ROLE OF PROGESTERONE IN THE CONTROL OF SECRETION OF FOLLICLE-STIMULATING HORMONE IN THE IMMATURE FEMALE RAT

1981 ◽  
Vol 89 (1) ◽  
pp. 99-106 ◽  
Author(s):  
H. M. A. MEIJS-ROELOFS ◽  
P. KRAMER ◽  
L. GRIBLING-HEGGE
Keyword(s):  
Body Weight ◽  
Inhibitory Action ◽  
Ovariectomized Rats ◽  
Female Rat ◽  
Serum Concentrations ◽  
Immature Female ◽  
Progesterone Treatment ◽  
Age Dependent ◽  
Intact Rats

The inhibitory action on FSH secretion of combined oestradiol and progesterone treatment of ovariectomized, immature rats was studied at various ages. At all ages studied (13–35 days) an additional inhibitory action of progesterone, if combined with oestradiol, could be found as compared with the effect of oestradiol alone. Until 20 days of age, the rise in serum FSH concentration as measured 2 days after ovariectomy could be completely prevented by administration of 0·05 μg oestradiol/100 g body weight or by administration of a lower dose of oestradiol (0·01–0·025 μg) combined with progesterone (0·5–1·5 mg/100 g body weight). After 20 days neither oestradiol nor the combined oestradiol/progesterone treatment resulted in an FSH concentration similar to that found in intact rats. However, the lowest FSH concentrations were reached by using combinations of oestradiol and progesterone. Using progesterone alone, FSH concentration in ovariectomized rats was significantly reduced between 18 and 30 days of age, but not before or after this period. Taken together with data on uterine weight and serum concentrations of progesterone, these findings suggest that (1) both oestradiol and progesterone exert an age-dependent role in regulating FSH secretion in the immature female rat, and (2) amounts of oestradiol and progesterone capable of maintaining, in ovariectomized rats, uterine weights not different from those in intact rats will maintain near-physiological concentrations of FSH before but not after day 20. Thus, ovarian factors other than oestradiol and progesterone must be involved in the regulation of FSH secretion in the female rat after 20 days of age.

POSSIBLE ROLE OF 5α-ANDROSTANE-3α,17β-DIOL IN THE CONTROL OF FOLLICLE-STIMULATING HORMONE SECRETION IN THE IMMATURE FEMALE RAT

1982 ◽  
Vol 92 (1) ◽  
pp. 37-42 ◽  
Author(s):  
H. M. A. MEIJS-ROELOFS ◽  
P. KRAMER ◽  
L. GRIBLING-HEGGE
Keyword(s):  
Inhibitory Action ◽  
Combined Treatment ◽  
Hormone Secretion ◽  
Inhibitory Effect ◽  
Ovariectomized Rats ◽  
Female Rat ◽  
Immature Rat ◽  
Rat Strain ◽  
Intact Rats

A possible role of 5α-androstane-3α,17β-diol (3α-androstanediol) in the control of FSH secretion was studied at various ages in ovariectomized rats. In the rat strain used, vaginal opening, coincident with first ovulation, generally occurs between 37 and 42 days of age. If 3α-androstanediol alone was given as an ovarian substitute, an inhibitory effect on FSH release was evident with all three doses tested (50, 100, 300 μg/100 g body wt) between 13 and 30 days of age; at 33–35 days of age only the 300 μg dose caused some inhibition of FSH release. Results were more complex if 3α-androstanediol was given in combined treatment with oestradiol and progesterone. Given with progesterone, 3α-androstanediol showed a synergistic inhibitory action on FSH release between 20 and 30 days of age. However, when 3α-androstanediol was combined with oestradiol a clear decrease in effect, as compared to the effect of oestradiol alone, was found between 20 and 30 days of age. Also the effect of combined oestradiol and progesterone treatment was greater than the effect of combined treatment with oestradiol, progesterone and 3α-androstanediol. At all ages after day 20 none of the steroid combinations tested was capable of maintaining FSH levels in ovariectomized rats similar to those in intact rats. It is concluded that 3α-androstanediol might play a role in the control of FSH secretion in the immature rat, but after day 20 the potentially inhibitory action of 3α-androstanediol on FSH secretion is limited in the presence of oestradiol.

MATURATION OF THE INHIBITORY FEEDBACK ACTION OF OESTROGEN ON FOLLICLE-STIMULATING HORMONE SECRETION IN THE IMMATURE FEMALE RAT: A ROLE FOR ALPHA-FOETOPROTEIN

1979 ◽  
Vol 81 (2) ◽  
pp. 199-208 ◽  
Author(s):  
H. M. A. MEIJS-ROELOFS ◽  
P. KRAMER
Keyword(s):  
Body Weight ◽  
Hormone Secretion ◽  
Ovariectomized Rats ◽  
Female Rat ◽  
Immature Female ◽  
Subsequent Decrease ◽  
Inhibitory Feedback ◽  
Increased Sensitivity ◽  
Constant Dose

The maturation of the inhibitory feedback action of oestrogen on FSH secretion in the immature female rat was studied from 5 days of age until after the first ovulation. To study the role of the oestrogen binding alpha-foetoprotein (AFP) which is present in the blood of young animals, the effects of various doses of oestradiol and of the synthetic oestrogen R2858 (11β-methoxy-17-ethynyl-oestradiol), which is not bound by AFP, were compared in ovariectomized rats. A rise in the serum concentration of FSH within 2 days of ovariectomy was first observed in rats ovariectomized at 8 days of age. Between 8 and 28 days of age the rise in FSH after ovariectomy could be prevented by oestrogen injections in such a way that the resulting FSH concentration amounted to 50% of that in ovariectomized control rats. This was achieved with a constant dose of 0·00015 μg R2858/100 g body weight, whereas the dose of oestradiol needed decreased from 0·05 to 0·01 μg/100 g body weight indicating an increased sensitivity to the feedback action of oestradiol. After day 28, sensitivity to the feedback action of both R2858 and oestradiol decreased progressively up to the time of the first ovulation. In contrast to results at earlier ages, none of the doses of either oestrogen was capable of maintaining near-physiological concentrations of FSH after 20 days of age. It is concluded that the apparent increase in sensitivity to the feedback action of oestradiol occurring before 28 days of age reflects the disappearance of AFP from the blood, whereas the subsequent decrease in sensitivity is independent of AFP. Moreover, it is concluded that up to about 20 days of age oestradiol could be, though not necessarily is, the sole ovarian factor involved in regulating FSH secretion, whereas at later ages additional steroids and/or factors must be involved.

Role of the Splanchnic Nerve and the Adrenal Medulla in the Genesis of ‘Preoptic Pulmonary Edema’

1956 ◽  
Vol 184 (2) ◽  
pp. 351-355 ◽  
Author(s):  
Frederick W. Maire ◽  
Harry D. Patton
Keyword(s):  
Body Weight ◽  
Protective Effect ◽  
Pulmonary Edema ◽  
Adrenal Medulla ◽  
Adrenal Glands ◽  
Splanchnic Nerve ◽  
Lung Edema ◽  
Splanchnic Nerves ◽  
Intact Rats

The pulmonary edema which follows preoptic lesions in rats is prevented by antecedent bilateral section of the splanchnic nerves. Intravenous epinephrine in doses exceeding 0.0125 mg/100 gm body weight causes fatal lung edema in rats comparable to that produced by preoptic lesions. Moreover, extracted pressor amines from rat adrenal glands cause lung edema, often fatal, when injected into the donor or into intact rats. However, adrenal demedullation does not prevent lung edema following preoptic lesions. Hence the protective effect of splanchnectomy against preoptic lesions is not wholly due to adrenal denervation. It is tentatively suggested that preoptic lung edema results from overloading of the pulmonary circuit owing to splanchnic mediated constriction of visceral venous reservoirs. Liver and spleen weights of animals dying from preoptic lung edema were significantly less than normal.

PREGNANCY MAINTENANCE AND THE INHIBITION OF PARTURITION IN RATS WITH 17α-HYDROXYPROGESTERONE ESTERS: THE ROLE OF OESTROGENIC AND ANDROGENIC ACTIVITY

1960 ◽  
Vol XXXIII (I) ◽  
pp. 73-80 ◽  
Author(s):  
J. C. Stucki ◽  
A. D. Forbes
Keyword(s):  
Testosterone Propionate ◽  
Ovariectomized Rats ◽  
Androgenic Activity ◽  
Hydroxyprogesterone Caproate ◽  
In Pregnancy ◽  
Intact Rats

ABSTRACT 17α-Hydroxyprogesterone acetate (AP) and 17α-hydroxyprogesterone caproate (HPC) were found to be incapable of maintaining pregnancy in ovariectomized rats when administered alone, even if administration of the drugs was started several days prior to surgery. Further studies with AP demonstrated that it could maintain pregnancy in the castrate rat when oestrone or testosterone propionate (TP) were concomitantly administered. The addition of TP to a regimen of concomitant AP and oestrone did not result in further improvement in the quality of pregnancy maintenance. TP and oestrone alone or together were incapable of maintaining pregnancy. Parturition could be delayed or prevented in intact rats with either progesterone or TP when administration of the steroids was started 3 days before the date of expected delivery. HPC and AP alone or with oestrone, and oestrone alone did not delay parturition when administration was begun late in pregnancy. Parturition was prevented when administration of AP was begun at least 11 days before expected delivery.

Role of the subcommissural organ in the control of gonadotrophin secretion in the female rat

1982 ◽  
Vol 95 (2) ◽  
pp. 207-213 ◽  
Author(s):  
Patrizia Limonta ◽  
Roberto Maggi ◽  
Luciano Martini ◽  
Flavio Piva
Keyword(s):  
Subcommissural Organ ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Normal Female ◽  
Female Rat ◽  
Thermal Lesions ◽  
Gonadotrophin Secretion

Thermal lesions were placed in the subcommissural organ (SCO) of female rats with normal cycles and long-term ovariectomized rats. In normal female rats SCO lesions disrupted the oestrous cycle in more than half of the animals, the majority of which entered a state of prolonged dioestrus. In these animals, serum gonadotrophin levels were similar to those of rats with regular cycles on day 2 of dioestrus. In animals in which the oestrous cycle was maintained, a delayed LH surge occurred on the day of pro-oestrus and the pro-oestrous FSH surge was absent. The usual increase in FSH on the day of oestrus was present. Lesions in the SCO did not change the high gonadotrophin levels typical of ovariectomized animals. These results suggested that the SCO may play a role in the control of the cyclic but not the tonic release of the gonadotrophins. In particular, it appears that the SCO might be involved in the regulation of the hypersecretion of FSH during the day of pro-oestrus.

A FEMALE-LIKE RISE IN LUTEINIZING HORMONE AND FOLLICLE-STIMULATING HORMONE AFTER GONADECTOMY IN MALE RATS INDUCED BY OESTRADIOL PRETREATMENT

1979 ◽  
Vol 80 (1) ◽  
pp. 111-116 ◽  
Author(s):  
S. N. JUSTO ◽  
A. NEGRO-VILAR
Keyword(s):  
Sexual Difference ◽  
Female Rats ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Serum Concentrations ◽  
Control Male ◽  
Male And Female Rats ◽  
Series Of Experiments ◽  
And Control ◽  
Intact Rats

A marked sexual difference in the rise of serum gonadotrophin concentrations after gonadectomy has been described in the rat. Gonadectomy in males induced a rapid rise in the concentrations of both LH and FSH within 8 to 12 h, whereas ovariectomy invoked a rapid increase in the concentration of FSH while the response by LH was delayed for several days. To determine whether these differences could be explained, at least in part, by the different steroid milieu at the time of gonadectomy, a series of experiments were performed to analyse the rise in both LH and FSH serum concentrations in control male and female rats and in male rats that had been pretreated with oestradiol-17β. Adult male rats received an s.c. implant of a silicone elastomer capsule filled with crystalline oestradiol-17 β. Controls received empty capsules. Twenty-four hours later, the oestradiol-implanted rats were castrated and control animals were sham-operated. Both LH and FSH levels remained within control levels after castration in the oestradiol-implanted rats, indicating that the oestradiol implant was preventing any rise of either gonadotrophin. On day 5 after implantation, the capsules were removed, sham-implanted animals were castrated and LH and FSH levels at 12, 24, 48 and 72 h were measured and compared with those of ovariectomized rats at similar intervals. The control male rats displayed the pattern of gonadotrophin increments normally found after castration, with both LH and FSH concentrations rising significantly by 12 h after castration and with further increments at later periods. Oestradiol-treated rats showed a female-like gonadotrophin pattern. FSH levels started to rise significantly at 24 h compared with values from intact rats and increased further at 48 and 72 h. During the first 48 h, FSH levels in both oestradiol-treated, castrated rats and female gonadectomized rats were significantly lower than in castrated animals. LH levels, on the other hand, remained low in both groups during the first 48 h, starting to rise significantly above control levels by 72 h. These results indicate that the different pattern of response to gonadectomy in rats of both sexes may be altered by changes in steroid environment and, therefore, may not be genetically predetermined.

EXAMINATION OF THE ROLE OF 'NON-FUNCTIONAL' CORPORA LUTEA IN THE FEMALE RAT

1979 ◽  
Vol 83 (2) ◽  
pp. 205-209 ◽  
Author(s):  
W. J. DE GREEF ◽  
P. VAN DER SCHOOT
Keyword(s):  
Single Injection ◽  
Corpora Lutea ◽  
Female Rat ◽  
Serum Concentrations ◽  
Vaginal Smears ◽  
Progesterone Production ◽  
Baseline Levels ◽  
Reproductive Cycles

In rats with 5 day reproductive cycles, 'anovulatory' cycles were induced by blockade of ovulation with sodium pentobarbitone injected at pro-oestrus. Such anovulatory cycles were characterized in the ovaries by gradual atresia of the large follicles present at the time of the injection and the growth of a new cohort destined for the next ovulation. In the vaginal smears, anovulatory cycles were indistinguishable from normal ovulatory cycles. The serum concentrations of progesterone remained at baseline levels during dioestrus of anovulatory cycles whereas increased concentrations of progesterone were observed during dioestrus of ovulatory cycles. It is concluded that the 'non-functional' corpora lutea of the cycle are the source of dioestrous progesterone. The length of anovulatory cycles after a single injection of pentobarbitone was 5 days despite the absence of any increase in progesterone concentrations during dioestrus. It is concluded that progesterone production during dioestrus plays no major role in the control of the duration of 5 day reproductive cycles.

scholarly journals Uterus Weight of Ovariectomized Rats Given Cocoa Powder and Extract

2017 ◽  
Vol 33 (1) ◽  
pp. 45
Author(s):  
Ariza Budi Tunjung ◽  
Misnawi Jati ◽  
Pratiwi Pudjiastuti ◽  
Afaf Baktir
Keyword(s):  
Body Weight ◽  
Olive Oil ◽  
Estrogenic Activity ◽  
The Body ◽  
Ovariectomized Rats ◽  
Estradiol Valerate ◽  
Cocoa Powder ◽  
Positive Correlation ◽  
Treatment Groups ◽  
Intact Rats

Estrogen is a hormone that influences the growth of uterus. Ovariectomized rats lose their ovaries as the main source of estrogen so their uterus tends to shrink. The objective of thise study was to evaluate the potency of cocoa as an estrogen substitute, which was done through an experiment that tested the influence of cocoa products on the uterus weight of ovariectomized rats. There were five treatments and in each of the treatments, six wistar rats were given the substance for three days. Four groups of treatment consisted of ovariectomized rats given cocoa extract (875.2 ppm of polyphenols, 1 g/kg of body weight, BW), cocoa powder (369.8 ppm of polyphenols, 1 g/kg BW), olive oil (10 mL/kg BW), or estradiol valerate (1 mg/kg BW). The fifth group consisted of intact (non-ovariectomized) rats given 10 mL/kg BW of water. The finding showed that the ovariectomized rats given olive oil had lower uterus weight than that of intact rats, while the ovariectomized rats given estradiol valerate had higher uterus weight compared to the intact and olive oil groups. The ovariectomized rats given cocoa powder and extract had higher uterus weight compared to those given only olive oil; although they were not significantly different. Correlation between the body weight and uterus weight varied across treatment groups. The rats given olive oil showed significant, positive correlation, while the intact rats showed moderate, positive correlation. The rats given estradiol valerate and cocoa powder showed non-significant correlation. Since the polyphenol content in cocoa powder was at lower concentration than that in the cocoa extract, it was predicted that cocoa polyphenols are more potential in the lower concentration. This study concludes that even though consumption of cocoa powder and extract did not significantly induced uterus growth, cocoa is still considered having estrogenic activity by lowering the correlation between the body weight and uterus weight in ovariectomized rats.

242 POTENTIAL ESTROGENIC EFFECT(S) OF PARABENS AT THE NEONATAL STAGE OF AN IMMATURE FEMALE RAT MODEL

2010 ◽  
Vol 22 (1) ◽  
pp. 279
Author(s):  
S. H. Hyun ◽  
E. B. Jeung
Keyword(s):  
Body Weight ◽  
Rat Model ◽  
Estrogenic Activity ◽  
Female Rats ◽  
Female Rat ◽  
Dependent Manner ◽  
Methyl Ethyl ◽  
Immature Female ◽  
Immature Rats ◽  
Dose Dependent

In this study, to examine the estrogenic activity effects of parabens on hormonal responsiveness and on change in the morphology of reproductive target tissues during a critical development stage in female rats, analyses for parabens including methyl-, ethyl-, propyl-, isopropyl-, butyl-, and isobutylparaben were performed in an immature female Sprague-Dawley rat model. Two hundred female immature rats (n = 10/group) were orally treated with these parabens from postnatal day 21 to 40 in a dose-dependent manner based on our previous study [62.5, 250, and 1000 mg/kg of body weight (BW) per day]. 17α-ethinylestradiol (EE;1 mg/kg of BWper day) was used as a positive control and corn oil as a vehicle.A high doseofmethyl- and isopropylparaben (1000 mg/kg of BW per day) resulted in a significant delay in the date of vaginal opening and a decrease in length of the estrous cycle (P < 0.05). In measurements of organ weight and body weight, we observed significant weight changes in ovaries, adrenal glands, thyroid glands, liver, and kidneys(P < 0.05); conversely, body weight was not altered following paraben treatment. In all groups exposedto paraben treatment, histological analysis of the ovaries from the immature rats revealed interstitial cell disorders, a lack of corpora lutea, an increase in the number of cystic follicles, and thinning of the follicular epithelium, which occurred in a dose-dependent manner. In addition, morphological studies of the uterus revealed the myometrial dysplasia suchas myometrial hyperplasia inthe high-doseofpropyl- and isopropylparaben (1000 mg/kgof BWper day) group and in all dose of butyl- and isobutylparabens groups. We also observed a significant decrease in serum estradiol and T4 concentrations in methyl-, ethyl-, propyl-, isopropyl-, and isobutylparaben-treated groups (P < 0.01 and 0.05).A receptor-binding assay indicated that the relative binding affini- ties of parabens to estrogen receptors occurred in the order: isobutylparaben > butylparaben > isopropylparaben = propylparaben > ethylparaben. These values were much less than the binding affinity for 17?-estradiol. Taken together, long-term exposure to parabens, which show less estrogenic activity than EEl, can produce suppressive effects on hormonal responsiveness and can disrupt the morphology of reproductive target tissues during this critical stage of development in immature female rats.

scholarly journals Effects of reduction of the number of primordial follicles on follicular development to achieve puberty in female rats

Reproduction ◽  
2003 ◽  
pp. 85-94 ◽  
Author(s):  
M Shirota ◽  
S Soda ◽  
C Katoh ◽  
S Asai ◽  
M Sato ◽  
...  
Keyword(s):  
Corn Oil ◽  
Follicular Development ◽  
Primary Phase ◽  
Female Rats ◽  
Female Rat ◽  
Serum Concentrations ◽  
Immature Female ◽  
Primordial Follicles ◽  
Preantral Follicles ◽  
Rat Offspring

Effects of reduction of the number of primordial follicles on follicular development and concentrations of circulating hormones were examined in immature female rat offspring of dams given busulfan intraperitoneally on day 14 of gestation. The offspring of dams treated with 5 mg busulfan kg(-1) showed vaginal opening at an age comparable with the offspring of dams treated with 2.5 mg busulfan kg(-1) or with corn oil as a control, although they exhibited an irregular oestrous cycle until week 14 after birth. The serum concentrations of immunoreactive inhibin and FSH on day 26 after birth of the offspring treated with 5 mg busulfan kg(-1) were similar to those of age-matched controls. On day 15 after birth, however, the concentration of their immunoreactive inhibin was markedly lower than that of controls, whereas the concentration of their FSH was increased inversely. Comparison of the numbers of ovarian follicles in the controls and groups treated with 2.5 mg busulfan kg(-1) and 5 mg busulfan kg(-1) revealed that prenatal treatment with busulfan reduced the number of follicles in the primordial or primary phase and in the preantral phase on day 7 after birth. Although the increase of the ratio of the number of preantral follicles during days 7-13 after birth tended to vary with the prenatal dose of busulfan, the number of preantral follicles in the group treated with 5 mg busulfan kg(-1) was still smaller than in the controls. The concentration of serum immunoreactive inhibin of the offspring treated with busulfan was reduced on day 7 after birth without alteration of the concentration of gonadotrophin. On day 13 after birth, the concentration of serum immunoreactive inhibin was reduced only in the offspring treated with 5 mg busulfan kg(-1), and the concentration of serum FSH of the offspring was increased inversely as found on day 15 after birth. These results indicate that a reduction in the number of primordial follicles decreases the number of follicles that enter the growing phase, a major source of circulating inhibin in the neonatal and infantile ovary, and that consequently increased circulating FSH may accelerate follicular development to achieve puberty.

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