bluuebunny/crossref_metadata_2025_split huggingface dataset:
ADENYL CYCLASE ACTIVITY IN THE MOUSE THYROID GLAND
Authors: KENDALL-TAYLOR PAT 
Published: December 2008

SUMMARY
The activation of adenyl cyclase in intact mouse thyroid glands was measured by the conversion of [3H]ATP to [3H]cyclic AMP.
Untreated serum had an inhibitory effect. Human thyroid-stimulating hormone (TSH) and γG-globulin prepared from serum containing the long-acting thyroid stimulator (LATS), activated adenyl cyclase and the log-dose—response relationship did not deviate from parallelism. The rate of activation by LATS was slower and the peak response was delayed, compared with the response to TSH. The possible significance of this is discussed.
Other hormones and neurotransmitters examined had no effect on thyroidal adenyl cyclase.
PLASMA AND PITUITARY LUTEINIZING HORMONE AND PERIPHERAL PLASMA OESTRADIOL CONCENTRATIONS IN THE NORMAL OESTROUS CYCLE OF THE RAT AND AFTER EXPERIMENTAL MANIPULATION OF THE CYCLE
Authors: NAFTOLIN F. , BROWN-GRANT K. , CORKER C. S. 
Published: December 2008

SUMMARY
Plasma and pituitary luteinizing hormone (LH) concentrations were measured by radioimmunoassay at different stages of the normal 4- and 5-day oestrous cycle of rats. Plasma levels were low except between the afternoon of pro-oestrus and the morning of oestrus when levels were high but variable. Pituitary LH content and concentration were less consistent but averaged values showed a steady rise from a low level after ovulation to a peak on the afternoon of pro-oestrus, and a rapid fall that evening when plasma levels rose rapidly.
No significant differences were observed in plasma LH between 4- and 5-day cycles; in particular there was no reduction at metoestrus or dioestrus-1 or increase on the evening of dioestrus-2. Plasma oestradiol was already high on the morning of dioestrus-2 in some rats and in all rats by that evening. On the morning of pro-oestrus in the 5-day cycle, plasma oestradiol was still high but somewhat lower than at the corresponding stage in the 4-day cycle.
Blocking ovulation by administration of sodium pentobarbitone at prooestrus in a 4-day cycle prevented the rise in plasma LH and the fall in pituitary content. Blocking generally failed in animals whose plasma LH had reached the level of 20 ng/ml or more at the time of injection. Plasma oestradiol levels on the morning of the expected day of oestrus were higher than normal in animals in which ovulation was blocked by pentobarbitone but were below pro-oestrous values. In the anovulatory state induced by exposure to constant light no major increase in plasma LH was detected after 24 days of illumination or after 3 months exposure. Animals rendered anovulatory by injection of testosterone propionate on the 4th day of postnatal life had low plasma LH levels as adults. All three groups had a low pituitary LH content. The animals exposed to long-term light and those treated with androgen generally had plasma oestradiol concentrations below the peak levels seen on the morning of pro-oestrus in the normal cycle.
INFLUENCE OF THE REPRODUCTIVE STATE AT THE TIME OF OPERATION ON THE EARLY RESPONSE TO OVARIECTOMY IN THE RAT
Authors: TAPPER C. M. , NAFTOLIN F. , BROWN-GRANT K. 
Published: December 2008

SUMMARY
The changes in plasma luteinizing hormone (LH) concentration during the first few days after ovariectomy in the rat differ according to the stage of the cycle at which the operation is performed. When carried out at oestrus there was no increase in LH concentration in the first 4 days. After operation at metoestrus the concentration was increased at 3 days but not earlier. Ovariectomy at dioestrus resulted in an immediate increase after 8 h, a subsequent fall, though not to basal levels, and a fairly steady rise thereafter. Ovariectomy at pro-oestrus produced a very large initial rise in plasma LH which probably represents an accelerated release of the ovulatory surge of LH rather than a specific response to ovariectomy. At 24 h after ovariectomy at pro-oestrus levels were below normal and did not increase again for a further 3 days. In contrast, male rats showed a rapid and sustained rise in plasma LH concentration after castration. It is suggested that the different patterns seen in the female may be related to the time that elapsed since the hypothalamo—pituitary system was exposed to high levels of circulating oestradiol. The changes in plasma LH concentration observed after ovariectomy in neonatally androgen-treated rats, rats in persistent oestrus due to exposure to constant light, and rats in early pregnancy are consistent with this hypothesis. Differing responses to the administration of sodium pentobarbitone between male and female rats even 21 days after gonadectomy suggest that there may also be differences in this negative feedback system between the two sexes that are independent of the nature of the gonadal steroid secreted.
ULTRASTRUCTURAL AND HISTOCHEMICAL STUDIES ON THE TESTIS OF THE RIVER LAMPREY, LAMPETRA FLUVIATILIS (L.)
Authors: BARNES K. , HARDISTY M. W. 
Published: December 2008

SUMMARY
The structure of interstitial cells and the cells of the lobule wall was studied in the lamprey testis throughout the period of sexual maturation. In the course of their secretory cycle the interstitial cells showed the usual characteristics of vertebrate steroidogenic tissues; a well-developed agranular reticulum, mitochondria with a dense matrix and tubular cristae, and lipid inclusions. Similar characteristics were also seen in the cells of the lobule wall in the period immediately preceding spermiation. In the interstitial cells, hydroxysteroid dehydrogenase (HSD) activity reached a maximum in late January and February, in advance of the development of the secondary sex characteristics, and was correlated with the abundance of interstitial lipid. After hypophysectomy, no changes were detected in the numbers or volume of interstitial tissue, and HSD activity was apparently unaffected. Characteristic multivesiculate bodies were not observed in the cells of the lobule wall in hypophysectomized animals.
THE RETICULO—HYPOTHALAMIC PATHWAY CONTROLLING THE RELEASE OF OXYTOCIN IN THE EWE
Authors: RICHARD Ph. 
Published: December 2008

SUMMARY
The pathways of the milk-ejection reflex in the ewe have been described at the spinal and mesencephalic levels (Richard, 1970; Richard, Urban & Denamur, 1970). The present paper describes the pathways followed by impulses of mammary and vaginal origin between the mesencephalic reticular formation and the neurohypophysis.
In the anaesthetized ewe the thalamus is not necessary for the transfer of impulses to the neurohypophysis as shown by studying the electrical activities evoked in the pituitary stalk by mammary or vaginal stimulation. These impulses follow a subthalamic pathway through the medial forebrain bundle. In conscious ewes small areas of coagulations in the pathways did not block the milk-ejection reflex during milking because the fibres are diffuse at all levels of the central nervous system. Larger lesions result in non-specific effects which interrupt milk secretion.
Supra-diencephalic structures are not necessary for the milk-ejection reflex.
DISTRIBUTION OF 5α-DIHYDROTESTOSTERONE IN THE EPIDIDYMIS OF BULL AND BOAR, AND ITS CONCENTRATION IN RAT EPIDIDYMIS AFTER LIGATION OF EFFERENT TESTICULAR DUCTS, CASTRATION AND UNILATERAL GONADECTOMY
Authors: AAFJES J. H. , VREEBURG J. Th. M. 
Published: December 2008

SUMMARY
5α-Dihydrotestosterone concentrations were appreciably higher than testosterone concentrations in the epididymides of both a bull and a boar. The highest concentration of 5α-dihydrotestosterone was found in the heads of these organs. When tritiated testosterone was injected into a castrated rat most of the radioactivity recovered from the epididymis was present as 5α-dihydrotestosterone. Recrystallization confirmed the identity of this compound. In a separate experiment the concentration of 5α-dihydrotestosterone in the epididymis after castration decreased to unmeasurable amounts in about 27 h. This was not the case when only one testis was removed or when testosterone was injected after castration. Ligation of the efferent ducts of a testis on one side resulted in a lowered 5α-dihydrotestosteron concentration in the epididymis of that side. This finding suggests a possible role of spermatozoa in the metabolism of testosterone to 5α-dihydrotestosterone. However, the presence of 5α-dihydrotestosterone in the epididymis of very young rats without spermatozoa showed that spermatozoa are not required for this metabolism.
THE ROLE OF PROLACTIN IN THE REGULATION OF TESTIS FUNCTION: THE SYNERGISTIC EFFECTS OF PROLACTIN AND LUTEINIZING HORMONE ON THE INCORPORATION OF [1-14C]ACETATE INTO TESTOSTERONE AND CHOLESTEROL BY TESTES FROM HYPOPHYSECTOMIZED RATS IN VITRO
Authors: HAFIEZ A. A. , BARTKE A. , LLOYD C. W. 
Published: December 2008

SUMMARY
Hypophysectomized adult male rats were treated twice daily for 3½ days with 0·9% NaCl solution, 200 μg ovine prolactin, 5 μg ovine luteinizing hormone (LH), or 200 μg prolactin +5 μg LH, starting 18 days after the operation. Minced testes from these animals were incubated in Krebs—Ringer bicarbonate buffer containing [1-14C]acetate for 3 h at 37 °C. The conversion of acetate into testosterone was calculated. It was not changed by prolactin treatment, was increased by LH (P < 0·01), and further increased by prolactin + LH (P < 0·01) to approximately the level observed in intact adult controls. The amount of testosterone in some of the incubates was measured by gas liquid chromatography. It was not changed in prolactin-treated animals and was increased in LH-treated animals (P < 0·02 compared with hypophysectomized controls). Treatment with prolactin+LH resulted in an increase in testosterone above that after treatment with LH alone (P < 0·01) and to a value similar to that in intact adult males. The incorporation of acetate into esterified cholesterol was decreased (P < 0·05) in groups treated with LH or prolactin + LH in which testosterone synthesis was increased. The incorporation of acetate into free cholesterol was not changed by any of the treatments. These results demonstrate synergistic action of prolactin and LH on the synthesis of testosterone in vitro confirming our earlier suggestions.
HUMAN OVARIAN RESPONSE TO GONADOTROPHINS WITH DIFFERENT RATIOS OF FOLLICLE-STIMULATING HORMONE: LUTEINIZING HORMONE ASSESSED BY DIFFERENT PARAMETERS
Authors: BERTRAND P. V. , COLEMAN J. R. , CROOKE A. C. , MACNAUGHTON M. C. , MILLS I. H. 
Published: December 2008

SUMMARY
Eight women with secondary amenorrhoea were treated, four at each of two centres. They were each given four preparations of gonadotrophin having different ratios of follicle-stimulating hormone (FSH) to luteinizing hormone (LH) and the order of treatment with the preparations was determined at each centre by a latin square design. At the completion of these treatments each patient received a fifth preparation of gonadotrophin. The dosage of FSH was determined for each woman by a previous sensitivity test and remained constant for each of her 5 months of treatment. Each gonadotrophin preparation was given in approximately equal daily injections on days 1, 2 and 3 of each course of treatment and was invariably followed by a single injection of 12000 i.u. human chorionic gonadotrophin on the 10th day. Treatment was assessed by the measurement of the excretion of oestriol and pregnanediol, by vaginal cytology, by the degree of ferning of cervical mucus and by the basal body temperature (BBT). The administration of gonadotrophin with a ratio of FSH:LH < 1·0 produced a greater excretion of oestriol than gonadotrophin with a ratio of FSH:LH > 4·0. There was no significant loss of sensitivity to treatment with time. The karyopyknotic index was correlated with the excretion of oestriol but neither was of use in predicting the other because of the wide scatter. There was no correlation between the degree of ferning and the excretion of oestriol. Assessments of ovulation by the pregnanediol response and by the BBT were in good agreement. These results are discussed.
QUANTIFICATION OF ULTRASTRUCTURAL CHANGES IN THE 'MELANOCYTE-STIMULATING HORMONE CELL' OF THE PARS INTERMEDIA OF THE PITUITARY OF XENOPUS LAEVIS, PRODUCED BY CHANGE OF BACKGROUND COLOUR
Authors: WEATHERHEAD B. , WHUR P. 
Published: December 2008

SUMMARY
The fact that the transfer of amphibians between black and white backgrounds causes the 'melanocyte-stimulating hormone (MSH) cells' of the pars intermedia of the pituitary to undergo considerable morphological change has been established for some time. The application of morphometric techniques to the 'MSH cells' of Xenopus has permitted the quantitative analysis of these changes at the ultrastructural level. Of the nine classes of organelle selected for analysis in these cells, three, namely nucleus, plasma membrane and dense bodies, showed no statistically significant changes. The remaining classes of organelle all showed significant changes in the percentage of the total cell volume that they occupied, although not all the organelles changed at the same rate. Transfer of animals from a white to a black background for up to 12 days was associated with increase in the percent volume of rough endoplasmic reticulum, Golgi membranes, Golgi granules and mitochondria and with a decrease in the percent volume of the fibrous granules. Return of animals to a white background after 6 days on a black background produced a reversal of the above changes with return to, or close to, white background (control) levels. This quantitative ultrastructural approach also highlights discrepancies in both the rate and magnitude of the changes in some of the organelles and related non-morphological parameters previously reported, e.g. the size of the rough endoplasmic reticulum and the rate of incorporation of labelled amino acid into protein; or the numbers of fibrous granules and the levels of detectable pituitary MSH. Some possible interpretations of these discrepancies are discussed.
PARATHYROID HORMONE IN FOETAL AND ADULT SHEEP: THE EFFECT OF HYPOCALCAEMIA
Authors: SMITH F. G. , ALEXANDER D. PAULINE , BUCKLE R. M. , BRITTON H. G. , NIXON D. A. 
Published: December 2008

SUMMARY
Measurable levels of immunoassayable parathyroid hormone (PTH) were present in the plasma of two out of five sheep foetuses of 80–142 days gestational age, and in three of the mothers at Caesarian section. There was no correlation between foetal and maternal concentrations although the range of values was similar.
In response to foetal hypocalcaemia induced by EDTA infusion the plasma PTH concentration rose in all of the foetuses and there was a highly significant inverse correlation between the foetal plasma calcium and PTH levels. During the period of foetal hypocalcaemia the maternal plasma PTH levels did not change significantly. EDTA was also infused into three adult ewes. There was a similar rise in the concentration of PTH in the plasma of these ewes and it was concluded that the level of responsiveness of the foetal parathyroid gland to plasma calcium concentration was similar to that of the adult.
The parathyroid glands would appear to be active from an early stage in foetal life and responsive to changes in serum calcium level.
THE DISTRIBUTION OF [3H]PROGESTERONE AND [3H]MEGESTROL ACETATE IN THE UTERUS OF THE OVARIECTOMIZED RAT
Authors: JOHN P. N. , ROGERS A. W. 
Published: December 2008

SUMMARY
The distribution of radioactivity was studied autoradiographically in the uterus of the ovariectomized rat from 1 to 7 h after the s.c. injection of [3H]progesterone. Luminal and glandular epithelia were less radioactive than stroma or muscle. Grain densities over nuclei were the same as those over cytoplasm in the epithelial tissues and the muscle. Pretreatment with non-radioactive progesterone did not alter the pattern of distribution of radioactivity though in one experiment grain densities were significantly decreased in the pretreated animal; this decrease involved nucleus and cytoplasm in epithelial cells and in the muscle.
The interpretation of grain densities after the administration of [3H]progesterone is complicated by the presence of labelled metabolites. Further experiments were therefore carried out with [3H]megestrol acetate, a progestin which is not significantly metabolized in the uterus or plasma during the first 3 h after injection s.c. At 30 min, 1 and 2 h after [3H]megestrol acetate administration, the stroma and muscle were twice as radioactive as the epithelial tissues of the uterus. Nuclear and cytoplasmic grain densities were the same, both in the luminal epithelium and the stroma. Pretreatment with non-radioactive progesterone decreased the observed grain densities by 20–30% in all tissues including the extracellular spaces of the stroma. Though stromal cells were more radioactive than the surrounding extracellular spaces 1 h after [3H]megestrol acetate, the luminal epithelium was significantly less radioactive.
These results are consistent with the hypothesis that binding sites for progesterone are at relatively low concentrations in the uterus of the ovariectomized rat, that they are widely distributed in the uterus, and that after binding to these sites progestins are distributed between nucleus and cytoplasm in approximately equal proportions.
OESTROGEN SYNTHESIS IN RAT OVARIES IN VITRO: EFFECTS OF ENDOGENOUS AND EXOGENOUS GONADOTROPHINS
Authors: ROBINSON BRENDA , OAKEY R. E. 
Published: December 2008

SUMMARY
The rate of synthesis of [14C]oestrone and [14C]oestradiol-17β from [14C]testosterone in vitro by ovaries from rats at different stages of the oestrous cycle was measured. The rate of [14C]oestrogen synthesis was highest in ovaries taken from rats in pro-oestrus and lowest in ovaries taken from rats early in the dioestrous phase of the cycle. Rates of synthesis in ovaries obtained from rats in the late dioestrous stage were intermediate between the rates of the other groups. The rates of [14C]oestrogen synthesis at these periods of the cycle paralleled the concentrations of oestrogens in ovarian vein plasma reported by other authors.
Gonadotrophin preparations with either luteinizing hormone activity or both follicle-stimulating hormone and luteinizing hormone activities had no effect on [14C]oestrogen synthesis by rat ovaries in vitro at any of these stages of the oestrous cycle.
FEEDING AND CALCITONIN SECRETION IN SHEEP
Authors: PHILLIPPO M. , LAWRENCE C. B. , BRUCE J. B. , DONALDSON D. R. 
Published: December 2008

SUMMARY
Calcitonin (CT) secretion was measured before, during and after feeding in three sheep with an exteriorized lobe of the thyroid gland. A significant (P < 0·05) increase in the rate of CT secretion occurred during the 15-min period immediately after the presentation of the food: this increase could be blocked by the local infusion of 35 nm-( ± )-propranolol. During the subsequent 165 min, the secretion of CT was not significantly altered from that before feeding. These results suggest that in the sheep there is an initial increase in CT secretion mediated via a β-adrenergic system and it is possibly associated with the excitement of receiving the food. In the remainder of the first 180 min after presentation of a feed, the rate of release was unaffected.
URINARY EXCRETION OF SODIUM AND POTASSIUM IN RELATION TO PLASMA ALDOSTERONE CONCENTRATION
Authors: ADAMSON A. R. , JAMIESON S. W. 
Published: December 2008

SUMMARY
The effect of a low dose infusion of aldosterone (7·0–8·4 ng/kg/min) on urinary sodium and potassium excretion was assessed in six normal subjects. Plasma aldosterone levels during these infusions (mean 38, range 23–62 ng/100 ml) compared favourably with levels obtained during Na+ deprivation (mean 38, range 30–46 ng/100 ml). In four paired experiments, aldosterone infused in this dose for 2 h produced a significant reduction in Na+ excretion (P < 0·01) and urine volume (P < 0·05) in the 4th hour after the start of the infusion compared with the control infusions. There was no significant change in K+ excretion. Prolonging the aldosterone infusion reduced Na+ excretion. A 10 h infusion of aldosterone (7·7 ng/kg/min) in one subject reduced Na+excretion to 6 μequiv./min. These results are compared to the levels of Na+ excretion obtained in dietary Na+ deprivation.
PLASMA PROLACTIN MEASURED BY RADIOIMMUNOASSAY AND BIOASSAY IN PREGNANT AND LACTATING GOATS AND THE OCCURRENCE OF A PLACENTAL LACTOGEN
Authors: BUTTLE H. L. , FORSYTH ISABEL A. , KNAGGS G. S. 
Published: December 2008

SUMMARY
Plasma samples from five goats taken during their first pregnancies and subsequent lactation were examined for prolactin concentration by a radioimmunoassay and for total lactogenic activity by a rabbit mammary gland organ culture assay.
Prolactin was released in response to suckling and there was a fair correlation between prolactin concentrations as measured by radioimmunoassay and the levels of total lactogenic activity in the plasma samples from the lactating animals. During pregnancy, however, high levels of lactogenic activity were detected in the second and last thirds of pregnancy when the concentration of immunoreactive prolactin was low or even absent. This discrepancy in the results of the two assays suggests that the blood of pregnant goats contains a second lactogen of placental origin which does not cross-react with prolactin.
THE PENETRATION OF IODINE-LABELLED FOLLICLE-STIMULATING HORMONE AND ALBUMIN INTO THE SEMINIFEROUS TUBULES OF SHEEP AND RATS
Authors: SETCHELL B. P. , WALLACE A. L. C. 
Published: December 2008

SUMMARY
The entry of 125I-labelled ovine follicle-stimulating hormone (FSH) and human serum albumin into the seminiferous tubules of rams has been studied by measuring radioactivity in blood plasma and rete testis fluid after an intravenous injection of the labelled protein. After the injection of FSH, radioactivity/mg total protein in rete testis fluid exceeded that in blood plasma from the first day onwards, but after the injection of human serum albumin, radioactivity/mg total protein in rete testis fluid only reached that in plasma after 4–5 days and never exceeded it. Protein-bound radioactivity disappeared from the blood more quickly after an injection of FSH than after an injection of albumin.
The volume of distribution for ovine FSH in the testes of rats was greater than that for human serum albumin. The volume of distribution for FSH was greater, in absolute terms, in the testes with the efferent ducts ligated 24 h previously than in the contralateral control testes when the FSH was injected at the time of efferent duct ligation. The volume of distribution for albumin was slightly less in the ligated testes than in the control testes. This suggests that FSH but not albumin had penetrated into the fluid trapped inside the testis. The liver and kidney had much higher concentrations of protein-bound radioactivity per unit weight than did the testis after the injection of FSH, so it does not seem that FSH is selectively taken up by the testis.