Preparation and properties of human chorionic gonadotropin antagonist for biological studies: antifertility effects in the female rat

1986 ◽  
Vol 112 (4) ◽  
pp. 586-594 ◽  
Author(s):  
M. R. Sairam ◽  
K. Kato ◽  
A. K. Mukhopadhyay ◽  
H. G. Bohnet
Keyword(s):  
Antagonistic Activity ◽  
Female Rat ◽  
Serum Progesterone ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Trifluoromethane Sulfonic Acid ◽  
Ovarian Granulosa Cell ◽  
Biological Studies ◽  
Stable Product ◽  
High Level

Abstract. We compared the effects of treatment of clinical grade hCG powders with anhydrous HF (hydrogen fluoride) or TFMS (trifluoromethane sulfonic acid). HF treatment yielded stable product (DG-hCG), which had desirable antagonistic activity in mouse Leydig cells. Binding of HF-hCG to ovarian granulosa cell FSH receptors was < 5% as compared to purified ovine FSH. As LH/hCG receptor specificity was not significantly compromised crude hCG could be directly used in obtaining large amounts of the antagonist. The effects of antagonist (DG-hCG) and agonists crude hCG and purified hCG were evaluated in pregnant rats. When administered between days 1 to 5 of pregnancy, crude DG-hCG inhibited serum progesterone and oestradiol levels and implantation. The effect was dose-dependent. However, both crude hCG and purified hCG elevated progesterone level and partially inhibited implantation (up to about 40%). In the post-implantation period (days 8–11) crude DG-hCG treatment induced abortion due to a decrease in circulating progesterone and oestradiol levels. The agonists, crude hCG and purified hCG, on the other hand, elevated both steroid levels in serum and induced partial termination of pregnancy (up to 50%). During the second half of pregnancy, when luteotropic support of LH becomes unnecessary in the rat, crude DG-hCG (antagonist) had no effect on parturition. However, crude or purified hCG caused delay in parturition by sustaining high level of progesterone in circulation. Our data demonstrate that the antifertility effects of crude DG-hCG are more potent and consistent than the administration of either crude or purified hCG in the pregnant rat.

A modulatory role of endogenous opioids on prolactin secretion at the end of pregnancy in the rat

1994 ◽  
Vol 140 (1) ◽  
pp. 97-102 ◽  
Author(s):  
M Soaje ◽  
R P Deis
Keyword(s):  
Time Course ◽  
Prolactin Secretion ◽  
Endogenous Opioids ◽  
Opioid Antagonist ◽  
Serum Prolactin ◽  
Serum Progesterone ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Ru 486 ◽  
Prolactin Suppression

Abstract It is well known that the fall in serum progesterone concentrations during late pregnancy induces prolactin secretion in rats. On day 19 of pregnancy, administration of 10 mg of the antiprogesterone RU-486/kg induced a small but significant increase in serum prolactin. A lower dose (2 mg/kg) was not effective. Administration of naloxone (2 mg/kg) to pregnant rats on day 19 of pregnancy did not modify circulating prolactin but, after RU-486 treatment, a notable increase in serum prolactin was obtained 30 min after naloxone was given. The lack of effect of naloxone-methobromide in pregnant rats pretreated with RU-486 may indicate that the opioid-induced prolactin suppression acts centrally, most probably at the hypothalamic level. During day 21 of pregnancy, the time-course of prolactin secretion, measured at 0900, 1400, 1900 and 2200 h, was inversely correlated with circulating progesterone levels. At 0900 h, serum prolactin was very low with high serum progesterone concentrations but a significant increase in serum prolactin occurred at 2200 h; this was coincident with a significant decrease in the steroid. The stimulatory effect of naloxone on prolactin secretion was clearly dependent on the circulating progesterone level. Thus, at 1900 h of day 21, naloxone induced a significant increase in serum prolactin but, at 2200 h, the opioid antagonist dramatically enhanced the circulating level of prolactin. The serum prolactin increase induced by naloxone at 1900 h was prevented by the s.c. administration of 5 mg progesterone given 7 h earlier. Similarly, the large increase in serum prolactin levels at 1800 h on day 19 of pregnancy, after administration of RU-486 plus naloxone, was completely abolished by treatment with CB154. The lack of effect of RU-486 and naloxone on serum prolactin levels in virgin rats on the day of pro-oestrus demonstrates that the effect of naloxone on prolactin in pregnant rat is peculiar to the end of pregnancy. In conclusion, the attenuation of the central inhibitory action of progesterone facilitates the release of prolactin which is dramatically enhanced by naloxone treatment. These results provide an important new insight into the existence of a neuromodulatory regulation of prolactin secretion by the opioid system showing a paradoxical opioid-induced prolactin suppression at the end of pregnancy. Journal of Endocrinology (1994) 140, 97–102

scholarly journals Different characteristics of solubilized lactogen receptors from livers of pregnant and non-pregnant female rats

1982 ◽  
Vol 203 (3) ◽  
pp. 653-662 ◽  
Author(s):  
Norio Sasaki ◽  
Yuko Tanaka ◽  
Yasuo Imai ◽  
Toshio Tsushima ◽  
Fukashi Matsuzaki
Keyword(s):  
Binding Capacity ◽  
Pregnant Female ◽  
Female Rats ◽  
Scatchard Analysis ◽  
Female Rat ◽  
Binding Studies ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Stokes Radius ◽  
Rat Livers

Receptors specific for lactogenic hormones were solubilized by 1% (v/v) Triton X-100 from the crude particulate membrane fraction of livers of pregnant and non-pregnant female rats and the characteristics of both preparations were compared. Human 125I-labelled somatotropin was used for binding studies of lactogenic hormone. The solubilized receptor retained most of the characteristics noted in the particulate fraction. The binding of human 125I-labelled somatotropin to the solubilized receptor is a saturable process, depending on temperature and time. Scatchard analysis of displacement curves revealed similar affinity constants ranging from 1.02 × 109 to 1.20 × 109 1/mol, while the binding capacity was 4.5 times greater in the pregnant rat livers than in the non-pregnant female rat livers. The receptors for human 125I-labelled somatotropin from livers of non-pregnant and pregnant female rats were equally adsorbed onto a concanavalin-A-Sepharose column and were dissociated from the column with α-methyl-d-glucoside or α-methyl-d-mannoside in the same manner. By gel filtration on Sepharose 6B, however, the molecular sizes of the hepatic receptors were found to be different. The apparent Mr value was approx. 270000 with a Stokes‘ radius of 5.5nm in the non-pregnant female rats and approx. 330000 with a Stokes’ radius of 5.5nm in the pregnant rats. Furthermore, isoelectric-focusing experiments showed that a major part of the receptor from the non-pregnant female rat livers had a neutral pI (7.0—8.5), whereas that from pregnant-rat livers had an acidic pI (4.2—4.7). These data suggest that the increase in the lactogenic binding capacity in rat liver membranes during pregnancy may be associated with marked changes of the physicochemical properties of the receptors.

Luteolytic effect of LH: inhibition of 3β-hydroxysteroid dehydrogenase and stimulation of 20α-hydroxysteroid dehydrogenase luteal activities in late pregnant rats

1996 ◽  
Vol 150 (3) ◽  
pp. 423-429 ◽  
Author(s):  
C O Stocco ◽  
R P Deis
Keyword(s):  
Hydroxysteroid Dehydrogenase ◽  
Good Evidence ◽  
Progressive Decrease ◽  
Control Groups ◽  
Serum Progesterone ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Luteal Function ◽  
Treatment Administration ◽  
Stimulation Of

Abstract The mechanisms associated with the onset of luteolysis in the pregnant rat are not well known. The effect of a specific rat LH antiserum (AS-rLH) and of ovine LH (oLH) on luteal steroidogenesis on day 19 of pregnancy was examined. Rat LH antiserum administered intrabursally at 1000–1100 h on day 19 of pregnancy prevented the physiological decrease in 3β-hydroxysteroid dehydrogenase (3β-HSD) activity, the increase in 20α-hydroxysteroid dehydrogenase (20α-HSD) activity and the fall in serum progesterone (P4) level observed at 1800 h on day 21 of pregnancy. To see if oLH has a direct effect on luteal steroidogenesis, the gonadotrophin was injected into the periovarian bursa. The intrabursa treatment with 1 μg oLH on day 19 of pregnancy at 0800–0900 h did not modify corpus luteal function 36 h after treatment, but treatment with 4 μg oLH per ovary induced a significant progressive decrease in luteal 3β-HSD activity starting 12 h after treatment, while a significant increase in 20α-HSD activity, concomitant with a decrease in serum P4 level, occurred 48 h after treatment. Luteal P4 content decreased with respect to control groups 36 and 48 h after intrabursal treatment with 4 μg oLH. The intrabursal administration of 8 μg oLH induced an increase in 20α-HSD activity and a decrease in 3β-HSD activity 36 h after treatment. Administration of 4 μg oLH per ovary on day 8 of pregnancy induced a significant increase in serum P4 levels without modifying 3β-HSD activity. In rats treated with oLH on day 19 of pregnancy the decrease in 3β-HSD activity occurred 36 h before the significant increase in 20α-HSD activity and serum P4 level. In conclusion, the luteal enzymatic activity changes and the significant decrease in the intraluteal P4 concentration induced by the intrabursal administration of oLH and the clear effect of AS-rLH preventing the physiological luteal changes preceding parturition provide good evidence of an intraovarian action of LH during the normal progression of luteolysis in late pregnant rats. Journal of Endocrinology (1996) 150, 423–429

Fluprostenol-induced softening of the cervix of the pregnant rat

1983 ◽  
Vol 97 (2) ◽  
pp. 283-290 ◽  
Author(s):  
L. M. Williams ◽  
M. Hollingsworth ◽  
M. Dukes ◽  
I. D. Morris
Keyword(s):  
Binding Capacity ◽  
Direct Action ◽  
Prostaglandin E ◽  
Uterine Contractility ◽  
Serum Progesterone ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Uterine Contractions ◽  
Prostaglandin F

Fluprostenol, an analogue of prostaglandin F2α, administered s.c. to rats on day 18 of pregnancy increased cervical creep, or softness, by the following day. Doses of fluprostenol 100-fold larger were necessary to increase uterine contractions. Fluprostenol produced falls in serum progesterone concentrations, increases in 20α-dihydroprogesterone concentrations, no changes in oestradiol or relaxin concentrations and a reduction in the ovarian human chorionic gonadotrophin binding capacity in vitro. Fluprostenol was less potent in inducing cervical softness when administered per vaginam, and a dose which produced softening in pregnant rats was ineffective in ovariectomized steroid-maintained pregnant or pro-oestrous rats. The findings suggest that cervical softening by fluprostenol does not result from a simple direct action on the cervix or by increasing uterine contractions, but rather by an indirect hormonal action mediated by the ovaries. The results with the lowest dose of fluprostenol indicate that cervical softening could be produced without a sustained fall in serum progesterone concentrations. Fluprostenol is much more potent at increasing cervical softness in the pregnant rat than prostaglandin F2α or prostaglandin E2. With fluprostenol the ratio of dose to induce uterine contractility relative to that to produce cervical softness was greater than with these natural prostaglandins, indicating the greater selectivity of fluprostenol in the pregnant rat.

Potentiation by prolactin of the luteotrophic effect of oestradiol in the pregnant rat

1982 ◽  
Vol 101 (2) ◽  
pp. 287-292 ◽  
Author(s):  
Richard G. Rodway ◽  
David R. Garris
Keyword(s):  
Sampling Period ◽  
Daily Treatment ◽  
Serum Prolactin ◽  
Renal Capsule ◽  
Serum Progesterone ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Luteal Function ◽  
Progesterone Secretion

Abstract. The luteotrophic effects of elevated prolactin levels with or without concomitant oestradiol treatment were investigated in the pregnant rat after hysterectomy or hysterectomy plus hypophysectomy. On day 2 of pregnancy, rats were given a single pituitary transplant beneath the renal capsule and were subsequently hysterectomised on day 12. This treatment delayed the next ovulation (as judged by vaginal di-oestrus length) compared to sham-transplanted controls, but did not prevent the fall in serum progesterone concentrations (i.e. luteolysis) resulting from hysterectomy. The administration of 1 or 2 pituitary homo-transplants on day 12 at the time of hysterectomy again prolonged the di-oestrus length but did not prevent subsequent luteolysis. However, daily treatment with 100 μg of oestradiol given to rats which received 2 pituitary transplants on day 2 and which were then hysterectomised on day 12, did result in a maintenance of serum progesterone levels compared to those of oil-treated controls. In a separate study, pregnant rats were hysterectomised and hypophysectomised on day 12. Administration of either 1 or 2 pituitary transplants failed to maintain luteal function. However, concomitant daily treatment with 100 μg of oestradiol from day 12 onward prevented luteolysis and re-instated the day 12–16 rise in serum progesterone common to the intact pregnant rat. Progesterone levels then declined slowly until the end of the sampling period (day 23). Serum prolactin concentrations rose steadily for the first 10 days after insertion of pituitary transplants on day 12 of pregnancy. These data indicate that prolactin and oestradiol can act synergistically to stimulate progesterone secretion from the rat corpus luteum but only in the absence of the in situ pituitary; the effect is not seen unless hypophysectomy has been performed.

EFFECTS OF AN ANTISERUM TO LUTEINIZING HORMONE AND STEROID REPLACEMENT THERAPY ON MAINTENANCE OF PREGNANCY IN THE RAT: SERUM AND LUTEAL LEVELS OF PROGESTERONE, TESTOSTERONE AND OESTRADIOL

1981 ◽  
Vol 90 (1) ◽  
pp. 9-18 ◽  
Author(s):  
P. F. TERRANOVA ◽  
G. S. GREENWALD
Keyword(s):  
Testosterone Propionate ◽  
Normal Values ◽  
Single Injection ◽  
Vaginal Smear ◽  
Corpora Lutea ◽  
Serum Progesterone ◽  
Rat Serum ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Daily Dose

Pregnant rats were injected s.c. with antiserum to LH (anti-LH) on days 8 or 10 of pregnancy (day 1 = day of sperm-positive vaginal smear) and subsequently given various steroids s.c. to prevent luteolysis and/or abortion. A single injection of 4 mg progesterone on day 8 prevented abortion and luteolysis as shown on day 12 by the presence of fetal swellings and levels of progesterone in serum (88 ±6 (s.e.m.) ng/ml) and corpora lutea (26±3 ng/mg) comparable to control values. After 0·5 ml anti-LH on day 10, a daily dose of 4 mg progesterone prevented abortion in five out of eight animals but by day 13 luteal progesterone was 3·0 ± 0·7 compared with 24±3 ng/mg in controls. After anti-LH on day 8 or 10, daily injections of 1 or 4 mg testosterone propionate or 10 μg, 100 μg or 1 mg oestradiol failed to prevent abortion or to raise luteal concentrations of progesterone to normal values. However, 4 mg testosterone propionate on day 8 or 100 or 500 μg oestradiol on day 10 maintained serum progesterone levels at approximately half those of control values. Treatment with 4 mg testosterone propionate on days 8–11 led to significant increases in serum and luteal levels of testosterone and oestradiol on day 12; on day 10 exogenous oestradiol (100 or 500 μg) increased serum and luteal levels of oestradiol by day 13. These results, especially treatments begun on day 8, are difficult to reconcile with the current concept that the luteotrophic action of LH in the pregnant rat is exerted by increasing luteal androgens that are aromatized to oestrogens which then act as the direct luteotrophic stimulus.

PLASMA PROLACTIN AND PROGESTERONE RESPONSES TO MATING ARE ALTERED IN AGED RATS

1981 ◽  
Vol 90 (2) ◽  
pp. 179-191 ◽  
Author(s):  
S. HENDRICKS ◽  
C. A. BLAKE
Keyword(s):  
Plasma Concentrations ◽  
External Jugular Vein ◽  
Female Rats ◽  
Plasma Prolactin ◽  
Aged Rats ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Plasma Progesterone ◽  
The One ◽  
The Right

The effects of varying amounts of copulatory stimulation on patterns of plasma concentrations of prolactin and progesterone were evaluated in 3- and 12-month-old female rats. The 12-month-old group included rats which still exhibited oestrous cycles and rats in persistent vaginal oestrus (PVO). The extent of copulatory stimulation was defined by the number of intromissions received during mating: ≤5,15 or > 50. Blood samples were drawn over the 8 days after mating through a cannula inserted into the right external jugular vein. Plasma from the samples was assayed for prolactin and progesterone. In aged but still cyclic rats, pregnancy rates were positively correlated with the number of intromissions received during mating. Only one rat in PVO became pregnant. All animals which became pregnant and rats in PVO which, after mating, exhibited a disruption of the pattern of PVO, showed the nocturnal surge of plasma prolactin characteristic of pregnant and pseudopregnant rats. While these surges persisted until day 8 after mating in pregnant animals, they were absent by this time in the rats in PVO. Prolactin surges were present in some but not all of the aged rats which did not become pregnant. Progesterone concentrations were raised in all pregnant animals except the one pregnant rat in PVO and, while not related to the number of intromissions, concentrations were higher 8 days after mating in young compared with those in aged pregnant rats. Plasma progesterone was low in rats in PVO regardless of disruption of the pattern of PVO. We have concluded that the failure of limited copulatory stimulation to induce pregnancy in older rats results, at least in part, from its failure to initiate nocturnal prolactin surges. Nevertheless, our data suggest that matings which are not experimentally limited should provide ample stimulation to establish such surges. Although reduced plasma concentrations of prolactin and progesterone at pro-oestrus and reduced plasma progesterone through part of gestation may contribute to decreasing fertility in aged rats, other unidentified factors appear to be involved in mediating the capacity of extensive copulatory stimulation to induce pregnancy in these animals.

Glucose uptake and oxidation in fat cells of trained and sedentary pregnant rats

1986 ◽  
Vol 60 (5) ◽  
pp. 1704-1709 ◽  
Author(s):  
B. W. Craig ◽  
J. Treadway
Keyword(s):  
Glucose Uptake ◽  
Exercise Program ◽  
Cell Number ◽  
Fat Cells ◽  
Sedentary Control ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Fed State ◽  
Exercise Period ◽  
Fat Pads

The purpose of this investigation was to examine the relationship between an exercise program and fetal development to determine whether training could influence insulin sensitivity in the pregnant rat. Prior to impregnation one group of animals was exercise trained on a Quinton shock-stimulus rodent treadmill. The exercised group was trained to run 5 days/wk, for 2.0 h/day at 31 m/min up an 8 degree incline for 8 wk before mating. Following mating the training intensity was reduced to 27 m/min up a 5 degree incline, and the exercise period decreased to 1 h/day. On day 19 of gestation, 24 h postexercise for the trained mothers, the animals were killed in the fed state and the parametrial fat pads were removed. The parametrial depot of the trained mother was smaller than the sedentary control dam. This was due to a change in cell size and did not involve alterations in cell number. Isolated adipocytes of the parametrial fat pads were used to measure the rates of 2-deoxy-D-[3H]glucose uptake and D-[1–14C]glucose oxidation to 14CO2. The results indicated that the adipocytes from the dam trained prior to and during pregnancy were significantly (P less than 0.05) more responsive to insulin than those of animals remaining sedentary during the same period. At the maximal insulin concentration tested, the fat cells from trained mothers were able to take up and metabolize approximately twice as much glucose as the sedentary control dams. However, the increase in insulin responsiveness induced by the training program did not match the changes observed in trained nonpregnant rats of prior investigations.

MORPHOLOGICAL CHANGES IN THE ENDOCRINE PANCREAS IN PREGNANT RATS WITH EXPERIMENTAL DIABETES

1979 ◽  
Vol 80 (2) ◽  
pp. 175-179 ◽  
Author(s):  
F. A. VAN ASSCHE ◽  
L. AERTS ◽  
W. GEPTS
Keyword(s):  
Endocrine Pancreas ◽  
Experimental Diabetes ◽  
Morphological Changes ◽  
Normal Pregnancy ◽  
Β Cells ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Human Pregnancy ◽  
The Individual

This present study has demonstrated that during normal pregnancy in the rat the number of β-cells is increased (hyperplasia) and the volume of the individual β-cells is increased (hypertrophy). During experimental diabetes, however, the endocrine pancreas has an impaired capacity to compensate during pregnancy. In the experimental diabetic pregnant rat the β-cells cannot replicate due to the unfavourable metabolic environment. This could reflect the complications caused by diabetes during human pregnancy.

Production rate, metabolic clearance rate and blood concentration of progesterone in conscious and anaesthetized pregnant rats

1984 ◽  
Vol 102 (3) ◽  
pp. 357-363 ◽  
Author(s):  
B. J. Waddell ◽  
N. W. Bruce
Keyword(s):  
Production Rate ◽  
Clearance Rate ◽  
Blood Concentration ◽  
Constant Infusion ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Short Term ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Anaesthetized Rats

ABSTRACT Both production rate and metabolic clearance rate (MCR) of progesterone may vary rapidly and so effect short-term changes in blood concentration of the hormone. Here, a constant infusion and sampling technique was used to estimate these three characteristics of progesterone metabolism in seven conscious and ten anaesthetized rats on day 16 of pregnancy. After steady state was achieved, four samples were collected during a 1-h period from each rat. Mean values for production rate and MCR of progesterone in conscious rats were 14·0 ±1·4 μmol/day and 63·2 ± 6·2 litres/day respectively. Both values were substantially reduced in anaesthetized rats (8.6 ±0·8 μmol/ day and 39·4± 3·4 litres/day respectively) and so blood concentration was unchanged. The production rate was positively related to the total mass of luteal tissue (common correlation coefficient, r = 0·61, P <0·05). There were no consistent changes in the three characteristics with time but variation within rats was high. The estimated coefficients of variation for production rate, MCR and blood concentration within rats were 26, 18 and 17% in conscious and 27, 20 and 23% in anaesthetized rats respectively. Short-term changes in production rate and MCR generally were in the same direction (P <0·05). This reduced variation in blood concentration which would otherwise have occurred if production rate and MCR were unrelated. The pregnant rat is clearly capable of rapid shifts in production rate, MCR and blood concentration of progesterone and the positive relationship between production rate and MCR has a homeostatic effect on blood concentration. J. Endocr. (1984) 102, 357–363

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