bluuebunny/crossref_metadata_2025 huggingface dataset:
Consecutive administration of synthetic LRH in the evaluation of gonadotrophin reserve in children
Authors: Tomita Masako
Published: December 2008

Initial injection of synthetic luteinizing hormone releasing hormone (LRH) into 40 children elicited no response in LH and follicle stimulating hormone (FSH) in 15 patients with pituitary dwarfism, one with Kallmann's syndrome and in 3 anorexia nervosa patients. These patients were further treated with LRH for periods of either 3 or 14 days and the second LRH test showed an increase in LH and/or FSH in 67% of the patients with pituitary dwarfism, in the Kallmann's syndrome and in all of the anorexia nervosa patients. This result suggested that while pituitary gonadotrophs did not respond at the first LRH test because of the chronic absence of stimulation, consecutive LRH therapy, however, restored the ability to secrete LH and FSH and indicated that the pituitary was not the site of the primary lesion in these patients. The LRH test following consecutive administration of LRH may be valuable in determining whether the lesion is located in the hypothalamus or the pituitary.
Pituitary Cushing's disease without adenoma
Authors: Schnall Adrian M. , Kovacs Kalman , Brodkey Jerald S. , Pearson Olof H.
Published: December 2008

Recent reports of patients with Cushing's disease who have been explored via the transsphenoidal route indicate that the great majority has pituitary adenomas. We report a patient with biochemically documented pituitary-based hypercortisolism who had a clinical and biochemical remission following hypophysectomy. Serial sections of the pituitary tissue removed showed hyperplasia of corticotroph cells but no adenoma. Hypophysectomy was complete as documented by serum levels of FSH, LH, TSH, prolactin, hGH and ACTH at the lower limits of the respective assays, with no response to appropriate stimuli. This case demonstrates that a minority of patients with Cushing's disease has corticotroph cell hyperplasia without a pituitary adenoma.
Effect of nutrition on growth and somatomedin A levels in the rat
Authors: Takano Kazue , Hizuka Naomi , Shizume Kazuo , Hasumi Yoko , Tsushima Toshio
Published: December 2008

Serum somatomedin A was significantly reduced after 3 days of fasting in rats with a mean decrease of 23.6 ± 2.4% (N = 18) of initial values. Re-feeding for one day produced a definite increase in somatomedin A, with a rise in body weight.

When re-fed isocalorically for 21 days with diets of different quality, a low protein diet led to smaller increases in both seum somatomedin A and body weight in comparison to those of control-, high-protein- and high fat-diets (P < 0.001). There is a positive correlation between the increase in body weight and serum somatomedin A levels (N = 70, r = 0.71, P< 0.001). The effect of growth hormone on somatomedin generation was abolished in hypophysectomized rats fed with low-protein diet.

Our study suggests that protein in the diet is important for the generation of somatomedin A, which is necessary for normal growth.
Circadian variations of the response of plasma prolactin to brief exposure to ether in the male rat
Authors: Mattheij John A. M. , Swarts Hans J. M.
Published: December 2008

Male adult rats, supplied with an indwelling chronic intrajugular cannula, were exposed to ether for 1 min at various times of the day. Blood samples were taken before and at regular intervals during 1 h following the ether exposure. Basal plasma prolactin showed a circadian variation. The highest level occurred at 1.00 h, and the lowest values were measured at 10.00 and 13.00 h, while a significant increase was observed at 16.00 h compared to the level at 10.00 and 13.00 h. At all times of the day studied exposure for 1 min to ether increased plasma prolactin for at least 30 min and the magnitude of this response to ether varied with the time of day. At 1.00 h the greatest response was observed, while at 10.00 and 13.00 h the most moderate response was measured. The data indicate that there is either a circadian rhythm in basal prolactin, which may cause a significant circadian variation in the magnitude of the stress response, or there is over the 24 h period a significant variation in stress-sensitivity of the hormone, which may contribute to the circadian variation of'basal' prolactin.
Parathyroid response to EDTA in hypoparathyroidism and in tetany
Authors: Burckhardt P. , Tscholl-Ducommun J. , Ruedi B.
Published: December 2008

The parathyroid response to an EDTA infusion was measured in 11 patients with hypoparathyroidism and 22 patients with normocalcaemic tetany, and compared to that of normal controls and of 23 patients with primary hyperparathyroidism. Despite comparable basal PTH values, the patients with hypoparathyroidism and the normocalcaemic patients, with tetany following thyroid surgery, responded less than normals to EDTA, while normocalcaemic patients with tetany due to psychogenic hyperventilation responded more than normals. In hypoparathyroidism, mainly three types of results were observed: no response (total hypoparathyroidism), diminished or delayed response (partial hypoparathyroidism), and discrepant results using different antisera in cases of idiopathic hypoparathyroidism, suggesting the secretion of immunologically abnormal PTH. In tetany due to psychogenic hyperventilation, parathyroid hyperreactivity might be explained by repeated stimulation through respiratory alkalosis. Although the EDTA test rarely improved the diagnostic accuracy of basal PTH measurements in primary hyperparathyroidism, it was useful for differentiating between latent hypoparathyroidism and tetany due to psychogenic hyperventilation, both presenting with normal plasma calcium.
Studies of the human testis. XIV. Properties of C17-C20 lyase
Authors: Hosaka Masahiko , Oshima Hiroyuki , Troen Philip
Published: December 2008

The properties of C17-C20 lyase in the human testis were investigated using a microsome fraction in the presence of NADPH. Michaelis constants (Km) of the enzyme were 1.7 × 10−5 m for 17α-hydroxyprogesterone and 5.9 × 10−7 m for 17α-hydroxypregnenolone. Km of the lyase for NADPH were determined as 6.3 × 10 −6 m in the presence of either 17α-hydroxyprogesterone or 17α-hydroxypregnenolone. In both instances, the maximum velocity (Vmax) of the lyase for 17α-hydroxyprogesterone was approximately two times higher than that for 17α-hydroxypregnenolone. Optimal pH and temperature of the enzyme for both 17α-hydroxyprogesterone and 17α-hydroxypregnenolone were 7.7 and 40°C, respectively. Each steroid substrate inhibited competitively the lyase activity for the other with inhibition constants (Ki) of 1.9 × 10−5 m for 17α-hydroxyprogesterone and 6.0 × 10−7 m for 17α-hydroprogesterone and 20α-dihydropregnenolone showed non-competitive inhibition of the lyase for either 17α-hydroxyprogesterone or 17α-hydroxypregnenolone. In contrast, testosterone inhibited the enzyme activity for 17α-hydroxyprogesterone competitively, but revealed typical uncompetitive inhibition of the lyase for 17α-hydroxypregnenolone. Similarly, the inhibition of the lyase by 5-androstenediol was competitive for 17α-hydroxyprogesterone and of the mixed type for 17α-hydroxypregnenolone. Furthermore, oestradiol-17β was found to be a competitive inhibitor of the lyase for 17α-hydroxyprogesterone, while it showed almost no inhibition of the enzyme for 17α-hydroxypregnenolone. The monosulphate steroids examined showed significant inhibition of the lyase for 17α-hydroxyprogesterone, but not for 17α-hydroxypregnenolone. From these results, it appears most likely that there are two different active sites for lyase, one for 17α-hydroxyprogesterone and the other for 17α-hydroxypregnenolone, although both sites show very similar properties.
17-ketosteroid reductase deficiency — plasma steroids and incubation studies with testicular tissue
Authors: Schnakenburg K. v. , Bidlingmaier F. , Engelhardt D. , Butenandt O. , Unterburger P. , Knorr D.
Published: December 2008

The patient, diagnosed as a case of testicular feminisation in infancy, was examined at the age of 15 years because of severe symptoms of virilising puberty with poor breast development. Plasma steroid analyses revealed a 10-fold elevated androstenedione concentration (A: 1562 ng/100 ml). Testosterone (T: 266 ng/100 ml) was in the male pubertal range. Thus the A/T-ratio was far above normal. The oestrone/oestradiol ratio was also elevated (Oe1/Oe2: 10.2/2.2 ng/100 ml). A, T, Oe1 and Oe2 could not be suppressed by dexamethasone, but reacted promptly to fluoxymesterone (A: 781 ng/100 ml). hCG caused a further increase of the A/T-ratio (2220/246 ng/100 ml); ACTH did not alter the A-concentration. These findings together with simular investigations after gonadectomy suggest that the failure to convert A to T and Oe1 to Oe2 is essentially located in the testes. In vitro incubations of testicular tissue showed reduced 17-ketosteroid reductase activity in tissue slices and in the subcellular fractions microsomes and cytosole. This form of male pseudohermaphroditism can easily be detected already in infancy, if steroid analyses and stimulation tests are performed. In case of female sex assignment patients should be submitted to early orchidectomy in order to avoid virilisation in puberty.
Age-dependent variations in serum 1,25-dihydroxyvitamin D in childhood
Authors: Lund Bjarne , Clausen Niels , Lund Birger , Andersen Else , Sørensen Ole H.
Published: December 2008

Circulating 1,25-dihydroxyvitamin D (1,25-(OH)2D) was measured in 87 children aged 3 months to 15 years, and in 11 adolescents 16–19 years of age. A positive correlation to growth velocity was observed, indicating that the biologically active vitamin D metabolite is an important physiological factor in the regulation of growth and development of the skeleton.
Post-encephalitic hypothalamic-pituitary insufficiency
Authors: Kupari Markku , Pelkonen Risto , Valtonen Ville
Published: December 2008

Pituitary function was investigated in 3 patients who developed hypothalamic-pituitary insufficiency after viral meningoencephalitis. In 2 patients the causative agents were probably Influenza-A- and Herpes simplex virus whereas in the third patient it was not identified. The pattern of hormonal deficiencies indicated that all the central regulatory areas - hypothalamus, pituitary stalk and pituitary gland - may be injured after viral meningoencephalitis. Usually, the hormonal deficiency is permanent but it can also be transient.
Glucose tolerance, growth hormone and somatomedin levels in osteosarcoma patients
Authors: Adamson U. , Broström L.-Å. , Efendić S. , Hall K.
Published: December 2008

Intravenous glucose tolerance, insulin response to glucose, the sensitivity of the periphery to insulin as well as growth hormone and somatomedin levels were determined in osteosarcoma patients and control subjects matched by age, sex, weight and length. The insulin response to glucose and the peripheral sensitivity to insulin were evaluated by using the individual blood glucose and plasma insulin curves for parameter identification in a mathematical model. The mean glucose tolerance was significantly decreased in the patients, most likely due to decreased peripheral insulin sensitivity. Plasma growth hormone levels were normal in all patients which was also the case with somatomedin levels determined by both radioreceptor- and radioimmunoassay.
Changes in polyploidization of exocrine pancreas in db/db diabetic and normal mice
Authors: White J. W. , Swartz F. J.
Published: December 2008

Polyploidy in tele-insular and peri-insular exocrine pancreas of C57BL/KsJ-db/db diabetic mice and normal littermate controls was quantitated, because the diseased state has been shown to produce an increase in the percentage of polyploid islet B-cells. Three diabetic and 3 normal animals were sacrificed at 4.5, 7, 9.5, 12, 14.5, and 17 weeks of age. Semi-automatic nuclear size analysis on Feulgen stained sections separated the nuclei into polyploid classes, with the following results: 1) In both normal and diabetic mice, percentages of polyploid cells in peri-insular and tele-insular regions differed significantly from one another, and from that of the islet B-cells. Per-cent polyploidy was highest in the peri-insular regions, and lowest in the islets. 2) In the tele-insular regions, per cent polyploidy did not differ between normals and diabetics at 4.5 weeks. By 17 weeks, polyploidy in the diabetics was essentially unchanged, while that of the normal animals had risen and become significantly elevated over that of both the 4.5 week normal and the 17 week diabetic animals. 3) In peri-insular regions, per cent polyploidy did not differ significantly between normals and diabetics throughout the period studied.
Effect of age on plasma aldosterone response to exogenous angiotensin II in normotensive subjects
Authors: Takeda Ryoyu , Morimoto Shinpei , Uchida Kenzo , Miyamori Isamu , Hashiba Tetsuji
Published: December 2008

The plasma aldosterone response to angiotensin II (10 ng/kg/min for 30 min, iv) under conditions of varied sodium intake was studied in 10 young subjects (20 to 35 years), 9 middle-aged (41 to 56 years) and 11 elderly (66 to 73 years) normotensive subjects. Basal plasma renin activity, basal plasma level and urinary excretion of aldosterone were significantly lower in the elderly than in the young and middle-aged groups on both 130 and 25 mEq sodium intakes. When sodium intake was reduced to 25 mEq for 3 days, the weight loss was significantly greater in the elderly than in the young and middle-aged groups. No significant differences in blood pressure and serum electrolytes were found between the three groups. Angiotensin II infusion caused significant increases in the mean blood pressure in all the three groups, but to a greater extent in the elderly group. Plasma aldosterone level and its absolute increment, but not its per cent increment, after angiotensin II infusion were significantly lower in the elderly than in the young and middle-aged groups. In combined young, middleaged and elderly subjects, the absolute plasma aldosterone increment correlated positively with basal plasma aldosterone and plasma renin activity levels on a 25 mEq sodium intake, and with plasma renin response to sodium restriction.

These results suggest that ageing may cause a lesser plasma aldosterone response to angiotensin II with a decrease in basal plasma aldosterone, in parallel with a decrease in plasma renin activity, under condition of low sodium diet.
Biosynthetic and morphological evidence for inhibition of aldosterone production following administration of ACTH to sheep
Authors: McDougal John G. , Butkus Aldona , Coghlan John P. , Denton Derek A. , Müller Jürg , Oddie CatherineJ. , Robinson Peter M. , Scoggins Bruce A.
Published: December 2008

The effect of ACTH administration for 1—5 days on the morphology and steroidogenic capability of sheep adrenal tissue has been examined. During this period of treatment there was a gradual decline in the in vitro conversion of 3H-labelled precursors to products of solely zona glomerulosa origin (aldosterone and 18-hydroxycorticosterone) while conversion to products of zona fasciculata origin (17-hydroxyprogesterone, 11-deoxycortisol and cortisol) was stimulated throughout. Conversion to DOC, 18-hydroxydeoxycorticosterone and corticosterone (steroids produced by both the zona glomerulosa and the zona fasciculata) declined after initial stimulation.

Within 2—3 days of the commencement of treatment, the zona glomerulosa showed a progressive decrease in cell number associated with disruption of cords and cell separation. Ultrastructurally, it was found that typical zona glomerulosa cells had almost disappeared. The majority of residual cells in this area had a structure intermediate between zona glomerulosa and zona fasciculata cells.

The similarity in time-course of the alterations in both the morphological and biosynthetic characteristics suggests that the decline in aldosterone output caused by ACTH administration to sheep results from the loss of adrenal zona glomerulosa cells, predominantly due to selective cellular degeneration.
Umbilical serum DHAS and total oestriol in relation to gestational age and mode of delivery
Authors: Noguchi Akihiko , Turnipseed Marvin R. , Bentley Karen , Reynolds John W.
Published: December 2008

The concentrations of mixed umbilical cord serum dehvdroepiandrosterone sulphate (DHAS) and total oestriol, were determined by radioimmunoassay in 301 infants. Of 280 infants born between 36 and 42 weeks of gestation, 260 were born by vaginal delivery and 20 were delivered by Caesarean (C-section). We found that there was a significant elevation of serum total oestriol (P < 0.005) after 35 weeks with no concomitant gestational change of DHAS. Within the vaginal delivery group steroid values were similar among infants born following spontaneous, oxytocin augmented, and oxytocin induced labour. Within the C-section delivery group, steroid values were similar in infants who experienced spontaneous labour and those who did not. However, DHAS level was significantly higher (P < 0.005) in the vaginal delivery group than in the C-section group. We postulate that the higher DHAS levels in the vaginal delivery group are the result of stress during the late first stage of labour or later.
Free and bound androgens in the female guinea pig during gestation and after parturition and in the offsprings during the perinatal period
Authors: Rigaudière N. , Pradier P. , Delost P.
Published: December 2008

Total amounts of testosterone (T) and dihydrotestosterone (DHT) and their distribution between non-protein-bound (free), albumin-bound and PBG-(progesterone binding globulin)-bound fractions were determined by radioimmunoassay and equilibrium dialysis from plasma samples. The samples were taken from male guinea pigs during the perinatal period and from pregnant females during gestation and after parturition. Plasma proteins of the foetus and newborn animals appeared to have no high binding affinity for androgens. On the other hand albumin having a binding capacity of 56% for testosterone and 75% for DTH irrespective of the total androgen concentration may be considered to be an important low affinity binding protein.

Maternal plasma developed a specific binding activity with the appearance of PBG in early pregnancy. Alterations in the binding capacity of PBG for T or DHT paralleled changes in plasma concentrations of both androgens, the highest values being observed on day 48 of pregnancy, with a prompt return to normal after parturition. Irrespective of the total androgen concentration, it was evident that PBG was capable of maintaining the free T and DHT at low concentrations (about 0.20 and 0.17 ng/10 ml, respectively). Besides the specific binding due to PBG a non-specific binding due to albumin was observed. The competition which exists between these two binding systems for T and DHT was evident when the quantity of bound androgens was expressed as a percentage. Neither the sex, nor the number of the foetuses, nor the interaction between the two, was found to have any significant effect in the maternal androgens, whether total or free hormone was considered.
The effect of clomiphene citrate on pubertal gynaecomastia
Authors: LeRoith D. , Sobel R. , Glick S. M.
Published: December 2008

Clomiphene citrate 100 mg daily was used to treat 28 boys with pubertal gynaecomastia. Six failed to complete the course and of the remaining, 14 (64%) responded within 6 months of commencement of therapy. LH, FSH, testosterone and oestradiol levels rose during therapy. It is suggested that clomiphene affects gynaecomastia locally as an anti-oestrogen.
Gonadal dysfunction in adult men with congenital adrenal hyperplasia
Authors: Moore G. W. , Lacroix A. , Rabin D. , McKenna T. J.
Published: December 2008

Two adult males are described with congenital adrenal hyperplasia (21-hydroxylase deficiency). Patient 1 was receiving therapy with cortisone acetate and presented with clinical features of glucocorticoid excess and uncontrolled adrenal androgen activity. It was established that the short-acting steroid which the patient was receiving was cleared so rapidly that endogenous ACTH secretion was not inhibited.

Patient 2 presented with enlarged and painful testes in association with poor compliance with corticosteroid therapy. The histologic picture of the testis was compatible with 'Leydig cell hyperplasia'. However, successful response to dexamethasone therapy suggests that the testes harboured an adrenal rest. These observations highlight the need for careful follow-up and treatment of adult male patients with congenital adrenal hyperplasia.
Long-term effect of glucocorticoid on connective tissue of aorta and skin Morphological and biochemical studies of tissues from rabbits with intact and injured aortas
Authors: Manthorpe R. , Garbarsch C. , Lorenzen I.
Published: December 2008

The long-term effect of prednisolone — 0.6 mg/day for 63 days — upon mechanically induced inflammation and repair processes in vascular connective tissue was compared with that upon undamaged vascular wall and intact skin of rabbits. The investigations included histological examination of aorta as well as biochemical analyses of collagen and various glycosaminoglycan fractions, RNA, DNA and alpha-amino nitrogen. The metabolism of collagen was estimated by in vitro labelling with [14C]proline and the metabolism of glycosaminoglycans by in vivo labelling with [35S]O4. The radioactivity of [125I]albumin in the aorta and serum was also studied.

The collagen, glycosaminoglycans, RNA, DNA and water of vascular connective tissue during inflammation and repair and of intact skin was found to be more sensitive to the action of prednisolone than the connective tissue of undamaged vascular wall. An increased degradation of newly synthesized collagen was observed in damaged aorta as well as in skin in which also the biosynthesis of collagen was inhibited. Prednisolone inhibited the biosynthesis of glycosaminoglycans and decreased the total amount of glycosaminoglycans and of nucleic acids in the damaged aortas and the skin. The [125I]albumin aorta-to-serum ratio was significantly increased in the damaged aorta. Prednisolone treatment decreased the ratio in injured aortas, but elevated the ratio in the undamaged vessels. Prednisolone inhibited intimal thickening of the injured aortas.
Interrelationships between tumour size, age, plasma growth hormone and incidence of extrasellar extension in acromegalic patients
Authors: Klijn J. G. M. , Lamberts S. W. J. , de Jong F. H. , van Dongen K. J. , Birkenhäger J. C.
Published: December 2008

In 44 consecutive acromegalic patients we studied the interrelationships between tumour size, age, incidence of extrasellar extension, growth hormone levels and 'tumour growth'. These parameters were compared with results from a previous study in 62 prolactinoma patients. It appeared that the incidence of extrasellar extension in acromegalic patients was lower than in the prolactinoma patients (32 versus 44%). In acromegalic patients extrasellar extension occurred on the average at a lateral sellar and tumour area of almost 1 cm2 larger than in prolactinoma patients (with respect to sellar size generally above 3 cm2 versus 2 cm2, with respect to tumour size generally above 4 cm2 versus 3 cm2).

Log tumour size and log basal growth hormone level were positively correlated (P < 0.0005). In the acromegalic patients there was a negative correlation between the size of the pituitary tumour and the age of the patient (P < 0.005) in contrast to the absence of such a relationship in the prolactinoma patients. In the group of acromegalic patients mean tumour size decreased gradually from the third to the sixth decade (5.0, 3.8, 3.0 and 2.3 cm2, respectively). The interval between the time of appearance of symptoms and the time of diagnosis was significantly shorter in younger patients and in women. The restriction of large tumours (lateral area > 5 cm2) to young patients (< 35 year) and the short period between the appearance of symptoms and the time of diagnosis in these patients indicate that growth hormone secreting pituitary tumours generally grow more rapidly in younger patients.
Insulin secretory reserve in insulin dependent patients at time of diagnosis and the first 180 days of insulin treatment
Authors: Madsbad Sten , Krarup Thure , Regeur Lisbeth , Faber Ole K. , Binder Christian
Published: December 2008

Eleven newly diagnosed insulin dependent patients were studied before and during the first 16 h after start of insulin treatment. All the patients were found to have significant amounts of C-peptide in plasma indicating residual insulin secretion. The fall in blood glucose after start of insulin therapy was followed by a parallel decrease in C-peptide (R = 0.99, P < 0.01) suggesting that the beta-cells may respond to variation in blood glucose.

Eight of the patients were studied 1, 4, 7, 14, 90 and 180 days after start of insulin therapy. During the first 90 days of treatment an increasing maximal C-peptide concentration was found after a standard breakfast test meal. Two thirds of this improvement i beta-cell function was found after the initial 14 days with an average increase in maximal C-peptide of 260 per cent. The sensitivity to glucose improved.
Urinary excretion of albumin and total protein in normal and streptozotocin diabetic rats
Authors: Rasch R. , Mogensen C. E.
Published: December 2008

Using a radioimmunoassay the urinary albumin excretion rate has been measured in groups of streptozotocin diabetic female Wistar rats and non-diabetic control rats. Total protein excretion has been measured with the Biuret technieque in the same animals.

One group of 4 rats was given 35 mg streptozotocin iv. The rats remained non-ketotic and were not treated with insulin. The geometric mean albumin excretion before the induction of diabetes was 0.38 mg/24 h. For the next 4 days after streptozotocin the albumin excretion was not significantly increased. From day 16 to day 30 the mean albumin excretion was 2.4 mg/24 h, which is a significant increase from the initial value (2P = 0.0082). Another group of 8 rats showed ketonuria on the second day after the injection of 100 mg streptozotocin iv, and they were treated with insulin daily. Geometric mean albumin excretion before the induction of diabetes was 0.38 mg/24 h, and the next 4 days after the induction of diabetes it was not significantly increased. During the period from day 16 to day 30 a small, but significant, increase to 0.76 mg/24 h (2P = 0.029) occurred when compared to prevalues.

Total protein excretion showed a significant increase in both diabetic groups just after the streptozotocin injection.

In a long-term study albumin excretion was measured every month up to the age of 12 months in 8 insulin treated rats. The results obtained in this group have been compared to that of a non-diabetic control group. Both groups showed a steady increase in albumin excretion. However, the slope of the curves was significantly steeper in the diabetic rats (2P = 0.0000095).
Cyclic AMP phosphodiesterases of the rat ovary. Oestrous cycle dependent activity change of high affinity form
Authors: Schmidtke J. , Meyer H. , Epplen J. T.
Published: December 2008

In the rat ovary, from prenatal to adult stages, two electrophoretically distinct forms of cyclic AMP phosphodiesterase (E.C.: 3.1.4.17) occur. These forms were analysed for their affinity towards cAMP in both crude and partially purified preparations. Whereas the slow electrophoretic form, which has a low affinity towards cAMP, shows a linear Lineweaver-Burk plot, the fast electromorph exhibits anomalous kinetic behaviour in that cAMP affinity appears to increase with decreasing cAMP-concentration. This form shows dramatic alteration of maximum velocity during the oestrous cycle, attaining maximum activity at metoestrus. This rise of activity is sensitive to inhibition of protein synthesis.
The inability of Angiotensin II infusions to raise plasma vasopressin levels in haemodialysis patients
Authors: Hammer M. , Ølgaard K. , Madsen S.
Published: December 2008

Since it has previously been claimed that angiotensin II (All) stimulates vasopressin (AVP) secretion, the effect of All-infusions was studied in 1) 6 normals, 2) 5 non-nephrectomized haemodialysis (HD) patients, and 3) 6 nephrectomized HD patients. In dialysis patients the infusion rate was increased step-wise from 2–12 ng AII/kg bw × min−1 and was terminated if diastolic blood pressure (BP) increased more than 20 mmHg. Normals were infused at a constant rate of 4 ng AII/kg bw × min−1.

In all the groups significant increments in BP and plasma aldosterone occurred while plasma renin activity decreased. The plasma vasopressin level was unchanged in normals, while in the two groups of dialysis patients a minor decrease was found. The present study has therefore not been able to confirm a stimulating effect of a physiological dose of All on AVP secretion, and the results in anephric patients indicate that a normal plasma All concentration is of no importance for the plasma AVP level.
The effect in post-menopausal women of natural human and artificial oestrogens on the concentration in serum of prolactin
Authors: Andersen Jesper Rye , Schroeder Erik , Lebech Paul Erik
Published: December 2008

25 women aged 53–78 years with at least two vears menopause were divided in three groups receiving one of the following oral treatments for three weeks: 2 mg oestradiol-17β plus 1 mg oestriol, 4 mg oestradiol-17β plus 2 mg oestriol or 50 μg ethinyloestradiol daily. Blood samples were collected before, during and after the treatment and the effect on the serum concentration of prolactin, oestradiol-17β, follicle-stimulating hormone and luteinizing hormone was evaluated.

During treatment with natural human oestrogens serum oestradiol-17β levels were significantly higher than before treatment. The serum concentration of prolactin was unchanged in patients receiving 2 mg oestradiol-17β plus 1 mg oestriol but increased in patients receiving 4 mg oestradiol-17β plus 2 mg oestriol or 50 μg ethinyloestradiol, thus indicating dose-dependence for natural human oestrogens. However, the increase was moderate, and these higher levels were not significantly different from levels of prolactin in serum found in 16 younger women. Concentrations of follicle-stimulating hormone and luteinizing hormon were depressed during treatment, the former to significantly lower levels when higher doses of oestrogens were used.
Dynamic study of antidiuretic hormone during benign mineralocorticoid and metacorticoid hypertension
Authors: Marchetti Jeannine , Thibonnier Marc , Gonzales M. Françoise , Corvol Pierre , Menard Joël
Published: December 2008

Deoxycorticosterone-treated rats with benign hypertension were observed for changes in antidiuretic hormone (ADH) excretion during the mineralocorticoid hypertension phase (weeks 4–8 after DOC implantation) and the metacorticoid phase (weeks 16–18 after DOC). During the latter period, blood pressure was still high but electrolytic abnormalities due to excess DOC had disappeared. Urinary ADH excretion was studied in rats with normal sodium intake (Group I) and in rats which drank a 1% NaCl solution (Group II) under three conditions: basal conditions, after water loading and after hypertonic sodium loading. The rise in blood pressure (BP) was larger, lasted longer and was more frequently accompanied by malignant hypertension in Group II than in Group I animals. During the mineralocorticoid hypertension, a 2- and 3-fold increase in urinary ADH excretion occurred in all DOC-treated rats, concomittantly with a rise in plasma osmolality. ADH excretion did not change in control rats drinking sodium chloride solution. In hyper- and normotensive animals, oral water loading reduced ADH excretion and hypertonic saline loading increased it. However, under both these conditions, ADH excretion remained higher in hypertensive than normotensive rats. During metacorticoid hypertension, BP was normal in Group I rats, but remained elevated in Group II rats. In both groups, electrolyte abnormalities disappeared and urinary AVP excretion returned to normal under basal conditions and after suppression and stimulation tests.

The present results show that increased ADH excretion is characteristic of DOC-induced benign hypertension even in the absence of sodium from drinking water. There are two possible mechanisms through which ADH might raise BP: 1) by expanding plasma volume, and 2) by acting as a vasoconstrictor agent directly affecting the arterial walls. However, vasopressin does not seem necessary to maintain hypertension, since ADH excretion was normal during the metacorticoid phase.
Plasma and pituitary gonadotrophins before and after LRH in normal, cryptorchid and castrated rats
Authors: Grizard Geneviève , André Max , Boucher Daniel
Published: December 2008

Rats were either castrated or made cryptorchid at 1, 8, 21 or 49 days of age. Sham-operated animals were used as controls. At 70 days, all the animals were anaesthetized and then injected with saline or 100 ng of LRH (time 0). Blood samples were collected before and after the injection (time – 15, 0, 8, 15, 45 min), and the animals were killed by decapitation. Plasma LH and FSH were measured by radioimmunoassays (RIA) and pituitary gonadotrophins were measured by bioassays and RIA.

Irrespective of the age of surgery, plasma gonadotrophin levels of cryptorchid rats were elevated: they were nearly tripled for LH and doubled for FSH but they always remained distinctly below those of castrated rats. The LH response to LRH injection was higher in cryptorchid rats than in controls, but this response was lower than in castrated rats. Plasma FSH response to LRH injection depended on the age of surgery and FSH levels were not always significantly increased.

In rats operated on at 49 days, following cryptorchidism, or castration, pituitary gonadotrophin content was increased. The highest value was found in castrated rats. After LRH injection pituitary LH content was unchanged in controls but decreased in other animals, pituitary FSH content was decreased in castrated rats and unchanged in cryptorchid rats.

These results showed, in the adult rat that at any time of operative cryptorchidism between 1 and 49 days of age, a negative feedback control persisted, exerted by the testicular system on the hypothalamo-hypophyseal system as regards the secretion of both LH and FSH.
Circadian rhythm of TSH in adult men and women
Authors: Custro N. , Scaglione R.
Published: December 2008

The circadian rhythm of TSH secretion and its typical pattern were investigated during the spring of two successive years in a group of 12 adult women, and then in a group of 12 adult men, both having normal thyroid function. Blood samples were obtained from each individual every two h for 24 h. TSH was measured by RIA.

Data were processed by inferential analysis and represented using the cosinor method. The chronobiological rhythm of TSH is in good agreement with the typical function of circadian rhythms both in men and in women, significance averaging ‰.

The typical parameters of the rhythm (M = mesor, i.e. the mean level of the rhythm; A = amplitude of the sinusoidal function approximating the rhythm; Ø = acrofase, i.e. the lag from a reference timepoint of the crest time in the function) under the conditions used in our investigation were shown to be: Male subjects: mean ± se = 3.72 ± 0.21 mU/l, A (95% C.I.) = 1.15 (0.93–1.47) mU/l; Ø (95% C.I.) = 3.9° (−8.6° + 23.8°). Female subjects: mean ± SE = 5 ± 0.13 mU/l; A (95% C.I.) = 0.96 (0.86–1.11) mU/l; Ø (95% C.I.) = 8.8° (−0.2° + 20.5°). The patterns of TSH biorhythm are practically identical in both sexes.

Taking into account the methods used and the results obtained we think that the circadian rhythm of TSH secretion is programmed in both sexes in order to meet the cyclic requirements of the target gland, while several other factors which mark the course of the day at the level of central nervous structures function as rhythm harmonizers.
An ultrastructural stereologic study of the effects of angiotensin II on the zona glomerulosa of rat adrenal cortex
Authors: Mazzocchi Giuseppina , Rebuffat Piera , Belloni Anna S. , Robba Claudia , Nussdorfer Gastone G.
Published: December 2008

The effects of angiotensin II on the rat zona glomerulosa were investigated by morphometric and radio-immunological methods. Short-term (l h) angiotensin-administration induced lipid depletion in zona glomerulosa cells and a significant rise in the plasma aldosterone concentration. Chronic angiotensin-treatment provoked a noticeable increase in the volume of the zona glomerulosa and its cells, which was mainly due to the hypertrophy of smooth endoplasmic reticulum and mitochondrial compartment. In chronically treated animals the output of aldosterone in response to a short-term stimulation with angiotensin II displayed a significant increase. These findings are interpreted as indicating that angiotensin II is involved in the stimulation of the growth and steroidogenic capacity of the rat zona glomerulosa.
The growth of different organs of normal and dwarfed Snell mice, before and during growth hormone therapy
Authors: van Buul-Offers Sylvia , Van den Brande Jan Leo , Dumoleijn L. , Male A. M. Korteland-van , van de Klundert P. L. M.
Published: December 2008

This study was performed in order to obtain more insight in the relationship between the growth of different organs of normal Snell mice and their dwarfed littermates before and during growth hormone therapy. Beside body weight the weights of the following organs were studied: liver, kidneys, heart, the muscles quadriceps femoris and gastrocnemius, submandibular salivary glands, testes, epididymal fatpads, thymus, spleen and skinfold thickness.

The data show that, similar to body weight, growth of these organs in dwarf mice is arrested at approximately 2½ weeks of age, after which little further growth occurs, leaving their absolute weight far below normal. Related to body weight the liver is close to normal, lower values are obtained for the heart and very low ones for the kidneys, the lymphoid organs, thymus and spleen, and the epididymal fatpads. At two weeks of age the weight of the brain is only slightly less than normal, but gradually stays behind until it is only 2/3 of normal at the age of 17 weeks. Due to the small weight of the dwarfs the contribution to body weight of the brain is higher than normal.

Growth hormone, after 4 weeks of treatment, had induced significant growth of all organs studied, except for the testes and the thickness of the skinfold. After 10 weeks of treatment all organ weights were significantly increased. Growth was most marked in the lymphoid organs, spleen and thymus, and the epididymal fatpads (155–173% of controls). The submandibular salivary glands and the testes increased more than body weight (respectively 141 and 136% vs. 123%). Increase proportional to body weight was found for the muscles quadriceps femoris and gastrocnemius, heart, liver and kidneys. In contrast, increase of the brain (106%) and skinfold (111%) was much lower.
Hypoparathyroidism in diabetes mellitus
Authors: McNair P. , Christensen M. S. , Madsbad S. , Christiansen C. , Transbøl I.
Published: December 2008

Serum immunorecative parathyroid hormone (iPTH) and indices of mineral and glucose metabolism were determined in 58 insulin treated diabetic patients (duration of disease 1–11 years). The mean serum iPTH level in all diabetic patients, measured simultaneously with sera from normal subjects, was 55% of normal mean (P < 0.01). The diabetic patients had hypomagnesaemia (P < 0.001), hypercalciuria (P < 0.001) and a 9.6% decrease in bone mass (P < 0.001).

Low serum iPTH values were correlated with high glycosuria (R = −0.28, P < 0.05) and with long duration of diabetes (R = −0.31, P< 0.02). Patients with both high glycosuria and long diabetes duration had especially low iPTH values (mean 16 ng/l, n = 16) compared with patients with both low glycosuria and short diabetes duration (mean 32 ng/l, n = 15, P < 0.005) and with normal subjects (mean 37 ng/l, n = 28, P < 0.001). The 16 patients with low serum iPTH values also had higher urinary calcium excretion rate (P < 0.05) than the 15 patients with low glycosuria and short duration of diabetes.

The diabetic hypoparathyroidism may be secondary to a primary disturbance of bone metabolism, with a negative net calcium balance.
Essential hypernatraemia, antidiuretic hormone and neurophysin secretion: response to chlorpropamide
Authors: AvRuskin T. W. , Tang S. C. , Juan Christina
Published: December 2008

An adolescent boy with essential hypernatreamia, absent corpus callosum, mental retardation, hypodipsia, and partial diabetes insipidus with 'inappropriate' ADH regulation and secretion was studied regarding factors controlling ADH and neurophysin release. Persistent hyperosmolality was noted while on 100 mEq sodium intake daily. Endogenous vasopressin activity was demonstrated after prolonged water deprivation. Hypertonic saline infusion produced increased volumes but dilute urine. Aqueous pitressin increased urinary osmolality, decreased serum osmolality, urine flow rate, and free water clearance. Stable water diuresis was induced by water loading and on normal saline infusion. Nicotine-stimulated neurophysin remained unexpectedly low and below the level of detectability when sampled during the physiologic studies, whereas oestrogen-stimulated neurophysin was elevated during oestrogen stimulation, water loading, and orthostasis procedures. Plasma vasopressin was suppressed with water loading but remained suppressed 90 min after tilt table testing. These data indicate impairment of the osmoreceptor mechanism; however, since the patient had a normal response of oestrogen-stimulated neurophysin, that part of the neurohypophysis appears intact. Chlorpropamide was effective in alleviating the hyperosmolar state acutely and maintained normal osmolar concentrations during two years of therapy.
Responses of the anterior pituitary of ovariectomized rats to oestradiol-17β administration
Authors: Kapp R. , Fox J. L.
Published: December 2008

The response of the female rat anterior pituitary gland to oestradiol-17β administered sc by silastic capsule implants (6–120 μg/day) has been examined. Cholesterol, oestradiol-17α, and testosterone were used as control hormone implants. The biochemical changes in the gland as assayed by DNA, RNA, and protein contents were monitored at intervals of 7, 21,42, and 120 days. In addition, the number of cells per gland was determined by an experimental cell counting technique and correlated to the number of cells based on total DNA content. These results extend previous observations of the hypertrophy of the anterior pituitary and show essentially parallel increases in cell number, DNA, RNA, and protein contents.
Syndrome of inappropriate ADH secretion concealed by hypokalaemia due to ectopic ACTH production
Authors: Corrall R. J. M. , Frier B. M. , Ratcliffe J. G. , Podmore J. , Ramsay W. , Hare K. M.
Published: December 2008

A case is described of a patient with an oat cell carcinoma of the bronchus with moderately elevated levels of plasma corticotrophin (ACTH) and antidiuretic hormone (ADH). Ectopic secretion of ACTH induced severe hypokalaemia and concealed the effects of concomitant ADH secretion on renal function. Normal renal responsiveness was restored following correction of hypokalaemia.

The hypokalaemia was associated with evidence of a marked increase in corticosteroid secretion but plasma ACTH concentrations did not show a proportionate elevation. Chromatographic studies on tumour extracts suggest that the presence of a large fraction of high molecular weight ACTH in plasma could explain this discrepancy.
Role of the adenylate cyclase system in altered insulin release from islets of Langerhans of aging rats
Authors: Lipson Loren G. , Bush Michael J. , Tietjen Gretchen E. , Yoon Aeree
Published: December 2008

In attempting to understand the causes of the hyperglycaemia observed in aging populations and to determine the mechanism(s) for the diminished in vitro insulin release from islets of Langerhans of older rats, the adenylate cyclase-cyclic AMP system was studied in isolated islets from 12 month old and 2½ month old (control) male rats to determine its role in this altered insulin secretion. Islets of Langerhans were isolated by collagenase digestion and then either incubated in the presence of low or high concentrations of glucose for studies of insulin release or were sonicated and assayed for determinations of activities of adenylate cyclase and phosphodiesterase. Insulin release was identical from islets of 12 month old and 2½ month old rats to 2.8 mm D-glucose, while in the presence of 16.7 mm D-glucose, insulin release was decreased by 33% (P < 0.02) from islets of the older animals. Adenylate cyclase activity was diminished by 60% (P < 0.005) from the 12 month old rats as compared with islets from the 2½ month old controls, while low Km phosphodiesterase activity was similar in islets from both groups of animals. From these studies it appears that the adenylate cyclase-cyclic AMP system may play a role in the altered insulin release from islets of aging rats.
Changes in pituitary LH content and LH secretion in the long-term ovariectomized rat during prolonged infusion of LRH
Authors: Koiter T. R. , Pols-Valkhof N. , Schuiling G. A.
Published: December 2008

LH secretion and the depletion of the pituitary LH stores caused by continuous infusion of LRH, were studied in the 5-weeks ovariectomized rat.

After 1 day of infusion at the rate of 416 ng/h, pituitary LH content decreased to about 40% of its initial value. Upon continuation of the infusion the LH content increased slowly until, after 7 days, it increased to about 54% of the original value. The plasma LH concentrations, after having reached peak values of 7122 ± 291 ng/ml after 2 h of infusion, declined to a plateau at about 300 ng/ml but it took 5 days to reach this value.

When after either 2 or 8 days of LRH infusion at the rate of 416 ng/h the infusion was changed to a 'supramaximal' rate of 10 400 ng/h for 24 h, a transient secondary rise of LH secretion was induced. The magnitude of the secondary response, was essentially the same after 2 or 8 days of LRH infusion, but these secondary reponses were significantly smaller than the LH-response during a similar LRH-infusion in previously untreated ovariectomized rats.