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I Rothchild

Publications and source records attributed to I Rothchild.

At least 19 recordsLinked to original sources
PubMed1988

Does exposure of preovulatory oocytes to ultrasonic radiation affect reproductive performance?

Ultrasonography of preovulatory oocytes has been reported to lead to reduced litter size in rats. Because of the growing popularity of ultrasound-guided follicular aspiration in human in vitro fertilization programs, further study of ultrasonic radiation's effect on the preovulatory oocyte is warranted. We used 106 virgin Sprague-Dawley rats which, on the evening of proestrus, received ultrasonic radiation of sham treatment after the onset of the luteinizing hormone (LH) surge. No differences were found between control (C) and experimental (US) animals in pregnancy rate, number of corpora lutea, implantations, pups, and mean pup and placental weights at autopsy on day 22 of pregnancy. Ultrasonic radiation applied to meiotically active, preovulatory oocytes did not affect the reproductive performance of these rats.

Animals↗
PubMed1988

Time course of the luteolytic action of LH in 4-day estrous cyclic rats.

In 4-day estrous cyclic rats the neutralization of postovulatory biological activity of LH (by means of a single 0.5 ml sc injection of an anti-LH serum) (LHAS) at any time between 12.00 h on estrus and 12.00 h on metestrus prolongs the estrous cycle corpus luteum (CL) progesterone secretion for almost 24 hours. Injection of LHAS later on during the estrous cycle has no effect on CL progesterone secretion. It is concluded that postovulatory LH secreted up to time of CL maximum capacity to produce progesterone (metestrus afternoon) accelerates the intrinsic luteolytic mechanism, and that once the intrinsic luteolytic process has been switched on (shortly after noon of metestrus), it will lead to the CL functional demise regardless of the luteolytic action of LH.

Animals↗
PubMed1987

Indomethacin treatment prevents prolactin-induced luteolysis in the rat.

Adult female rats were hypophysectomized and their pituitary glands autotransplanted beneath the left kidney capsule on day 2 (day 1 was the day of ovulation). In such rats the pituitary secretes prolactin fairly constantly and the corpora lutea secrete progesterone for several months. To induce the luteolytic effect of prolactin the rats were first injected s.c. with 2-bromo-alpha-ergocryptine (CB-154) on cycle days 12, 13 and 14 (i.e. 10, 11 and 12 days after operation) to depress prolactin secretion, and then with CB-154 vehicle (70% ethanol) daily until cycle day 21, to allow prolactin secretion to resume. One ovary was removed from each rat on day 15 and the remaining one on day 22. The mean (+/- S.E.M.) weight of the corpora lutea on day 15 was 1.46 +/- 0.06 mg and 0.98 +/- 0.07 mg on day 22 (n = 17). In contrast, rats in which the CB-154 treatment was maintained to day 21 had corpora lutea which weighed 1.31 +/- 0.09 on day 15 and 1.47 +/- 0.08 mg on day 22 (n = 15). To investigate whether indomethacin, a prostaglandin synthesis inhibitor, affected the luteolytic action of prolactin, the experiment was repeated, but on day 15 (after the removal of one ovary) the groups in which CB-154 treatment was stopped, as well as the group in which CB-154 treatment was maintained, were each divided into two groups. In one, indomethacin-containing silicone elastomer wafers and, in the other, blank silicone elastomer wafers, were placed within the bursa of the remaining ovary.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

The relation between the effects of hysterectomy, decidual tissue, prolactin, or luteinizing hormone (LH) and the ability of indomethacin to prevent luteolysis in rats bearing LH-dependent corpora lutea.

In adult rats hysterectomized on day 8 of pseudopregnancy, the mean serum progesterone (P) level fell from 88 ng/ml on day 8 to 44 ng/ml on day 15 (n = 61). In response to a single sc injection of 0.5 ml of a specific antiserum to LH (LHAS) on day 10, the P level fell to less than 10 by day 15 in 29 of 33 rats; however, this fall, which was indicative of luteolysis, was briefly interrupted by a return to the control level 36 h after treatment. Indomethacin (400 micrograms, sc) administered 12 h before, during, and 12 h after the LHAS injection prevented the luteolysis that followed the 36 h surge in 10 of 15 rats (P less than 0.001). Treatment with 400 micrograms 2Br-alpha ergocryptine (CB 154), sc, on day 10, with or without indomethacin, however, induced a rapid, uninterrupted, and permanent fall to less than 10 in 13 of 13 rats. Treatment with both LHAS and CB 154 reduced the luteolytic effect of CB 154 (P less than 0.001), and indomethacin treatment combined with both LHAS and CB 154 tended to further reduce the luteolytic effect of CB 154 (P less than 0.01). Hypophysectomy on day 10, however, induced rapid, uninterrupted and permanent luteolysis in all rats (15); this was not affected by indomethacin (7 rats) or LHAS (8 rats). Pituitary homotransplantation on day 8 prevented the luteolytic effect of LHAS on day 10 in 6 of 6 rats (P less than 0.003). In decidual tissue (DT)-bearing rats, LHAS on day 10 induced rapid, uninterrupted, and permanent luteolysis in 18 of 18 rats. The response to LHAS on day 10 changed to that of the hysterectomized rat when the DT-bearing uterus was removed on day 8 (12 of 12 rats) or 10 (7 of 7 rats) (P less than 0.001), but did not change when it was removed on day 11 (5 of 5 rats). In DT-bearing rats hysterectomized on day 8, indomethacin in intrabursal Silastic wafers prevented luteolysis in response to LHAS on day 10 (6 of 6 rats; P less than 0.001). Intrabursal indomethacin had no effect on the response to LHAS in intact DT-bearing rats (3 of 3 rats). These results suggest that even when the corpus luteum becomes LH dependent, PRL may retard or prevent LHAS-induced luteolysis in hysterectomized rats. (ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

The pattern of progesterone secretion in hypophysectomized rats bearing pituitary transplants: effects of hysterectomy, estrogen, and indomethacin.

Cyclic rats were hypophysectomized and their pituitaries transplanted beneath the kidney capsule on day 2 (day 1, ovulation); they were then either hysterectomized or sham hysterectomized (uterus intact rats) and injected sc daily with either 1.0 micrograms 17 beta-estradiol (E1) or with the sesame oil vehicle until autopsy on day 105. Blood samples were drawn by jugular venipuncture every 2 to 3 days until day 21 and once weekly thereafter. In these rats the serum progesterone level rose until about day 8 and tended to reach a plateau between days 8 and 14. The regression phase began, in general, after days 8 to 14 and continued, without change in rate, for at least 3 months. In both the uterus-intact and the hysterectomized rats, E1 seemed to induce an earlier onset of regression and a brief increase in its rate, but did not otherwise affect the rate of regression. In the hysterectomized rats regression began later than in the uterus-intact rats, but its rate was also not different from the latter. The serum progesterone pattern of rats subjected to pituitary autotransplantation on day 2 was compared with that of pseudopregnant rats which were either subjected to pituitary autotransplantation on day 2, 5, 7, or 9, or were given a pituitary homotransplant on day 2, and then hypophysectomized on day 2, 3, 5, or 7. A group of rats with sham operations served as additional controls. In these rats, the same pattern of serum progesterone already described was seen in those subjected to either pituitary autotransplantation on or before day 5, or to pituitary homotransplantation, and to hypophysectomy on or before day 5. However, when the pituitary was autotransplanted on day 7 or day 9, or when the pituitary homotransplant-bearing rat was hypophysectomized on day 7, regression began earlier and was more rapid than in rats operated on on or before day 5. In fact, in the rats operated on on day 9, regression was as rapid as it was in the intact (sham operation) controls. Another group of rats subjected to pituitary autotransplantation and hysterectomy on day 2 was divided into four subgroups on day 21. In two of these, the rats received indomethacin-containing Silastic capsules inserted into each ovarian bursa; in the other two groups blank capsules were similarly inserted.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

A luteotrophic action of prolactin: suppression of intraluteal prostaglandin production or effect?

Adult rats were hypophysectomized and their pituitary glands autotransplanted on day 2 of an estrous cycle (day 1, ovulation); the rats were either hysterectomized or sham hysterectomized immediately before this operation. On day 21, a few days after the beginning of the 3+ month period of regression of progesterone secretion, they were injected sc with 500 micrograms prostaglandin F2 alpha (PGF2 alpha) either on day 21 alone, on days 21 and 22, on days 21, 22, and 23, or on days 21 and 23; controls were injected with saline on days 21, 22, and 23. In the latter the serum progesterone level slowly fell, as it does in untreated rats subjected to pituitary autotransplantation on day 2. PGF2 alpha treatment induced a rapid, drastic fall in the progesterone level, but in each group except the one injected on days 21 and 23, the level returned to, or close to, the control level in about 10 days. Even in the group injected on days 21 and 23, the pattern of serum progesterone resembled the others although the values were much lower. In a similar group of rats subjected to pituitary autotransplantation on day 2 (all of which were also hysterectomized on day 2), a single injection of 500 micrograms PGF2 alpha (which again induced the same changes in serum progesterone as in the first experiment) was combined with either a 6-h or 4-h withdrawal of PRL; this was achieved by injecting 2 bromo-alpha-ergocryptine (CB-154) at zero time to lower PRL secretion, and beef PRL, in a delaying vehicle, 6 or 4 h later, followed by a second dose of PRL 18 h after the first. When combined with such a brief period of PRL withdrawal, the PGF2 alpha treatment induced a very rapid, drastic and permanent fall in serum progesterone, equal to that induced by CB-154 alone, or by removing the pituitary transplant on day 21. The brief periods of PRL withdrawal, by themselves had very little (6 h) or no (4 h) effect on the progesterone level, and treatment with PRL alone was also without effect. Treatment with CB-154, PGF2 alpha, and PRL simultaneously (i.e. without a period of PRL withdrawal) had the same effect as treatment with PGF2 alpha alone.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1983

The importance of a luteolytic effect of the pituitary in understanding the placental control of the rat corpus luteum.

In rats bearing a full complement of conceptuses (FC-bearing rats) progesterone secretion increases about 1.5 times and the corpora lutea double in weight between days 12 and 16. Reducing the number of conceptuses to one (by aspirating all but the single conceptus) at any time between days 7 and 12 of pregnancy (day 1 = insemination) caused progesterone secretion and corpus luteum weight to remain at or below the day 12 level until term. When rats bearing one conceptus were hypophysectomized on day 12, however, serum progesterone increased and fell after day 12 in a pattern almost identical to that in FC-bearing rats, except that the peak and trough occurred about 2 days later; hypophysectomy on day 15 or 18 also increased serum progesterone to values approaching those in intact FC-bearing rats. In a series of rats bearing experimentally determined conceptus numbers between 0 and 5 or naturally occurring ones of 6-16, the serum level of placental lactogen on day 12 (the day of the first peak of secretion of this hormone) was directly proportional to conceptus number over the entire range. The pattern of rat placental lactogen secretion between days 7 and 23 in FC-bearing rats included two peaks, on day 12 and on days 18-21, but in one-conceptus-bearing rats, the level was only slightly higher than the PRL level, and it remained unchanged, even by hypophysectomy, until term. Serum PRL levels bore no relation to conceptus number, were very low, and were unaffected by hypophysectomy except in the FC-bearing rats, in which lypophysectomy prevented the rise that normally occurs after day 21. These results, especially in relation to others previously reported, show that by day 12 of pregnancy, the rat pituitary, instead of merely becoming luteotropically inactive, produces a substance that inhibits further development of the corpora lutea. The results also imply that the placentas maintain luteal growth and progesterone secretion as much by suppressing this luteolytic activity as by stimulating the corpus luteum directly.

Animals↗
PubMed1983

The role of decidual tissue in the development of the dependency on luteinizing hormone in the rat corpus luteum.

In pregnant rats, treatment with an antiserum to LH (LHAS) on days 2-5 inclusive (early LHAS treatment; day 1 = insemination) delayed implantation by about 4 days. The appearance of the dependency of the corpora lutea on LH for the maintenance of progesterone secretion (LH dependency), as determined by the rate of fall in progesterone secretion after a single test injection of LHAS, was also delayed by 4 days. Treatment with a small amount of estradiol on either day 4 or days 4-9 prevented the delay in both implantation and LH dependency. Implantation thus prevented early LHAS treatment from delaying LH dependency, but its effect seems to have been due to decidualization, which accompanies implantation in the rat. In decidual tissue (DT)-bearing pseudopregnant rats, early LHAS treatment delayed LH dependency for only 1 day, while it delayed LH dependency for at least 3 days in ordinary pseudopregnant rats and for at least 4 days in hysterectomized pseudopregnant rats. Estrogen itself seems to have prevented the delay in LH dependency only by inducing implantation, since it had no effect in the DT-bearing pseudopregnant rats. How DT affects the corpus luteum's dependency on LH is unknown, but it may be related to whatever effect DT has on prostaglandin production in the endometrium.

Animals↗
PubMed1980

Temporal aspects of the involvement of the uterus and prolactin in the establishment of luteinizing hormones-dependent progesterone secretion in the rat.

This paper deals with some of the temporal aspects of the inhibition by PRL and the promotion by the uterus of the development of a crucial need for LH (LH dependency) in the maintenance of progesterone secretion by the rat corpus luteum. A severe and permanent fall in the concentration of progesterone in the serum and a shortening of the duration of the vaginal diestrus in response to 0.5 ml of a specific antiserum to LH, injected sc on the morning of day 9 of pseudopregnancy (day 1 = ovulation), confirmed the presence of LH dependency. In rats hysterectomized before the induction of pseudopregnancy or on days 2, 3, or 4 of pseudopregnancy, LH antiserum did not induce luteolysis, but in rats hysterectomized on day 5, it did. In rats subjected to chronic PRL treatment (through the homotransplantation of a rat pituitary beneath the kidney capsule) from day 2 onward, LH antiserum did not induce luteolysis if the uterus was removed on day 5, 6, or 7; if the uterus remained in place until at least day 8, however, LH antiserum induced luteolysis. In rats hysterectomized on day 5, the presence of a pituitary homotransplant only between 2 and 5 or only from day 5 onward prevented the luteolytic response to LH antiserum; if the pituitary was not transplanted until day 8, however, LH antiserum induced luteolysis. These results imply that there probably is a quantitative relationship between the duration (as well as time of onset) of the mutually opposing effects of PRL and the uterus on the appearance of LH dependency.

Animals↗
PubMed1980

Effects of oestradiol on steroid dehydrogenase activities in rat corpora lutea.

The activities of 20alpha-hydroxysteroid dehydrogenase and 3beta-hydroxysteroid dehydrogenase in rat corpora lutea during the second half of pregnancy were measured. In luteal tissue of the intact pregnant rat, 20alpha-hydroxysteroid dehydrogenase activity was undetectable between days 12 and 18 of pregnancy but appeared slowly after hypophysectomy and hysterectomy on day 12. Treatment of the hypophysectomized and hysterectomized animal with oestradiol delayed this increase until day 17, at which time a rapid induction of this enzyme occurred. In the normal pregnant rat mean luteal 3beta-hydroxysteroid dehydrogenase activity increased between days 12 and 18 (P less than 0.05, Student's t-test) but fell rapidly after hypophysectomy and hysterectomy on day 12. Oestradiol treatment prevented this fall in activity and enzyme activity was not distinguishable from that of the intact rat. Progesterone secretion correlated well with the activities of these two enzymes in the three conditions examined.

20-Hydroxysteroid Dehydrogenases↗
PubMed1979

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Androgens↗
PubMed1978

The attenuation of prostaglandin-induced luteolysis in decidual tissue-bearing pseudopregnant rats.

Decidual tissue (DT)-bearing pseudopregnancy (PSP) rats, in contrast to hysterectomized PSP rats, were resistant to a luteolytic regimen of either PGF2alpha or PGE2 when examined for the duration of PSP diestrus. The PG treatments, however, caused a marked fall in the serum progesterone levels on days 10 and 12, although the levels in DT-bearing rats on day 10 were significantly higher than in the hysterectomized rats.

Animals↗