bluuebunny/crossref_metadata_2025_split huggingface dataset:
ULTRASTRUCTURAL EVIDENCE FOR THE STIMULATION OF NUCLEAR RIBONUCLEIC ACID SYNTHESIS BY OESTRADIOL-17β IN THE VAGINAL EPITHELIUM OF THE OVARIECTOMIZED MOUSE
Authors: POLLARD IRINA 
Published: December 2008

SUMMARY
The cytochemical nature of the ultrastructural nucleolar transformation previously observed in the vaginal epithelium of the ovariectomized mouse after local application of oestradiol-17β was investigated using a recently developed ultrastructural staining technique. Oestradiol treatment induced ribonucleic acid (RNA) synthesis, especially in the nucleolus but also in the nuclear chromatic region and ribosomes. Actinomycin D administered simultaneously with oestradiol reduced the oestrogen-induced nucleolar response to the control level. These findings are discussed with special reference to the mode of action of oestrogens.
KINETIC STUDIES ON THE BIOSYNTHESIS OF CORTICOSTEROIDS IN VITRO FROM EXOGENOUS PRECURSORS BY THE INTERRENAL GLANDS OF THE NORMAL, CORTICOTROPHIN-TREATED AND ADENOHYPOPHYSECTOMIZED XENOPUS LAEVIS DAUDIN
Authors: CHAN S. T. H. , EDWARDS B. R. 
Published: December 2008

SUMMARY
Incubation of the adrenocortical tissue of Xenopus with labelled steroidal precursors gave aldosterone, corticosterone, 11-deoxycorticosterone and 18-hydroxycorticosterone as the major products. Kinetic studies indicated that the major biosynthetic pathway in Xenopus is the same as that in the duck, cobra and frog, and follows the sequence: pregnenolone → progesterone → 11-deoxycorticosterone → corticosterone → aldosterone + 18-hydroxycorticosterone.
The effects of adenohypophysectomy and of injection of mammalian corticotrophin (ACTH) on the corticosteroidogenetic capacity of Xenopus were also studied. The production of both aldosterone and corticosterone increased after ACTH administration and decreased markedly after adenohypophysectomy. Some of the evidence suggests that ACTH was effective at biosynthetic stages following the formation of pregnenolone. The present studies on corticosteroid production were done in conjunction with parallel investigations on osmoregulation and electrolyte and water changes in Xenopus (Edwards, 1969).
KINETICS OF DISTRIBUTION OF RADIOACTIVE PERCHLORATE IN RAT AND GUINEA-PIG THYROID GLANDS
Authors: CHOW SIEN YAO , WOODBURY D. M. 
Published: December 2008

SUMMARY
The thyroidal uptake of 36ClO4− and the effect of stable perchlorate ion and functional state of the thyroid, such as after long-term administration of propylthiouracil (PTU) or after hypophysectomy, on the uptake of 36ClO4− were studied in rats and guinea-pigs. Based on the analysis of uptake curves, radioactive inulin and sulphate spaces, and histological measurements of compartmental sizes of the thyroid, the relative concentrations of 36ClO4− in the various compartments were calculated and compared with those of 36Cl-. The passage of 36ClO4− and 36Cl− across both the basal and the apical membranes of the follicular cells in the different conditions were analysed. The results suggest that 36ClO4− is concentrated in the lumen of the thyroid by a two-step process. It is actively transported across the basal cell membrane from the interstitial fluid into follicular cells, and is further concentrated in passage across the apical membrane into the lumen. The evidence suggests that the latter process is also an active one.
ADRENAL FUNCTION IN BREAST CANCER: BIOGENESIS OF ANDROGENS AND CORTISOL BY THE HUMAN ADRENAL GLAND IN VIVO
Authors: DESHPANDE N. , JENSEN VIBEKE , CARSON PAMELA , BULBROOK R. D. , DOOUSS T. W. 
Published: December 2008

SUMMARY
A variety of 14C and 3H-labelled steroids have been perfused through the human adrenal gland in situ and their metabolic products isolated from adrenal venous blood.
Progesterone, dehydroepiandrosterone and cortisol were isolated after infusion of [3H]pregnenolone; 17α-hydroxyprogesterone, dehydroepiandrosterone and cortisol after infusion of [3H]17α-hydroxypregnenolone and [14C]progesterone; androstenedione and cortisol after infusion of [3H]17α-hydroxyprogesterone and [14C]dehydroepiandrosterone; and 11β-hydroxyandrostenedione after infusion of [3H]androstenedione and [14C]cortisol.
From a consideration of the incorporation of radioactivity into the metabolic products, the3H: 14C ratios and the tissue pool sizes it was concluded that the major biosynthetic pathway to cortisol in the human adrenal glands was: pregnenolone→ 17α-hydroxypregnenolone → cortisol. Progesterone was not an important intermediary.
Androstenedione was mainly formed by way of 17α-hydroxypregnenolone → 17α-hydroxyprogesterone → androstenedione. 11β-Hydroxyandrostenedione was formed mainly from cortisol and only a minor amount came from the hydroxylation of androstenedione.
PATHWAYS OF STEROID BIOSYNTHESIS IN THE INTACT GRAAFIAN FOLLICLE OF MARES IN OESTRUS
Authors: YOUNGLAI E. V. , SHORT R. V. 
Published: December 2008

SUMMARY
Two mares were operated on during oestrus; in the first animal a mixture of [16-3H]pregnenolone and [4-14C]androstenedione was injected into the largest Graafian follicle; in the second animal, [4-14C]pregnenolone and [7-3H]androstenedione were injected into the follicle. By cannulating the ovarian veins it was possible to measure the rate of transfer of radioactivity from the follicular fluid into the ovarian vein. This ranged from 3 to 9% of the injected dose per hour. At the end of each experiment, 45–52 min. after the injection of the labelled precursors, the follicular fluid was aspirated. Negligible amounts of radioactivity were recovered from the rest of the ovary and from the 'conjugated' fraction of the ovarian vein plasma and follicular fluid. Within the follicle 6·2 and 12·2% of the injected pregnenolone were converted to progesterone. Further metabolism to 17 α-hydroxyprogesterone, androstenedione and oestradiol-17β was very limited. Oestradiol-17β isolated from the ovarian vein had a higher specific activity than that from the follicular fluid while the 3H: 14C ratios were similar in both compartments. In addition, the 3H:14C ratios of androstenedione and oestradiol-17β in the ovarian vein were similar. Therefore it seems likely that oestradiol-17β in the follicular fluid is derived mainly from an extra-follicular source, probably the theca interna cells.
THE ACTION OF DIBUTYRYL CYCLIC 3′,5′-ADENOSINE MONOPHOSPHATE ON THE MOUSE THYROID GLAND IN VITRO
Authors: KENDALL-TAYLOR PAT , MUNRO D. S. 
Published: December 2008

SUMMARY
The effects of dibutyryl cyclic 3′,5′-adenosine monophosphate (DBc-AMP) on the mouse thyroid gland have been investigated in the in-vitro assay of Brown & Munro (1967). The distribution of 131I-labelled compounds in the glands and the supporting medium have been analysed by thin-layer chromatography and the changes induced by cyclic 3′,5′-adenosine monophosphate (c-AMP), DBc-AMP or thyroid-stimulating hormone (TSH) compared.
The release of 131I was increased when the glands were incubated with DBc-AMP, c-AMP or TSH. The potency of DBc-AMP was approximately 50 times that of c-AMP on a basis of molarity. Like TSH, DBc-AMP increased the proportion of iodothyronines in the system as a whole, whereas c-AMP had little effect. The possible explanations for this are discussed.
EFFECT OF GONADOTROPHINS ON THE OESTROUS CYCLE IN THE GUINEA-PIG
Authors: DAS R. M. , BENSON G. K. 
Published: December 2008

SUMMARY
Adult virgin, regularly cyclic female guinea-pigs were treated with different doses of luteinizing hormone (LH) and follicle-stimulating hormone during the late luteal phase of the oestrous cycle. The onset of the next oestrus was delayed and the length of the dioestrous stage was prolonged beyond the normal range in all the treated groups, but for a maximum period in the animals receiving LH alone.
The results indicate a dual role of LH on the normal cycle of the guineapig. It has been suggested that either luteotrophin release from the pituitary or an intrinsic luteotrophic action is probably a part of the function of LH in addition to its ovulation-inducing function in the guinea-pig.
A POSSIBLE ROLE FOR THE ADENYL CYCLASE SYSTEM IN CALCITONIN RELEASE
Authors: CARE A. D. , BATES R. F. L. , GITELMAN H. J. 
Published: December 2008

SUMMARY
A possible role of the adenyl cyclase system in calcitonin (CT) release has been investigated by measurement of the rate of CT secretion in isolated porcine thyroid glands perfused in situ. Dibutyryl cyclic AMP increased the rate of secretion of CT and this effect was enhanced by theophylline. Concentrations of glucagon as low as 1·4 nm (5 ng/ml) induced a significant increase in the rate of CT secretion when precautions were taken to prevent enzymic degradation of glucagon. This stimulatory effect of glucagon on CT secretion was also increased by theophylline. Significant stimulation of CT release was demonstrated with adrenaline in the presence of α-adrenergic blockade with phentolamine and could be inhibited by β-adrenergic blockade with propranolol. In contrast, thyrotrophin, tri-iodothyronine, serotonin, parathyroid hormone and cyclic guanosine monophosphate had no significant acute effects on CT secretion. It is suggested that the C-cells of the thyroid gland contain an adenyl cyclase system similar to that described in other tissues and that physiological concentrations of glucagon and catecholamines may influence the response of the C-cell to plasma calcium concentration.
URINARY AND BILIARY EXCRETION OF [4-14C]PROGESTERONE, [4-14C]20α- AND [4-14C]20β-HYDROXYPREGN-4-EN-3-ONE METABOLITES IN THE RABBIT
Authors: SENCIALL I. R. , THOMAS G. H. 
Published: December 2008

SUMMARY
[4-14C]Progesterone, [4-14C]20α- and 20β-hydroxypregn-4-en-3-one were injected intravenously into deeply anaesthetized rabbits and the bile and urine collected for 6 h. Neutral metabolites recovered after Ketodase hydrolysis of bile accounted for a mean of 82·8% (range 68·0–98·8%), 68·4% (61·0–80·0%) and 59·0% (57·0–61·0%) of the metabolites of progesterone, 20α-and20β-hydroxypregn-4-en-3-one, respectively. Acidic metabolites accounted for no more than 14·7% of the biliary radioactivity. Similar recoveries of neutral metabolites were obtained after hydrolysis of bile with 15% HCl, but only 41·0% (22·2–62·0%), 45·3% (36·4–55·4%) and 13·7% (10·6–16·9%) of the urinary metabolites were extractable as neutral metabolites. Acidic metabolites represented a further 33·9% (28·9–49·5%), 34·9% (27·5–40·4%) and 38·6% (29·4–47·8%) of the urinary radioactivity, respectively.
Neutral ether soluble metabolites more polar than 5β-pregnane-3α,20α-diol were the most abundant metabolites. 3α-Hydroxy-5β-pregnan-20-one was identified in the bile as a metabolite of [4-14C]progesterone whereas 20α-hydroxypregn-4-en-3-one was present in the urine. 5β-Pregnane-3α, 20α-diol was identified as a biliary metabolite of [4-14C]20β-hydroxypregn-4-en-3-one.
THE EFFECTS OF THYROTROPHIC HORMONE AND OF THYROXINE ON THE RESPONSE OF THE SEBACEOUS GLANDS OF THE RAT TO TESTOSTERONE
Authors: EBLING F. J. , EBLING ERIKA , SKINNER J. 
Published: December 2008

SUMMARY
Treatment with thyrotrophic hormone (TSH) significantly enhanced the action of testosterone in increasing sebum secretion in both castrated and hypophysectomized—castrated male rats. The dose of TSH, equivalent to about 0·1 i.u./24 h for 24 days, was insufficient to increase thyroid weight, even though this was only half of normal in the hypophysectomized—castrated rats.
Treatment with thyroxine (T4) significantly added to the action of testosterone in increasing sebum production in castrated rats, but the effect was accompanied by a decreased incidence of mitoses in the sebaceous glands.
Treatment with propylthiouracil did not by itself affect sebaceous activity in castrated rats, nor did it inhibit the action of testosterone. Sebum secretion in castrated animals treated with propylthiouracil and testosterone was significantly higher than in those treated with testosterone alone.
In view of the evidence that TSH and T4, although similar in their effects on sebum secretion, appeared to act in opposite ways on the incidence of sebaceous mitoses, and that the response of the sebaceous glands to testosterone was increased rather than inhibited by treatment of the rats with propylthiouracil, it is concluded that the action of TSH in enhancing the sebaceous response is more likely to be direct than indirect by stimulation of the thyroid gland.
INTERRELATIONSHIP OF THE EFFECTS OF ALDOSTERONE AND THYROID HORMONES ON SODIUM TRANSPORT AND ELECTRICAL PROPERTIES OF RAT COLON
Authors: EDMONDS C. J. , THOMPSON B. D. , MARRIOTT JANE 
Published: December 2008

SUMMARY
Transmucosal electrical potential difference (p.d.), short-circuit current, electrical resistance and Na+ influx rate of the descending colon were similar in euthyroid and hypothyroid rats, the latter having been treated earlier with an ablation dose of 131I. However, in contrast to the considerable p.d. increase found in normal rats, little change of p.d. was found in hypothyroid rats when they were Na+ depleted or given an intravenous aldosterone infusion. A single small dose of tri-iodothyronine (T3) (1 μg/100g body weight) or a larger dose of thyroxine given to hypothyroid rats 10–16 h before aldosterone, restored the p.d. response to normal, although these doses did not influence the animal's oxygen consumption. Fasting for 3 days or giving actinomycin D (8 μg/100 g body weight) abolished the effect of T3 but this did not influence the action of aldosterone in euthyroid animals.
SUBCELLULAR LOCALIZATION OF NEUROTRANSMITTERS AND RELEASING FACTORS IN THE RAT MEDIAN EMINENCE
Authors: CLEMENTI F. , CECCARELLI B. , CERATI E. , DEMONTE M. L. , FELICI M. , MOTTA M. , PECILE A. 
Published: December 2008

SUMMARY
The neurohaemal part of the median eminence of the rat hypothalamus is characterized by numerous nerve terminals which end near a rich network of fenestrated capillaries. An attempt was made to isolate different types of nerve terminals by means of sucrose density-gradient centrifugation. The subcellular fractions obtained were assayed for dopamine, noradrenaline and 5-hydroxytryptamine. In addition FSH- and GH-releasing activities were determined. A sample of each fraction obtained was taken for electron microscopical observations.
Dopamine, noradrenaline, 5-hydroxytryptamine, GH- and FSH-releasing factors were present in higher concentration in the nerve endings. A further fractionation showed that noradrenaline was present in the lightest synaptosomal band, dopamine in the middle one, and 5-hydroxytryptamine in the heaviest. GH-RF and FSH-RF were recovered mainly from the band containing dopamine. The relevance of this localization to the physiological role of the median eminence is discussed.
THE PLASMA GROWTH HORMONE CONCENTRATION OF THE FOETAL LAMB
Authors: BASSETT J. M. , THORBURN G. D. , WALLACE A. L. C. 
Published: December 2008

SUMMARY
Growth hormone (GH) concentrations in the plasma of foetal lambs (range 20–150 ng/ml) were ten or more times those in the plasma of ewes during the last third of pregnancy. Blood samples obtained from foetuses with indwelling vascular catheters indicated that there was a steady rise in foetal plasma GH concentrations from 40–50 ng/ml at 100–110 days gestation to maximum values of 110–120 ng/ml between 130 and 140 days gestation and then a rapid decrease around the time of birth.
Growth hormone disappeared from the foetal plasma after hypophysectomy of the foetus and there was no evidence for a placental source of the hormone. Ovine pituitary growth hormone given by intravenous injection disappeared from the foetal plasma at a similar rate to the endogenous hormone following hypophysectomy. The rate of GH removal from foetal plasma was slower than that in lambs 4–12 days after birth.
Glucose infusion into foetal lambs did not alter their plasma GH concentration significantly, but infusion of the catecholamine, isoprenaline, decreased the foetal plasma GH concentration rapidly. Cessation of infusion was followed by very rapid restoration of the former high plasma GH concentration. The results indicate that the high foetal plasma GH concentration is maintained by active secretion of the hormone, but its function in the foetal lamb remains obscure.
ALTERATION IN THE OESTROUS CYCLE LENGTH AFTER PITUITARY HOMOTRANSPLANTATION IN THE GUINEA-PIG
Authors: DAS R. M. , BENSON G. K. 
Published: December 2008

SUMMARY
Pituitaries from adult or young guinea-pigs were implanted under the kidney capsule of intact adult female guinea-pigs between the 3rd and 5th days of the oestrous cycle.
The oestrous cycles in the recipients of adult pituitaries were mostly normal in length. Seven out of nine animals engrafted with pituitaries from their own litters had a prolonged dioestrus, ranging from 8 to 16 days longer than normal, at the end of which oestrus and ovulation occurred. When the grafts contained pituitaries from one male and one female pup the cycle extension was more pronounced than when they were composed of pituitaries from two or three female pups.
The occurrence of prolonged dioestrus accompanied by a delayed ovulation in the graft-bearing animals is suggested to be associated with the production of luteotrophic hormone by the graft tissue, possibly deriving from basophil cells.
HUMAN PITUITARY FOLLICLE-STIMULATING HORMONE: DISTRIBUTION, PLASMA CLEARANCE AND URINARY EXCRETION AS DETERMINED BY RADIOIMMUNOASSAY
Authors: AMIN H. K. , HUNTER W. M. 
Published: December 2008

SUMMARY
The volume of distribution, plasma clearance and urinary recovery of human follicle-stimulating hormone (FSH) after intravenous injection has been estimated in healthy men. A human FSH-anti FSH radioimmunoassay was used which, though not completely specific, discriminates against luteinizing hormone (LH) by at least 10:1 in terms of i.u.
The half-life in the circulation was 24–38 min in three subjects who received the same dose. Urinary recovery, when expressed as a percentage of the injected dose, was 36·8 ± 7·7 (s.d.)% in nine experiments with three different doses in six subjects. The time-course and percentage recovery were similar for all doses used.
EFFECTS OF HUMAN PITUITARY EXTRACTS ON ANDROGEN BIOSYNTHESIS BY HUMAN ADRENALS IN VITRO
Authors: MILNER A. JOSEPHINE , MILLS I. H. 
Published: December 2008

SUMMARY
The effects of human pituitary extracts upon steroid biosynthesis by pieces of human adrenal tissue incubated in Krebs—Ringer bicarbonate buffer have been studied. Experiments with both adult and foetal adrenal tissue have been carried out. Radioactive precursor (either [7-3H]pregnenolone or [4-14C] progesterone) was added to each incubation vessel and the synthesis of radioactively labelled products was estimated by reverse isotope dilution. Individual steroids were characterized by paper and thin-layer chromatography; the radiochemical purity of cortisol, androstenedione, dehydroepiandrostenedione (DHA) and DHA sulphate was established following derivative formation. There was no consistent effect of the pituitary preparations upon the biosynthesis of cortisol, DHA or DHA sulphate, nor upon the ratio of cortisol to the combined production of DHA and DHA sulphate. However, the production of androstenedione from both [7-3H]pregnenolone and [4-14C]progesterone was significantly increased in the presence of pituitary and gonadotrophic preparations.
EFFECT OF HYPOPHYSECTOMY OF FEMALE RATS ON THE ACTIVITY OF PANCREATIC ELASTOLYTIC ENZYMES AND THE ELASTIN CONTENT OF HEART, LUNG AND AORTA
Authors: LOEVEN W. A. 
Published: December 2008

SUMMARY
Since previous findings suggest that the production and secretion of elastolytic enzymes by the pancreas are under endocrine control, the activity of elastoproteinase and the elastomucases Em-I and Em-S in the pancreas was determined in two groups of 19-month-old female rats. The first group of 12 animals was hypophysectomized at the age of 9 months, the second group of nine rats served as controls. The enzyme activities were measured using as substrates: unstained alkali-treated elastin and unstained and orcein-stained acid-treated elastin. Thus, data could be obtained for both the Em-I and Em-S activities. Hypophysectomy decreased the level of pancreatic elastoproteinase and increased the total activity of both elastomucases. Further, it was found that the elastin content in heart, lung and aorta of the hypophysectomized rats was increased as compared with that in the controls.
CHANGES IN THE METABOLIC CLEARANCE RATE OF PROGESTERONE IN THE GUINEA-PIG
Authors: ILLINGWORTH DOREEN V. , HEAP R. B. , PERRY J. S. 
Published: December 2008

SUMMARY
The metabolic clearance rate (MCR) of progesterone was measured by continuous infusion of the tritium-labelled steroid in guinea-pigs under light sodium pentobarbitone anaesthesia. In normal animals during the oestrous cycle, the MCR was 112·8 ± 7·0 (s.e.) 1 plasma/day/kg. In pregnant animals there was a sharp decrease in MCR between days 15 and 20, to 8·3 ± 0·8 1/day/kg. This low clearance rate was observed throughout the remainder of gestation. After parturition MCR returned slowly to non-pregnant levels, reaching 85 1/day/kg by day 12 post partum.
The decrease in metabolic clearance rate occurred at the same time as the increase in plasma concentration of progesterone. This may be related to an increase in binding proteins with a high affinity for progesterone. The stimulus for the decrease in MCR in pregnancy is obscure but appears to depend on the presence of a viable conceptus. In the non-pregnant guinea-pig the MCR is not reduced by exogenous oestrogen, hysterectomy or hypophysectomy.
FOLLICLE-STIMULATING HORMONE CONTENT OF THE PITUITARY GLANDS OF INTACT AND OVARIECTOMIZED MICE OF DIFFERENT STRAINS
Authors: KARANDE K. A. , SHETH N. A. , RANADIVE K. J. 
Published: December 2008

SUMMARY
The follicle-stimulating hormone (FSH) content of the pituitaries of intact and ovariectomized mice of the strains C3H/Jax and ICRC, which differ in their adrenocortical responses to ovariectomy was measured at different ages. It was always higher in intact ICRC than that in intact C3H mice, particularly in younger age groups. Ovariectomy caused a fivefold increase in the FSH content in C3H mice after 1 month which was maintained up to 6 months. Thereafter there was a gradual decrease up to 12 months. The increase in pituitary FSH content in ICRC mice after ovariectomy was much less and occurred at a later age. These results agree with cytological observations on the pituitaries of these two strains.
SERUM RENIN ACTIVITY DURING EXPOSURE TO HYPOXIA
Authors: TUFFLEY R. E. , RUBENSTEIN D. , SLATER J. D. H. , WILLIAMS E. S. 
Published: December 2008

SUMMARY
Changes of serum renin activity, heart rate, blood pressure, renal sodium, potassium and metadrenaline excretion and alveolar gas tensions were recorded during two 2–3 h exposures to 446 mmHg barometric pressure (simulated altitude of 4279 m or 14000 ft). Serum renin activity rose considerably during the first exposure and only slightly during the second. This effect was positively correlated with the changes of heart rate. There was little change in blood pressure or in the rate of renal excretion of sodium, potassium or the metadrenalines.
It is suggested that the change of serum renin activity cannot be explained by a direct effect of hypoxaemia, emotion, posture or the diurnal rhythm of renin secretion but that it may be correlated with changes of cardiovascular function.