adrenalectomy, the number of unoccupied oestradiol-binding sites was significantly increased in cytosols prepared from LA/BC muscles while these treatments had no effect on thigh muscles from male rats. Only a combination of both treatments led to a significant increase of oestradiol-binding sites in cytosols prepared from the thigh muscles of female rats when compared with those of intact rats at dioestrus. The number of oestradiol-binding sites in the thigh muscles of female rats was found to vary during the oestrous cycle with values significantly lower at pro-oestrus than at dioestrus. The increase in oestradiol-binding sites observed in cytosols prepared from muscles of adrenalectomized or gonadectomized plus adrenalectomized rats was prevented by an injection of corticosterone (3 mg, s.c.) at the time of surgery. Twenty-one days after gonad and/or adrenal ablation, the mean concentration of oestradiol-binding sites in the three tissues under study was higher than in these tissues from intact rats, and in some groups the levels of oestradiol-binding sites were significantly higher than they had been 24 h after the same surgical treatments. Muscles from male rats hypophysectomized for 28 days possessed levels of oestradiol-binding sites equivalent to male rats deprived of steroid hormones for 21 days. Dexamethasone treatment of male rats (100 μg/day for 14 days) led to a progressive decrease of oestradiol-binding sites of LA/BC and thigh muscles. This study has shown that adrenal and gonadal hormones exert both short- and long-acting repressive effects on the oestradiol-binding capacity of rat muscles.
EVIDENCE FOR THE PARTICIPATION OF OPIOIDS IN THE REGULATION OF CARBOHYDRATE METABOLISM IN RAT MAMMARY GLANDS
Authors: DESHPANDE N. , MITCHELL IRENE
Published: December 2008

The possible involvement of opioids in carbohydrate metabolism in rat mammary glands was investigated by studying the effects of administration of morphine and naloxone on six enzymes. Morphine inhibited phosphofructokinase (PFK) and stimulated phosphohexose isomerase (PHI) activities. Naloxone treatment alone, to both intact and ovariectomized/adrenalectomized animals, resulted in stimulation of PFK and inhibition of PHI activities. A combined dose of morphine and naloxone to intact animals showed that the opiate antagonist was able to reverse the morphine-induced changes. Evidence is presented to show that the changes observed in PHI activity may be the result of the indirect action of opioids on luteinizing hormone releasing hormone. However, the changes observed in PFK activity might be the result of direct action of opioids. Failure to observe changes in enzyme activities after naloxone treatment of hypophysectomized animals suggests the opiate antagonist might be acting on the pituitary gland to block the release of endorphins.
PROSTATIC INDUCTION: INTERACTION OF EPITHELIUM AND MESENCHYME FROM NORMAL WILD-TYPE MICE AND ANDROGEN-INSENSITIVE MICE WITH TESTICULAR FEMINIZATION
Authors: LASNITZKI ILSE , MIZUNO TAKEO
Published: December 2008

The prostate gland develops from the urogenital sinus as epithelial buds projecting into the surrounding mesenchyme. The role of the mesenchyme in this process was determined using sinuses from normal and androgen-insensitive Tfm mice which are deficient in androgen receptors. Epithelium and mesenchyme from both types of sinus were separated and recombined and the recombinants grown in organ culture in the presence of testosterone.

Recombinants consisting of normal epithelium and normal mesenchyme developed epithelial buds projecting into the surrounding mesenchyme but no buds were formed in recombinants of epithelium and mesenchyme from mutant mice. In recombinants of epithelium from mutant mice with normal mesenchyme the epithelium developed prostatic buds and the number was similar to that found if normal epithelium was associated with normal mesenchyme. In contrast, normal epithelium combined with mesenchyme from mutant mice failed to form prostatic buds. The results suggested that the mesenchyme determines the development of prostatic buds and that the lack of inductive capacity of the mesenchyme from mutant mice may be due to a deficiency of mesenchymal androgen receptors.
A RADIOIMMUNOASSAY OF GASTRIC INHIBITORY POLYPEPTIDE IN HUMAN PLASMA
Authors: SARSON D. L. , BRYANT M. G. , BLOOM S. R.
Published: December 2008

A sensitive radioimmunoassay for the measurement of human gastric inhibitory polypeptide (GIP), using pure porcine GIP, has been developed. Cross-reactivity of the antiserum with all available mammalian gut peptide preparations was negligible with the exception of glucagon when it was approximately 1%. Two major molecular forms of GIP were detectable in plasma and tissue extracts, one of large molecular size and the other corresponding to the elution coefficient of pure porcine standard.

Concentrations of GIP in plasma from 50 normal subjects after overnight fasting were 9 ± 1·0 (s.e.m.) pmol/l rising to a peak of 34 ± 2·8 pmol/l following the ingestion of a small mixed test meal. Ingestion of glucose or fat resulted in a similar rise of plasma GIP, whereas no change was observed after the ingestion of protein.
EFFECT OF GONADECTOMY, SEASON AND THE PRESENCE OF FEMALE TAMMAR WALLABIES (MACROPUS EUGENII) ON CONCENTRATIONS OF TESTOSTERONE, LUTEINIZING HORMONE AND FOLLICLE-STIMULATING HORMONE IN THE PLASMA OF MALE TAMMAR WALLABIES
Authors: CATLING P. C. , SUTHERLAND R. L.
Published: December 2008

Concentrations of FSH, LH and testosterone in plasma were measured in groups of adult male tammar wallabies before and after gonadectomy, and during the breeding and non-breeding seasons. Gonadectomy resulted in a rapid fall in plasma testosterone to undetectable levels by day 2, and significant increases in plasma LH and FSH levels. The concentrations of FSH, LH and testosterone did not change significantly between the non-breeding and breeding seasons in groups of male wallabies maintained in the absence of females. However, when male wallabies were associated with sexually mature females there were significant three- to fourfold increases in concentrations of LH and testosterone in plasma at the commencement of the breeding season. The observed increases in LH and testosterone were highly synchronized in the eight animals studied and occurred approximately 2 weeks before the synchronous onset of mating. Concentrations of FSH did not change significantly at this time.
EFFECTS OF HUMAN GROWTH HORMONE ON THE SECRETION OF RAT GROWTH HORMONE
Authors: WILLOUGHBY J. O. , MENADUE MARGARET , ZEEGERS P. , WISE P. H. , OLIVER J. R.
Published: December 2008

Human growth hormone (hGH) was administered to chronically cannulated male rats and its effect upon the physiological secretory patterns of rat growth hormone (rGH) and prolactin were observed.

In comparison with injected control animals, a reduction in the size of spontaneous secretory bursts of rGH was apparent when hormone concentrations were compared 3–6 h after administration of hGH (136·27 ± 27·31 (s.e.m.) v. 76·22 ± 20·98 ng/ml respectively). However, the mean frequency of secretory episodes of rGH was unaltered.

It is therefore postulated that endogenous rGH may modulate the amplitude but not the rhythmicity of secretory episodes of rGH.
SOMATOMEDIN-LIKE ACTIVITY IN CATTLE: THE EFFECT OF BREED, LACTATION AND TIME OF DAY
Authors: FALCONER J. , FORBES J. M. , BINES J. A. , ROY J. H. B. , HART I. C.
Published: December 2008

Somatomedin-like activity (SLA) was measured in plasma samples from cattle using the porcine costal cartilage disk bioassay. In 40-day-old pre-ruminant bull calves, SLA was highest in the plasma of eight Friesians (mean potency 0·97±0·06 (s.e.m.) units/ml), lowest in five Aberdeen Angus × Friesians (0·78±0·03, P<0·05) and intermediate in six Hereford × Friesians (0·89±0·09). Plasma levels of SLA were significantly (P<0·01) lower in eight lactating Friesian (high-yielding) cows (0·53 ± 0·04) than in five dry cows (0·76±0·06). Levels of SLA in the plasma of a further eight lactating Hereford × Friesian (low-yielding) cows (0·76±0·07) were similar to the levels in the plasma of the five dry dairy cows.

Large diurnal changes in plasma SLA occurred in lactating Hereford × Friesian and Friesian heifers. In three Hereford × Friesian heifers plasma levels of SLA were lowest at 19.00 h (0·39±0·07) and highest at 03.00 h (0·77±0·08). A similar pattern was present in plasma samples from three Friesian heifers; the lowest levels of SLA being at 21.00 h (0·37±0·07) and the highest at 05.00 h (0·61±0·13). Throughout the period of 24 h the overall mean levels of SLA were significantly (P<0·01) higher in the plasma samples from the three Hereford × Friesian heifers (0·6 ±0·01) than in the samples from the three Friesian heifers (0·49 ± 0·02 units/ml).