bluuebunny/crossref_metadata_2025_split huggingface dataset:
PLASMA AND ADRENAL CORTISOL CONCENTRATIONS IN FOETAL, NEWBORN AND MOTHER GUINEA-PIGS DURING THE PERINATAL PERIOD
Authors: DALLE M. , DELOST P. 
Published: December 2008

SUMMARY
Concentrations of cortisol, corticosterone and cortisone in the plasma and adrenal glands, liver glycogen and plasma glucose of foetal, newborn and mother guinea-pigs were estimated during the last 6 days of pregnancy and throughout the first 24 h post partum. At the same time progesterone was measured in the plasma of the mother. During the prepartum rise in foetal plasma cortisol levels and liver glycogen, no significant change in the foetal adrenal cortisol content was observed. The plasma and adrenal cortisol concentrations of the mother were much higher than those observed in the foetus and increased significantly before parturition. In the mother as in the foetus, cortisone and corticosterone represent only a small percentage of corticosteroids compared with cortisol. These results indicate that the autonomous capacity of foetal adrenals, inhibited by maternal secretions before term, appears suddenly at birth.
TESTOSTERONE CONCENTRATION IN THE FLUIDS OF SEMINIFEROUS TUBULES, THE INTERSTITIUM AND THE RETE TESTIS OF THE RAT
Authors: COMHAIRE F. H. , VERMEULEN A. 
Published: December 2008

SUMMARY
Testosterone was measured by radioimmunoassay in interstitial fluid, 'free-flow' seminiferous tubular fluid, obtained by micropuncture, and rete testis fluid from intact adult anaesthetized rats. Under non-stimulated conditions the concentration of testosterone in interstitial fluid was below the limit of detection in two rats and achieved a mean level of 150 ± 27 (s.e.m.) ng/ml in the remaining 17 determinations. The testosterone concentration of the seminiferous tubular fluid was below the limit of detection in two rats, and had a mean level in the remaining 15 determinations of 91 ± 14 ng/ml, which is significantly lower (P < 0·02) than that in interstitial fluid. The mean ratio of seminiferous tubular:interstitial fluid testosterone concentration calculated in 14 rats was 0·94 ± 0·24. This ratio was less than unity whenever the interstitial fluid testosterone concentration was more than 50 ng/ml, whereas in all animals with interstitial fluid testosterone of 50 ng/ml, or less, the ratio was greater than or equal to one. The mean testosterone concentration of rete testis fluid in 32 samples was 33 ± 3 ng/ml.
After HCG stimulation in 12 rats, testosterone concentration in interstitial fluid increased to a mean value of 660 ± 83 ng/ml, and in seminiferous tubular fluid to 460 ± 44 ng/ml; the difference between the two was significant (P < 0·05).
These results are discussed in relation to the presumed dilution of seminiferous tubular fluid in rete testis fluid and the role of androgen-binding proteins in the transport of steroids.
STUDIES ON THE DURATION OF THE BREEDING SEASON AND PHOTOREFRACTORINESS IN FEMALE FERRETS PINEALECTOMIZED OR TREATED WITH MELATONIN
Authors: THORPE PENELOPE A. , HERBERT J. 
Published: December 2008

SUMMARY
Oestrous ferrets became anoestrous on exposure to short photoperiods (8 h light: 16 h darkness, 8L:16D) at the summer solstice, and this effect was prevented by pinealectomy. Removal of the pineal alone did not alter the duration of oestrus in animals kept in natural daylight. Melatonin (1 mg, thrice weekly) given to oestrous ferrets kept in daylight also terminated oestrus prematurely. Animals made photorefractory by prolonged exposure to long photoperiods (14L:10D) became photosensitive again if either given melatonin or transferred to short photoperiods (8L:16D) for 7 weeks. These findings show that the pineal gland of the oestrous ferret is involved in the termination of oestrus when the animal is exposed to experimental short photoperiods. This is in addition to its role in inducing oestrus when anoestrous animals are exposed to long days, an effect shown previously. Thus, neither phase of the annual breeding cycle is altered by experimental lighting regimes in pinealectomized animals. Furthermore, some of the effects of short days (but not of long days), including that on photosensitivity, can be replicated by melatonin in the ferret.
STIMULATION OF NUCLEIC ACID AND PROTEIN SYNTHESIS IN THE EPIDIDYMIS AND ACCESSORY ORGANS OF THE RAT BY TESTOSTERONE
Authors: RAJALAKSHMI M. , PRASAD M. R. N. 
Published: December 2008

SUMMARY
The effects of a single dose of testosterone on the content of DNA, RNA and protein and the incorporation of [3H]phenylalanine into protein in the epididymis, vas deferens and ventral prostate of the rat were studied. A single dose of testosterone did not increase the weights of the accessory organs but restored the incorporation of [3H]phenylalanine into proteins in the caput, corpus and cauda epididymides, vas deferens and ventral prostate to the normal level. Within 1 h of hormone administration, significant increases in the content of DNA, RNA and protein were noticed in the cauda epididymidis and ventral prostate. The caput and corpus epididymides and vas deferens showed decreasing order of responsiveness to testosterone. These data are discussed with respect to the relative responsiveness of these organs to reinitiation of their function by administration of a single dose of testosterone. The new protein(s) synthesized in response to hormonal stimulation associated with growth and secretory activity of the cells may be different from the new protein macromolecules synthesized after hormone withdrawal or inhibition of hormone action which are involved in autolytic processes.
LORDOSIS BEHAVIOUR IN MALE, FEMALE AND ANDROGENIZED FEMALE RATS
Authors: SÖDERSTEN P. 
Published: December 2008

SUMMARY
Sex differences in the lordosis response of adult rats to ovarian hormones were studied in a series of experiments. Male rats were less sensitive to oestradiol benzoate (OB, a single injection of 10, 100 or 1000 μg/kg or seven daily injections of 2, 10 or 50 μg/kg) than were female rats. Oestradiol benzoate-primed (10 μg/kg) female, but not male, rats showed dose-dependent responses to progesterone (0·4, 2·0 or 10·0 mg/kg). Male rats responded clearly to progesterone (2 mg/rat) only when primed with a high dose of OB (100 μg/rat). Display of the whole pattern of female sexual behaviour was induced in male rats by treatment with 100 μg OB and 2 mg progesterone. Female rats treated with 1 mg testosterone propionate (TP) on day 4 of life, ovariectomized as adults and tested under the same endocrine conditions as the rats described above, retained behavioural OB sensitivity but responded poorly to progesterone. Evidence is presented that ovarian secretions during development significantly modify the response of neonatally TP-treated and normal female rats to OB in adulthood.
PLASMA CONCENTRATIONS OF PROLACTIN AND THYROTROPHIN DURING SUCKLING IN URETHANE-ANAESTHETIZED RATS
Authors: BURNET F. R. , WAKERLEY J. B. 
Published: December 2008

SUMMARY
Plasma levels of prolactin and TSH were determined by radioimmunoassay in urethane-anaesthetized lactating rats during suckling. Oxytocin release was monitored by recording intramammary pressure. Application of ten pups, 3 h after administration of urethane (1·1 g/kg, i.p.), evoked a parallel rise in prolactin and TSH concentrations which reached a maximum during the 3rd hour of suckling and then declined. Peak hormone concentrations represented a 25-fold increase in prolactin and a ten-fold increase in TSH. Suckling also elicited a pulsatile (every 5–10 min) release of 0·5–1·0 mu. oxytocin. The gradual rise in prolactin and TSH occurred between the 1st and 20th oxytocin pulses.
Intravenous injection of thyrotrophin-releasing hormone (TRH) into unsuckled, anaesthetized lactating rats resulted in a 7- to 30-fold increase in TSH concentration, whereas prolactin levels showed no substantial change.
These results indicate that suckling releases TSH as well as prolactin in the urethane-anaesthetized rat. However, the absence of prolactin release after injections of TRH makes it unlikely that both endocrine responses are regulated solely by the actions of this one releasing hormone.
SERUM FOLLICLE-STIMULATING HORMONE, LUTEINIZING HORMONE AND PROGESTERONE CONCENTRATIONS IN PSEUDOPREGNANT RATS TREATED WITH MEDROXYPROGESTERONE ACETATE
Authors: DE GREEF W. J. , DULLAART J. , ZEILMAKER G. H. 
Published: December 2008

SUMMARY
Pseudopregnant rats were treated early in pseudopregnancy with 1 or 10 mg medroxyprogesterone acetate (MPA). Serum FSH, LH and progesterone concentrations were determined on days 2–20 of pseudopregnancy in treated and control rats.
The mean duration of pseudopregnancy was 13·5 days in the control animals, but when animals were treated with 1 mg MPA a dioestrous period of 21·4 days was observed. A period with leucocytic vaginal smears of at least 2 months was observed after treatment with 10 mg MPA.
Injection with MPA on day 3 of pseudopregnancy did not affect the serum FSH concentrations during the subsequent days. The progesterone pattern was alike in the three groups of animals, i.e. the duration of the activity of the corpora lutea was similar in all groups. However, 10 mg MPA slightly lowered progesterone concentrations on days 4–8 of pseudopregnancy. In the saline-treated rats, LH concentrations decreased from days 2–5, and remained low until they increased after day 11 of pseudopregnancy. This increase was delayed until day 20 in the animals treated with 1 mg MPA, and was not observed in the animals treated with 10 mg MPA.
It is argued that the increase of LH concentration at the end of pseudopregnancy is not instrumental in the decrease of peripheral progesterone concentration but rather that the decrease in the progesterone concentration leads to the increase in the LH concentration.
SECRETION OF LUTEINIZING HORMONE CAUSED BY CONTINUOUS INFUSIONS OF LUTEINIZING HORMONE RELEASING HORMONE IN THE LONG-TERM OVARIECTOMIZED RAT: EFFECT OF OESTROGEN PRETREATMENT
Authors: SCHUILING G. A. , GNODDE H. P. 
Published: December 2008

SUMMARY
Continuous infusions of luteinizing hormone releasing hormone (LH-RH) into phenobarbitone-treated long-term ovariectomized rats, resulted in patterns of LH secretion which were determined by the blood LH-RH concentration. Infusions of 52 ng LH-RH/h caused steadily increasing plasma LH levels, which stabilized after about 2 h of infusion and were maintained for the rest of the experiment (9 h).
A similar course of plasma LH concentration was observed as a result of infusions of 104 ng LH-RH/h, though in this case LH concentrations reached higher levels than those induced by infusion of 52 ng LH-RH/h. Higher rates of LH-RH infusion (208 and 416 ng/h), however, induced clear-cut LH peaks, which reached their maximal plasma values after 2–3 h of infusion and then declined again until, at the end of the experiment, they were only slightly higher than the LH levels induced by infusions of 52 ng LH-RH/h.
A similar series of LH-RH infusions given to ovariectomized rats pretreated with oestradiol benzoate during 3 days (the rats were injected daily with 7 μg steroid), produced a highly augmented response of the pituitary gland, but all LH-RH concentrations infused induced rather sharp LH peaks, reaching their maximum after 2–3 h of infusion. After 5 h of infusion the descending parts of all these peaks appeared to converge.
In both control and oestradiol benzoate-pretreated rats there appeared to be a linear relationship between the logarithm of the blood LH-RH concentration and the maximal plasma LH values on one hand, and the amount of LH secreted during the first 5 h of infusion on the other. Furthermore, it appeared that the longer the period of oestrogen action, the more the response of the pituitary gland to a certain dose of LH-RH was enhanced.
SERUM CORTICOSTERONE IN RATS WITH DELAYED ANOVULATION
Authors: RAMALEY JUDITH A. 
Published: December 2008

SUMMARY
The purpose of this study was to investigate adrenal function in rats during the development of persistent oestrus to determine whether a change in blood levels of corticosterone would precede or coincide with the onset of infertility. The syndrome of delayed persistent oestrus and anovulation was induced by administration of a low dose (10 μg) of testosterone propionate (TP) at 5 days of age. Control animals were handled without injection or received the vehicle (sesame oil) only. Half of each group was ovariectomized at weaning and received Silastic implants of either oestradiol benzoate (OB) or cholesterol, 3 mm tube length/100 g body weight. Intact rats given the low TP dose showed precocious vaginal opening (27·3 ± 2·1 days v. 37·6 ± 2·4 (s.e.m.) days in unhandled controls) and ovulated within 2 days. Persistent vaginal cornification developed in 22 out of 26 rats by 75 days of age. The TP-treated rats had higher corticosterone values than the controls and did not show a further increase after OB implantation. Cholesterol implantation depressed corticosterone levels in the TP-treated rats. The effects of the low TP dose were not dependent upon gonadal function since they persisted in ovariectomized rats. The results suggest that early exposure to androgen can modify the sensitivity of the adrenal system to oestrogen, and can also lead to persistently high values of corticosterone which are not depressed by ovariectomy. These changes precede the onset of persistent oestrus.
PITUITARY–ADRENAL FUNCTION IN THYROPARATHYROIDECTOMIZED MALE AND FEMALE RATS
Authors: DUNN J. D. , HESS M. E. 
Published: December 2008

SUMMARY
The influence of thyroid hormones on pituitary–adrenal function was assessed by studying several aspects of adrenocortical function approximately 30 days after thyroparathyroidectomy (TPTx). Both male and female rats showed evidence of rhythmic adrenocortical activity; peak plasma corticosterone levels occurred just before the dark phase of the lighting schedule. Only the amplitude of the rhythm appeared altered by TPTx. Peak plasma corticosterone levels in TPTx male and female animals were less (P < 0·05) than corresponding levels in intact control rats. Both sexes showed significant responses to stress, but the morning stress response in TPTx females was less (P < 0·01) than the stress response in intact controls. Concomitant with the reduced stress response, the adrenocortical response to exogenous ACTH was reduced in TPTx female rats.
PROSTAGLANDINS IN THE PLASMA AND AMNIOTIC FLUID OF RHESUS MONKEYS DURING PREGNANCY AND AFTER INTRA-UTERINE FOETAL DEATH
Authors: MITCHELL M. D. , PATRICK J. E. , ROBINSON J. S. , THORBURN G. D. , CHALLIS J. R. G. 
Published: December 2008

SUMMARY
Prostaglandin F (PGF) was measured in amniotic fluid, and 13,14-dihydro-15-keto-prostaglandin F2α (PGFM) was measured in maternal peripheral venous plasma and amniotic fluid of rhesus monkeys during late pregnancy. 13,14-Dihydro-15-keto-PGF2α was determined in the maternal peripheral venous plasma of two animals following intrauterine foetal death. The mean concentration of PGF and PGFM in amniotic fluid increased fourfold during the last 5 days of pregnancy. This increase was associated with an increase in the oestrone concentration in amniotic fluid and in maternal plasma. In normal pregnancy there was no increase in PGFM levels in the maternal peripheral vein, up to 1–2 days pre partum. After intra-uterine death, progesterone concentration in the maternal peripheral vein was unaltered, but oestrone and oestradiol declined. In plasma samples taken within 12 h of delivery, the concentration of PGFM was raised. It is concluded that an increase in prostaglandin production accompanies delivery at normal term, and at delivery past term following intra-uterine foetal death.
INDUCTION OF LUTEINIZING HORMONE RELEASE BY GONADAL STEROIDS IN THE OVARIECTOMIZED DOMESTIC HEN
Authors: WILSON SUSAN C. , SHARP P. J. 
Published: December 2008

SUMMARY
The ability of intramuscular injections of gonadal steroids to exert a positive feedback action on LH secretion was investigated in the ovariectomized hen. Plasma LH was measured by radioimmunoassay.
Single injections of progesterone (dose range: 0·05–10 mg/kg) or oestradiol benzoate (dose range: 0·01–1 mg/kg) did not result in an increase in plasma LH concentration. After priming with 0·1 mg oestradiol benzoate/kg on alternate days for 7 days and with 0·5 mg progesterone/kg on days 5, 6 and 7, a single injection of progesterone on day 8 (dose range: 0·1–2 mg/kg) caused the plasma LH concentration to start increasing after 15 to 30 min. Peak LH concentration was reached around 1·5–2 h after injection. The magnitude of LH response to progesterone was dose related. In contrast, a single injection of oestradiol benzoate (dose range: 0·01–1 mg/kg) failed to stimulate LH release in the oestrogen– progesterone primed ovariectomized (O-P-OVX) hen. A single injection of testosterone (dose range: 0·1–2·0 mg/kg) failed to stimulate LH release in ten out of 12 O-P-OVX hens. A small increase in LH secretion was observed in the two remaining birds.
When oestrogen or progesterone was omitted from the priming schedule, a LH positive feedback response to a single injection of progesterone was not observed. Increasing or decreasing the amount of oestrogen or progesterone in the priming schedule modified the LH response to a single injection of progesterone on the day following the last priming injection. This suggested that a critical oestrogen to progesterone ratio was required to prime the LH positive feedback mechanism.
It is suggested that, in the hen, the release of LH is facilitated by the positive feedback effect of a combination of oestrogen and progesterone in a two-phase process. The first is the priming phase, which depends on the presence in the blood of oestrogen and progesterone; the second is the inductive phase, which depends only on an incremental change in plasma progesterone concentration. Oestrogen is not involved in the inductive phase.
INHIBITION OF PITUITARY PROLACTIN SECRETION BY HUMAN PLACENTAL LACTOGEN IN RATS
Authors: NAGASAWA HIROSHI , YANAI REIKO , YAMANOUCHI KOREHITO 
Published: December 2008

SUMMARY
Intact female rats given twice daily injections of 1 mg human placental lactogen (HPL) showed continued dioestrous vaginal smears and their ovarian corpora lutea were found to be hypertrophied and functional. The serum prolactin level was significantly lower in these rats than in the controls at dioestrus as well as at pro-oestrus. Twice-daily injections of 0·5 or 2 mg HPL to ovariectomized rats decreased serum and pituitary levels of prolactin and increased hypothalamic activity of prolactin inhibiting hormone, although the effect was less at the lower dose. Human placental lactogen had no direct effect on pituitary prolactin secretion in vitro. These findings have demonstrated that HPL, like prolactin itself, inhibits prolactin secretion by acting indirectly on the pituitary through the hypothalamus.
TESTOSTERONE SECRETION BY FOETAL RAT TESTES IN VITRO
Authors: PICON RÉGINE 
Published: December 2008

SUMMARY
Testosterone secretion by foetal rat testes (13½–21½ days of gestation) explanted for 3 days in a synthetic medium was measured every 24 h by radioimmunoassay.
During the first day of explantation, the foetal testis produced, respectively, 1013 ± 132, 8734 ± 1118, 9179 ± 2185 and 3886 ± 309 (s.e.m.) pg/testis when explanted at 14½, 16½, 18½ and 21½ days respectively.
Testosterone production by 13½-day-old testes was not detectable on the first day of culture, but appeared on subsequent days. Daily testosterone secretion increased on the 2nd and 3rd days of culture in 14½-day-old testes and decreased in older stages. These results suggest that the functional differentiation of the testis is independent of stimulatory factors like gonadotrophins.
Dibutyryl cyclic AMP was found to stimulate testosterone production significantly from 14½ days of gestation onwards.
EFFECT OF INTRAVENOUS OR INTRA-AMNIOTIC INJECTION OF DEHYDROEPIANDROSTERONE SULPHATE ON OESTROGEN LEVELS IN URINE AND SERUM IN LATE PREGNANCY WITH LIVE ANENCEPHALIC FOETUSES
Authors: MAEYAMA M. , ICHIMARU S. , NAKAHARA K. , NAKAYAMA M. , MIYAKAWA I. 
Published: December 2008

SUMMARY
Dehydroepiandrosterone sulphate (DHAS) was injected intravenously or intra-amniotically into eight volunteers carrying live anencephalic foetuses (including one microcephalic foetus). Urinary and unconjugated serum oestrone, oestradiol and oestriol were measured before and after DHAS administration. In seven pregnant women with live anencephalic foetuses the urinary excretion of oestriol was very low, and the ratio of oestriol to oestrone+ oestradiol was much less than that during normal pregnancy. Increases of urinary oestrone and oestradiol but no significant change in the ratio of oestriol to oestrone + oestradiol were observed 24 h after i.v. administration of DHAS to five patients. In three patients, between 1 and 12 h after i.v. administration of DHAS (100–200 mg), the concentrations of serum oestrone, oestradiol and oestriol increased to 13·5, 6·8 and 3·1 times the control values, respectively. After injection of DHAS (200 mg) intra-amniotically into two patients, the urinary excretion of all three oestrogens increased much more on day 2 than on day 1, and the ratio of urinary oestriol to oestrone + oestradiol rose greatly. On the other hand, the concentrations of unconjugated serum oestrogens in these patients increased progressively between 1 and 12 h or more after DHAS administration, and the maximal level of serum oestriol was 9·8 times the control value while those of oestrone and oestradiol were 4·6 times and 5·0 times the control values, respectively. These results suggest that in late human pregnancy DHAS in the circulation of the mother is converted to oestriol largely via the phenolic pathway (DHAS → oestrone → oestriol), whereas DHAS circulating within the foeto-placental compartment is converted to oestriol via both the phenolic and the neutral intermediates.