SERUM LEVELS OF OESTRADIOL-17β AND PROGESTERONE IN RELATION TO SEXUAL RECEPTIVITY IN INTACT AND OVARIECTOMIZED RATS

1981 ◽  
Vol 89 (1) ◽  
pp. 45-54 ◽  
Author(s):  
P. SÖDERSTEN ◽  
P. ENEROTH

Serum levels of oestradiol-17β fluctuated markedly during the oestrous cycle of rats. The onset of sexual receptivity occurred in close correlation with increasing serum levels of progesterone. The serum levels of oestradiol and progesterone in ovariectomized rats implanted with constant-release implants filled with oestradiol or progesterone were related to the amount of hormone in the implants. Constant low serum levels of oestradiol stimulated sexual behaviour in ovariectomized rats, but progesterone stimulation was required for maximum behavioural responses. Peak levels of progesterone in the serum during the oestrous cycle were much higher than those needed for induction of the behaviour in ovariectomized, oestradiol-treated rats. Progesterone, administered in physiological doses, inhibited the induction of sexual receptivity caused by oestradiol and progesterone and the inhibition depended on the strength of the stimulation with oestradiol.

1979 ◽  
Vol 80 (3) ◽  
pp. 389-395 ◽  
Author(s):  
P. SÖDERSTEN ◽  
S. HANSEN

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.


1981 ◽  
Vol 89 (1) ◽  
pp. 63-69 ◽  
Author(s):  
P. SÖDERSTEN ◽  
P. ENEROTH

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.


1981 ◽  
Vol 89 (1) ◽  
pp. 55-62 ◽  
Author(s):  
P. SÖDERSTEN ◽  
P. ENEROTH ◽  
S. HANSEN

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.


1978 ◽  
Vol 77 (3) ◽  
pp. 373-379 ◽  
Author(s):  
S. HANSEN ◽  
P. SÖDERSTEN

Ovariectomized rats, pre-implanted with elastomer capsules containing oestradiol, became sexually receptive after exposure to progesterone (implanted in elastomer capsules) for 4–6 h. Implantation of progesterone capsules facilitated receptivity in oestradiol-implanted rats independently of both previous exposure to progesterone implants and the presence of progesterone at the time of implantation. The duration of sexual receptivity in ovariectomized rats implanted with oestradiol and progesterone capsules was dependent upon the length of both the oestradiol and progesterone capsules, but the decline in sexual behaviour of receptive rats was independent of the continued presence of either oestradiol or progesterone. Repeated implantation of progesterone capsules at 6 hourly intervals prevented the decline of sexual receptivity.


1987 ◽  
Vol 112 (1) ◽  
pp. 133-138 ◽  
Author(s):  
P. Södersten ◽  
P. Eneroth

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


1987 ◽  
Vol 113 (3) ◽  
pp. 429-434 ◽  
Author(s):  
G. Forsberg ◽  
I. Bednar ◽  
P. Eneroth ◽  
P. Södersten

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


1962 ◽  
Vol 25 (2) ◽  
pp. 175-182 ◽  
Author(s):  
C. A. BARRACLOUGH ◽  
R. A. GORSKI

SUMMARY In the present investigation the mating behaviour of the androgensterilized rat has been studied. It was observed that rats sterilized by prepubertal administration of 1·25 mg. of testosterone propionate were sexually unreceptive to the male. Progesterone, when given as either spaced or daily injections, did not restore mating behaviour. Furthermore, although mating behaviour could be restored in normal ovariectomized rats by combinations of oestrogen and progesterone, identical treatment of spayed sterile rats was ineffective. Rats pretreated with 10 μg. of testosterone propionate at 5 days of age were found to be sexually receptive to the male even though they exhibited the same anovulatory persistentoestrous syndrome as did rats which received the higher dose. One rat accepted the male for nine consecutive days whilst others exhibited more bizarre patterns of sexual receptivity. It is suggested from these and other studies that a ' mating centre' exists in the hypothalamus of the rat and that it is located in the anterior hypothalamus.


1979 ◽  
Vol 80 (3) ◽  
pp. 381-388 ◽  
Author(s):  
S. HANSEN ◽  
P. SÖDERSTEN

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.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Jae Hwa Kim ◽  
Go-Tak Kim ◽  
Siyeoung Yoon ◽  
Hyun Il Lee ◽  
Kyung Rae Ko ◽  
...  

Abstract Background Vitamin B12 (Vit B12) deficiency results in elevated homocysteine levels and interference with collagen cross-linking, which may affect tendon integrity. The purpose of this study was to investigate whether serum Vit B12 levels were correlated with degenerative rotator cuff (RC) tear. Methods Eighty-seven consecutive patients with or without degenerative RC tear were enrolled as study participants. Possible risk factors (age, sex, medical history, bone mineral density, and serum chemistries including glucose, magnesium, calcium, phosphorus, zinc, homocysteine, Vitamin D, Vit B12, homocysteine, and folate) were assessed. Significant variables were selected based on the results of univariate analyses, and a logistic regression model (backward elimination) was constructed to predict the presence of degenerative RC tear. Results In the univariate analysis, the group of patients with degenerative RC tear had a mean concentration of 528.4 pg/mL Vit B12, which was significantly lower than the healthy control group (627.1 pg/mL). Logistic regression analysis using Vit B12 as an independent variable revealed that Vit B12 concentrations were significantly correlated with degenerative RC tear (p = 0.044). However, Vit B12 levels were not associated with tear size. Conclusion Low serum levels of Vit B12 were independently related to degenerative RC tear. Further investigations are warranted to determine if Vit B12 supplementation can decrease the risk of this condition.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jung-Lung Hsu ◽  
Ming-Feng Liao ◽  
Chun-Che Chu ◽  
Hung-Chou Kuo ◽  
Rong-Kuo Lyu ◽  
...  

AbstractOur study aimed to investigate the incidence, risk factors and time to occurrence of malignancy in patients with dermatomyositis (DM) and polymyositis (PM). The electronic medical records of 1100 patients with DM and 1164 patients with PM were studied between January 2001 and May 2019. Malignancies after myositis were diagnosed in 61 (5.55%) patients with DM and 38 (3.26%) patients with PM. The cumulative incidence of malignancies in patients with DM were significantly higher than patients with PM (hazard ratio = 1.78, log-rank p = 0.004). Patients with DM had a greater risk of developing malignancy than those with PM at 40–59 years old (p = 0.01). Most malignancies occurred within 1 year after the initial diagnosis of DM (n = 35; 57.38%). Nasopharyngeal cancer (NPC) was the most common type of malignancy in patients with DM (22.95%), followed by lung, and breast cancers. In patients with PM, colorectal, lung and hepatic malignancies were the top three types of malignancy. The risk factors for malignancy included old age (≥ 45 years old) and low serum levels of creatine phosphokinase (CPK) for patients with DM and male sex and low serum levels of CPK for patients with PM. Low serum levels of CPK in patients with myositis with malignancy represented a low degree of muscle destruction/inflammation, which might be attributed to activation of the PD-L1 pathway by tumor cells, thus inducing T-cell dysfunction mediating immune responses in myofibers. A treatment and follow-up algorithm should explore the occurrence of malignancy in different tissues and organs and suggested annual follow-ups for at least 5.5 years to cover the 80% cumulative incidence of malignancy in patients with DM and PM.


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