bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECT OF HYPOTHALAMIC LESIONS ON MATURATION AND ANNUAL CYCLICITY OF THE FERRET TESTIS
Authors: BAUM M. J. , GOLDFOOT D. A.
Published: December 2008

Sexually immature male ferrets received electrolytic lesions in the rostral mediobasal hypothalamus, and another group of males received sham operations. Testicular size, as estimated by weekly palpation, increased rapidly after the placement of lesions. Four weeks after the operation the right testis and epididymis were found to weigh significantly more in lesioned than in sham-operated animals, whereas body weight was the same in the two groups. The right testis of lesioned ferrets had a significantly higher Leydig cell index as well as significantly larger luminal and outer diameters of the seminiferous tubules. In addition, histological examination and classification of the seminiferous tubules showed that spermatogenesis was advanced in lesioned ferrets, with pachytene spermatocytes being the most advanced germ-cell type present in a significantly higher percentage of tubules, and spermatogonia being the most advanced germ-cell type present in a significantly lower percentage of tubules. Finally, at this time the concentration of testosterone per testis was significantly higher in lesioned than in sham-operated ferrets. When the remaining testis was biopsied 20 weeks after the operation it was found that spermatogenesis was still more advanced and the concentration of testosterone in blood was significantly higher in lesioned ferrets. By the time autopsy was performed 38 weeks after the operation, all parameters of testicular function in the sham-operated male ferrets had caught up with those of lesioned animals.

In a second experiment it was found that hypothalamic lesions accelerated testicular growth without interfering with the subsequent occurrence of an annual regression and recrudescence of the testes.
UPTAKE AND METABOLISM OF TRITIATED OESTRADIOL AND OESTRONE BY HUMAN ENDOMETRIAL AND MYOMETRIAL TISSUE IN VITRO
Authors: GABB R. G. , STONE G. M.
Published: December 2008

Human endometrial and myometrial tissues were incubated in vitro with [3H]oestradiol-17β and [3H]oestrone to study the uptake and interconversion of these two steroids by the tissues. Endometrial tissue displayed a higher capacity for oestrogen interconversion than myometrial tissue and the oxidation of oestradiol-17β to oestrone was favoured, rather than the reverse reaction. A greater degree of oxidation was found in tissue taken from uteri in the secretory phase than in the proliferative phase. A study of the distribution of radiometabolites between 'soluble' and 'particulate' fractions of tissue homogenates showed that a greater proportion of the tissue radioactivity was associated with the 'particulate' fraction in the proliferative phase than in the secretory phase. After incubation of endometrial tissue from the secretory phase with tritiated oestrogens there was evidence of the formation of chloroform-insoluble radiometabolites and some of these were tentatively identified as oestrogen sulphates. In a second experiment, the uptake and metabolism of the same two oestrogens by tissue from leiomyomata uteri (fibroids) and normal myometrial tissue were compared. No significant difference between these tissues was found.

The results suggest that the levels of 17β-hydroxysteroid dehydrogenase in the human uterus may be dependent upon the levels of oestrogens in the blood. The lack of a difference in the treatment of oestrogens by fibroid and normal myometrial tissue suggests that these tissues may have a similar mechanism for the uptake and retention of oestrogens.
FURTHER STUDIES ON THE STIMULATION OF PROSTATIC RIBONUCLEIC ACID POLYMERASE BY 5α-DIHYDROTESTOSTERONE—RECEPTOR COMPLEXES
Authors: DAVIES PETER , GRIFFITHS KEITH
Published: December 2008

The stimulation in vitro of prostatic RNA polymerase activity by prostatic 5α-dihydrotestosterone—receptor complexes has been previously reported. Further investigations into the nature of the stimulation have now been carried out. By use of the selective inhibitor, α-amanitin, and by varying the concentration of ammonium sulphate in the assay media, both the nucleolar and extranucleolar forms of RNA polymerase could be stimulated, depending upon the ionic conditions employed. High ionic strength inhibited stimulation, either by interference with the association between steroid—receptor complexes and chromatin components, or by blocking the conversion of cytoplasmic complexes to a more 'active' form of the complex. 5α-Dihydrotestosterone—receptor complexes appeared to affect the template availability of prostatic chromatin, possibly in a way similar to that of the chromatin-associated proteins.
EFFECT OF ACUTE REDUCTION IN MILK REMOVAL FROM SOME GLANDS UPON THE ABILITY OF A SINGLE RABBIT MAMMARY GLAND TO SECRETE MILK
Authors: MENA F. , REYES G. , AGUAYO D. , GROSVENOR C. E.
Published: December 2008

Milk yield fell in a single rabbit mammary gland within 24 h after the litter had been reduced from six to eight pups to one pup. The diminished secretion lasted 2–3 days, then rebounded to the expected level over the next 1–2 days and thereafter maintained this level. During early to mid-lactation the decrease in milk secretion after reduction of the litter to one pup was prevented either by s.c. injections of prolactin or by s.c. injections of the β-adrenergic blocking drug, propranolol. These results suggest that milk secretion was reduced in the single gland as the result of sympathetic activation, triggered possibly by the turgid state which developed in the remaining glands after the litter was reduced. The results suggest also that the depression of milk secretion by the sympathetic system was due to a reduction in the effective amount of prolactin and probably of other adenohypophysial hormones reaching the mammary secretory cells rather than to an impairment of their release from the anterior pituitary.

The magnitude of the depression and rebound in milk secretion of a single rabbit mammary gland, and the effectiveness of the preventive action of either propranolol or prolactin, was considerably less during late as compared with early to mid-lactation. We postulate from these results that the mammary gland of the rabbit has a functional lability, i.e. responsiveness, which diminishes as lactation progresses and which dictates the extent to which local, neural and humoral factors may alter the milk secretory function of the mammary gland. Since suckling in the rabbit does not change from a once-a-day frequency throughout lactation, a diminishing lability may be an important factor in the decline and cessation of lactation in this species.
AN IN-VITRO BIOASSAY FOR PROLACTIN BASED ON STIMULATION OF CASEIN SYNTHESIS BY A DISPERSED CELL PREPARATION FROM MOUSE MAMMARY GLAND
Authors: BULLOUGH W. A. , WALLIS M.
Published: December 2008

An in-vitro bioassay for prolactin has been devised, based on the stimulation of casein synthesis in a mouse mammary gland preparation. Dispersed mammary gland cells were superior to intact explants for this purpose. Casein synthesis by dispersed cells was stimulated by added prolactin, and a linear log dose—response curve was established (for the range 5–20 μg prolactin/ml).

The precision of the assay was high (λ = 0·10–0·15). Sensitivity was rather low, but could be improved by increasing the concentration of amino acids in the medium. The response to prolactin was not influenced by thyroxine, adrenocorticotrophin or oestradiol, but thyrotrophin appeared to inhibit it slightly. Both human placental lactogen and bovine growth hormone showed lactogenic activity in the assay.
ALDOSTERONE, SODIUM DEPLETION AND HYPOTHYROIDISM ON THE ATPASE ACTIVITY OF RAT COLONIC EPITHELIUM
Authors: THOMPSON B. D. , EDMONDS C. J.
Published: December 2008

Transmucosal electrical potential difference and short-circuit current of an in-vitro preparation of mucosal epithelium of rat colon were almost abolished and active sodium transport ceased when ouabain (1 mmol/l) was present on the serosal side of the epithelium.

A considerable fraction of the total ATPase activity in the mucosa was sodium dependent and concentrations of ouabain of 0·5 mmol/l or more completely eliminated the activity of this fraction.

Adenosine triphosphatase activities in mucosa taken from normal, hypothyroid, aldosterone-treated and sodium-depleted rats were compared. The activity of the ouabain-sensitive, sodium-dependent fraction was similar in all groups except for the hypothyroid rats in which it was considerably reduced.

There was no evidence from the present study that the increased active sodium transport by colonic mucosa, associated with aldosterone action or sodium depletion, depended upon a change in ATPase activity. In hypothyroidism, reduction of ouabain-sensitive ATPase activity may be responsible for the observed impairment of the sodium transport mechanism.
A RADIOIMMUNOASSAY FOR OVINE CALCITONIN: AN EVALUATION OF CALCITONIN SECRETION DURING GESTATION, LACTATION AND FOETAL LIFE
Authors: GAREL J. M. , CARE A. D. , BARLET J. P.
Published: December 2008

A radioimmunoassay capable of measuring ovine calcitonin in unextracted ovine plasma has been developed. Guinea-pig antisera to partially purified porcine calcitonin were highly specific for calcitonin and were capable of detecting 5 pg porcine calcitonin. One of these antisera cross-reacted significantly with pure ovine calcitonin and with foetal ovine plasma. The mean basal calcitonin secretion rate for the left thyroid lobe found in sheep foetuses 10 days before term was 3·36 ng/min/kg body weight. An infusion of calcium into the foetus was followed by an increase in the calcitonin secretion rate. The mean fasting calcitonin concentration in samples from the jugular vein of five pregnant ewes 10 days before term was 5·28 ng/ml. An infusion of calcium into the mother induced a sevenfold increase in plasma calcitonin concentration whereas the calcitonin concentration was unchanged in the foetal thyroid venous plasma. At parturition the plasma calcitonin concentration fell in the mother (1·85 ng/ml), and a sharp increase was observed during lactation (11·60 ng/ml). In the lamb from birth to 6 weeks post partum the calcitonin concentration was very high (8·10–10·40 ng/ml).
A BIOASSAY FOR PARATHYROID HORMONE USING WHOLE MOUSE CALVARIA IN TISSUE CULTURE
Authors: WEBSTER LESLEY A. , ATKINS D. , PEACOCK M.
Published: December 2008

A parallel-line bioassay for parathyroid hormone based on the release of stable calcium from whole mouse calvaria in tissue culture has been developed from the method of Zanelli, Lea & Nisbet (1969). There has been no change in either the dose range (0·06–1·2 units/2 ml culture) or the bioassay statistics over a prolonged working period but the total assay time has been shortened and the preparative stages made easier.
EFFECTS OF LUTEINIZING HORMONE RELEASING HORMONE AND THYROTROPHIN RELEASING HORMONE ON RABBIT ADIPOSE TISSUE
Authors: MURTHY G. G. , MODESTO R. R.
Published: December 2008

The effects of luteinizing hormone releasing hormone (LH-RH) and thyrotrophin releasing hormone (TRH) on rabbit adipose tissue were studied. LH-RH increased [14C]glucose oxidation and incorporation into fatty acids and had lipolytic activity, at the same time decreasing [14C]glucose incorporation in glyceride—glycerol fractions. TRH had no significant effect on glucose oxidation or lipolysis but decreased [14C]fatty acid synthesis and [14C]glucose incorporation into glyceride—glycerol fractions.
SEPHADEX GEL FILTRATION ANALYSIS OF IMMUNOREACTIVE THYROTROPHIC HORMONE IN HUMAN URINE
Authors: KUKU S. F. , HARSOULIS P. , YOUNG J. L. , QUE N. D. , FRASER T. R.
Published: December 2008

To assess whether urinary immunoassayable thyroid-stimulating hormone (TSH) differed from pituitary and serum TSH, urinary concentrates from two hypothyroid subjects were analysed by Sephadex G-100 gel filtration.

The elution profiles, measured by radioimmunoassay, were then compared with those of neat sera from hypothyroid patients and human pituitary TSH preparations. The pituitary preparations and the hypothyroid serum were eluted as a comparable single symmetrical peak corresponding to that obtained from a highly purified radio-iodinated human TSH of pituitary origin; no evidence of 'big' TSH emerged. In contrast, however, the material eluted from the hypothyroid urine concentrates not only revealed an asymmetrical peak corresponding to that described above but several other minor peaks eluting later and probably corresponding to fragments of TSH.

When human pituitary TSH was infused into two normal subjects, gel filtration analysis of concentrates from urinary samples obtained during and at fixed periods after the infusion revealed a single peak during the infusion but more peaks appeared with the later samples.
A MODIFIED BIOASSAY FOR THYROID-STIMULATING HORMONE AND LONG-ACTING THYROID STIMULATOR
Authors: NUTT J. , HUMPHREYS K. , CLARK F.
Published: December 2008

After iodine depletion of mice, the time needed for the bioassay of long-acting thyroid stimulator (LATS) and thyroid-stimulating hormone (TSH) can be shortened to allow the completion of two assays per week. Suppression of mouse TSH with 0·1 μg tri-iodothyronine was necessary in the TSH assay and with 5 μg thyroxine in the LATS assay. These can be administered as a single i.p. injection with the 131I. The response of the assay mice to TSH can be improved by giving theophylline (0·5 mg) just before, with and after the stimulus.
EFFECTS OF SEX HORMONES AND ENVIRONMENTAL LIGHTING ON RAT HARDERIAN GLAND PORPHYRIN
Authors: ULRICH RENÉE , YUWILER ARTHUR , GELLER EDWARD , WETTERBERG LENNART
Published: December 2008

Ovariectomy of adult female rats significantly decreased the porphyrin content of the Harderian glands compared with intact control rats. Treatment of ovariectomized rats for 5 days with testosterone propionate, progesterone or oestradiol did not alter porphyrin content or concentration; however, administration of oestradiol plus progesterone significantly increased Harderian gland porphyrin content to values indistinguishable from those of intact controls. Additionally, oestradiol treatment lowered the weight of the Harderian glands.

Constant light or constant darkness for 35 days significantly decreased Harderian gland porphyrins compared with those of rats kept in diurnal lighting conditions. Constant light significantly lowered porphyrin values compared with those obtained from rats maintained in constant darkness. The effects of constant light were not altered by either ovariectomy or enucleation. Harderian gland weight was reduced in all groups kept in constant light.
PLASMA LEVELS OF OESTROGEN AND PROGESTERONE IN PREGNANT AND LACTATING HAMSTERS
Authors: BARANCZUK RICHARD , GREENWALD G. S.
Published: December 2008

Oestrone (OE1), oestradiol (OE2) and progesterone were measured by radioimmunoassay in the same samples of peripheral plasma from pregnant and lactating hamsters. The levels of progesterone during most of pregnancy did not exceed the values found during the first 2 days of the oestrous cycle. However, on day 14 of pregnancy (2 days before parturition) the level of progesterone abruptly increased to 29 ng/ml and fell rapidly thereafter. Hysterectomy on day 12 of pregnancy resulted in baseline levels of progesterone ( < 2 ng/ml) on day 13 and no peak in progesterone comparable to the one observed on day 14 of normal gestation. Injecting progesterone on day 14 or later prolonged gestation and caused maternal and foetal death.

Oestradiol concentration showed peaks on days 7 (67·3 pg/ml), 11 (117·6 pg/ml) and 14 (81·8 pg/ml) of pregnancy and dropped precipitously between days 14 and 16 of pregnancy. The highest values obtained on day 11 correlated with the maximal proliferation of antral follicles. The abrupt decline of oestrogen concentration at parturition is different from the pattern found in the mouse and rat but is consistent with the lack of post-partum ovulation in the hamster. Injecting 50–150 μg oestradiol cyclopentylpropionate between days 12 and 16 did not interfere with parturition by the morning of day 16. Oestrone was detectable throughout pregnancy; the levels were lower than for OE2. In general, the oestrogen patterns were parallel.

During lactation, progesterone secretion remained relatively constant at about 10–11 ng/ml, presumably synthesized by the hypertrophied interstitium which is the dominant ovarian tissue. In most instances OE1 and OE2 were not detectable during lactation, consistent with the absence of antral follicles.
METABOLISM OF [7α-3H]DEHYDROEPIANDROSTERONE AND [4-14C]ANDROSTENEDIONE IN VITRO BY TESTICULAR TISSUE FROM ADULT AND PREPUBERTAL WISTAR RATS
Authors: RICHARDS GWEN , NEVILLE A. MUNRO
Published: December 2008

The metabolism of [7α-3H]dehydroepiandrosterone (DHA) and [4-14C] androstenedione in vitro was investigated in 30-day-old (prepubertal) and adult rat testicular tissue in the presence of cyanoketosteroid, a 5-ene-3β-hydroxysteroid oxidoreductase inhibitor.

Whereas both substrates were converted to 5α-reduced steroids by the prepubertal testis, 4-ene-steroid-5α-reductase activity was negligible in the adult gland. Cyanoketosteroid prevented the formation of 5α-reduced steroids from DHA by the prepubertal testis indicating testosterone and androstenedione as intermediates in their production.
EFFECT OF OESTROGEN ADMINISTERED IN EARLY OR LATE LACTATION ON THE YIELD AND COMPOSITION OF MILK IN SHEEP
Authors: FULKERSON W. J. , McDOWELL G. H.
Published: December 2008

Subcutaneous injections of oestradiol benzoate (OB) were given daily to lactating ewes for 7 days beginning 20 (early lactation) or 46 (late lactation) days after parturition.

Injections of 50 and 500 μg OB enhanced milk yield in ewes during late lactation and resulted in significant increases in the proportion and daily production of milk components. During early lactation, injections of 500 μg OB failed to enhance milk yield but significant increases in the fat content of milk were recorded.

The administration of 5000 μg OB resulted in a marked decline in milk yield. In milk from these ewes there was a fall in lactose content with a concomitant rise in the number of leucocytes and proportion of vacuolated macrophages suggesting that mammary involution had begun.
SECRETIN-LIKE ACTIVITY IN SUBCELLULAR FRACTIONS OF CHICKEN INTESTINAL MUCOSA
Authors: FIDDES I. J. S. , TROTMAN C. N. A.
Published: December 2008

Differential centrifugation of chicken intestinal mucosal homogenates showed that particles containing a material with secretin-like activity can be sedimented. The activity appeared to be contained in structures smaller than mitochondria. Approximately 70% of the stimulatory effect of the whole homogenate was sedimented in 10 min at 15000 g. The secretin-like material was released from the particles by treatment with hydrochloric acid and partially purified by heat denaturation of large proteins at pH 3. The relationship between relative dose of mucosal extract and secretory response in the anaesthetized cat was slightly different from that of porcine secretin.
THE BREAST CANCER DISCRIMINANT: EFFECT OF AGE, OBESITY, HIRSUTISM, STARVATION, AND CHANGES IN ADRENOCORTICAL AND GONADAL ACTIVITY
Authors: METCALF MARY G.
Published: December 2008

The relationship between 17-oxogenic steroid excretion and the urinary output of certain 17-oxosteroids has been widely used to select women with metastatic breast cancer for ablation of endocrine organs. In this report, the effect of factors other than breast cancer on the ratio of androsterone plus aetiocholanolone to the 17-oxogenic steroids in urine is examined. For 83 normal women the mean value of the ratio was 0·351 ± 0·121 (s.d.). In menstruant women the ratio did not correlate with oestrogen excretion, and was little affected by increasing age, the taking of oral contraceptive tablets, obesity, and the presence of reversible amenorrhoea. Factors causing a marked reduction in the ratio were the absence of functional ovaries (47 women, mean ratio 0·116 ± 0·066), food deprivation (15 obese women, mean decrease by the 9th day of starvation, 53·4 ± 11·7%), and adrenocortical stimulation (14 women, mean decrease on day 2 of corticotrophin infusion, 52·0 ± 17·0%). Suppression of adrenocortical function with dexamethasone treatment caused no systematic change in the value of the ratio, and hirsutism was associated with a significant increase (67 women, mean value 0·447 ± 0·165). The variability of the ratio from day to day in individual women (coefficient of variation, 20·7%) suggests that it is inadvisable to select patients for treatment on the basis of measurements made on a single 24 h sample of urine.
DIURNAL CHANGES IN PLASMA TESTOSTERONE AND STUDIES ON PLASMA CORTICOSTEROIDS IN NON-ANAESTHETIZED MALE RHESUS MONKEYS (MACACA MULATTA)
Authors: MICHAEL R. P. , SETCHELL K. D. R. , PLANT T. M.
Published: December 2008

The assays of testosterone and corticosteroids in plasma from adult male rhesus monkeys using competitive protein-binding and radioimmunoassay techniques are described. The radioimmunoassay for testosterone was conducted without chromatography and, therefore, additionally estimated 17β-hydroxy-5α-androstan-3-one (dihydrotestosterone). Levels of testosterone in the peripheral plasma of 14 intact male rhesus monkeys showed marked fluctuations over a period of 24 h. Concentrations of testosterone at 22.00 h (1776 ± 814 ( ± s.d.) ng/100 ml) were approximately double those at 08.00 h (858 ± 407 ng/100 ml), 12.00 h (898 ± 316 ng/100 ml) and 16.00 h (784 ± 530 ng/100 ml). Castration resulted in low plasma testosterone levels (85 ± 29 ng/100 ml), and the increases at 22.00 h were no longer observed. In intact males, the 'basal' plasma corticosteroidlevel(08.00 h) was 22·4 ± 6·0 μg/100 ml. Administration of synthetic corticotrophin raised plasma corticosteroid levels without changing plasma testosterone concentration. Because plasma testosterone levels were not related to changes in adrenocortical activity, the noctural rises appear to be due to changes in testicular secretion.
EFFECTS OF OESTROGEN PRIMING ON THE UPTAKE, METABOLISM AND BIOLOGICAL ACTIVITY OF PROGESTINS IN THE MOUSE UTERUS
Authors: CLARK B. F.
Published: December 2008

The effects of single subcutaneous injections of progesterone on uterine stromal and uterine epithelial mitosis and morphology varied non-linearly during the 6 days after oestrogen priming. Retention of locally applied progesterone was significantly less and recovery of its metabolites greater on day 1 after oestrogen priming than on day 6. Recovery of metabolites of two potent synthetic progestins, megestrol acetate and medroxyprogesterone acetate, was negligible after injection on either day. Retention of these progestins was the same whether given on day 1 or day 6, and was similar to the retention of progesterone when injected on day 6.
BINDING OF THYROID HORMONE IN RABBIT SERUM: DEFINITION OF A PREALBUMIN AND EFFECTS OF STRAIN VARIATION ON BINDING
Authors: DAVIS P. J. , LAIRD C. W. , FOX R. R.
Published: December 2008

Sera from inbred rabbit strains have been studied to determine radio-thyroxine distribution after electrophoresis, to measure protein binding capacity for thyroxine (T4) and to examine possible interrelationships of binding capacity and serum protein-bound iodine (PBI). In electrophoretic studies at pH 7·4, serum albumin and prealbumin, the latter a previously unrecognized carrier of T4 in the rabbit, are the principal transport proteins. At pH 9·0, prealbumin is the major carrier (61% of tracer). Prealbumin also binds significant quantities of tri-iodothyronine. The mean binding capacity of serum prealbumin for T4 in 12 rabbit strains was 500 μg/100 ml.

Protein-bound iodine levels are known to be strain-dependent in the rabbit. In the current studies, however, there was no strain-specificity of prealbumin binding capacity, and no correlation between PBI and binding capacity of prealbumin, the principal T4-specific transport protein. These observations suggest that factors other than the capacity of binding proteins for T4 may be primary determinants of hormone levels (PBI) in blood in the rabbit.
PARTURITION IN THE COW: ENDOCRINE CHANGES IN ANIMALS WITH CHRONICALLY IMPLANTED CATHETERS IN THE FOETAL AND MATERNAL CIRCULATIONS
Authors: COMLINE R. S. , HALL L. W. , LAVELLE R. B. , NATHANIELSZ P. W. , SILVER MARIAN
Published: December 2008

Intravascular catheters were placed in the umbilical, uterine and maternal peripheral circulations of 16 Jersey cows between 240 and 260 days of gestation. Foetal plasma cortisol, blood gases and pH, and maternal plasma oestrogen, progesterone and cortisol were measured in ten animals during late pregnancy and throughout spontaneous parturition; all delivered live foetuses although parturition was earlier than normal and the placenta was generally retained. The gradual pre-partum rise in foetal plasma cortisol during the last week of gestation (from 10–20 ng/ml 7 days before parturition to 51 ± 5 ng/ml in the last 3 h before delivery) was much less marked than the abrupt increase immediately after birth when the cortisol concentration invariably doubled. Maternal plasma oestrogen rose from 0.35 ± 0.04 ng/ml to 1·20 ± 0.11 ng/ml during the week before parturition. Progesterone concentrations remained stable until a sudden fall 1–2 days before delivery. The slight alterations in maternal plasma cortisol during this period were not statistically significant. The maternal plasma oestrogen levels were higher in the uterine vein than in the periphery, whereas uterine venous progesterone concentrations were significantly lower than in the peripheral circulation.
EFFECT OF DIBUTYRYL CYCLIC AMP ON THE RELEASE OF MELANOCYTE-STIMULATING HORMONE FROM RAT NEUROINTERMEDIATE LOBES IN VITRO
Authors: BAKER BRIDGET I.
Published: December 2008

A method for measuring melanocyte-stimulating hormone (MSH) in rat neurointermediate lobe in vitro and in incubation medium, using polyacrylamide gel electrophoresis, is described. Using this technique, it was shown that dibutyryl cyclic AMP increased the release of MSH in vitro, the degree of stimulation depending on the concentration of the nucleotide. The effect of low concentrations of the nucleotide was potentiated by theophylline.
LEVELS OF FOLLICLE-STIMULATING HORMONE, LUTEINIZING HORMONE, OESTRADIOL-17β AND PROGESTERONE, AND FOLLICULAR GROWTH IN THE PSEUDOPREGNANT RAT
Authors: WELSCHEN R. , OSMAN P. , DULLAART J. , DE GREEF W. J. , UILENBROEK J. TH. J. , DE JONG F. H.
Published: December 2008

Throughout a period of pseudopregnancy the peripheral blood levels of progesterone, oestradiol-17β, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), as well as the size-distribution of ovarian antral follicles were estimated in the rat. The progesterone concentrations, as measured by a competitive protein-binding technique, exceeded metoestrous values (25 ng/ml plasma) from day 3 of pseudopregnancy onwards. The highest levels were found on days 6 and 8 (91 ng/ml). From day 8 onwards the levels decreased gradually but were still above metoestrous values on the day of pro-oestrus after pseudopregnancy. Concentrations of oestradiol-17β, as measured by radioimmunoassay, were within the range of those at metoestrus (about 5 pg/ml plasma) until day 10. Thereafter levels increased to a value of 57 pg/ml.

Concentrations of FSH, measured by radioimmunoassay, were within the range of metoestrous values until day 10 (about 100 ng NIAMD-rat-FSH RP-1/ml serum), but declined to a level of 33 ng/ml on day 12. Concentrations of LH, measured by radioimmunoassay, were generally within the wide range of metoestrous values (9–60 ng NIAMD-rat-LH RP-1/ml serum), but concentrations found on days 4, 8 and 10 were significantly lower than those found on preceding or subsequent days.

Histological determination of the number of follicles present in various volume-classes, showed an increase in antral follicles on days 1 and 2, comparable to the increase observed during metoestrus and dioestrus 1 of the normal cycle. There was no change in the follicles between days 3 and 10 and they resembled those of early dioestrus. Preovulatory growth had occurred by day 12. Injection of human chorionic gonadotrophin (HCG) on days 2, 4 or 6 showed that ovulation could be induced only in some of the larger follicles.

On the basis of these results it is suggested that during pseudopregnancy the high progesterone levels present result in a decreased plasma LH level which is insufficient to cause full maturation of the follicles and to stimulate oestrogen secretion to the levels required for induction of an ovulatory surge of LH release.
RELATIVELY GREATER INCREASE OF OXYTOCIN THAN VASOPRESSIN IN THE SUPRAOPTIC NUCLEUS OF RATS AFTER HYPOPHYSECTOMY
Authors: DYBALL R. E. J. , HENRY JUDITH A.
Published: December 2008

The vasopressor and milk ejection activities were estimated in the supraoptic region of the hypothalamus of rats which had been hypophysectomized 30 min, 4 and 8 days earlier. Both pressor and milk ejection activities were significantly greater 4 days after hypophysectomy than those in sham-operated control rats. Eight days after hypophysectomy, pressor activity decreased below control values but milk ejection activity was still significantly raised. Increased biological activity after hypophysectomy is thus associated with the previously observed increase in neurosecretory material within the supraoptic nucleus so these results provide additional evidence that neurosecretory material represents stored hormone. Milk ejection activity increased relatively more than pressor activity which supports the suggestion that the final stage in the formation of neurohypophysial hormones occurs as they pass from the hypothalamus to the neural lobe. If this final maturation normally occurs more slowly for oxytocin than for vasopressin, the obstruction to the flow of hormones down the neural stalk caused by hypophysectomy would result in a greater increase in milk ejection than pressor activity.
SUPERFUSION IN VITRO IN THE STUDY OF OVARIAN STEROIDOGENESIS
Authors: WATSON JOHN , LEASK J. T. S.
Published: December 2008

A method for the continuous superfusion of porcine corpus luteum tissue is described which readily allows both the introduction of regulatory factors to the incubating tissue, and sampling of the tissue. Oestrogen (principally oestradiol) and progestin (principally progesterone) can be measured for up to 24 h in the superfusate from corpora lutea of all ages, and the secretion of both steroids is stimulated by the addition of luteinizing hormone. The pattern of response of both steroids to a pulse of gonadotrophin was similar in that a rapid transient increase in secretion occurred followed some time later by a secondary and more prolonged response. A second pulse of gonadotrophin introduced 6 h after the first also stimulated steroid secretion, indicating that during superfusion in vitro the porcine corpus luteum does not become refractory to the steroidogenic effect of gonadotrophin.
EFFECTS OF HYPOTHALAMIC EXTRACT AND DIBUTYRYL CYCLIC ADENOSINE MONOPHOSPHATE ON FOLLICLE-STIMULATING HORMONE PRODUCTION IN THE RAT ADENOHYPOPHYSIS IN VITRO
Authors: DAVIS J. C. , HYMER W. C.
Published: December 2008

An assay system, using the characteristic migration of follicle-stimulating hormone (FSH) on polyacrylamide gels, was developed to evaluate the effects of hypothalamic factors on amino acid incorporation into FSH in the rat adenohypophysis incubated in vitro. Follicle-stimulating hormone extracted from rat pituitary secretory granules was found to migrate on 7·5% polyacrylamide gels, pH 9·5, as a protein with an RF of 0·614. The characteristic RF was used to measure [14C]amino acid incorporation into FSH in rat adenohypophyses in vitro. Follicle-stimulating hormone synthesis increased after addition of crude hypothalamic extract to the incubation medium. Hormone synthesis was also increased three times after the addition of dibutyryl cyclic AMP.
PARTIAL FEMINIZATION OF HEPATIC STEROID METABOLISM IN MALE RATS AFTER NEONATAL ADMINISTRATION OF CYPROTERONE ACETATE
Authors: GUSTAFSSON JAN-ÅKE , INGELMAN-SUNDBERG MAGNUS , STENBERG ÅKE , NEUMANN FRIEDMUND
Published: December 2008

The metabolism of [4-14C]4-androstene-3, 17-dione, [4-14C]5α-androstane-3α, 17β-diol and 1,2-3H]5α-androstane-3α, 17β-diol 3,17-disulphate was studied using the microsomal fraction and the metabolism of [4-14C]4-androstene-3, 17-dione was studied using the 105 000 g supernatant fraction of liver from male and female rats aged 5 months that had been treated with cyproterone acetate before (from day 13 of pregnancy) and after birth (until 3 weeks of age). Nearly all sex-dependent enzyme activities in the treated male rats were changed in a direction characteristic of female rats: 5α-reductase active on 4-androstene-3, 17-dione increased in activity whereas 3β- and 17α-hydroxysteroid reductases and 6β- and 16α-hydroxylases active on 4-androstene-3, 17-dione and 2α-, 2β- and 18-hydroxylases active on 5α-androstane-3α, 17β-diol decreased in activity. Enzyme activities not under gonadal control, i.e. 3α- and 17β-hydroxysteroid reductases active on 4-androstene-3, 17-dione and 7α-hydroxylase active on both 4-androstene-3, 17-dione and 5α-androstane-3α, 17β-diol, were not affected by cyproterone acetate. The liver enzyme activities in treated female rats were generally not affected although significant effects were noted in two cases; in one of these (17α-hydroxysteroid reductase) a testosterone-like effect was observed.

The results obtained are probably best explained in the following way: treatment with the anti-androgen during the neonatal period results in less efficient imprinting of the hypothalamo-hypophysial system leading to less pronounced masculine setting of sex-dependent enzyme levels and also to a relative androgen unresponsiveness. It is suggested that the biochemical methods used in the present investigation may be used for more exact estimation of the degree of neonatal sexual differentiation of the hypothalamo-hypophysial system than biological and psychological methods previously available.
ESTIMATION OF ALDOSTERONE, 11-DEOXYCORTICOSTERONE, 18-HYDROXY-1 1-DEOXYCORTICOSTERONE, CORTICOSTERONE, CORTISOL AND 11-DEOXYCORTISOL IN HUMAN PLASMA BY GAS–LIQUID CHROMATOGRAPHY WITH ELECTRON CAPTURE DETECTION
Authors: MASON P. A. , FRASER R.
Published: December 2008

A method for determining the plasma concentrations of six major corticosteroids, aldosterone, 18-hydroxy-11-deoxycorticosterone (18-OH-DOC), corticosterone, deoxycorticosterone (DOC), cortisol and 11-deoxycortisol using gas–liquid chromatography with electron capture detection is described. Esterification of suitable derivatives of these compounds with heptafluorobutyric anhydride (HFB) allowed detection of quantities of steroid, ranging from 0·3 pg for androstenetrione HFB (from cortisol) to 2·3 pg for corticosterone HFB. No detectable reagent blank was obtained for any compound when water was used instead of plasma and this was also the case when plasma from an adrenalectomized subject was analysed, with the exception of 18-OH-DOC where a reproducible but negligibly small blank occurred. Coefficients of variation for replicate determinations ranged from 8% for corticosterone to 17% for aldosterone. Concentrations in a series of normal human plasma samples were as follows: aldosterone, 4·0–18·0 ng/ 100 ml; 18-OH-DOC, 20–160 ng/ml; corticosterone, 0·08–0·80 μg/100 ml; DOC, 2·8–16·0 ng/100 ml; cortisol, 2·5–10·0 μg/100 ml;and 11-deoxycortisol, 40·0–400·0 ng/100 ml. When seven normal subjects were treated with dexamethasone, concentrations of DOC, cortisol and 11-deoxycortisol fell to below the limit of the normal range, those of 18-OH-DOC and corticosterone were at the lower end of the normal range while the concentration of aldosterone was not significantly affected.
PLASMA PROGESTERONE AND ITS RELATIONSHIP TO SERUM GONADOTROPHINS IN IMMATURE FEMALE RATS
Authors: MEIJS-ROELOFS H. M. A. , DE GREEF W. J. , UILENBROEK J.TH.J.
Published: December 2008

In immature female rats, low values for concentrations of plasma progesterone were generally found from days 6–15 and from days 25–32 of life. Maximum progesterone concentrations (13·0–14·1 ng/ml), comparable to metoestrous values in the adult rat, occurred on days 20–22. The progesterone appeared to be of ovarian origin since after ovariectomy, on day 18, low progesterone concentrations were found 1 and 2 days later (2·5 ng/ml and 1·3 ng/ml) as compared with control values of 10·7 ng/ml and 14·1 ng/ml. However, adrenalectomy also lowered progesterone concentrations, 1 and 2 days later (6·4 and 4·9 ng/ml).

The effect of progesterone, either alone or in combination with oestradiol benzoate (OB), on serum gonadotrophins was studied in rats ovariectomized on day 18. The highest dose of progesterone (0·15 mg) only slightly diminished the rise in serum luteinizing hormone (LH) after ovariectomy and had no effect on serum follicle-stimulating hormone (FSH).

Oestradiol benzoate in a dose of 0·025 μg/100 g body weight was highly effective in preventing the rise in both LH and FSH concentrations, and OB treatment (resulting in a near-physiological oestradiol concentration) combined with progesterone treatment was more effective than treatment with OB alone.

The results suggest that the amounts of progesterone and oestradiol present in the 20-day-old rat are adequate to cause the decrease in FSH level normally observed in immature female rats around this age.
CHANGES IN THE CONCENTRATION OF PITUITARY AND STEROID HORMONES IN THE FOLLICULAR FLUID OF HUMAN GRAAFIAN FOLLICLES THROUGHOUT THE MENSTRUAL CYCLE
Authors: McNATTY K. P. , HUNTER W. M. , McNEILLY A. S. , SAWERS R. S.
Published: December 2008

The concentrations of FSH, LH, prolactin, oestradiol and progesterone were measured in peripheral plasma and follicular fluid of women throughout the menstrual cycle. With the exception of prolactin, concentrations of pituitary and steroid hormones in follicular fluid correlated with those in peripheral plasma.

Follicle-stimulating hormone was present in a greater number of small follicles ( < 8 mm) during or just after the peaks of FSH in peripheral plasma. During the mid-follicular phase the concentration of both FSH and oestradiol in fluid from large follicles ( ≥ 8 mm) was high. During the late follicular phase the large follicles ( ≥ 8 mm) contained high amounts of progesterone in addition to oestradiol, low physiological levels of prolactin, and concentrations of LH and FSH about 30 and 60% respectively of those found in plasma. By contrast no large 'active' follicles ( ≥ 8 mm) were found during the luteal phase although many contained both LH and FSH. Luteinizing hormone was present in a proportion of small follicles ( < 8 mm) during the late follicular and early luteal but not at other stages of the menstrual cycle.

It is suggested that a precise sequence of hormonal changes occur within the microenvironment of the developing Graafian follicle; the order in which they occur may be of considerable importance for the growth of that follicle and secretory activity of the granulosa cells both before and after ovulation.
A COMPARISON OF THE EFFECTS OF THE CALCITONINS, STEROID HORMONES AND THYROID HORMONES ON THE RESPONSE OF BONE TO PARATHYROID HORMONE IN TISSUE CULTURE
Authors: ATKINS D. , PEACOCK M.
Published: December 2008

A bone culture system was used to compare the effects of several hormones on the response of 5-day-old mouse calvaria to parathyroid hormone (PTH). The results showed that salmon calcitonin was almost 105 times more active than any other hormone in preventing the PTH-induced release of calcium and caused a dose-related inhibition of calcium release over a range of 0·2–200 milli MRC units/culture. A high dose of calcitonin (200 milli MRC units) caused a net accretion of calcium in the absence of PTH. Progesterone and testosterone were more active than the naturally occurring oestrogens although a synthetic oestrogen (stilboestrol diphosphate) had approximately the same potency. High concentrations of these hormones caused a net accretion of calcium whether or not PTH was present. Cortisol was only effective at high doses, as was the steroid precursor cholesterol. In the present culture system the thyroid hormones (triiodothyronine and thyroxine) inhibited the action of PTH.

It was concluded that these agents acted in a similar fashion to the oestrogens. That is, they prevented the accumulation of citric acid induced by PTH by reducing the rate of glycolysis. None of the hormones affected the inhibition of citrate oxidation caused by PTH.

The results also showed that, whilst these hormones inhibited PTH-mediated bone resorption, they had an action on bone independent of PTH. Experiments with clomiphene citrate failed to demonstrate an oestrogen receptor in bone.
RELEASE OF CORTICOTROPHIN RELEASING FACTOR AND OTHER HYPOPHYSIOTROPIC SUBSTANCES FROM ISOLATED NERVE-ENDINGS (SYNAPTOSOMES)
Authors: BENNETT G. W. , EDWARDSON J. A.
Published: December 2008

Synaptosomes isolated from the sheep and the rat hypothalamus contain corticotrophin releasing factor, vasopressin, prolactin-release inhibiting factor and probably all of the substances which participate in the regulation of adenohypophysial function. Electrical field stimulation or depolarizing concentrations (55 mmol/l) of potassium ions cause a release of these factors from the incubated nerve-endings in a calcium-dependent manner. It is suggested that synaptosomes may provide a valuable approach to the study of mechanisms involved in hypothalamic neurosecretion in vitro.
OESTRADIOL-INDUCED SYNTHESIS OF A SPECIFIC UTERINE PROTEIN IN PROPRANOLOL-TREATED RATS
Authors: DUPONT-MAIRESSE N. , GALAND P.
Published: December 2008

While there is conflicting evidence concerning an effect of oestradiol on uterine cyclic AMP concentration, results from different laboratories (including ours) are in agreement that even when observed, the early increase in uterine cyclic AMP after oestradiol injection fails to occur when propranolol, a β-adrenergic blocking agent, is given (50 μg, i.p.) 20 min before the oestradiol.

The present work shows that pretreatment with propranolol failed to inhibit an early uterine response to oestradiol, namely the synthesis after 1 h of uterine protein, or class of proteins, IP. It is concluded that the induction of IP by oestradiol does not depend on an increase in uterine cyclic AMP concentration and that β-adrenergic receptors do not have a role in this oestrogenic response.
5α-DIHYDROTESTOSTERONE STIMULATION OF HUMAN PROSTATE IN ORGAN CULTURE
Authors: GHANADIAN R. , CHISHOLM G. D. , ANSELL I. D.
Published: December 2008

Explants of human benign hypertrophied prostate were cultured for 8 days. The effect of 5α-dihydrotestosterone on the morphology, DNA and glucose utilization of 14 cases was investigated. In four cases proliferation was clearly more extensive in the dihydrotestosterone-treated explants than in the controls. In six explants, there were no morphological differences between those cultured with or without dihydrotestosterone and in half of these, proliferation was present. Four explants were either necrotic or did not contain epithelial cells. The mean DNA content of the treated explants was higher than that of the controls (P < 0·01). There was no significant difference in the rate of glucose utilization by the explants treated with dihydrotestosterone, and by the controls.
ANDROGENIC REGULATION OF RAPIDLY SYNTHESIZED RNA IN THE RAT VENTRAL PROSTATE
Authors: HONMA YOSHIO , NOUMURA TETSUO
Published: December 2008

The influence of castration on the incorporation of nucleotide precursors into RNA of isolated prostatic tissue has been investigated. Castration brought about an apparent increase of incorporation by increasing the specific activity of the uridine nucleotide pool and not by an enhancement in synthesis of rapidly labelled RNA. An actual decrease in this reaction was shown by dividing the radioactivity incorporated into RNA by the specific activity of the uridine nucleotide. Administration of testosterone brought about enhanced synthesis of RNA in the prostates of rats castrated for 3 days as early as 4 h after injection, reaching maximum effect at 8 h. No significant difference was found between the turnover rates of rapidly labelled RNA from castrated, androgen-treated castrated and intact rats. The increased prostatic permeability to nucleosides as an early action of androgens in this organ is discussed.
A RADIOIMMUNOASSAY FOR PLASMA ARGININE-VASOPRESSIN IN MAN AND DOG: APPLICATION TO PHYSIOLOGICAL AND PATHOLOGICAL STATES
Authors: MORTON J. J. , PADFIELD P. L. , FORSLING MARY L.
Published: December 2008

A radioimmunoassay has been developed for plasma arginine-vasopressin in man and dog. The mean recovery of added arginine-vasopressin (AVP) was 60 ± 6·9 (s.d.)% and the lower threshold of detection 2·0 pmol/l. A close correlation was found between concurrent radioimmunoassay and bioassay values. The mean concentration found in peripheral venous blood in healthy men after overnight fasting was 5·3 pmol/l (range 4·6–6·2 pmol/l). In man, significant increases in plasma AVP occurred after dehydration (5·9–9·5 pmol/l) and significant decreases after oral water-loading (5·2–3·7 pmol/l). During i.v. infusion of graded doses of synthetic AVP in normal men, plasma levels were closely correlated with infusion rate. On stopping the infusion, plasma vasopressin fell exponentially with a half-life of between 7 and 8 min. In man, plasma AVP was unaffected by tilting head-up for 2 h, or by a non-hypotensive bleeding of 500 ml in 10 min. In the dog, haemorrhage of 5 ml/kg and over caused proportionate increases in AVP in the circulation. In normal men, plasma vasopressin was significantly correlated with concurrent urinary osmolality. Five patients with oat-cell bronchial carcinoma and hyponatraemia showed a marked increase of plasma vasopressin. Five patients with diabetes insipidus had significantly reduced, but detectable, levels of plasma AVP. The plasma concentration in these patients did not increase after water restriction.
INHIBITORY EFFECT OF PROGESTERONE ON THE LACTOGENIC AND ABORTIVE ACTION OF PROSTAGLANDIN F2α
Authors: VERMOUTH NELIA T. , DEIS R. P.
Published: December 2008

The effect of ovariectomy, progesterone and prolactin treatment on the action of prostaglandin F2α (PGF2α) was determined in pregnant rats. PGF2α (150 μg × 2) injected i.p. on day 19 or 18 of pregnancy induced lactogenesis about 25 h later and abortion on days 20 and 21 of pregnancy. Treatment with PGF2α (100 μg × 2 or 50 μg × 2) on day 19 induced lactogenesis around 22 or 38 h later, respectively, and abortion on day 21. PGF2α treatment on day 17 was less effective. Unilateral ovariectomy on day 17 of pregnancy induced lactogenesis 32 h later but not abortion. PGF2α (150 μg × 2) given on the day of surgery advanced lactogenesis 12 h and rats aborted on day 19. Bilateral ovariectomy on day 17 induced abortion between days 20 to 21, but if a single dose of PGF2α (300 μg) was injected on day 18, all the ovariectomized rats aborted on day 19. Progesterone (10 mg) injected into rats treated with PGF2α (150 μg × 2) on day 18, prevented abortion and delayed lactogenesis. Prolactin (1 mg × 4) treatment delayed only abortion. Serum prolactin levels were significantly higher 12 h after the last dose of PGF2α (150 μg × 2) in rats treated on days 17, 18 or 19 of pregnancy. Pretreatment with progesterone prevented the rise in prolactin concentration. These results suggest that the lactogenic and abortive action of PGF2α may be dependent on the uterine and plasma concentration of progesterone.