EFFECTS OF OESTRADIOL AND PROGESTERONE ON THE INDUCTION AND DURATION OF SEXUAL RECEPTIVITY IN CYCLIC FEMALE RATS

1977 ◽  
Vol 74 (3) ◽  
pp. 477-485 ◽  
Author(s):  
P. SÖDERSTEN ◽  
S. HANSEN
Keyword(s):  
Behavioural Response ◽  
Female Rats ◽  
Sexual Receptivity ◽  
Repeated Treatment ◽  
Progesterone Treatment ◽  
Oestradiol Benzoate

SUMMARY Intact 4-day cyclic rats showed sexual receptivity 24 h after an injection of oestradiol benzoate (OB) on any day of the cycle except on the second day after the display of spontaneous oestrus. Ovariectomy at the time of OB treatment abolished the behavioural response, but receptivity was restored by progesterone. Progesterone treatment early on the day of behavioural oestrus advanced the display of receptivity but did not affect the time at which oestrus ended. Repeated treatment of sexually receptive rats with progesterone did not affect the duration of oestrus. These results show that sexual receptivity in the intact rat cannot occur in the absence of oestradiol and progesterone. The results further suggest that progesterone may not be associated with the mechanisms terminating behavioural oestrus in rats. Treatment with OB on the day of oestrus can prolong the duration of receptivity but only at a higher dosage than that needed for induction of receptivity.

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.

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.

EFFECTS OF OESTRADIOL-17β, OESTRADIOL BENZOATE AND THE SYNTHETIC OESTROGEN RU 2858 ON SEXUAL DIFFERENTIATION IN THE NEONATAL FEMALE RAT

1975 ◽  
Vol 67 (3) ◽  
pp. 419-424 ◽  
Author(s):  
CYNTHIA DOUGHTY ◽  
JANET E. BOOTH ◽  
P. G. McDONALD ◽  
R. F. PARROTT
Keyword(s):  
Rat Brain ◽  
Sexual Differentiation ◽  
Neonatal Rat ◽  
Female Rats ◽  
Sexual Receptivity ◽  
Female Rat ◽  
Neonatal Rats ◽  
Oestradiol Benzoate ◽  
Ovarian Cyclicity ◽  
Neonatal Rat Brain

SUMMARY Groups of neonatal female rats were treated for the first 5 days of life with oestradiol-17β, oestradiol benzoate or a synthetic oestrogen, 11β-methoxy-17-ethynyl-1,3,5(10)-oestratriene-3,17β-diol (RU 2858), in daily doses ranging from 0·5 to 1000 ng. Oestradiol-17β had no effect on adult ovarian cyclicity or sexual receptivity after ovariectomy and oestrogen + progesterone treatment. Ovarian cyclicity was prevented by 100 ng or more oestradiol benzoate/day, and by all doses of RU 2858. Only rats receiving 50 ng oestradiol benzoate/ day or 0·5 ng RU 2858/day showed normal receptivity. The defeminizing action of RU 2858 was at least 100 times greater than that of oestradiol benzoate; it is suggested that this greater potency is due to the low affinity of RU 2858 for the oestradiol-binding protein in the plasma of neonatal rats. These results indicate that defeminization of the neonatal rat brain can be induced by physiological amounts of oestrogen, and are discussed with reference to the action of testosterone.

Dissociation between the ovarian factors controlling sexual receptivity and preovulatory secretion of LH in cyclic female rats

1987 ◽  
Vol 112 (1) ◽  
pp. 133-138 ◽  
Author(s):  
P. Södersten ◽  
P. Eneroth
Keyword(s):  
Sexual Behaviour ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Sexual Receptivity ◽  
Serum Progesterone ◽  
Lh Surge ◽  
Oestradiol Benzoate ◽  
Lh Release ◽  
Lh Secretion ◽  
Intact Rats

ABSTRACT Ovariectomy and treatment with oestradiol benzoate (10 μg OB) on the day before behavioural oestrus eliminated the preovulatory surge of LH and reduced the level of sexual receptivity on the following day. Sexual behaviour, but not the LH surge, was restored by progesterone (0·5 mg) given 18 h later. Injection of OB on the day after behavioural oestrus induced a small release of LH and normal sexual behaviour on the following day. Ovariectomy on the day after behavioural oestrus reduced the stimulatory effect of OB on sexual behaviour and eliminated its weakly stimulatory effect on LH release. Sexual behaviour, but not the small LH surge, was restored in these animals by progesterone (0·5 mg) given 18 h later. Treatment of rats ovariectomized 2 days before the day of the LH surge with implants containing oestradiol or injections of oestradiol (1 μg) induced LH surges but the amplitudes of these LH surges were much smaller than those of the normal LH surge. Treatment of intact rats with OB increased serum progesterone levels 24 h later, an effect which was eliminated by ovariectomy. Injections of LH (20 μg) into intact rats on the day after behavioural oestrus also increased serum progesterone concentrations but failed to stimulate sexual behaviour. It is suggested that OB treatment of intact rats on the day after behavioural oestrus stimulates sexual behaviour by inducing a surge of LH secretion which activates ovarian secretion of progesterone. Thus, oestrogen and progesterone but not the LH surge are essential for sexual behaviour. Whereas oestradiol and progesterone restore normal sexual behaviour in ovariectomized rats, additional ovarian factors may be required for induction of normal LH surges. J. Endocr. (1987) 112, 133–138

Naloxone reverses post-ejaculatory inhibition of sexual behaviour in female rats

1987 ◽  
Vol 113 (3) ◽  
pp. 429-434 ◽  
Author(s):  
G. Forsberg ◽  
I. Bednar ◽  
P. Eneroth ◽  
P. Södersten
Keyword(s):  
Sexual Behaviour ◽  
Opioid Peptide ◽  
Female Rats ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Sexual Receptivity ◽  
Peptide Receptor ◽  
Oestradiol Benzoate ◽  
Brain And Spinal Cord ◽  
The Brain

ABSTRACT Sexual receptivity was inhibited in ovariectomized rats treated with oestradiol benzoate (OB: two injections of 2 μg) and progesterone (0·5 mg) immediately after ejaculation by the male and restored after the end of the post-ejaculatory refractory period in the male. The post-ejaculatory inhibition of sexual receptivity was reversed by i.p. (5 mg), intracerebroventricular (50 μg) or intrathecal (50 μg) injection of the opioid peptide receptor antagonist naloxone. The concentration of serum β-endorphin-like immunoreactivity in ovariectomized rats treated with OB plus progesterone was unaltered by sexual interactions with males (18·3 ± 6·0 (s.e.m.), 26·4 ± 2·1 and 21·8 ± 6·1 pmol/l before sexual activity, after ejaculation and after the end of the post-ejaculatory interval) but reduced to non-detectable by hypophysectomy. Subcutaneous injection of 10 μg β-endorphin raised serum concentrations of β-endorphin-like immunoreactivity but did not affect the display of sexual behaviour. The behaviour was also unaffected by intracerebroventricular injection of 0·1, 0·2 or 1·0 μg β-endorphin or by injections of 0·25 μg β-endorphin in the periaqueductal central grey of the mesencephalon. The results show that ejaculation by male rats causes a transient inhibition of sexual receptivity in the female which may be dependent upon opioid peptide receptor mechanisms in the brain and spinal cord. It is unlikely that the peptide is β-endorphin. J. Endocr. (1987) 113, 429–434

EVIDENCE THAT PROGESTERONE DOES NOT INHIBIT THE INDUCTION OF SEXUAL RECEPTIVITY BY OESTRADIOL-17β IN THE RAT

1981 ◽  
Vol 89 (1) ◽  
pp. 63-69 ◽  
Author(s):  
P. SÖDERSTEN ◽  
P. ENEROTH
Keyword(s):  
Serum Levels ◽  
Behavioural Response ◽  
Oestrous Cycle ◽  
Implant Removal ◽  
Ovariectomized Rats ◽  
Sexual Receptivity ◽  
Behavioural Effect ◽  
Inhibitory Role ◽  
Progesterone Treatment

Progesterone-filled constant-release implants facilitated the induction of sexual receptivity in ovariectomized rats given implants of oestradiol-17β precisely 32 h before testing, irrespective of the time of implantation. Inhibition by progesterone implants of the behavioural response to an injection of progesterone occurred after the facilitation 32 h after oestradiol implantation. Sexual receptivity could be induced in pseudopregnant rats in the absence of progesterone treatment by injection of 1 μg oestradiol 32 and 16 h before testing at a time when endogenous serum levels of oestradiol were low and progesterone levels were high. The behavioural response of ovariectomized rats implanted with oestradiol and tested daily was unaffected by implantation of progesterone at the time of oestradiol implantation, although serum levels of progesterone varied with the number of progesterone implants inserted. Inhibition by progesterone implants of the behavioural response to an injection of progesterone 6 h before behavioural testing occurred only if the progesterone implants were present for at least 32 h of a 48 h period. Serum levels of progesterone were raised within 1 h of progesterone implantation and declined within a 6 h period after implant removal. It is concluded that progesterone does not inhibit the behavioural effect of oestradiol and that progesterone does not play an inhibitory role in the regulation of the behavioural oestrous cycle in our strain of rats.

PLASMA PROGESTERONE AND ITS RELATIONSHIP TO SERUM GONADOTROPHINS IN IMMATURE FEMALE RATS

1975 ◽  
Vol 64 (2) ◽  
pp. 329-336 ◽  
Author(s):  
H. M. A. MEIJS-ROELOFS ◽  
W. J. DE GREEF ◽  
J.TH.J. UILENBROEK
Keyword(s):  
Body Weight ◽  
Luteinizing Hormone ◽  
Follicle Stimulating Hormone ◽  
Female Rats ◽  
Immature Female ◽  
Plasma Progesterone ◽  
Adult Rat ◽  
Progesterone Treatment ◽  
Serum Luteinizing Hormone ◽  
Oestradiol Benzoate

SUMMARY In immature female rats, low values for concentrations of plasma progesterone were generally found from days 6–15 and from days 25–32 of life. Maximum progesterone concentrations (13·0–14·1 ng/ml), comparable to metoestrous values in the adult rat, occurred on days 20–22. The progesterone appeared to be of ovarian origin since after ovariectomy, on day 18, low progesterone concentrations were found 1 and 2 days later (2·5 ng/ml and 1·3 ng/ml) as compared with control values of 10·7 ng/ml and 14·1 ng/ml. However, adrenalectomy also lowered progesterone concentrations, 1 and 2 days later (6·4 and 4·9 ng/ml). The effect of progesterone, either alone or in combination with oestradiol benzoate (OB), on serum gonadotrophins was studied in rats ovariectomized on day 18. The highest dose of progesterone (0·15 mg) only slightly diminished the rise in serum luteinizing hormone (LH) after ovariectomy and had no effect on serum follicle-stimulating hormone (FSH). Oestradiol benzoate in a dose of 0·025 μg/100 g body weight was highly effective in preventing the rise in both LH and FSH concentrations, and OB treatment (resulting in a near-physiological oestradiol concentration) combined with progesterone treatment was more effective than treatment with OB alone. The results suggest that the amounts of progesterone and oestradiol present in the 20-day-old rat are adequate to cause the decrease in FSH level normally observed in immature female rats around this age.

REVERSAL OF PROGESTERONE INHIBITION OF SEXUAL BEHAVIOUR IN OVARIECTOMIZED RATS BY HIGH DOSES OF PROGESTERONE

1979 ◽  
Vol 80 (3) ◽  
pp. 381-388 ◽  
Author(s):  
S. HANSEN ◽  
P. SÖDERSTEN
Keyword(s):  
Sexual Behaviour ◽  
Inhibitory Effect ◽  
Behavioural Response ◽  
Ovariectomized Rats ◽  
Sexual Receptivity ◽  
High Dose ◽  
Progesterone Treatment ◽  
High Doses ◽  
Sequential Inhibition ◽  
Very High

Considerably less progesterone was needed to facilitate than was required to inhibit sexual receptivity induced by oestradiol benzoate (OB) and progesterone in the ovariectomized rat. Inhibition of sexual receptivity occurred if progesterone was given at the time of OB treatment (concurrent inhibition). If progesterone was given 42 h after the OB treatment it first acted to facilitate the behaviour and then to inhibit the response to renewed progesterone treatment 24 h later (sequential inhibition). Both concurrent and sequential inhibition of sexual receptivity by progesterone could be reversed by increasing the dose of progesterone before behavioural testing. Sexual receptivity could be induced in the pseudopregnant rat by using a low dose of OB (2 μg) in combination with a very high dose of progesterone (50 mg). Sexual receptivity induced in ovariectomized rats by injection of a single large dose of OB was unaffected by progesterone treatment in both the concurrent and sequential paradigm. Concurrent and sequential inhibition of sexual behaviour by antioestrogen (nitromophene monocitrate, CI-628) treatment could not be reversed by increasing the dose of progesterone before testing. The behavioural response to OB treatment in combination with progesterone and OB treatment alone was markedly inhibited by CI-628 treatment. It is suggested that prior treatment with progesterone raises the threshold of the behavioural response to subsequent progesterone treatment. It is also suggested that the inhibitory effect of progesterone on sexual behaviour cannot only be accounted for by the previously suggested antioestrogenic effect of progesterone.

OESTROGEN-PROGESTERONE RELATIONSHIPS IN THE INDUCTION OF OESTRUS IN SPAYED HEIFERS

1969 ◽  
Vol 45 (1) ◽  
pp. 99-109 ◽  
Author(s):  
M. J. CARRICK ◽  
J. N. SHELTON
Keyword(s):  
Behavioural Response ◽  
Normal Response ◽  
Oestradiol Benzoate ◽  
Small Doses ◽  
Refractory State ◽  
Increased Sensitivity ◽  
Repeated Doses ◽  
Effective Doses ◽  
Response Line ◽  
Normal Sensitivity

SUMMARY Experiments were conducted to examine the behavioural response of spayed heifers to oestrogen, and its modification by progesterone. In two groups of heifers, the median effective doses (MED) of oestradiol benzoate (ODB) were 121 and 132 μg. Repeated doses of ODB at physiological levels did not induce a state of refractoriness; in this respect the heifer is dissimilar to the ewe. However, repeated doses of 10 mg. ODB induced refractoriness to 400 μg. ODB. When such refractory heifers were treated with 10 mg. progesterone/day for 5 days, they showed a normal response to 400 μg. ODB given 3 days later. This return to normal sensitivity was not sustained, and pretreatment with progesterone was necessary for a normal response to subsequent small doses of ODB. The transient removal of the refractory state appears not to be due to a simple synergistic effect of residual progesterone, but to an effect of preconditioning a neural centre to respond to oestrogen. Increasing the duration of pretreatment with progesterone beyond 5 days did not result in a greater sensitivity to ODB. Pretreatment with progesterone in heifers not made refractory to ODB did not result in an increased sensitivity to ODB. Moreover, up to 7 days after termination of the progesterone treatment, the response to ODB was reduced and the slope of the dose-response line was less steep than when ODB was injected alone. The reduction of the response was more pronounced with 40 mg. progesterone/day than with 10 mg. The possible significance of these results in intact animals is discussed.

Recovery of sexual receptivity in female rats with lesions of the ventromedial hypothalamus

1980 ◽  
Vol 68 (3) ◽  
pp. 595-600 ◽  
Author(s):  
Reiko Okada ◽  
Hiroshi Watanabe ◽  
Korehito Yamanouchi ◽  
Yasumasa Arai
Keyword(s):  
Ventromedial Hypothalamus ◽  
Female Rats ◽  
Sexual Receptivity
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