Induction of puberty in gilts 2. The effect of boars on maintenance of cyclic activity in gilts induced to ovulate with pregnant mare's serum gonadotrophin and human chorionic gonadotrophin

1981 ◽  
Vol 32 (1) ◽  
pp. 51-54 ◽  
Author(s):  
A. M. Paterson ◽  
D. R. Lindsay
Keyword(s):  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Ovulation Rate ◽  
Ovarian Activity ◽  
Corpora Lutea ◽  
Cyclic Activity

ABSTRACTIn two experiments prepubertal gilts were injected with a combination of 400 international units pregnant mare's serum gonadotrophin and 200 international units human chorionic gonadotrophin. The gilts were housed either in contact with or isolated from mature boars. Data were obtained of ovarian activity determined immediately after gonadotrophin treatment and at the anticipated time of the second oestrus.All treated gilts ovulated in response to the treatment and 83% displayed oestrus. Ovulation rate varied both within and between experiments, in experiment 1 the range being 7 to 19 corpora lutea and in experiment 2, between 5 to >30 corpora lutea. Four distinct types of behaviour were observed at the time of the second cycle: ovulation associated with oestrus; ovulation without oestrus; oestrus but no ovulation; and a return to a prepubertal state with no oestrus or ovulation. The presence of boars enhanced the maintenance of cyclic activity. Overall, more gilts displayed a second oestrus (33/39 v. 19/41, X2 = 11·2, P<0·001), and more had a second ovulation (32/39 v. 24/41, X2=4·2, P<0·05) when boars were run with the gilts.

Induction of puberty in gilts 3. Ovulation, plasma oestradiol and progesterone in gilts injected with pregnant mare's serum gonadotrophin and human chorionic gonadotrophin

1981 ◽  
Vol 32 (1) ◽  
pp. 55-59 ◽  
Author(s):  
A. M. Paterson ◽  
G. B. Martin
Keyword(s):  
Luteal Phase ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Corpora Lutea ◽  
Progesterone Concentration ◽  
Cyclic Activity ◽  
Vulval Development ◽  
Subsequent Rise ◽  
Plasma Oestradiol ◽  
Second Peak

ABSTRACTNineteen prepubertal gilts were injected with a combination of 400 international units pregnant mare's serum gonadotrophin and 200 international units human chorionic gonadotrophin. Blood was sampled throughout the ensuing oestrous cycle and assayed for progesterone and oestradiol-17β.Eighteen gilts had vulval development consistent with oestrus within 5 days and had ovulated by day 12. Oestradiol levels in the plasma were elevated between days 2 and 6, and progesterone concentration increased between days 6 and 10 due to the establishment of functional corpora lutea. Progesterone concentration in the luteal phase was related to ovulation rate (r = 0·72, P<0·001).Three types of cyclic activity followed the luteal phase and a characteristic hormone profile was established for each. Five gilts exhibited a second ovulation accompanied by signs of oestrus. They had a second peak of oestradiol around days 24 to 26 and a subsequent rise in progesterone concentration. Four gilts displayed vulval development at this time but did not ovulate. A peak of oestradiol was detected. The remaining gilts did not display oestrus, nor did they ovulate. Oestradiol and progesterone concentrations remained basal in these gilts. The ovaries of prepubertal gilts treated with this combination of gonadotrophins produce normal patterns and levels of oestradiol and progesterone. Cyclic activity is not always maintained, probably due to differences in the maturity of the hypothalamic-pituitary-ovarian axis.

Endocrine response to superovulatory treatment in pre-pubertal beef heifers: its lack of ability to induce puberty

1988 ◽  
Vol 46 (2) ◽  
pp. 163-167 ◽  
Author(s):  
J. J. Bonavera ◽  
D. J. Tortonese ◽  
J. M. Doray ◽  
F. Petraglia
Keyword(s):  
Luteal Phase ◽  
Single Injection ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Ovarian Activity ◽  
Corpora Lutea ◽  
Strongly Correlated ◽  
Beef Heifers ◽  
Endocrine Response ◽  
Plasma Oestradiol

AbstractThis study was carried out to investigate: (1) changes in plasma oestradiol-17β and progesterone concentrations in six pre-pubertal beef heifers, 9 months old, subjected to a superovulatory treatment, consisting of a single dose of PMSG followed 120 h later by a single injection of human chorionic gonadotrophin (HCG); and (2) the ability of this treatment to trigger cyclic gonadal activity. After PMSG administration, oestradiol-17β levels increased from 11·8 (s.d. 10·78) to 92·9 (s.d. 38·15) ng/1 just before HCG injection. The oestradiol-17β increase during the superovulatory treatment and numbe r of ovulations were correlated (r = 0·83; P < 0·05). After HCG injection, progesterone concentrations rose significantly reaching values which in some cases were higher than 60 [μg/1. The progesterone peak on days 9 and 10 post HCG was strongly correlated with the number of corpora lutea (r = 0·95; P < 0·01 and r = 0·92; P < 0·01, respectively). Progesterone determinations were performed for a period of 90 days after HCG administration. No evidence was found for the induction of permanent cyclic ovarian activity since all heifers returned, after the induced luteal phase, to their pre-pubertal condition.

STIMULATION BY HUMAN CHORIONIC GONADOTROPHIN OF OESTRADIOL PRODUCTION BY DISPERSED CELLS FROM HUMAN CORPUS LUTEUM: COMPARISON WITH PROGESTERONE PRODUCTION; UTILIZATION OF EXOGENOUS TESTOSTERONE

1981 ◽  
Vol 91 (2) ◽  
pp. 197-203 ◽  
Author(s):  
M. C. RICHARDSON ◽  
G. M. MASSON
Keyword(s):  
Luteal Phase ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Cell Suspensions ◽  
Corpora Lutea ◽  
Progesterone Production ◽  
Late Luteal Phase ◽  
Oestradiol Production ◽  
Dispersed Cells

Cell suspensions were prepared from tissue samples of human corpora lutea obtained during the mid- and late-luteal phase of the menstrual cycle. Both oestradiol and progesterone production by dispersed cells were stimulated by similar concentrations of human chorionic gonadotrophin (hCG). As the degree of stimulation of production by hCG was greater for progesterone than for oestradiol (five- to tenfold compared with two- to threefold higher than basal production), the ratio of progesterone to oestradiol produced varied according to the level of trophic stimulation. A comparison of cell suspensions prepared from mid- and late-luteal phase corpora lutea, exposed to the same concentration of hCG (10 i.u./ml) in vitro, did not reveal a shift to oestradiol production in the late-luteal phase. Provision of additional testosterone during incubation raised the level of oestradiol production by dispersed luteal cells. At an optimum concentration of testosterone (1 μmol/l), oestradiol synthesis was not raised further in the presence of hCG or N6, O2-dibutyryl cyclic AMP, suggesting a lack of induction or activation of the aromatase system by gonadotrophin in short-term cultures. Basal and stimulated levels of progesterone production were not significantly impaired in the presence of testosterone.

Oxytocin may play a role in the control of the human corpus luteum

1982 ◽  
Vol 95 (1) ◽  
pp. 65-70 ◽  
Author(s):  
G. J. S. Tan ◽  
R. Tweedale ◽  
J. S. G. Biggs
Keyword(s):  
Menstrual Cycle ◽  
Corpus Luteum ◽  
Inhibitory Action ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Corpora Lutea ◽  
Luteal Cells ◽  
Progesterone Production ◽  
Human Corpus Luteum

The effects of oxytocin on dispersed luteal cells from human corpora lutea of the menstrual cycle were studied. Oxytocin at a concentration of 4 mi.u./ml produced a slight increase in basal progesterone production. However, higher oxytocin concentrations (400 and 800 mi.u./ml) markedly inhibited both basal and human chorionic gonadotrophin-induced progesterone production. These data provide evidence for an effect of oxytocin on the human corpus luteum. In view of the inhibitory action of oxytocin, increased secretion of this hormone may be important in the demise of the corpus luteum at the end of the menstrual cycle.

Ovulation rate in ewes treated with pregnant mares' serum gonadotrophin and luteinizing hormone releasing factor

1976 ◽  
Vol 86 (1) ◽  
pp. 127-129 ◽  
Author(s):  
P. T. McGovern ◽  
J. A. Laing
Keyword(s):  
Luteinizing Hormone ◽  
Domestic Animals ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Ovulation Rate ◽  
Commercial Application ◽  
Established Procedure

Although the administration of pregnant mares' serum gonadotrophin (PMSG) to induce superovulation is a well established procedure (see Anderson, Schultz & Melampny, 1963), the unpredictability of the response to this treatment continues to impose a constraint on the commercial application of egg transfer techniques in the large domestic animals. In sheep, the additional use of human chorionic gonadotrophin (HCG) has been mainly centred on attempts to control the time of ovulation (Ortavant, Thibault & Wintenberger, 1949; Braden, Lamond & Radford, 1960; Dziuk et al. 1964; McGovern, Williams & Hancock, 1969). However, Killeen & Moore (1970) found that the proportion of follicles which rupture was increased in PMSG-treated ewes which had been given HCG at the beginning of oestrus. The purpose of the observations recorded here was to examine the possibility that a further gain in ovulation rate in PMSG-treated sheep might be obtained with the use of luteinizing hormone releasing factor (LHRF). No attempt was made to reproduce physiological levels of the releasing factor and dosage was aimed at achieving a superovulatory effect.

CONCENTRATIONS OF CYCLIC AMP IN RABBIT OVARIAN TISSUE DURING THE PREOVULATORY PERIOD AND PSEUDOPREGNANCY AFTER INDUCTION OF OVULATION BY ADMINISTRATION OF HUMAN CHORIONIC GONADOTROPHIN

1975 ◽  
Vol 65 (1) ◽  
pp. 73-82 ◽  
Author(s):  
A. K. GOFF ◽  
PATRICIA W. MAJOR
Keyword(s):  
Cyclic Amp ◽  
Dose Response ◽  
Ovarian Tissue ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Corpora Lutea ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Induction Of Ovulation ◽  
Relationship Of

SUMMARY Concentrations of cyclic AMP were measured in rabbit ovaries at various times after injection of an ovulatory dose of human chorionic gonadotrophin (HCG). A biphasic increase in cyclic AMP concentration occurred during the preovulatory period, with peaks 30 min and 3–4 h after HCG injection. Concentrations of cyclic AMP had returned to those observed in ovaries of control oestrous animals before the onset of ovulation 10–12 h after administration of HCG, and remained low throughout the period of pseudopregnancy. Concentrations of cyclic AMP in the newly formed and developing corpora lutea were similar to the concentrations observed in the remainder of the tissue during this period. No significant increase in cyclic AMP concentration was observed 7–9 days after initiation of ovulation. Concentrations of ATP were also investigated during the preovulatory period. The dose– response relationship of HCG to cyclic AMP production in oestrous rabbit ovaries was investigated.

Induction of selective release of FSH in castrated male rats bearing an ovarian transplant by the administration of human chorionic gonadotrophin

1985 ◽  
Vol 106 (1) ◽  
pp. 31-NP ◽  
Author(s):  
G. Watanabe ◽  
K. Taya ◽  
S. Sasamoto
Keyword(s):  
Adult Male ◽  
Sex Differentiation ◽  
Plasma Concentrations ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Male Rats ◽  
Corpora Lutea ◽  
Female Rat ◽  
Nacl Solution ◽  
Abrupt Decrease

ABSTRACT The present study was undertaken to determine whether hypothalamic differentiation is involved in the selective release of FSH during the periovulatory period using adult male rats castrated and implanted with an ovary. Adult male rats (70–90 days old) were castrated and an ovary obtained from a prepubertal female rat (26 days old) was immediately grafted subcutaneously. Four weeks later, human chorionic gonadotrophin (hCG, 10 i.u.) was injected i.v. into the experimentally manipulated rats to induce ovulatory changes in the grafted ovaries. Another group of similarly prepared rats was injected with 0·9% (w/v) NaCl solution as controls. After injection of hCG, plasma concentrations of FSH increased significantly by 6 h, reached peak values at 12 h and declined to control levels at 36 h. On the other hand, plasma concentrations of LH were reduced by 6 h and decreased further during the next 36 h. An abrupt fall in plasma concentrations of oestradiol-17β occurred within 3 h of the administration of hCG. Histological examination revealed that ovulatory changes and luteinization of follicles were induced in grafted ovaries by 18 h after the injection of hCG. Thirty-six hours after treatment with hCG, a set of newly formed corpora lutea was observed in grafted ovaries and plasma concentrations of progesterone were raised. Treatment with oestradiol-17β did not inhibit the selective release of FSH after the administration of hCG, suggesting that the abrupt decrease in secretion of oestradiol-17β from the grafted ovary is not involved in the occurrence of the FSH surge. These results indicate that a selective release of FSH can be induced in castrated male rats bearing an ovarian transplant probably due to decreased secretion of inhibin by the luteinized follicles in the grafted ovaries. Sex differentiation of the hypothalamus is not, therefore, involved in the selective surge of FSH. J. Endocr. (1985) 106, 31–36

Effects of prolactin on steroid production by human luteal cells in vitro

1983 ◽  
Vol 96 (3) ◽  
pp. 499-503 ◽  
Author(s):  
G. J. S. Tan ◽  
J. S. G. Biggs
Keyword(s):  
Menstrual Cycle ◽  
Ovarian Function ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Corpora Lutea ◽  
Short Term ◽  
Steroid Production ◽  
Luteal Cells ◽  
Progesterone Production

The effects of prolactin on steroidogenesis were studied in dispersed luteal cells prepared from human corpora lutea of the menstrual cycle. Prolactin, at concentrations of 0·1–1000 ng/ml, had no effect on progesterone production by luteal cells during short-term incubation (3 h). However, in two out of five corpora lutea, higher concentrations of prolactin (100 and 1000 ng/ml) significantly reduced the oestradiol-17β production induced by human chorionic gonadotrophin (hCG; 10 i.u./ml); lower doses of prolactin had little effect. In the remaining corpora lutea, prolactin failed to affect either basal or hCG-induced production of oestradiol-17β. These results are discussed in relation to the mechanism by which prolactin influences human ovarian function.

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