ENDOCRINE AND REPRODUCTIVE REPERCUSSIONS OF IMMUNIZATION AGAINST PROGESTERONE AND OESTRADIOL IN FEMALE RATS

1977 ◽  
Vol 84 (4) ◽  
pp. 795-803 ◽  
Author(s):  
A. Kaushansky ◽  
S. Bauminger ◽  
Y. Koch ◽  
H. R. Lindner
Keyword(s):  
Luteinizing Hormone ◽  
Mature Female ◽  
Oestrous Cycle ◽  
Female Rats

ABSTRACT Mature female rats were immunized with BSA-conjugates of oestradiol17β-6-carboxymethyloxime or progesterone-11-hemisuccinate. Sera tested two months later at 1/2000 dilution bound 63.3 % ± 3.1 sem and 21.2% ± 2.3 of the homologous tritiated hormone (10 pg), - oestradiol-17β (Oe2) and progesterone (P), respectively. Rats immunized against Oe2 had a significantly longer oestrous cycle (8.2 days vs. 4.5 days in BSA-immunized rats), with a prolonged leukocytic phase. The cycle of rats immunized against P was also prolonged (10.5 days), but in this group the cornified smear phase was abnormally extended. The luteinizing hormone (LH) normally observed on the afternoon of pro-oestrus failed to occur in the rats immunized against Oe2 and in 70 % of rats immunized against P. The latter animals, however, showed sporadic LH discharges during periods of persistent cornification. Immunization against P resulted in elevated total (free plus bound) plasma P levels; immunization against Oe2 prevented the pro-oestrous rise in plasma P. Mating of rats immunized against Oe2 resulted in normal pregnancies, while none of the rats immunized against P delivered.

Cyclic and diurnal alterations in the response of luteinizing hormone and prolactin to prostaglandin E2 during the rat oestrous cycle

1984 ◽  
Vol 106 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Lise Wogensen ◽  
Jørgen Warberg
Keyword(s):  
Luteinizing Hormone ◽  
Prostaglandin E2 ◽  
Lateral Ventricle ◽  
Mature Female ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Male Rats ◽  
Prostaglandin E ◽  
The Brain ◽  
Time Of Administration

Abstract. Two μg of prostaglandin E2 (PGE2) was infused into a lateral ventricle of the brain of female rats at 09.00 or 13.00 h on the different days of the oestrous cycle and the effect on luteinizing hormone (LH) and prolactin (Prl) release was determined. At 09.00 h PGE2 caused a pronounced release of LH in pro-oestrous, oestrous and metoestrous rats whereas the LH response in dioestrous rats was moderate. The secretion of Prl was only stimulated in rats from the pro-oestrous phase. When infused at 13.00 h PGE2 had a marked stimulatory effect on the release of LH in all groups of rats. The response was almost the same in oestrous, metoestrous and dioestrous rats but pro-oestrous rats a 2-fold higher LH response was observed. On each day of the oestrous cycle it was found that the LH-releasing activity of PGE2 was greater at 13.00 h than at 09.00 h. Thus, the overall greatest responsiveness of LH to PGE2 was noted at 13.00 h on pro-oestrus i.e. at a time which was prior to the onset of the spontaneous LH surge. At 13.00 h – as at 09.00 h – PGE2 was only capable of stimulating Prl release in pro-oestrous rats. Resembling the LH response it was found that PGE2-induced Prl release was greater at 13.00 h than at 09.00 h. In adult male rats the stimulatory effect of PGE2 on LH and Prl release was independent of the time of administration. It is concluded that the neuroendocrine elements of the hypothalamo-pituitary unit in mature female rats exhibit cyclic as well as diurnal alterations in the responsiveness to PGE2.

EFFECT OF SYNTHETIC LUTEINIZING HORMONE RELEASING HORMONE ON OVULATION DURING THE OESTROUS CYCLE IN THE RAT

1974 ◽  
Vol 76 (3) ◽  
pp. 431-437 ◽  
Author(s):  
H. Morishita ◽  
H. Mitani ◽  
Y. Masuda ◽  
K. Higuchi ◽  
M. Tomioka ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Pituitary Gland ◽  
Critical Period ◽  
Early Period ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Average Volume ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Lh Rh

ABSTRACT The effect of synthetic luteinizing hormone releasing hormone (LH-RH) on ovulation has been studied during the oestrous cycle in adult female rats. Ovulation could be induced by the administration of 1 μg synthetic LH-RH at 1:00 a. m. on the day of dioestrus II (lights on from 10:00 p.m. to 10:00 a.m.). At 1:00 a.m. on the day of dioestrus II, the average volume of the largest follicles reached a volume of 83 × 106 μm3 and was three fifth of the volume of that at 6:00 a. m. on the day of pro-oestrus (critical period). These findings suggest that the luteinizing hormone (LH) content in the pituitary gland during the early period of dioestrus II is sufficient to induce ovulation and that the follicles that reach to three fifth of the volume at the critical period are capable of ovulating providing endogenous ovulatory LH released.

STUDIES ON LUTEINIZING HORMONE RELEASE AND INHIBITION

1961 ◽  
Vol 38 (1) ◽  
pp. 1-12 ◽  
Author(s):  
G. Giuliani ◽  
L. Martini ◽  
A. Pecile ◽  
M. Fochi
Keyword(s):  
Ascorbic Acid ◽  
Luteinizing Hormone ◽  
Electric Shock ◽  
Mature Female ◽  
Female Rats ◽  
Normal Female ◽  
Hormone Release ◽  
Luteinizing Hormone Release ◽  
Ether Anaesthesia ◽  
Total Adrenalectomy

ABSTRACT Secretion of LH, as measured by ovarian ascorbic acid depletion in mature female rats with luteinized ovaries, is induced by pitressin and adrenaline. Other drugs (pitocin, histamine, acetylcholine, serotonin, salycilate, insulin) and stress procedures (formalin, ether anaesthesia, unilateral and total adrenalectomy, laparatomy, asphyxia and electric shock) are without effect in this test. No LH activity is detectable by the ovarian ascorbic acid method in 0.5 ml of serum of normal female rats; LH becomes detectable in 0.5 ml of serum 2 weeks after castration; high titers of blood LH are observed in female animals which have been castrated for more than 12 months. No LH is present in the blood of female castrated rats treated with progesterone.

CHANGES IN HYPOTHALAMIC PEPTIDASE ACTIVITY DURING THE OESTROUS CYCLE IN THE ADULT FEMALE RAT

1973 ◽  
Vol 74 (1) ◽  
pp. 41-48 ◽  
Author(s):  
E. C. Griffiths ◽  
K. C. Hooper
Keyword(s):  
Enzyme Activity ◽  
Luteinizing Hormone ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Male Rats ◽  
Supernatant Fraction ◽  
Normal Male ◽  
Normal Female ◽  
Peptidase Activity ◽  
Female Rat

ABSTRACT The activity of peptidases in the rat hypothalamus which are capable of inactivating oxytocin has previously been found to vary with stimuli known to influence gonadotrophin release and may be related to both luteinizing hormone (LH) and luteinizing hormone releasing factor (LH-RF) release (Griffith & Hooper 1972a,b). In the present study, enzyme activity was determined in normal female rats during the morning and afternoon of each stage of the oestrous cycle, in normal rats, and in female rats injected neonatally with testosterone. The activity of the supernatant fraction was found to be not significantly different during the morning of each stage, but was greatly decreased on the afternoon of pro-oestrus; particulate activity did not vary during the oestrous cycle. Supernatant and particulate activities were found to be the same in normal male rats and testosterone-treated females, as previously shown. Both fractions' activities were significantly less than those found in the oestrous cycle, other than on the afternoon of pro-oestrus. These results indicate changes in hypothalamic peptidase activity during the oestrous cycle which may be inversely related to LH and LH-RF release; they also confirm the masculinizing effect of neonatal testosterone on the hypothalamus.

Luteinizing hormone responses to repeated injections of luteinizing hormone releasing hormone in the rat during the oestrous cycle and after ovariectomy with or without oestrogen treatment

1982 ◽  
Vol 93 (2) ◽  
pp. 161-168 ◽  
Author(s):  
Takashi Higuchi ◽  
Masazumi Kawakami
Keyword(s):  
Luteinizing Hormone ◽  
Priming Effect ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Oestrogen Treatment ◽  
Releasing Hormone ◽  
First Response ◽  
Serum Lh ◽  
Lh Rh ◽  
Lh Releasing Hormone

In order to characterize the nature of the LH response to exogenous LH releasing hormone (LH-RH) in female rats during the oestrous cycle and after ovariectomy with or without oestrogen treatment, serum LH levels were determined after repeated LH-RH injections (300 ng/kg body wt, six times with 30-min intervals). The LH response to the first LH-RH stimulation was greatest on the days of pro-oestrus and oestrus followed by dioestrus 2 and dioestrus 1. Second and subsequent LH-RH challenges enhanced the LH response only on pro-oestrus and dioestrus 2. Larger doses of LH-RH (3 μg/kg body wt) induced a small self-priming effect on dioestrus 1 and oestrus. The LH response to the first LH-RH administration increased with time up to 30 days after ovariectomy and then reached a plateau. A small self-priming effect was present in rats ovariectomized for 30 and 60 days, but absent in rats ovariectomized for 5, 10 and 120 days. Oestrogen treatment increased the self-priming effect in rats ovariectomized for 5 days, with little sensitization of the pituitary gland to the first LH-RH injection on the next day. In rats ovariectomized for 120 days, oestrogen treatment enhanced responsiveness to the first and successive LH-RH stimulations on the next day, and further enhancement to the first response only was induced 3 days after oestrogen treatment.

CHANGES IN RESPONSIVENESS OF DISPERSED PITUITARY CELLS TO LUTEINIZING HORMONE RELEASING HORMONE AT DIFFERENT TIMES OF THE OESTROUS CYCLE OF THE RAT

1981 ◽  
Vol 89 (1) ◽  
pp. 129-134 ◽  
Author(s):  
ALISON SPEIGHT ◽  
G. FINK
Keyword(s):  
Luteinizing Hormone ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Pituitary Cells ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Close Relationship ◽  
Specific Receptors ◽  
Lh Rh

Dispersed pituitary cells obtained from female rats with regular oestrous cycles were suspended in Bio-Gel columns and perfused with pulses of luteinizing hormone releasing hormone (LH-RH). There was a close relationship between the amount of LH released and the concentration of LH-RH in the perfusate. It was not possible to elicit the priming effect of LH-RH, but the LH-response changed markedly during the oestrous cycle in a manner similar to that seen in vivo; i.e. the responses of cells prepared from rats killed at pro-oestrus were much greater than the responses of cells prepared from rats killed on other days of the cycle. A similar change in responsiveness was obtained when the columns were perfused with 60 mmol K+/1, suggesting that at least part of the increase in pituitary responsiveness that occurs at pro-oestrus is not dependent upon changes in specific receptors for LH-RH.

TEMPORAL CHANGES IN THE HYPOTHALAMIC AND SERUM LUTEINIZING HORMONE-RELEASING HORMONE (LH-RH) LEVELS AND THE CIRCULATING OVARIAN STEROIDS DURING THE RAT OESTROUS CYCLE

1977 ◽  
Vol 85 (3) ◽  
pp. 449-455 ◽  
Author(s):  
Pushpa S. Kalra ◽  
Satya P. Kalra
Keyword(s):  
Luteinizing Hormone ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Medial Basal Hypothalamus ◽  
Luteinizing Hormone Releasing Hormone ◽  
Ovarian Steroids ◽  
Serum Luteinizing Hormone ◽  
Serum Lh ◽  
Early Afternoon ◽  
Lh Rh

ABSTRACT Cycling female rats were sacrificed at various times during the 4-day oestrous cycle. LH-RH in the medial basal hypothalamus (MBH) and serum LH-RH, LH, oestradiol (Oe2), and progesterone were analyzed by radioimmunoassays. The MBH LH-RH content was lowest at 19.55–20.15 h during pro-oestrus but increased gradually through oestrus and dioestrus I to significantly higher values at noon of dioestrus II, and then decreased precipitously at 18.00 h. Although serum LH levels remained basal from midnight of pro-oestrus through dioestrus II, serum LH-RH levels were significantly elevated at 12.00 and 21.00 h on oestrus (vs. the midnight prooestrus levels) and declined between 15.00 and 22.00 h of dioestrus I. In conjunction with high Oe2 titres, LH-RH in the MBH and serum declined initially during pro-oestrus between 14.07–14.45 h and then increased abruptly between 14.55–15.55 h; the pre-ovulatory rise in serum LH was observed from 16.05 h onwards. LH-RH activity in the MBH and serum receded gradually to the early afternoon levels by 19.55–24.00 h while the peak in serum LH was observed at 17.05–18.05 h. These studies suggested that the hypersecretion of the MBH LH-RH (synthesis + release) may be responsible for the pre-ovulatory discharge of LH.

THE EFFECT OF PREPUBERAL TREATMENT WITH RESERPINE ON PUBERTY, PITUITARY LUTEINIZING HORMONE AND THE OESTROUS CYCLE OF THE RAT

1965 ◽  
Vol 32 (3) ◽  
pp. 387-393 ◽  
Author(s):  
A. CARRARO ◽  
A. CORBIN ◽  
F. FRASCHINI ◽  
L. MARTINI
Keyword(s):  
Luteinizing Hormone ◽  
Neonatal Period ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Vaginal Opening ◽  
Long Term Effects

SUMMARY The long-term effects of a single s.c. injection of 50 μg. reserpine given on the 4th day of life were studied in female rats. Vaginal opening was probably delayed (P < 0·05) by the treatment. In addition those rats which had received reserpine in the neonatal period exhibited prolonged periods of dioestrus and only occasionally intermittent vaginal cornification. At 30 and 60 days of age pituitary LH concentration and content were significantly lower in reserpine-treated animals than in controls of the same age.

NEW DATA CONCERNING THE ROLE PLAYED BY PROGESTERONE IN THE CONTROL OF FOLLICULAR GROWTH IN THE RAT

1974 ◽  
Vol 75 (3) ◽  
pp. 569-578 ◽  
Author(s):  
G. Buffler ◽  
S. Roser
Keyword(s):  
Wistar Rats ◽  
Venous Blood ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Cycle Duration ◽  
Follicular Growth ◽  
The Third ◽  
Female Wistar Rats

ABSTRACT The mechanisms involved in the prolongation of the oestrous cycle following LH administration were studied in 4-day cyclic female Wistar rats. In females injected with LH on the morning of dioestrus I there was an increase in ovarian venous blood progesterone as compared with non-injected animals. In both LH-treated females, and those injected with progesterone on the morning of dioestrus I, a slowing up in follicular growth was observed from the afternoon of dioestrus I. The size of follicles greater than 400 urn present in LH or progesterone injected animals on the third day of cycle was similar to the size reached by the same range of follicles in non-injected animals on the second day of the cycle. Hence, the increase in endogenous ovarian progesterone elicited by LH was considered as the cause of the slowing up of follicular growth and therefore of the lengthening of the oestrous cycle duration in female rats injected with LH at the beginning of 4-day cycle.

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