Hormonal synchronization of ovulation in beef heifers and fertility after artificial insemination

1964 ◽  
Vol 15 (3) ◽  
pp. 461
Author(s):  
DR Lamond

After ovarian examination, and enucleation of corpora lutea where possible, groups of beef heifers on farms in the New England region were injected with progesterone in oil for 6 days. This was followed in some experiments by treatment with placental gonadotrophins. Artificial insemination was carried out 3–5 days after the final injection of progesterone. The effects of dose of progesterone, pregnant mare serum gonadotrophin, and human chorionic gonadotrophin on fertility were observed. Fertility was highest in heifers in which the corpus luteum was enucleated prior to injection of progesterone.

1982 ◽  
Vol 95 (1) ◽  
pp. 65-70 ◽  
Author(s):  
G. J. S. Tan ◽  
R. Tweedale ◽  
J. S. G. Biggs

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.


2020 ◽  
Vol 32 (2) ◽  
pp. 177
Author(s):  
K. Hazano ◽  
S. Haneda ◽  
M. Matsui

In cattle, human chorionic gonadotrophin (hCG) is administered at Day 5 post-ovulation to improve fertility. This treatment can induce ovulation of the first-wave dominant follicle (W1DF), from which an accessory corpus luteum (CL) is generated. In addition, hCG has the effect of promoting CL development. It is possible that the locational relationship between the original and accessary CLs influences the effect of hCG on CL development, because the locational relationship of the CLs affects intraovarian blood flow. The present study aimed to clarify whether the locational relationship between the original and accessory CLs influences the effect of hCG on their development. Cross-bred beef heifers (Holstein×Japanese Black, n=56) were used for the present study. The oestrus cycle was synchronized using oestradiol benzoate (EB) and a controlled internal drug release (CIDR)-based program. Briefly, an administration of EB (2mg) with 9-day CIDR insertion was followed by administration of prostaglandin F2a analogue (PGF2a) on the day of CIDR removal, EB (1mg) 1 day after a PGF2a injection, and GnRH 12h after the second EB injection. At Day 5 post-ovulation, the locational relationship between the original CL and the W1DF was confirmed using transrectal ultrasonography (USG), and two groups were defined: ipsilateral group (IG; n=30), in which the CL and the W1DF are in the same ovary, and contralateral group (CG; n=26), in which the CL and the W1DF are in separate ovaries. Moreover, IG and CG were respectively subdivided into two groups, with or without hCG (1500IU) treatment (IG/hCG, n=15; IG without hCG, n=15, and CG/hCG, n=14; CG without hCG, n=12). The diameter and luteal tissue area (i.e. minus the cavity area) of the original CL and the accessory CL were examined at Days 5, 7, and 14, using USG. Two-way repeated-measures ANOVA was used to compare the diameter and luteal tissue area between IG/hCG and IG without hCG, and between CG/hCG and CG without hCG. In CG, the diameter (P<0.01) and luteal tissue area of the original CL (P<0.001) at Day 7 was increased by receiving hCG, while it did not change in IG. The diameter and luteal tissue area of the original CL at Day 14 were not affected by the administration of hCG in either CG or IG. Moreover, for the accessory CL, no difference of the diameter and luteal tissue area was observed between CG and IG. The present study showed that hCG treatment at Day 5 post-ovulation stimulate the growth of the original CL at Day 7, when the original CL and accessory CL are on contralateral sides. Our results suggest that the effect of administration of the hCG at Day 5 post-ovulation on the original CL development depends on the locational relationship between the original and accessory CL (IG or CG). The function of the CL affects the intrauterine environment for embryonic development. Therefore, it is necessary to investigate the effect of the hCG injection at Day 5 on the function of CL (i.e. plasma P4 concentration) in IG and CG, respectively.


1977 ◽  
Vol 75 (3) ◽  
pp. 355-361 ◽  
Author(s):  
AKIRA SUZUKI ◽  
TAKAHIDE MORI ◽  
TOSHIO NISHIMURA

Rabbits were injected with human chorionic gonadotrophin (HCG), and slices of developing corpora lutea taken from the ovaries 15, 18, 24, 48, 72 and 96 h after injection were incubated with [1-14C]sodium acetate at 37 °C for 3 h. The incorporation of labelled acetate into ten steroids, including progestagens, androgens and oestrogens, was analysed. In the initial step of corpus luteal formation, the specific incorporation (incorporation of [1-14C]acetate/100 mg tissue) increased sharply. The major steroidal products were progesterone, 17-hydroxyprogesterone and 20α-hydroxypregn-4-en-3-one. Between 18 and 48 h, the increase in specific incorporation was more gradual than in the initial step. Although the pattern was also dominated by progestagens, a temporary increase in the incorporation of acetate into androgens and oestrogens was observed. In the final step, a sharp rise in the total incorporation (incorporation of [1-14C]acetate/corpus luteum) was found, whereas the specific incorporation increased only slightly. The principal steroids produced were progesterone, pregnenolone and 20α-hydroxypregn-4-en-3-one. Incorporation into C19 steroids declined markedly and that into C18 steroids could not be detected. This profile of steroidogenesis 96 h after injection of HCG was similar to that of the corpus luteum in pregnancy. Thus marked quantitative and qualitative changes have been demonstrated during the period of formation of corpora lutea in the rabbit.


1960 ◽  
Vol 11 (3) ◽  
pp. 389 ◽  
Author(s):  
AWH Braden ◽  
DR Lamond ◽  
HM Radford

Synchronization of ovulation in ewes during the breeding season was achieved by a 14 day course of progesterone injections followed by injections of pregnant mare serum gonadotrophin (PMS) and human chorionic gonadotrophin (HCG). Optimal control was attained when the PMS was given at the time of the last progesterone injection and the HCG 24 hr later. With this treatment most ovulations occurred between 20 and 28 hr after the HCG injection. However, none of the ewes exhibited oestrus at this time. Greater variability in the time of ovulation was found when the progesterone-PMS and PMS-HCG intervals were 0 hr and 48 hr, or 24 hr and 24 hr, and with these treatments about 80 per cent. of the ewes exhibited oestrus just before ovulation. On the 0-48 hr treatment schedule with artificial insemination 3-7½ hr after the HCG injection, 13 of 22 ewes had fertilized eggs or embryos when killed 3 or 35 days later.


1989 ◽  
Vol 120 (2) ◽  
pp. 325-330 ◽  
Author(s):  
J. Th. J. Uilenbroek ◽  
P. J. A. Woutersen ◽  
P. D. M. van der Vaart

ABSTRACT Corpora lutea could be identified under the dissection microscope up to 7 days after formation. They were isolated during the oestrous cycle and pseudopregnancy and the progesterone and 20α-OH-progesterone contents were compared with serum values of these steroids. The pattern of progesterone in serum resembled that found in the corpora lutea. However, the pattern of 20α-OH-progesterone concentrations in serum and corpora lutea were different. While 20α-OH-progesterone concentrations in the corpora lutea showed large variations during the cycle, changes in serum concentrations of 20α-OH-progesterone were relatively small. Measurement of hormone concentrations in isolated corpora lutea is therefore a sensitive method for studying corpus luteum activity. To study whether corpora lutea derived after ovulation of immature follicles showed deficient luteal activity, rats at dioestrus (2 days before pro-oestrus) were induced to ovulate by the injection of 10 IU human chorionic gonadotrophin (hCG) and subsequent luteal activity was studied by measuring hormone concentrations in the corpora lutea on day 5 of pseudopregnancy. Concentrations of progesterone, but not of 20α-OH-progesterone, in corpora lutea derived from follicles induced to ovulate at dioestrusday 1 were significantly lower than those in corpora lutea derived from follicles induced to ovulate at prooestrus. This difference was observed not only when pseudopregnancy was induced by cervical stimulation but also when it was induced by implantation of a pituitary gland under the kidney capsule. However, in the latter case, corpora lutea already present on the day of hCG injection also became activated. The present experiments demonstrate that by measuring hormone concentrations in isolated corpora lutea changes in luteal activity can be studied effectively. Moreover, it appears that corpora lutea derived from immature follicles contained less progesterone than those derived from fully mature follicles. Journal of Endocrinology (1989) 120, 325–330


1984 ◽  
Vol 103 (1) ◽  
pp. 107-110 ◽  
Author(s):  
M. G. Hunter

ABSTRACT Human luteal tissue recovered from varying stages of the luteal phase was minced and incubated for 3 h and the effect of human chorionic gonadotrophin (hCG), prolactin and hCG + prolactin on progesterone and oestradiol production measured. While hCG generally enhanced both progesterone and oestradiol synthesis, prolactin alone at either 20 or 200 μg/l had no significant effect on steroidogenesis. When prolactin was added along with hCG in four of six corpora lutea, however, progesterone production significantly increased and in three of six corpora lutea oestradiol production was increased above that induced by hCG alone. It is concluded that prolactin may play some role in the control of steroidogenesis by the human corpus luteum. J. Endocr. (1984) 103, 107–110


1987 ◽  
Vol 115 (3) ◽  
pp. 387-393
Author(s):  
B. Eckstein ◽  
I. Khan ◽  
G. Gibori

ABSTRACT The purpose of this study was to assess the substrate specificity of P45017α in both the corpus luteum and placenta of pregnant rats, and to analyse the site at which LH/human chorionic gonadotrophin (hCG) regulates the activities of this enzyme. To distinguish the substrate preference, placentas and corpora lutea were obtained from rats on day 15 of pregnancy. Tissues were homogenized and the 10 000 g supernatants incubated in the presence of equimolar concentrations of [14C]progesterone and [3H]17α-hydroxyprogesterone as substrate with either NADH or NADPH as cofactors for 2, 8, 16 and 24 min. The labelling pattern of both 17α-hydroxyprogesterone and testosterone indicated that the corpus luteum produced testosterone preferentially from progesterone, whereas the placenta principally used 17α-hydroxyprogesterone and synthesized six times as much testosterone from 17α-hydroxyprogesterone than from progesterone. Addition of either NADPH or NADH as cofactors had no effect on substrate preference. The products of the two enzymatic activities were identified by recrystallization to constant 14C/3H ratios. The ratio of 14C/3H in testosterone produced by the corpus luteum was 16-fold higher than in that produced by the placenta. To explore which of the two activities of P45017α is regulated by the gonadotrophin, rats were treated with either 1·5 IU hCG or vehicle between days 13 and 15 of pregnancy. Hydroxylase and lyase activities were determined on day 15 after incubation for 2,8,16 or 24 min in the presence of either NADH or NADPH. Administration of hCG significantly inhibited NADH-dependent 17α-hydroxylase in the placenta at each time-point studied. The inhibition reached 69% at 24 min. Human chorionic gonadotrophin did not affect the NADPH-dependent 17α-hydroxylase and had only a slight inhibitory effect on both NADH- and NADPH-dependent 17,20-lyase activities in the placenta. In contrast to its effect on the placenta, hCG stimulated both NADH- and NADPH-linked 17,20-lyase activities but had no measurable effect on 17α-hydroxylase activities in the corpus luteum. In summary, the results of the present investigation have revealed a significant difference in the behaviour of 17α-hydroxylase/17,20-lyase activities in the placenta and corpus luteum. The substrate preference and the control of both enzyme activities by LH/hCG differs dramatically. J. Endocr. (1987) 115, 387–393


1964 ◽  
Vol 30 (2) ◽  
pp. 235-245 ◽  
Author(s):  
M. J. K. HARPER

SUMMARY The effects of chlormadinone (6-chloro-Δ6-17α-acetoxyprogesterone), an orally active progestational agent without significant oestrogenic activity, on the response of the ovaries of intact and hypophysectomized immature female rats to exogenous gonadotrophin have been examined. Administration of the steroid whether starting on the same day as, or 4 days before treatment with gonadotrophin, did not depress the ovarian response in intact rats. In hypophysectomized animals, pretreated with the progestagen, the ovarian response to gonadotrophin was depressed. In intact rats, treatment with the steroid and pregnant mare serum gonadotrophin (PMSG) resulted in ovulation, whereas in similar animals given PMSG alone no corpora lutea were found. Corpora lutea were seen in all groups given PMSG and human chorionic gonadotrophin (HCG) but ovulation occurred earlier when, in addition, treatment with the steroid was included. In only one experiment with intact rats did administration of the steroid alone cause a significant increase in uterine weight compared with controls. In neither experiment on hypophysectomized animals did such an increase occur, and significant decreases were recorded.


1969 ◽  
Vol 45 (4) ◽  
pp. 505-513 ◽  
Author(s):  
B. G. ENGLAND ◽  
W. C. FOOTE ◽  
D. H. MATTHEWS ◽  
ARMANDO G. CARDOZO ◽  
S. RIERA

SUMMARY Results in 53 llamas (33 mated animals and 20 controls) showed that ovulation is copulation-induced in this species. Ovulation without copulation occasionally occurred during the height of the recognized breeding season in Bolivia. The first mating during the luteal phase (12–24 days after the preceding ovulation) resulted in ovulation in four out of ten llamas. Determination of pituitary luteinizing hormone (LH) content showed the highest level on the day before mating (9·00 μg./mg.) and the lowest level on day 4 (6·25 μg./mg.). LH level on day 8 was significantly higher than on day 4 (7·62 μg./mg.). Corpora lutea (c.l.) were well formed on day 4 after mating (408 mg.), reached a maximum size by day 8 (1920 mg.) and rapidly decreased in size to day 16 (136 mg.). The corpus albicans remained as an entity but decreased in size to 21 mg. on day 120. Similar changes were found in c.l. histology and progesterone content. The combined results indicate that the functional life of the c.l. in a non-pregnant llama is 16 days or less. Treatment with 25 i.u. human chorionic gonadotrophin was sufficient to cause ovulation in 50% of the animals treated. A large (150 mg.) dose of norethandrolone did not cause morphological regression of the c.l. when measured 5 days after treatment. Treatment with 5 mg. daily for 14 days caused regression of c.l. as compared with untreated controls and animals treated with oestradiol valerate.


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