Luteinizing hormone receptors in the bovine corpus luteum during the oestrous cycle and pregnancy

1999 ◽  
Vol 11 (3) ◽  
pp. 147 ◽  
Author(s):  
K. Okuda ◽  
Y. Uenoyama ◽  
C. Naito ◽  
Y. Sakabe ◽  
N. Kawate

The concentration and affinity of luteinizing hormone (LH) receptors in bovine luteal tissues during the oestrous cycle and pregnancy were investigated by Scatchard analysis of the binding of 125I-labeled human chorionic gonadotropin. Corpora lutea (CL) were classified into five stages of the oestrous cycle and three stages of pregnancy. The concentration of LH receptors sharply increased from the early I stage of the oestrous cycle (Days 2–3; 3.09 fmol mg-1 protein) to the early II stage (Days 5–6; 9.44 fmol mg-1 protein) and then remained constant until the late luteal stage (Days 15–17; 8.14–9.56 fmol mg-1 protein). The LH receptors could not be analysed in the regressed luteal tissue due to the small amounts of binding. There was no significant difference in the concentrations of LH receptors (5.63–9.64 fmol mg-1 protein) among the three stages of pregnancy. Moreover, the concentrations of the receptors in the CL of pregnancy were comparable to those in the mid-cycle CL. The binding affinity did not change significantly during the oestrous cycle and pregnancy. Based on these results, it is assumed that the luteal function during the entire period of pregnancy might be regulated, at least in part, by LH, which is mediated via its specific receptors, and that the luteal function during pregnancy seems not to be regulated by changes in the binding capacity and affinity of LH receptors. To understand the physiological roles of LH in regulating luteal function in pregnant cows, further studies are required.

1981 ◽  
Vol 88 (3) ◽  
pp. 401-408 ◽  
Author(s):  
RYOSUKE NAKANO ◽  
MAREO YAMOTO ◽  
MASAFUMI IWASAKI

The binding of 125I-labelled human LH (hLH) to the 2000 g subcellular fraction of human corpora lutea of the menstrual cycle was examined. Displacement studies demonstrated that 125I-labelled hLH was specifically bound in the 2000 g fraction of human luteal tissue. Specific binding of 125I-labelled hLH was demonstrated in all the corpora lutea examined except for two aged corpora lutea at an early proliferative phase of the cycle. The number of binding sites for hLH increased between the early to mid-luteal phase and decreased towards the late luteal phase. However, the apparent dissociation constant (Kd) in each corpus luteum did not vary throughout the menstrual cycle. In addition, the effects of treatment with diethylstilboestrol diphosphate (DES) and prostaglandin F2α (PGF2α) on the binding of 125I-labelled hLH to the 2000 g fraction of luteal tissue were investigated and the changes in hLH receptors were estimated by Scatchard analysis. The number of binding sites were 1·59 × 10−14 mol/mg protein in control tissue, 0·86 × 10 −14 mol/mg protein in DES-treated luteal tissue and 2·95 × 10−14 mol/mg protein in PGF2α-treated luteal tissue. Thus, the binding sites for hLH decreased as a result of treatment with DES and increased by treatment with PGF2α. In contrast, the apparent Kd in each luteal tissue revealed almost the same value (4·24 × 10−10 to 6·07 × 10−10 mol/l) after treatment with DES or PGF2α. The results of the present study suggest that oestrogen and prostaglandin might have an important role in modulating hLH receptor in human corpora lutea.


1967 ◽  
Vol 39 (2) ◽  
pp. 163-171 ◽  
Author(s):  
A. S. EL-SHEIKH ◽  
FRANÇOIS B. SAKLA ◽  
SAFAA O. AMIN

SUMMARY The histological and functional changes of 31 corpora lutea of Egyptian buffaloes during the various phases of the oestrous cycle were studied. The volumes of the corpora lutea were calculated, the volume per cell, the cell volume and the volume of the intercellular spaces were estimated from transverse serial sections stained with haematoxylin and eosin, Mallory's triple stain or van Gieson's stain. The nuclear volumes were also determined and the cytoplasmic volume was calculated. The progesterone content was estimated using column absorption chromatography and a counter-current distribution system. It was concluded that the luteal cells increase both in volume and in number due to mitosis. The luteal cells decrease in volume after the 15th day after ovulation, the cells lose their distinct outlines in the regressive stage and disappear completely in the corpus albicans. There was a parallel increase in luteal cell volume and progesterone content until the 15th post-ovulatory day followed by a decrease in the regressive phase and disappearance of the hormone in the corpus albicans. A highly significant correlation (r = +0·875) was found between the progesterone content and the cytoplasmic volume. Progesterone concentration/g. luteal tissue increased from the corpus haemorrhagicum to the mature corpus luteum, decreased in the regressive corpus luteum and completely disappeared in the corpus albicans.


1982 ◽  
Vol 92 (1) ◽  
pp. 63-72 ◽  
Author(s):  
FRANCESCA STEWART ◽  
C. H. TYNDALE-BISCOE

Prolactin and LH receptor concentrations in tammar wallaby corpora lutea (CL) have been examined and related to the control of luteal function in this and other marsupial species. During embryonic diapause, quiescent CL contained high concentrations of prolactin receptors. This was consistent with an earlier suggestion that prolactin may act directly on the CL to maintain its quiescent state. However, despite an apparent seasonal change in the mechanism by which the CL is maintained in quiescence, the number of luteal prolactin receptors remained constant throughout the year. Reactivation of quiescent CL led to an approximate halving of prolactin receptors on a per cell basis, but pregnancy had no effect. None of the wallaby CL showed any significant degree of LH binding, although wallaby follicles and testicular tissue did show binding. This lack of LH binding was consistent with previous findings that quiescent wallaby CL reactivate in response to hypophysectomy and are refractory to LH when cultured in vitro. Parturition, which occurs approximately 2 days before ovulation in this species, had no effect on numbers of either prolactin or LH receptors despite the occurrence of a peak of plasma prolactin at this time. The red kangaroo, which also exhibits embryonic diapause, showed a similar pattern of luteal receptor numbers with high prolactin and negligible LH binding, whereas the brush-tailed possum, which does not exhibit embryonic diapause, gave a pattern more like that seen in Eutheria with many more LH than prolactin receptors.


1986 ◽  
Vol 66 (2) ◽  
pp. 415-422 ◽  
Author(s):  
M. M. BUHR ◽  
R. M. McKAY ◽  
D. L. GRINWICH

The luteolytic action of prostaglandin F2α (PGF2α), 15-keto-PGF2α, 15-methyl-PGF2α, and cloprostenol was evaluated in cycling gilts and sows after intramuscular injection on day 13 of the estrous cycle. Only cloprostenol significantly shortened the mean cycle length (18.5 vs. 20.3 d, P < 0.05). Cloprostenol also caused a more rapid decline in serum progesterone concentrations than did the other prostaglandins. Serum concentrations of the prostaglandin metabolite 13,14-dihydro-15-keto-PGF2α (PGFM), showed rapid transitory peaks after PGF2α or 15-keto-PGF2α and a lower, later rise after cloprostenol. A second experiment examined luteal luteinizing hormone (LH) receptors and luteal membrane ultrastructure during the estrous cycle and pregnancy and the effect of cloprostenol on these parameters during the estrous cycle. The number of unoccupied luteal LH receptors, as measured by specific 125I-hCG binding, dropped significantly from mid to late pregnancy and from mid to late cycle. Cloprostenol lowered serum progesterone concentrations but did not affect hCG binding. X-ray diffraction showed no correlation of gel or liquid-crystalline phase lipids in luteal microsomes with the stage of the estrous cycle or pregnancy or cloprostenol treatment. Key words: Swine, luteolysis, estrous cycle, prostaglandins, luteal LH receptors


1995 ◽  
Vol 133 (6) ◽  
pp. 701-717 ◽  
Author(s):  
Bernd Hinney ◽  
Christina Henze ◽  
Wolfgang Wuttke

Hinney B, Henze C, Wuttke W. Regulation of luteal function by luteinizing hormone and prolactin at different times of the luteal phase. Eur J Endocrinol 1995;133:701–17. ISSN 0804–4643 In 54 healthy women luteal function was assessed by sequential withdrawals of blood samples at 10-min intervals for 8–10 h. Subgroups of the women were studied during the early and late ovulatory period and during the early, mid- and late luteal phase. Bio- and immunoreactive luteinizing hormone (LH), prolactin, testosterone, estradiol and progesterone levels were determined in each sample. While the bio- and immunoreactivity of LH pulses correlated fairly well, a number of bio- or immunoreactive LH pulses were observed that were not detected by the respective other method. Responsivity of the corpus luteum to LH episodes developed during the second half of the luteal phase and was most marked in cases where LH episodes were accompanied by prolactin episodes. In the absence of prolactin episodes, LH episodes did not stimulate progesterone or estradiol secretion. The highest incidence of coincident LH and prolactin pulses was observed during the mid- and late luteal phase. Serum testosterone levels showed also some fluctuations but these were independent of immuno- or bioactive LH episodes and therefore most likely not of luteal origin. Prior to menstruation LH episodes were not any more stimulatory to progesterone secretion, indicating that it is not the withdrawal of LH but, rather, another possibly intraovarian mechanism that results in luteolysis. In a number of women, increased estradiol and progesterone secretion was strictly related to the prior occurrence of LH and prolactin pulses. In other subjects, both gonadal steroids fluctuated largely with no discernible correlation to LH fluctuations. This may indicate that in these subjects the corpora lutea have some degree of autonomous regulation. W Wuttke, Abteilung für Klinische und Experimentelle Endokrinologie, Universitäts-Frauenklinik, Robert-Koch-Strasse 40, D-37075 Gottingen, Germany


1972 ◽  
Vol 54 (1) ◽  
pp. 25-NP ◽  
Author(s):  
J. DAVIES ◽  
L. H. HOFFMAN ◽  
G. R. DAVENPORT

SUMMARY Ovine luteinizing hormone (LH) (300 μg/day in divided subcutaneous doses) had a luteotrophic effect of limited duration in intact and hypophysectomized 10-day pseudopregnant rabbits (6–10 days in intact animals; 3–6 days in hypophysectomized animals). Higher dose levels caused reovulation in which case luteolysis occurred. Suppression of reovulation with anti-ovine follicle-stimulating hormone (FSH) serum permitted the daily dose of LH to be raised to 750 μg without causing luteolysis or reovulation. Anti-LH serum was luteolytic in the intact animals. A combination of ovine FSH (200 μg) and LH (300 μg) was indistinguishable from LH alone in terms of its luteotrophic effect in hypophysectomized 10-day pseudopregnant rabbits. Ovine FSH at large daily dose levels (1000 μg) was more effectively luteotrophic than LH alone in a significant number of animals for 10 days after hypophysectomy: endometrial changes in these animals resembled those only seen in normal pregnancy. The luteotrophic effect of 1000 μg FSH was believed to be dependent on a small but significant content of LH, estimated to be about 10 μg. Ovine FSH and anti-FSH serum in intact pseudopregnant rabbits had no detectable effect on luteal function. Animals hypophysectomized at the 7th day and treated with 300 or 500 μg LH/day showed no luteal maintenance for 6 days nor was reovulation induced. Sensitivity to the luteotrophic effect of LH was deemed, therefore, to be greater at 10 than at 7 days of pseudopregnancy. Endometrial criteria were found to be reliable indicators of luteal function. The appearance of ciliated cells was correlated with the decline of the corpora lutea. When reovulation occurred, a new progestational cycle was rapidly superimposed on the existing one.


1990 ◽  
Vol 70 (2) ◽  
pp. 719-721 ◽  
Author(s):  
R. N. KIRKWOOD ◽  
P. A. THACKER ◽  
B. L. GUEDO ◽  
B. LAARVELD

From 14 d after puberty, 37 Yorkshire Landrace gilts received nine daily injections of porcine growth hormone (GH) or vehicle. Gilts were killed 10 d after the onset of their second estrus and their ovaries recovered. Treatment with GH resulted in an increase (P < 0.05) in the hCG binding capacity of the corpora lutea (0.17 vs. 0.11 nmol L−1 mg−1 protein). These data provide a possible mechanism whereby GH may influence ovarian function. Key words: Gilts, hCG binding, growth hormone


Reproduction ◽  
2003 ◽  
pp. 53-64 ◽  
Author(s):  
U Boonyaprakob ◽  
JE Gadsby ◽  
V Hedgpeth ◽  
P Routh ◽  
GW Almond

Changes in the expression and localization of luteal mRNA for PGF(2alpha) (FP) receptors may be critical in determining the luteolytic action of PGF(2alpha) in pig corpora lutea. In this study, a full-length FP receptor (FPr) cDNA was isolated and cloned from pig corpora lutea. This isolate (GenBank accession no. U91520) contains an open reading frame of 1086 bases coding for a protein of 362 amino acids with seven potential transmembrane domains. The predicted amino acid sequence of this isolate was 83% identical to the FPr amino acid sequence of other species including sheep, cattle and humans. Northern blot analysis showed the presence of an FPr message of about 5 kb in mRNA from pig corpora lutea. Relatively weak FPr mRNA expression was detected on day 4 and day 7 of the oestrous cycle. The expression was greater (P < 0.05) on days 10, 13 and 15 than on days 4 and 7. In situ hybridization analysis revealed that mRNA for FPr was expressed predominantly in the steroidogenic large luteal subtype of cell, although there was some expression in small luteal cells, with histological appearance of steroidogenic small cells. Localization of hybridization signals of FPr was observed in luteal tissue at all stages examined. These data demonstrate that FPr is expressed in pig corpora lutea throughout the oestrous cycle and that upregulation of the FPr mRNA occurs when the corpora lutea becomes sensitive to PGF(2alpha). Direct luteal targets of PGF(2alpha) appear to be primarily large steroidogenic cells in this species.


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