PRE-TRAUMA OESTROGEN REQUIREMENTS FOR INDUCTION OF DECIDUALIZATION IN SPAYED, PROGESTERONE-TREATED RATS

1966 ◽  
Vol 53 (2) ◽  
pp. 212-224 ◽  
Author(s):  
Carla Rossi Cartoni ◽  
G. Bignami
Keyword(s):  
Single Dose ◽  
Hormonal Treatment ◽  
Normal Pregnancy ◽  
Carbonic Anhydrase Activity ◽  
The Other ◽  
Ovariectomized Rats ◽  
Uterine Weight ◽  
Experimental Conditions ◽  
Progesterone Treatment ◽  
Oestradiol Benzoate

ABSTRACT The formation of deciduomata was investigated in ovariectomized rats treated with various combinations of oestrogen and progesterone before traumatization. The hormonal treatment was kept constant for all groups of animals during the period between traumatization and autopsy (4 mg of progesterone and 0.2 μg of oestradiol benzoate daily). Uterine weight and carbonic anhydrase activity were measured 96 hours after trauma and compared with those of intact controls receiving traumatization on day 4 of pseudopregnancy. When a single dose of oestrogen was given on the day before traumatization, induction of decidualization was successful under a wide variety of experimental conditions (presence or absence of oestrogen »priming« before the beginning of the progesterone treatment; progesterone treatment of varying duration). On the contrary, treatment with divided doses of oestrogen, given for 3 days before trauma, allowed extensive decidualization only in rats »primed« with oestrogen, and traumatized on the fourth day of a progesterone treatment started 24 hours after vaginal keratinization. It appears therefore that only the »oestrogen surge« hypothesis of Shelesnyak and his collaborators can account for those conditions in which implantation occurs at variable intervals of time after the last oestrus (lactation, hypophyseal autotransplantation, administration of a tranquilizer and early ovariectomy followed by hormonal treatment). On the other hand, both the hypothesis of Shelesnyak and that proposed by Yochim & DeFeo (1963) (i. e. continuous secretion of small amounts of oestrogen during the first three days of pregnancy and pseudopregnancy) could account for the rapid waxing and waning of endometrial sensitivity to deciduoma-inducing stimuli observed in normal pregnancy and pseudo-pregnancy.

EFFECT OF FEEDING ETHINYLOESTRADIOL FOR VARIOUS PERIODS BEFORE MATING ON REPRODUCTION IN THE HAMSTER

1972 ◽  
Vol 70 (3) ◽  
pp. 582-590
Author(s):  
B. K. Davis ◽  
I. Noske ◽  
M. C. Chang
Keyword(s):  
Single Dose ◽  
Pregnancy Rate ◽  
Fertility Control ◽  
Normal Pregnancy ◽  
Oestrous Cycle ◽  
The Other ◽  
Feeding Schedule ◽  
Crown Rump Length ◽  
Essentially Normal ◽  
Effect Of Feeding

ABSTRACT Ethinyloestradiol (EO) fed for various periods before mating to female hamsters affected the timing of mating and pregnancy rate. Slight effects on ovulation, foetal-crown rump length and resorption may have occurred, but effects on implantation were not apparent among pregnant hamsters. The response observed depended upon the feeding schedule adopted: hamsters fed 2.5 mg EO in a single dose, on day 3 before mating, mated normally but had a significantly lower pregnancy rate; on the other hand, animals fed 2.5 mg EO (0.21 mg/day) over three oestrous cycles, days 14–3 before mating, showed variations in the time of mating but had an essentially normal pregnancy rate; and, a group of hamsters who received the same total amount of EO (0.63 mg/day) over one oestrous cycle, days 6–3 premating, showed untowards effects by the steroid on both the timing of mating and pregnancy rate. The implications of these results are considered in relation to fertility control.

OESTROGEN RESPONSES OF RATS NEONATALLY STERILIZED WITH STEROIDS

1969 ◽  
Vol 45 (3) ◽  
pp. 415-420 ◽  
Author(s):  
T. R. WRENN ◽  
JOAN R. WOOD ◽  
J. BITMAN
Keyword(s):  
Testosterone Propionate ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Uterine Weight ◽  
Oestradiol Benzoate

SUMMARY At 75 days of age, female rats neonatally sterilized with oestradiol benzoate or testosterone propionate were compared with normal and ovariectomized rats with regard to their 6-hr. response to 0·2 μg. oestradiol 17β. The greatest increases in uterine weight, glucose and glycogen concentrations and per cent uterine water occurred in the ovariectomized animals. A marked oestrogen response also occurred in the animals neonatally sterilized with oestradiol benzoate. The response of the normal rats was slight, and the testosterone propionate-treated rats were the least affected. Adrenal, pituitary, and ovarian weights were found to be affected by the neonatal hormone treatments. Vaginal patency was completely inhibited in the rats injected with testosterone propionate. It is concluded that rats neonatally sterilized with steroids are much less suitable than ovariectomized animals for oestrogen assays.

SPERM DISTRIBUTION IN FEMALE RABBITS: THE EFFECT OF OVARIAN STEROIDS

1974 ◽  
Vol 76 (4) ◽  
pp. 765-772 ◽  
Author(s):  
D. B. Morton ◽  
R. J. Fitzpatrick ◽  
T. D. Glover
Keyword(s):  
Cervix Uterus ◽  
Hormonal Treatment ◽  
The Other ◽  
Sperm Transport ◽  
Ovarian Steroids ◽  
Other Hand ◽  
Oestradiol Benzoate

ABSTRACT Oestradiol benzoate, progesterone and 20α-hydroxy-4-pregnen-3-one (20α-OH) were injected into ovariectomized rabbits and after either 4 or 5 days the rabbits were inseminated with a standardized inseminate, killed at 2 and 10 h after insemination and the number of spermatozoa in the vagina, cervix, uterus and oviducts was evaluated. The oestrogen increased the number of spermatozoa recovered from the cervix, uterus and oviduct compared with the control ovariectomized group receiving no hormonal treatment. The progestagens, on the other hand, tended to inhibit sperm transport through the cervix depending on the amount given. Injection of both oestrogen and progesterone simultaneously, illustrated their antagonistic actions. The effect of circulating progestagens on sperm transport during oestrus and pseudopregnancy is discussed, as well as their effects on the formation of the cervical reservoir.

INDUCTION OF SEXUAL RECEPTIVITY BY OESTRADIOL BENZOATE IN CYCLIC FEMALE RATS: INFLUENCE OF OVARIAN SECRETIONS BEFORE INJECTION OF OESTRADIOL BENZOATE

1979 ◽  
Vol 80 (3) ◽  
pp. 389-395 ◽  
Author(s):  
P. SÖDERSTEN ◽  
S. HANSEN
Keyword(s):  
Sexual Behaviour ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Sexual Receptivity ◽  
Behavioural Effect ◽  
Progesterone Treatment ◽  
Oestradiol Benzoate

The ability of cyclic female rats to show sexual receptivity 24 h after an injection of 2 μg oestradiol benzoate (OB) was lost 24 h after ovariectomy. Exposure of cyclic rats to anti-oestrogen (nitromophene monocitrate) implants 24 h before ovariectomy and OB treatment prevented the latter from inducing sexual receptivity within 24 h of administration. Treatment of ovariectomized rats with constant release implants filled with an oil solution of 15 μg oestradiol/ml had no behavioural effect in itself, but prepared the rats to show lordosis 24 h after administration of OB. Progesterone treatment (4 mg) induced sexual behaviour in cyclic rats on days other than that of the oestrous cycle when the rats are normally receptive. Evidence is presented that a lower level of oestradiol stimulation than that present during pro-oestrus was needed for the induction of sexual receptivity in ovariectomized rats. It is suggested that the low basal level of oestradiol which was present throughout the oestrous cycle was necessary for the induction of sexual receptivity and that an increase in oestradiol stimulation served to increase the behavioural sensitivity to progesterone.

Influence of oestrogen and noradrenergic afferent neurones on the response of LH and oxytocin to immobilization stress

1986 ◽  
Vol 110 (2) ◽  
pp. 245-250 ◽  
Author(s):  
T. Higuchi ◽  
K. Honda ◽  
H. Negoro
Keyword(s):  
Supine Position ◽  
Immobilization Stress ◽  
Rapid Decrease ◽  
The Other ◽  
Ovariectomized Rats ◽  
Noradrenergic Neurones ◽  
Oestradiol Benzoate ◽  
Adrenoceptor Blocker ◽  
Response To Stress ◽  
Induced Changes

ABSTRACT The influence of oestrogen on LH and oxytocin responses to immobilization stress, and the involvement of noradrenergic afferent neurones in these responses, was examined in ovariectomized rats with or without pretreatment with oestrogen or after noradrenergic transmitter blockade. Immobilization of the rats on a board in a supine position for 1 h brought about a rapid decrease in LH levels and an increase in oxytocin levels in the blood of ovariectomized rats. Oestradiol benzoate (20 μg) injected s.c. the day before immobilization, decreased basal LH levels but had no effect on basal oxytocin levels. Immobilization stress applied to oestrogen-treated rats induced a small but significant increase in LH concentrations and a rise in oxytocin concentrations similar to that in rats without oestrogen pretreatment. A dopamine-β-hydroxylase inhibitor or phenoxybenzamine (α-adrenoceptor blocker) injected into ovariectomized rats reduced basal LH levels and increased basal oxytocin levels in the blood. Immobilization stress induced an increase in LH levels in rats treated with dopamine-β-hydroxylase inhibitor, but had no effect in rats treated with phenoxybenzamine. Stress induced a larger increase in blood oxytocin levels in rats treated with either drug compared with that in control rats injected with vehicle. On the other hand, propranolol (β-adrenoceptor blocker) had no effect on basal or stress-induced changes in LH or oxytocin levels in the blood. These results indicate that the LH response to stress, which might be mediated through α-adrenergic neurones, depends on the circulating oestrogen or LH levels before the stress. In contrast, the oxytocin response to stress may not be mediated by noradrenergic neurones and may not be influenced by oestrogen. J. Endocr. (1986) 110, 245–250

INDUCTION OF SEXUAL RECEPTIVITY IN OVARIECTOMIZED RATS BY PULSE ADMINISTRATION OF OESTRADIOL-17β

1981 ◽  
Vol 89 (1) ◽  
pp. 55-62 ◽  
Author(s):  
P. SÖDERSTEN ◽  
P. ENEROTH ◽  
S. HANSEN
Keyword(s):  
Single Injection ◽  
Serum Levels ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Sexual Receptivity ◽  
Behavioural Responses ◽  
Time Points ◽  
Progesterone Treatment ◽  
Oestradiol Benzoate ◽  
Stimulation Of

Constant-release implants filled with oestradiol-17β induced sexual receptivity in ovariectomized rats in response to progesterone treatment if they were implanted 32 h before behavioural testing. A 20 h period of exposure to oestradiol, by implantation 32 h before testing and removal of the implants 20 h later, was sufficient for induction of the behaviour. The exposure time necessary for behavioural responses could be further reduced to two 4 h periods, between 32 and 28 h and between 16 and 12 h, before testing. Serum levels of oestradiol were raised within 1 h of oestradiol implantation and declined rapidly after implant removal. A single injection of oestradiol benzoate was much more potent than a single injection of oestradiol in inducing sexual receptivity in ovariectomized rats, but this difference in potency was reversed if two appropriately timed injections were given. Oestrone- or oestriol-filled implants were relatively ineffective in inducing sexual receptivity. It is suggested that oestradiol has to be present at crucial time points to prepare an ovariectomized rat to respond behaviourally to progesterone treatment and that oestradiol is the principal oestrogen in the stimulation of sexual behaviour in female rats.

UTERINE OESTROGEN AND PROGESTERONE RECEPTORS IN THE OVARIECTOMIZED RAT

1981 ◽  
Vol 91 (2) ◽  
pp. 281-287 ◽  
Author(s):  
ANDREA MANNI ◽  
REBECCA BAKER ◽  
B. M. ARAFAH ◽  
O. H. PEARSON
Keyword(s):  
Progesterone Receptors ◽  
Total Cell ◽  
Ovariectomized Rats ◽  
Oestrogen Receptors ◽  
Rat Uterus ◽  
Experimental Conditions ◽  
Cell Content ◽  
Transient Rise ◽  
Additional Group ◽  
Oestradiol Benzoate

The effect was studied of repeated injections of oestradiol-17β (5, 10, 25, 50 μg) given for various lengths of time (3, 5, 9 days) on total cell content of oestrogen receptors and cytosol progesterone receptors in the uteri of ovariectomized rats. An additional group of rats was injected daily with 50 μg oestradiol benzoate (OB) for 9 days in order to achieve a more sustained concentration of oestradiol in the blood. Injections were begun 24 h after ovariectomy and the rats were killed 24 h after the last injection. Daily administration of 5 μg oestradiol prevented the initial transient rise in oestrogen receptors which was observed in the uteri of untreated rats after ovariectomy. Repeated injections of 10 μg oestrogen produced an initial lowering in oestrogen receptors after 3 days of treatment which was followed by a prompt rise at 5 and 9 days when treatment was continued. A significant reduction in oestrogen receptors occurred at all times studied when rats were injected daily with 25 and 50 μg oestradiol. A more profound reduction in oestrogen receptors was observed in the group of rats treated for 9 days with 50 μg OB. Synthesis of progesterone receptors was stimulated by all doses of oestrogen studied. Concentrations of progesterone receptors were significantly higher after 3 and 5 days of treatment with 25 and 50 μg oestrogen. After 9 days of treatment, however, concentrations of progesterone receptors were virtually identical in all treated groups, including the group treated with OB. We have concluded that large doses of oestrogen significantly decrease oestrogen receptor content in the rat uterus, especially when OB is used. The degree of reduction, however, is only moderate under these experimental conditions and is insufficient to inhibit synthesis of progesterone receptors.

EFFECT OF AN OESTROGEN ANTAGONIST ETHAMOXY-TRIPHETOL (MER-25) ON OESTROUS BEHAVIOUR IN RATS

1968 ◽  
Vol 59 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Bengt J. Meyerson ◽  
Leif Lindström
Keyword(s):  
Ovariectomized Rats ◽  
High Dose ◽  
Time Intervals ◽  
Progesterone Treatment ◽  
Oestradiol Benzoate

ABSTRACT MER-25, 75–150 mg/kg, inhibited oestrous behaviour induced by oestradiol benzoate/progesterone treatment in ovariectomized rats. In experiments in which MER-25 was administered 2 hours before oestradiol benzoate, the extent of antagonism was dependent on the dose of MER-25. Single injections of MER-25, given at different time intervals in conjunction with oestrogen administration, showed that MER-25 effectively decreased the response when administered either 2 hours before, or 2 or 8 hours after oestradiol benzoate treatment. No significant effect occurred when MER-25 was given simultaneously with, 12 hours before, or 24 hours after the oestrogen injection. MER-25 had no effect when oestradiol was given instead of oestradiol benzoate in otherwise analogous experiments. It seems probable that the inability of MER-25 to antagonize the effect of oestradiol in these experiments was due to the fact that MER-25 cannot compete with the comparatively high dose of oestradiol which was necessary to obtain the same response as in the oestradiol benzoate experiments.

Interactions between phyto-oestrogens and steroids in the cervical mucus and uterine weight responses in ewes

1976 ◽  
Vol 27 (1) ◽  
pp. 101 ◽  
Author(s):  
RW Kelly ◽  
AJ Allison ◽  
DK Shirley
Keyword(s):  
Medicago Sativa ◽  
Intramuscular Injection ◽  
Testosterone Propionate ◽  
Red Clover ◽  
Cervical Mucus ◽  
The Other ◽  
Uterine Weight ◽  
Progesterone Treatment ◽  
Subcutaneous Implant

Cervical mucus and uterine weight responses were measured in ovariectomized ewes grazing pastures containing isoflavones and coumestans—red clover (Trifolium pyatense) and lucerne (Medicago sativa) respectively. The red clover pastures were highly oestrogenic to the ewes, large productions of mucus and high uterine weights being recorded. Grazing of these pastures for a 12-day period prior to bioassay had no significant effect on either response. The lucerne pastures were only mildly oestrogenic. Administration of progesterone either by subcutaneous implant (375 mg progesterone) or intramuscular injection (10 mg per ewe per day) inhibited the mucus responses to isoflavones but did not decrease the uterine weight responses. In one of two experiments, the uterine weight was unaffected and in the other experiment the weight was enhanced by progesterone treatment. Testosterone propionate injections (10 mg per ewe per day) had no effect on either the cervical mucus or uterine weight responses, but induced oestrus in all ewes.

EFFECT OF OESTROGEN UPON PARTURITION, MATERNAL BEHAVIOUR AND LACTATION IN OVARIECTOMIZED PREGNANT RATS

1973 ◽  
Vol 56 (2) ◽  
pp. 219-225 ◽  
Author(s):  
SILVIA CATALÁ ◽  
R. P. DEIS
Keyword(s):  
Single Dose ◽  
The Other ◽  
Maternal Behaviour ◽  
Milk Ejection ◽  
Pregnant Rats ◽  
Normal Delivery ◽  
Oestradiol Benzoate ◽  
Near Term

SUMMARY Ovariectomy of rats on day 20 of pregnancy impaired parturition and lactation. All rats showed prolonged delivery with many foetuses born dead and the mothers were unable to rear the young. Treatment with oestradiol benzoate (0·5 or 1 μg) in a single dose permitted normal delivery and lactation when the hormone was injected immediately after ovariectomy. Oestrogen administered the day after ovariectomy was not effective. The administration of prolactin and corticotrophin to ovariectomized pregnant rats did not prevent abnormal parturition but lactation improved in 50% of the mothers. A group of animals ovariectomized on day 20 was treated with oxytocin every 2 h on day 22 starting at 08.00 h. This treatment did not facilitate parturition and lactation. Maternal behaviour, which was always present in the other groups, was also impaired by this treatment. When ovariectomy was performed on the evening of day 21 of pregnancy, a partial impairment of parturition was observed but lactation was normal in seven out of eight rats. The results indicate that oestrogen is essential near term for normal parturition and lactation. The absence of the steroid may make the uteri less sensitive to oxytocic substances and also affect milk ejection.

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