bluuebunny/crossref_metadata_2025 huggingface dataset:
REGULATION OF PLASMA OESTROGENS IN NORMAL ADULT MALES
Authors: Doerr Peter , Pirke Karl M.
Published: December 2008

The response of plasma oestradiol (Oe2), oestrone (Oe1), testosterone (T) and cortisol to dexamethasone and ACTH administration in normal adult males was ascertained. After an oral dose of 1.5 mg dexamethasone Oe1 decreased from 2.51 to 1.85 ng/100 ml (74 % of the control level, mean of 15 subjects) over night and after continuing the dexamethasone administration for two more days (twice daily 1.5 mg) Oe1 decreased to 1.30 ng/100 ml (52 %). Oe2 (control level 1.71 ng/100 ml) and T (678 ng/100 ml) did not change over night, but at the end of the test Oe2 decreased to 84 % and T to 91 % of the control level.

After a single im injection of 2 mg β 1–24 cortrophin Oe1 increased 1.9 times (mean of 13 subjects) without further increase during two more days of treatment (twice daily 1 mg), while Oe2 did not change over night and decreased to 75 % of the control level at the end of the test. Under ACTH T decreased to 66% of the control level over night and to 50% at the end of the test indicating a suppression of the testicular hormone secretion. From these results and those reported previously it was concluded that the testicular hormone secretion influences mainly Oe2 in peripheral plasma, while Oe1 depends mainly on the adrenal hormone secretion.
BLOOD PLASMA LEVELS OF PROGESTERONE AND OESTRADIOL IN THE DOG DURING THE OESTROUS CYCLE AND PREGNANCY
Authors: Edqvist L.-E. , Johansson E. D. B. , Kasström H. , Olsson S.-E. , Richkind M.
Published: December 2008

Plasma oestradiol and progesterone levels were studied in German Shepherd and Greyhound bitches during the normal oestrous cycle, pregnancy and at parturition.

The mean oestradiol level increased from approximately 7 to 13 pg/ml during the fifth week before onset of oestrus. Oestradiol stayed at this level until pro oestrus which was characterized by a steady increase to a mean peak level of about 30 pg/ml 5–6 days before oestrus. At the start of oestrus the level was approximately 12 pg/ml. A level between 10–15 pg/ml was kept during the following 10 weeks whether or not the bitch was pregnant and no change occurred at parturition.

The mean progesterone level was found to be very low, around or under 1 ng/ml, until 1–4 days after the oestradiol peak after which the level gradually increased to around 10 ng/ml at the start of oestrus. During oestrus and metoestrus or pregnancy the pattern was inconsistent. In some bitches the level gradually increased during 3–4 weeks and reached a peak value of 30–50 ng/ml. The level then gradually decreased during 5–6 weeks. During the first 5 weeks of the same period progesterone in other bitches fluctuated between similar maximum levels and extremely low levels. After the fifth week the pattern was the same for all bitches. In the pregnant bitches there was a significant drop of the progesterone level at parturition.

The data suggest that the dog is not an ideal test animal for steroids synthetized for use in man.
SIMULTANEOUS DETERMINATIONS OF OESTRADIOL-17β, PROGESTERONE AND LUTEINIZING HORMONE IN THE PLASMA DURING THE OVULATORY CYCLE OF THE HEN
Authors: Shodono Masahide , Nakamura Takao , Tanabe Yuichi , Wakabayashi Katsumi
Published: December 2008

Simultaneous determinations of plasma levels of oestradiol-17β, progesterone and luteinizing hormone (LH) during the ovulatory cycles of hens were performed using radioimmunoassay techniques without chromatography. Blood samples were collected from the wing vein of 7 hens with regular ovulatory cycle at intervals of 1, 2 or 4 h throughout 36 h starting 24–25 h before the second egg (C2) ovulation of the clutch and ending 11–12 h after C2 ovulation. The oestradiol-17β level of the plasma during the ovulatory cycle varied from 50 pg/ml to 250 pg/ml. The value was high 24 h before ovulation and decreased until 10 h before ovulation, then increased and reached a peak 4–5 h before ovulation, when it started to decrease again until 12 h after ovulation. The plasma levels of progesterone varied from 1 ng/ml to 6 ng/ml, and reached a peak 4–6 h before ovulation. The plasma LH value varied from 1 ng/ml to 4 ng/ml, and the changes in the levels corresponded well with that of progesterone, also showing a coincident peak.
PROGESTERONE-BINDING PROTEINS FROM ENDOMETRIUM AND MYOMETRIUM OF SHEEP UTERUS: A COMPARATIVE STUDY
Authors: Kontula Kimmo
Published: December 2008

The binding of tritiated progesterone to the cytoplasmic progestogen receptors from oestrogen-primed sheep endometrium and myometrium has been investigated. The binding characteristics of the progesterone receptors from both sources were determined in the supernatant fractions obtained after high speed centrifugation of the myometrial and endometrial homogenates.

High affinity binding proteins with identical association constants for progesterone (1 × 109 m−1) were detected in both endometrium and myometrium. The concentration of binding sites was also of the same order of magnitude in both tissues. After centrifugation on sucrose gradients, these binding proteins were shown to have similar sedimentation constants, 7 S in a gradient containing no added KC1 and 4 S in a gradient containing 0.4 m KCI. The binding peaks from both sources could be abolished by heating the cytosol at 60°C for half an hour. The proteinaceous nature of the binding materials was demonstrated by incubation of the endometrial and myometrial cytosols with pronase, DNase and RNase: the binding was totally eliminated by the proteolytic action of pronase whereas DNase and RNase had no effect.

The ligand specificity of the two progesterone binding proteins was studied using a competitive protein-binding technique. Both the endometrial and the myometrial receptor proteins were shown to bind only steroids which are known potent progestogens. In addition, the relative affinities of the binding proteins for 37 steroidal compounds closely resembled each other. Thus, the physicochemical and binding data obtained show that a very close similarity exists between the progesterone-binding proteins in the endometrium and myometrium of ovariectomized sheep after oestradiol treatment.
THE HYPERCALCAEMIC SYNDROME IN RATS BEARING THE WALKER CARCINOSARCOMA 256
Authors: Minne H. , Raue F. , Bellwinkel S. , Ziegler R.
Published: December 2008

The strain of Walker carcinosarcoma 256 described induces hypercalcaemia, hyperphosphataemia and hyperuraemia in tumour bearing rats. Changes in calcium and phosphorus excretion are observed as well as accompanying calcification of soft tissue organs and loss of bone calcium. These changes in calcium metabolism disappear after removal of the tumour, so that long-range action of the tumour can be stated. The results are discussed in comparison with three other animal models of tumour dependent hypercalcaemia.
DIAGNOSTIC VALUE OF THE LH-RELEASING HORMONE STIMULATION TEST IN FUNCTIONAL AMENORRHEA
Authors: Vandekerckhove D. , Dhont M. , Van Eyck J.
Published: December 2008

LH-releasing hormone (25 μg, iv.) was administered to 37 women with functional amenorrhea. In addition to the clinical classification, these patients were divided into three groups according to the basal level of serum LH. A significant correlation was found between the base-line levels of LH and the serum concentration of oestradiol plus oestrone. The absolute increment of LH after the injection of LH-RH was found to be dependent only on the base-line level of LH. Except for the patients with anorexia nervosa, the base-line levels and the response pattern of FSH were almost the same for all three groups.

From the results of this study, it was concluded that:

The circulating levels of oestradiol and oestrone, where derived from ovarian secretion, actually depend on the gonadotrophic stimulus. In patients with functional amenorrhea, the oestrogens do not make an independent contribution to the pituitary response to LH-RH.

Dysregulation of releasing hormones, whether located at the hypothalamic or suprahypothalamic level, necessarily influences the secretory capacity of the pituitary gland; long-standing deficiency of LH-RH may finally lead to a state of pituitary "functional" unresponsiveness to releasing hormones.

In view of the excellent correlation between the base-line levels of LH and the absolute increment of LH following stimulation with LH-RH, this test only accentuates the existing pituitary secretory capacity, which can be roughly estimated from the circulating levels of LH and FSH.

This test may be useful in distinguishing the milder cases of psychogenic amenorrhea from extreme gonadotrophic dysfunction in patients with anorexia nervosa.
SHORT-LOOP FEEDBACK MECHANISM OF LUTEINIZING HORMONE: LH STIMULATES HYPOTHALAMIC L-CYSTINE ARYLAMIDASE TO INACTIVATE LH-RH IN THE RAT HYPOTHALAMUS
Authors: Kuhl Herbert , Taubert Hans-Dieter
Published: December 2008

The effect of the intravenous administration of several hormones on L-cystine arylamidase in the hypothalamus of the rat was examined. The injection of 10 μg LH into adult male and female rats was followed within 90 min by an increase of the enzyme activity by 50 %, while infantile animals were not affected. When prepuberal rats were pre-treated sc with testosterone and oestrogen respectively, the iv injection of LH brought about a rise in hypothalamic arylamidase activity. When ovariectomized rats were tested, no response was seen after LH injection unless the animals had been pre-treated with oestrogen and progesterone. The iv injection of 0.1 μg oestradiol-17β into female, and of 0.5 μg testosterone into male intact mature rats also resulted in an increase of hypothalamic enzyme activity. The maximal increase in enzyme activity was seen 16 h after steroid treatment. As it had previously been shown that L-cystine arylamidase inactivates LH-RH, it may be assumed that this enzyme is involved in the short-loop feedback of LH. This assumption is based on the observation that an elevation of plasma LH brings about an activation of the enzyme system, which subsequently leads to increased inactivation of LH-RH in the hypothalamus. This mechanism seems to depend on the presence of certain plasma levels of oestrogen in female, and of testosterone in male animals.
DIFFERENTIAL EFFECTS OF CASTRATION ON LH AND FSH SECRETION IN MALE AND FEMALE RATS
Authors: Zanisi M. , Martini L.
Published: December 2008

Serum levels of LH and of FSH have been measured using specific radioimmunological procedures in normal controls and in male and female rats submitted to castration 1, 2, 7, 14, 21, 28 and 35 days before. Gonadectomy is followed by a rapid increase of serum levels of LH in males, and by a delayed response in females. The responses of serum FSH to castration are quantitatively and qualitatively similar in the two sexes. Both in males and in females an elevation of serum FSH levels is already present 1 day after the operation. Serum FSH continues to rise, between post-castration days 1 and 7 with a rather rapid slope, and at later intervals with a smoother progression.
THE INFLUENCE OF TIME, DOSE AND GONADAL STEROIDS ON LH-RH-INDUCED GONADOTROPHIN RELEASE IN RATS
Authors: Lotz Wolfgang
Published: December 2008

Hypophyseal responses to LH-releasing hormone (LH-RH) were studied in ovariectomized rats, pre-treated once with 50 μg oestradiol-3-benzoate alone or in combination with 25 mg progesterone either 16, 24, 48 or 72 h before the administration of LH-RH. The highest serum gonadotrophin increase was detected in ovariectomized rats pre-treated with oestrogen 48 h before the LH-RH injection.

The serum LH concentration change in intact male rats was markedly lower in terms of order of magnitude than in ovariectomized, oestradiol-3-benzoate, progesterone-treated rats ("O. Oe. P."-rats). These latter test animals showed the maximal increase of serum LH concentration, depending on the dose of LH-RH, after 10 to 25 min and that of FSH after 40 min.

The dose-response curves for LH release in "O. Oe. P."-rats were linear for short (10 and 15 min) and sigmoid for longer time intervals (20, 30 and 40 min) between LH-RH injection and sacrifice.

The possible reasons for the difference in both magnitude and time-lapse for maximal increase of serum LH and FSH concentration, the influence of steroid pre-treatment and the variation of the time-course of serum LH concentration, depending on the dose of LH-RH, are discussed.
THE EFFECT OF ATROPINE ON INSULIN RELEASE CAUSED BY INTRAVENOUS GLUCOSE IN THE RHESUS MONKEY
Authors: Daniel P. M. , Henderson J. R.
Published: December 2008

Glucose was given as a rapid intravenous injection to fasted anaesthetized rhesus monkeys, and the concentrations of blood glucose and plasma insulin were measured. Glucose caused a biphasic insulin response. The first phase (which was short) occurred 1 min after the injection; the second was longer, and occurred 17 to 30 min after the injection. Following the control glucose injection, each animal was given atropine, and the insulin response to an identical glucose stimulus was measured. This produced a mean reduction of 45 % in the area under the curve of insulin release. Both phases of insulin release were inhibited by atropine. When glucose was given alone, its mean half-time of disappearance from the circulation (t1/2) was 25.4 (± 1.9 sem) min. After atropine the mean t1/2 was 36.6 (± 3.1 sem) min, a significant difference. It is suggested that the delayed rate of disappearance of glucose from the circulation is the result of inhibition of insulin release by atropine.
EFFECTS OF CALCIUM AND SODIUM ON VASOPRESSIN RELEASE IN VITRO INDUCED BY A PROLONGED POTASSIUM STIMULATION
Authors: Müller J. R. , Thorn N. A. , Torp-Pedersen C.
Published: December 2008

Groups of isolated hemilobes of rat neurohypophyses were stimulated for 90 min with a 56 mm K+ concentration in the surrounding medium. The rate of release of vasopressin into the medium showed an early maximum followed by a long phase of decline which lasted for most of the stimulation period. When 3 min collection periods were employed, higher secretion rates were obtained than when using 10 min periods. This may be due to a higher rate of removal of vasopressin from the tissue and a lower vasopressin inactivation when 3 min periods are used. When Na+ was replaced by sucrose in the incubation medium for the whole stimulation period, much higher secretion rates than previously reported were obtained (13 % of the total hormone content in the first 30 min period and 21 % for the total 90 min period).

When Na+ was removed from the incubation medium late in the stimulation period, a new high secretion rate was induced, provided that extracellular calcium was present.

When Ca2+ was removed from the medium 3 min after start of the stimulation with 56 mm K+, the secretion rate fell very rapidly. Reintroduction of a normal Ca2+ concentration caused a new marked increase in secretion rate.

These results further stress the importance of extra-cellular calcium for release of vasopressin. In addition they show that a considerable fraction of the vasopressin present in the neurohypophysis can be mobilized during a continued strong stimulation if sodium is omitted from the medium.
ALTERATIONS IN CYCLIC NUCLEOTIDES IN DOGS AFTER TRIIODOTHYRONINE
Authors: Fernandez-Pol J. A. , Hays Marguerite T.
Published: December 2008

The effects of triiodothyronine (T3) on plasma and tissue levels (liver, adipose tissue, muscle) of adenosine 3′,5′-monophosphate (cyclic AMP) and guanosine 3′,5′-monophosphate (cyclic GMP) were determined in Mongrel dogs. Plasma cyclic AMP increased to a mean plateau value 165 % greater than control values in response to a single intravenous injection of T3 (100–200 μg/kg body weight). This treatment resulted in no increase in plasma cyclic GMP. In liver, cyclic AMP concentration decreased 54 %, while cyclic GMP increased 137 %. Adipose tissue cyclic AMP levels decreased in control animals during the experimental procedure. On the other hand, animals given T3 had stable or (in one case) increasing adipose tissue cyclic AMP levels. Hence, T3, actually maintained higher levels than that expected, in comparison to the control. Cyclic GMP levels in adipose tissue were not affected by T3. Cyclic AMP and cyclic GMP were unchanged in muscle. In all cases, a time lag occurred (30–40 min) between administration of T3 and subsequent alterations in cyclic nucleotide levels.

It was concluded that T3 is capable of altering concentrations of cyclic AMP and cyclic GMP in vivo and that cyclic AMP and cyclic GMP patterns of response are completely different. In liver, a converse relation of the two nucleotides is present. These findings are compatible with the hypothesis that some of T3's action may be explained by its effects upon either cyclic AMP or cyclic GMP.
STUDIES ON 17β-HYDROXYSTEROID DEHYDROGENASE IN HUMAN ENDOMETRIUM AND ENDOMETRIAL CARCINOMA
Authors: Pollow K. , Lübbert H. , Boquoi E. , Kreutzer G. , Jeske R. , Pollow B.
Published: December 2008

Specific activity of 17β-hydroxysteroid dehydrogenase (17β-HSD) was measured in subcellular fractions of normal endometrium at different phases of the menstrual cycle, and of endometrial carcinoma at different degrees of differentiation. The purity of fractions was determined by marker enzymes, RNA/DNA ratio or electronmicrographs. Both in normal and neoplastic tissue 17β-HSD activity was located mainly in mitochondria and microsomes. The microsomal enzyme is bound tightly to the membranes of the endoplasmic reticulum. While in normal endometrium specific enzyme activity in subcellular fractions depended on the phase of the cycle, in endometrial carcinoma it depended on the degree of differentiation of the tumours. The highest values of 17β-HSD activity were found in mitochondria and microsomes of early secretory endometrium (factor 10 as compared to proliferative endometrium) and in particulate fractions of well differentiated carcinoma (factor 10 to ⪢ 10 as compared to undifferentiated carcinoma).
TESTOSTERONE 5α-REDUCTION IN THE SKIN OF NORMAL SUBJECTS AND OF PATIENTS WITH ABNORMAL SEX DEVELOPMENT
Authors: Kuttenn Frédérique , Mauvais-Jarvis Pierre
Published: December 2008

Human pubic skin was obtained from normal subjects and patients with abnormal sex differentiation. Skin samples (200 mg) supplemented with NADPH, were incubated for 1 h with labelled testosterone. The conversion of testosterone to dihydrotestosterone1), 3α- and 3β-androstanediol was calculated. This conversion averaged 14.9 ± 3.4 % (se) in 11 normal men and 3.6 ± 1.4 % (se) in 8 normal women. In 4 children as in 4 young hypogonadotrophic hypogonadal men, the conversion rate of testosterone to 5α-reduced metabolites was low (0.8 to 3.5%) and increased at puberty (13.5 to 19.2%). After administration of HCG for 3 months to 1 of the hypogonadal men, it reached 30.2 %. Inversely, the formation of dihydrotestosterone and androstanediols from testosterone was suppressed in 2 men treated with large doses of oestrogen. In 3 subjects with an incomplete form of testicular feminization syndrome, the conversion rate of testosterone to 5α-reduced metabolites was in the normal male range (6.4 to 18.3%), whereas it was low in one case of the complete form of the syndrome (1.5%). In 9 women with idiopathic hirsutism the rate of 5α-reduced metabolites recovered from testosterone was close to that of normal men (13.5 ± 5.5% (se).

From theseresults, it is postulated that in human subjects, there is a good correlation between hair growth in skin from a sexual area and the extent of testosterone 5α-reduction in this tissue. Such an enzymatic activity might be induced by active androgens; this latter hypothesis is in good agreement with the increase of 5α-reduction activity observed at puberty or after treatment of young hypogonadal males.

In addition, it is pointed out that a positive correlation is observed between the 5α-reductase activity present in each skin sample studied and the urinary 3α-androstanediol found for the same individual. This confirms our previous findings suggesting that the determination of urinary 3α-androstanediol might prove of clinical interest in the evaluation of the androgenic status in human subjects.
PEPTIDASES IN THE RAT HYPOTHALAMUS INACTIVATING THYROTROPHIN-RELEASING HORMONE (TRH)
Authors: Griffiths E. C. , Hooper K. C. , Jeffcoate S. L. , White N.
Published: December 2008

Peptidases capable of inactivating thyrotrophin-releasing hormone (TRH) have been demonstrated in the hypothalamus. With the development of a specific radioimmunoassay for TRH, this method was used to further study the enzymes acting on the releasing hormone. Whole hypothalamic homogenates from male and female rats inactivated TRH, with greater peptidase activity being found in the female animals. Separation of the homogenates into particulate (microsomal and mitochondrial) and supernatant (soluble/cytoplasmic) fractions showed approximately the same amounts of enzyme activity in both fractions, while dialysis of the fractions slightly reduced the TRH peptidase activity present, suggesting that a diffusible co-factor might be partially involved in the releasing hormone's degradation. These results confirm the presence of TRH-inactivating peptidases in the rat hypothalamus and suggest that the enzymes may be involved in some way in the mechanisms by which the brain controls thyrotrophin release by the anterior pituitary.
REDUCTION OF CIRCULATING INSULIN LEVELS DURING THE INFUSION OF DIFFERENT PROSTAGLANDINS IN THE RAT
Authors: Saccà L. , Perez G. , Rengo F. , Pascucci I. , Condorelli M.
Published: December 2008

The intravenous infusion of prostaglandin (PG) E1, E2, and A1 into normal rats at a dose of 2 μg/min significantly lowered plasma insulin levels with a tendency to recovery in the post-infusion period. Whereas PGA1 infusion resulted in a moderate but significant hypoglycaemia, the administration of E-series PGs always produced a hyperglycaemic effect. The interference of PGE1 on insulin response to classical insulinogogues (glucagon, aminophylline, and tolbutamide) was also investigated. The results of these experiments demonstrate that PGE1 exerts an inhibitory action on insulin response to all insulin releasing agents investigated. As regards the haemodynamic effects of PGs, PGE1 and PGE2 lowered the arterial blood pressure by about 20%, while PGA1 was almost completely ineffective. On the other hand, the lowering effect of PGE1 on circulating insulin levels remained unchanged in rats treated with reserpine. These findings thus rule out a sympathetic over-activity secondary to the lowered arterial blood pressure as the mechanism of action of PGE1. A possible direct interference with the adrenergic receptor system of the pancreatic islets was also ruled out since the inhibitory effect of PGE1 was not overcome by phentolamine pre-treatment.
EFFECTS OF PROSTAGLANDIN F2α ON OVARIAN BLOOD FLOW AND VASCULAR RESISTANCE IN THE PSEUDOPREGNANT RABBIT
Authors: Janson Per Olof , Albrecht Ivan , Ahrén Kurt
Published: December 2008

In the search for data supporting the hypothesis that the luteolytic effect of prostaglandins (PG) is initiated by a vascular mechanism, some haemodynamic parameters including ovarian blood flow and vascular resistance were measured in pseudopregnant anaesthetized rabbits before and after exogenous administration of PGF2α. The measurements were performed on days 5–10 of pseudopregnancy induced by 500 IU HCG iv.

Infusion of 50 μg/kg PGF2α iv over a one-minute period caused significant falls in cardiac output, heart rate and blood pressure after 1–3 min. Blood pressure and cardiac output were normalized after 16–49 min. Blood flow in the ovarian vein (direct measurements) decreased and returned to initial values parallel to the blood pressure and no change in resistance in the vascular bed drained by the vein was noted. Total ovarian blood flow and resistance, as measured in surgically intact ovaries before and after PG infusion, using 35 or 15 μm 169Yb and 46Sc-labelled microspheres, changed and remained constant respectively, according to the same pattern as in the direct measurements. The distribution of blood flow between the corpora lutea and the interstitial tissue of the ovary measured by 15 μm radioactive microspheres. PGF2α caused an interstitial vasodilation whereas no significant change in luteal vascular resistance was noted. Since luteal blood flow represented a predominant part of total ovarian flow in the type of ovary studied, the interstitial vasodilatation caused only negligible changes in blood flow to the whole ovary. The present study does not support the hypothesis of a PG-induced luteal blood flow reduction preceding luteolysis. The possible significance of the interstitial vasodilatation for luteal function remains to be elucidated.
ENDOCRINE TESTICULAR FUNCTION IN MINK DURING THE FIRST YEAR OF LIFE
Authors: Nieschlag E. , Bieniek H.
Published: December 2008

The endocrine testicular function in mink (Mustela vison) was investigated during the first year of life encompassing puberty, the first mating season and the phase of regression thereafter. The mink, relatively easily accessible as a semi-domesticated animal, was chosen as an example of a mammalian seasonal breeder. In plasma samples from 7 to 17 animals collected on 10 occasions between July and April testosterone and Δ4-androstenedione were determined by simultaneous radioimmunoassay. A steady increase of both androgens from November to early March, when the mating season occurs, and a rapid decline to pre-pubertal levels thereafter was observed. The ratio of testosterone to Δ4-androstenedione was 1:1 from November to April. These findings parallel the known morphological transitions of the testes.
RELATION BETWEEN CIRCULATING LEVELS OF TESTOSTERONE, LH AND FSH IN INTACT AND CASTRATED, ADULT, MALE RATS AFTER TESTOSTERONE ADMINISTRATION
Authors: Verjans H. L. , van der Molen H. J. , Eik-Nes K. B.
Published: December 2008

Serum levels of LH, FSH and testosterone were measured by radioimmunoassay in intact and castrated, adult, male rats after testosterone was administered subcutaneously for seven days in doses ranging from 25 to 200 μg per 100 g body weight per day. Such treatment increased circulating testosterone both in intact and castrated rats, but its effects on serum gonadotrophins were different in these animal groups. All doses of testosterone suppressed serum LH and FSH in the normal rat. In the castrates, treatment with the lowest dose of testosterone resulted in serum LH levels significantly above the high castrate levels, while serum FSH tended to drop. Administration of the highest doses of testosterone did not depress serum LH and FSH in the castrates to those of intact, normal animals, though serum testosterone in these castrates was much higher than in normal, male rats. It is concluded, that the sensitivity of the hypothalamic-pituitary system for daily, subcutaneous testosterone administration during seven days is not the same in the intact and castrated, adult, male rat and that testicular factors different from testosterone may play a role in regulating production and/or secretion of gonadotrophins by the hypophysis in male animals.
IN VIVO UPTAKE AND METABOLISM OF 3H-5α-ANDROSTANE-3α, 17β-DIOL AND OF 3H-5α-ANDROSTANE-3β,17β-DIOL BY HUMAN PROSTATIC HYPERTROPHY
Authors: Horst H.-J. , Dennis M. , Kaufmann J. , Voigt K. D.
Published: December 2008

Tritiated 5α-androstane-3α,17β-diol (3α-diol) and 5α-androstane-3β,17β-diol (3β-diol) respectively were administered to patients with benign prostatic hypertrophy (bph) undergoing prostatectomy. In prostate and skeletal muscle homogenates and in plasma the total radioactivity content as well as the formation of metabolites were measured. Histological examination of each ectomized prostate was performed to evaluate the cellular composition of the tissue.

After 3α-diol injection, a higher uptake of radioactivity in the prostate was obtained than after 3β-diol. Within 30 min the 3α-isomer was very efficiently converted to 5α-DHT, while most of the 3β-isomer remained unchanged. There was, however, also after administration of the 3β-diol a substantial biconversion to 5α-DHT as has been confirmed by recrystallization to constant specific radioactivity. Only after 3β-diol epiandrosterone was detected in small but significant amounts. 3α-diol administration resulted in distinct concentrations of 3β-diol, whereas the conversion of 3β-diol to the 3α-isomer was insignificant. When comparing the histological composition of the prostatic tissue with the accumulation of radioactivity and the formation of metabolites only a weak correlation between glandular structure and radioactivity uptake after 3α-diol administration could be revealed.
EFFECT OF IODIZED OIL ON IODINE CONTENT, THYROGLOBULIN MATURATION AND ON BIOCHEMICAL CONSTITUENTS OF ENDEMIC GOITRE IN BRAZIL
Authors: Medeiros-Neto Geraldo A. , Nicolau William , Takeda Augusta , Cintra A. B. Ulhoa
Published: December 2008

The biochemical and morphological changes in thyroid glands were studied in 5 patients with endemic goitre in the region before and one year after the administration of iodized oil. Each patient received a tracer dose of 125I 3–5 weeks before the biopsy and another tracer of 131I 12 h before surgery. It was observed that:

Iodine deficient goitrous glands had more protein per gram of tissue and that this was corrected by iodination.

The goitrous glands exhibited a higher relative proportion of particulate iodoprotein that incorporates more labelled iodine in relation to time of labelling. This abnormal situation is reverted to normal by iodination.

A significantly higher proportion of T3 + T4 is synthetized by the glands treated with iodized oil.

The increased amount of 127I per gram of tissue is followed by an increased iodination level of thyroglobulin.

The ultracentrifugal pattern of proteins observed for iodine deficient glands differed from the iodinated glands, indicating a failure of maturation of thyroglobulin and possibly a greater than normal degree of heterogeneity.

The shift in sedimentation pattern was clearly induced by the increased degree of iodination, as shown by the iodized oil injection.

The increased cellularity and the higher rate of protein synthesis in the goitrous glands are reverted to normal after the iodized oil injection.
IODINATED PARTICLES IN THE RAT THYROID
Authors: Dang J. , Miquelis R. , Bastiani P. , Simon C.
Published: December 2008

In a previous study (Simon et al. 1971) a procedure for the preparation and separation of iodinated particles was described in the rat. The present paper deals with further investigations on the nature of these particles.

Acid phosphatase and iodine are conjointly sedimentable and display a latency that is unmasked on dilution in a hypo-osmotic medium and under acidification to pH 5.0. These properties together with the sensitivity to Triton X-100 are best accounted for by assuming that iodinated particles of the thyroid gland are lysosomes.

Part of the particulate iodine is soluble in n-butanol (BEI fraction). The existence of this BEI fraction demonstrates that hydrolysis of thyroglobulin occurs within the particles which thus exhibit an acid protease activity. Both the sedimentable iodine pool and acid phosphatase are increased under TSH stimulation and decreased after thyroxine treatment. In addition, the general activity of the iodinated particles is dependent on the daily iodine intake as shown by the variation of their iodine pool, acid phosphatase activity and BEI fraction with the iodine diet. It is concluded that iodinated particles of the thyroid gland are secondary lysosomes which participate in iodine secretion under TSH control.

By in vitro treatment with destabilizing media or after in vivo treatment with thyroxine, iodinated particles exhibit a parallel loss of iodine and acid phosphatase. After a short-term TSH treatment in vivo, their iodine pool is more increased than their acid phosphatase activity. It is concluded that, at least in the normal rat thyroid, iodinated particles are essentially secondary lysosomes; true colloid droplets actually accumulate only after sufficient TSH stimulation.

After ultracentrifugation, 3 main subpopulations are separated for which iodine and acid phosphatase patterns are superimposed. In addition, they all exhibit properties characteristic of secondary lysosomes. Finally, the presence of a fourth sedimentable iodinated fraction with a high turnover rate is postulated.
POTENTIATION OF INSULIN RELEASE BY GLUCOSE IN MAN
Authors: Cerasi Erol
Published: December 2008

Glucose-induced potentiation of glucose-induced insulin release was quantitatively evaluated in 14 non-obese subjects with normal glucose tolerance but decreased insulin response, and in six non-obese patients with mild, adult-onset diabetes, by measuring the insulin responses to two consecutive glucose infusion tests, administered with 40 or 70 min interval. Enhancement of the second insulin response occurred in both groups. In low insulin responders, the dose-response relationship between blood glucose and plasma insulin was flatter and shifted to the right when compared to the control. Pretreatment with glucose increased strikingly the slope of this relationship, the responses now being within the normal range. The enhancement induced by glucose seems to be of multiplicative type. In mildly diabetic subjects, insulin response to glucose infusion was low and sluggish, only a minor initial response being observed. Pretreatment with glucose modified the profile of the insulin response, a clear-cut initial response of greater magnitude being obtained at least in some of the patients. The sensitivity of the islet to the potentiating action of glucose was higher in low insulin responders than in controls, the minimal glucose concentration needed to induce potentiation of the forthcoming response being much lower. The dose-response curve for the relationship between the blood glucose level of the preinfusion period and the percentual enhancement of the insulin response obtained at the second stimulation was, in low insulin responders, higher than and shifted to the left of the curve of the control subjects. In the group of diabetics, sensitivity for potentiation by glucose seemed not different from the controls.

These studies indicate that the ability of glucose to initiate insulin release and its ability to generate time-bound potentiation in the islet correspond to two distinct functions. In the early stages of the diabetic syndrome, only the recognition of glucose as the initiator of an insulinogenic signal is impaired. The pancreatic beta-cell in these subjects seems to recognize normally glucose as the promotor of the potentiation.
FOETAL AND MATERNAL PLASMA LEVELS OF STEROID SULPHATES IN HUMAN PREGNANCY AT TERM
Authors: Laatikainen T. , Peltonen J.
Published: December 2008

Umbilical cord arterial and venous, and maternal peripheral vein blood samples were collected during 20 deliveries after uncomplicated pregnancies. Using a gas chromatographic method, oestriol, oestriol sulphate, progesterone and a number of neutral steroid mono- and disulphates were quantitated in the cord plasma samples and a number of neutral steroid mono- and disulphates in the maternal plasma samples.

The cord venous and arterial plasma levels were compared. Higher concentrations of progesterone and unconjugated oestriol were found in the cord venous plasma. Their mean arteriovenous differences were 40 and 12 μg/100 ml of plasma, respectively. The levels of several steroid monosulphates were higher in cord arterial plasma. The following mean arteriovenous differences were calculated (μg/100 ml): pregnenolone 58, 16α-hydroxypregnenolone 36, 5-pregnene-3β,20α,21-triol 12, dehydroepiandrosterone 42, 16α-hydroxydehydroepiandrosterone + 3β,1 7β-dihydroxy5-androsten-16-one 82, 5-androstene-3β,16α,17β-triol 6, oestriol 29, and for the total pregnanediol mono- and disulphates 20. These results demonstrate that large amounts of steroid monosulphates are secreted by the foetus at term. The levels of individual steroid disulphates examined did not reveal any statistically significant arteriovenous differences. The arteriovenous difference for oestriol sulphate was found to be larger than the venous-arterial difference for unconjugated oestriol indicating that in addition to the unconjugated oestriol of placental origin there are also other precursors of oestriol sulphate.

The correlation between the foetal and maternal plasma levels of the steroid sulphates was investigated. A positive correlation was found, for example, between the cord arterial and maternal plasma levels of 16α-hydroxydehydroepiandrosterone monosulphate and between the maternal and cord venous plasma levels of 5α-pregnane-3α,20α-diol, 5β-pregnane-3α,20α-diol, and 5-androstene-3β,17β-diol disulphates.
A RADIOIMMUNOASSAY FOR 5α-ANDROST-16-EN-3-ONE IN PORCINE ADIPOSE TISSUE
Authors: Andresen Ø.
Published: December 2008

A simple and reliable radioimmunoassay (RIA) for the estimation of 5α-androstenone (5α-androst-16-en-3-one) in porcine adipose tissue has been developed. Fatty tissue samples weighing 40–60 mg were used for assay. The bulk of fat was separated from the steroid by centrifugation in an ethylacetate-ethanol solution at about −70°C.

The sensitivity of the standard curve was found to be 25 pg (P < 0.01) and the smallest amount of 5α-androstenone added to adipose tissue from castrated male pigs, that can be estimated by the method, is 0.09 μg/g. Analysis of the data from the accuracy study gave the regression line y= 1.09x+2.7.

The mean coefficients of variation for the inter- and intra-assay precision were 11.1 and 5.9 %, respectively.

In boars (n = 9) a mean value of 2.09 μg/g adipose tissue was found (sd = 2.56).

In adipose tissue from 9 female pigs and 8 castrated male pigs the level of 5α-androstenone was found to be undetectable by the present method. In adipose tissue from one castrated male pig trace amounts of 5α-androstenone were found.

Fifteen samples in duplicate can be analysed by one person in 1½ days.
THE SEQUENCE OF PITUITARY RESPONSES TO SYNTHETIC LUTEINIZING HORMONE RELEASING HORMONE (LH-RH) THROUGHOUT THE NORMAL MENSTRUAL CYCLE
Authors: Grimes Elwyn M. , Thompson Irwin E. , Taymor Melvin L.
Published: December 2008

Thirty-one ovulatory women between 20 and 33 years of age were given 150 μg of synthetic LH-RH during different phases of the menstrual cycle. Five patients were studied during the early follicular phase (days 4–7); 10 patients during the late follicular phase (days 9–12); 6 patients during the "LH Surge"; 5 patients during the early luteal phase (days 14–16); 3 patients during mid-luteal phase (days 17–21); and 2 patients during late luteal phase (days 22–27). Oestrogen, progesterone, FSH and LH levels were determined from 30 min prior to LH-RH administration to 90 min thereafter in all cases. LH response to LH-RH increased progressively during the follicular phase. Enhanced pituitary responsiveness to LH-RH occurred at mid-cycle for both LH and FSH and maximum LH responses occurred during the "LH Surge" and early luteal phase. LH responses during the mid and late luteal phases were similar to late follicular phase responses. There were no significant differences between FSH responses during the early follicular, late follicular, mid-luteal and late luteal phases. Maximum pituitary responsiveness appears to occur in a gonadal steroid milieu of high oestrogen levels in association with rising but low progesterone levels. Progesterone or a crucial oestrogen: progesterone ratio may in fact potentiate pituitary release of LH during the early stages of corpus luteum formation. Pituitary responsiveness to LH-RH correlates positively with basal LH and oestrogen levels during the menstrual cycle and with the oestrogen:progesterone ratio during the luteal phase.
ABNORMAL RESPONSE OF THYROTROPHIN AND GROWTH HORMONE TO THYROTROPHIN RELEASING HORMONE IN CHRONIC RENAL FAILURE
Authors: Hasegawa Koichi , Matsushita Yoshiki , Otomo Seima , Hamada Noboru , Nishizawa Yoshiki , Okamoto Teruo , Morii Hirotoshi , Wada Masahisa
Published: December 2008

Serum levels of TSH and GH were measured by radioimmunoassay after iv injection of 500 μg of TRH in 9 undialysed patients and 12 dialysed patients with chronic renal failure and in 6 healthy subjects. The basal level of the serum TSH was significantly higher in patients with chronic renal failure than that in healthy subjects. In healthy subjects, serum TSH rose to a maximum level 30 min after TRH injection, while in patients with chronic renal failure, serum TSH rose to a maximum level 60 min after TRH injection. The mean maximum increment of serum TSH in healthy subjects was significantly higher than that in patients with chronic renal failure. Although TSH levels rapidly decreased after initial rise at 30 min after TRH administration in healthy subjects, these did not show significant changes at 60 and 120 min compared with values at 30 min after TRH administration in both dialysed and undialysed patients. The basal level of serum GH was significantly higher in dialysed patients with chronic renal failure than in healthy subjects. Serum GH level was much higher in dialysed patients at 30 min after TRH injection compared with that in healthy subjects. These findings may indicate that the response of the pituitary to TRH is abnormal and that the turnover of TSH and GH is decreased in patients with chronic renal failure.
GLUCOSE METABOLISM DURING AND AFTER PREGNANCY IN NORMAL AND GESTATIONAL DIABETIC WOMEN
Authors: Kühl C.
Published: December 2008

Glucose and insulin concentrations during basal fasting conditions and after an oral challenge with glucose have been studied during early, mid and late pregnancy and also after delivery in a group of 9 normal women. No significant changes in the fasting serum glucose concentration was observed during pregnancy. In contrast the fasting serum insulin gradually increased.

No changes in the mean glucose concentration curve were observed until the second half of pregnancy where the level of the curve was significantly elevated, but statistically calculated limits of normality derived from a special study of non-pregnant normal controls were not exceeded. The serum insulin response to glucose was significantly increased at all stages of gestation and in parallel the insulin-to-glucose index calculated for the total areas below the insulin and glucose concentration curves increased significantly. The fasting insulin-to-glucose index also increased and was found to be significantly correlated to the stage of gestation.

The shape of the glucose and insulin curves was modified in the opposite direction by pregnancy: the peak value of glucose was delayed whereas that of insulin was advanced.

The results indicate that in pregnancy a diminished 'peripheral sensitivity' to endogenous insulin apparently develops.

As it can be seen both in the basal fasting state and after challenge with glucose a permanent influence of pregnancy on serum insulin secretion seems most likely. Therefore, the possible involvement of the hormones of pregnancy should first be considered as a cause of these findings. However, different factors, e. g. altered levels of pro-insulin or glucagon, might also be involved in the mechanism.
AUTO-TRANSPLANTATION OF RABBIT MYOMETRIUM INTO EAR-CHAMBER AND RECORDING OF ITS ACTIVITY
Authors: Wagner Gorm
Published: December 2008

A transparent ear-chamber and its installation in the rabbit is described as well as the subsequent autografting of myometrial tissue into the connective tissue formed in the chamber. Of the rabbits initially provided with ear-chambers 65 % were found to be suitable for grafting while finally only 40 % of these presented activity either spontaneously or induced by stretch or oxytocin.

Qualitative evaluation of the mechanical activity was obtained by photoelectric recording of the transmission of light through the graft. An evaluation of the electrical activity was made possible by recording volume conducted potentials from wire electrodes in contact with the grafted tissue. A close time interrelationship between electrical potentials and change in transmission of light of the graft was found. Oxytocin produced electrical activity and blanching of the graft.

It is concluded that recording of the electrical activity provides the most reliable way of expressing the activity of grafted myometrium.
ENDOCRINE DISTURBANCES IN PATIENTS WITH CONGENITAL AQUEDUCTAL STENOSIS
Authors: Fiedler Robert , Krieger Dorothy T.
Published: December 2008

Congenital stenosis of the aqueduct of Sylvius is reported to be associated with sella turcia enlargement and clinical and laboratory abnormalities of the hypothalamic-pituitary-target-organ axis. It is a surgically reversible lesion. In the present report, 3 female patients with this lesion were studied with tests of basal endocrine function, as well as insulin tolerance tests, response to metyrapone and determination of circadian periodicity of plasma cortisol levels. In one patient all testing was normal and no surgery was performed. In 2 other patients the insulin tolerance test revealed either abnormal cortisol or growth hormone responses and in one patient urinary gonadotrophins were absent. All tests became normal post-operatively although in one instance not completely so until 5 years after surgery.
DIFFERENT EFFECTS OF ORAL DOSES OF TRIIODOTHYRONINE OR THYROXINE ON THE INHIBITION OF THYROTROPHIN RELEASING HORMONE (TRH) MEDIATED THYROTROPHIN (TSH) RESPONSE IN MAN
Authors: Wenzel K. W. , Meinhold H. , Schleusener H.
Published: December 2008

Since contradicting results about the existence of T3 or T3 and T4 receptors in pituitary tissue have been reported, the influence of L-triiodothyronine (L-T3) or L-thyroxine (L-T4) on TRH stimulated TSH release was investigated. Oral administration of 50 μg L-T3 caused an increasing inhibition of TSH response to 400 μg TRH from 64 % 2 h after L-T3 intake to 29% after 24 h, while serum T3 peaks up to 5.45 ng/ml occurred between 2 to 4 h after L-T3 ingestion and became normal after 8 to 10 h. This delay in the T3 action on TRH inhibition agrees with the postulate that T3 induces the synthesis of an inhibiting protein which is blocking TSH liberation. Oral administration of 1000 μg L-T4 induced increments of serum T4 up to 221 ng/ml between 6 to 24 h after intake; however, a TRH inhibition of 62 % did not become evident before 48 h. At this time T3 levels had risen to the upper normal range. These results support the theory that T3 is responsible for the regulation of TSH secretion. An intra-pituitary conversion from T4 to T3 seems more likely the cause of the TRH inhibition rather than the peripheral T4-T3 conversion or a direct action by T4 binding sites in the pituitary.