THE LH-hCG RECEPTOR OF HUMAN OVARY AT VARIOUS STAGES OF THE MENSTRUAL CYCLE

1975 ◽  
Vol 79 (3) ◽  
pp. 568-576 ◽  
Author(s):  
S. Wardlaw ◽  
N. H. Lauersen ◽  
B. B. Saxena
Keyword(s):  
Menstrual Cycle ◽  
Binding Sites ◽  
Receptor Site ◽  
Binding Activity ◽  
Corpora Lutea ◽  
Human Ovary ◽  
Slow Decline ◽  
Number Of Binding Sites ◽  
Human Ovaries ◽  
Hcg Receptor

ABSTRACT Receptors specific for hCG were found in human corpora lutea and follicles. hCG and LH were found to bind at a similar receptor site. The dissociation constant for hCG ranged from 10−10 to 10−11 mol/l in human corpora lutea. The number of binding sites for 125I-hCG ranged from 10−14 to 10−15 moles/mg protein in human corpora lutea. The binding of 125I-hCG to ovary was found to vary at different stages of the menstrual cycle. The binding of 125I-hCG to human ovaries increased on days 13–15 of the cycle, then declined slightly, and increased again on days 22–23. Following day 23, there was a slow decline until day 27 when binding activity could no longer be measured. No binding could be measured by the corpus luteum after the onset of menstruation or in corpora albicans.

EFFECTS OF OESTROGEN AND PROSTAGLANDIN F2α ON LUTEINIZING HORMONE RECEPTORS IN HUMAN CORPORA LUTEA

1981 ◽  
Vol 88 (3) ◽  
pp. 401-408 ◽  
Author(s):  
RYOSUKE NAKANO ◽  
MAREO YAMOTO ◽  
MASAFUMI IWASAKI
Keyword(s):  
Menstrual Cycle ◽  
Binding Sites ◽  
Luteal Phase ◽  
Hormone Receptors ◽  
Specific Binding ◽  
Prostaglandin F2α ◽  
Scatchard Analysis ◽  
Corpora Lutea ◽  
Luteal Tissue ◽  
Number Of Binding Sites

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.

Masked gonadotropin-binding sites in human corpora lutea during menstrual cycle and pregnancy

1988 ◽  
Vol 50 (2) ◽  
pp. 239-244
Author(s):  
Mareo Yamoto ◽  
Keiji Nishimori ◽  
Ryosuke Nakano
Keyword(s):  
Menstrual Cycle ◽  
Binding Sites ◽  
Corpora Lutea

HISTOCHEMICAL LOCALIZATION OF FOUR DEHYDROGENASE SYSTEMS IN HUMAN OVARY DURING THE MENSTRUAL CYCLE

1961 ◽  
Vol 38 (2) ◽  
pp. 293-302 ◽  
Author(s):  
M. Ikonen ◽  
M. Niemi ◽  
S. Pesonen ◽  
S. Timonen
Keyword(s):  
Enzyme Activity ◽  
Menstrual Cycle ◽  
Endometrial Biopsy ◽  
Histochemical Localization ◽  
Vaginal Smear ◽  
Corpora Lutea ◽  
Human Ovary ◽  
Equal Distribution ◽  
Active Structures ◽  
Theca Interna

ABSTRACT The histochemical localization of four dehydrogenase systems (diphosphopyridine nucleotide diaphorase, lactic, succinic and steroid-3β-ol-dehydrogenase) has been studied in human ovary during the menstrual cycle. The phase of the cycle was determined using endometrial biopsy and vaginal smear examination and by estimations of the urinary excretion of pregnanediol-complex. All the dehydrogenases were found to exhibit equal distribution; the most active structures were the theca interna cells of the developing follicles and both thecal and granulosa lutein cells of the corpora lutea. Atretic follicles as well as corpora albicans consistently showed moderate dehydrogenase activity. Formazan deposit was always developed in the interstitial cells of the stroma. No changes were detected in the enzyme activity during the follicular and progestational phases of the cycle.

The interaction of sialidase-treated hCG with ovarian cellular membranes

1981 ◽  
Vol 97 (2) ◽  
pp. 270-280 ◽  
Author(s):  
E. C. Brand ◽  
J. Odink ◽  
G. Klok ◽  
E. V. van Hall
Keyword(s):  
Binding Sites ◽  
Association Constant ◽  
Apparent Difference ◽  
Receptor Complexes ◽  
Number Of Binding Sites ◽  
Biological Potency ◽  
The Difference ◽  
The Stability ◽  
Dissociation Curves ◽  
Hcg Receptor

Abstract. The potency of human chorionic gonadotrophin (hCG) in competition for binding to a gonadal membrane fraction is remarkably enhanced by sialidase treatment. The present study was undertaken to investigate the specificity and characteristics of the binding of sialidase-treated hCG (asialo-hCG) in a particulate hCG-binding system from luteinized rat ovaries. The competitive potency of asialo-hCG relative to hCG was 2.5, irrespective of whether [125I]hCG or [125I]asialo-hCG was used for tracer. This was due to a 2.1 times higher equilibrium association constant for asialo-hCG, whereas the estimated number of binding sites did not differ. There was no apparent difference in the stability of hCG and asialo-hCG, or in the stability of the respective hormone-receptor complexes. The effect of variation of the incubation conditions on the binding of both tracers was similar. In accordance with the difference in the equilibrium association constant, the association velocity of asialo-hCG was more than double that of hCG. With all of the tracers used the dissociation curves were biphasic, the size of the initial fast-dissociating fraction being inversely related to the pre-incubation time. Under identical conditions, the fast-dissociating fraction was smaller for the [125I]asialo-hCG complex than for the [125I]hCG complex. The dissociation velocities of these fractions appeared to be similar. The results indicate that asialo-hCG binds to the hCG receptor in a way similar to the binding of the unmodified hormone, but with a higher affinity. The smaller size of the fast-dissociation form of the asialo-hCG-receptor complex may be related to the lower biological potency of the hormone derivative.

Immunohistochemical localization of 17α-hydroxylase/C17–20 lyase and aromatase cytochrome P-450 in the human ovary during the menstrual cycle

1992 ◽  
Vol 135 (3) ◽  
pp. 589-NP ◽  
Author(s):  
T. Tamura ◽  
J. Kitawaki ◽  
T. Yamamoto ◽  
Y. Osawa ◽  
S. Kominami ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Corpus Luteum ◽  
Granulosa Cells ◽  
Polyclonal Antibodies ◽  
Immunohistochemical Localization ◽  
Corpora Lutea ◽  
Human Ovary ◽  
Normal Human ◽  
Theca Interna ◽  
Cytochrome P 450

ABSTRACT Immunohistochemical localization of 17α-hydroxylase/C17–20 lyase (P-45017α,lyase) and aromatase cytochrome P-450 (P-450arom) in normal human ovaries during the menstrual cycle was studied using specific polyclonal antibodies which were raised against corresponding enzymes. In the follicular phase of matured follicles, P-45017α,lyase was localized in theca interna cells and P-450arom in granulosa cells. P-45017α,lyase was expressed in theca interna cells before P-450arom was expressed in granulosa cells. The corpus luteum showed immunoreactivity to both enzymes and, after menstruation, immunoreactivity decreased gradually until it could not be detected in the corpus albicans. In corpus luteum graviditatis the immunoreactivity continued to be expressed strongly. In some atretic follicles, P-45017α,lyase and/or P-450arom continued to be expressed. In the stromal layer, P-45017α,lyase was detected in secondary interstitial cells, which originated from the theca interna of atretic follicles, and P-450arom was detected in hilar cells. Immunoreactivity to both enzymes was also detected in oocytes of developing follicles. These results are consistent with the two cell theory in the human ovary. They also suggest that androgens and oestrogens are produced not only by follicles and corpora lutea but also by stroma and oocytes. Journal of Endocrinology (1992) 135, 589–595

scholarly journals Effect of oxidized glutathione and temperature on inositol 1,4,5-trisphosphate binding in permeabilized hepatocytes

1995 ◽  
Vol 310 (1) ◽  
pp. 185-192 ◽  
Author(s):  
D C Renard-Rooney ◽  
S K Joseph ◽  
M B Seitz ◽  
A P Thomas
Keyword(s):  
Ligand Binding ◽  
Binding Sites ◽  
Binding Activity ◽  
Oxidized Glutathione ◽  
Ip3 Receptors ◽  
Ip3 Receptor ◽  
Temperature Dependent ◽  
Inositol 1,4,5 Trisphosphate ◽  
Number Of Binding Sites

The effect of oxidized glutathione (GSSG) on inositol 1,4,5-trisphosphate (IP3) binding and the activity of IP3-gated Ca2+ channels was examined in permeabilized hepatocytes. The permeability properties of the channel were measured by using Mn2+ quenching of compartmentalized fura-2 at 37 degrees C and at 4 degrees C for comparison with IP3-binding measurements. GSSG (2 mM) increased the IP3-sensitivity of Mn2+ quenching, consistent with previous studies based on Ca(2+)-release measurements [Renard, Seitz and Thomas (1992) Biochem. J. 284, 507-512]. Measurements of [3H]IP3 binding were made at 4 degrees C after preincubation of permeabilized hepatocytes at 37 degrees C in the absence or presence of GSSG. Under these conditions GSSG stimulated IP3 binding by increasing the number of binding sites without changing the Kd. This effect was observed in the absence or presence of Ca2+, but was abolished when the preincubation with GSSG was carried out at 4 degrees C. Thimerosal also stimulated [3H]IP3 binding, but this effect was mediated both by an increase in the maximum number of binding sites and by a decrease in the Kd. The effects of thimerosal and GSSG were not additive. Further analysis of the effect of GSSG revealed that preincubation of permeabilized hepatocytes at 37 degrees C results in a progressive loss of [3H]IP3-binding sites that can be prevented and reversed by inclusion of GSSG. A parallel loss of IP3-sensitive Mn(2+)-quenchable stores was observed after incubation at 37 degrees C, and this could also be reversed by adding back GSSG. The loss of IP3 binding was not the result of IP3-receptor proteolysis, as judged by Western blotting of immunoreactive protein. The sensitivity of [3H]IP3 binding in permeabilized hepatocytes to varied ratios of GSSG and GSH suggests that the IP3 receptor responds to an oxidized redox environment such as that found in the lumen of the endoplasmic reticulum. GSSG had no direct effect on the ligand-binding activity of detergent-solubilized and partially purified IP3 receptors. We conclude that GSSG exerts an indirect effect on the IP3 receptors in permeabilized hepatocytes by preventing a temperature-dependent loss of IP3-binding sites. We suggest that the hepatic IP3 receptors may interact with a thiol-disulphide oxidoreductase that utilizes GSSG as a substrate and prevents inappropriate unfolding of the ligand-binding domain occurring after incubation of the receptor at 37 degrees C in vitro.

Gonadotrophin-binding components in porcine follicular fluid

1990 ◽  
Vol 124 (3) ◽  
pp. 485-494
Author(s):  
T. A. Yarney ◽  
M. R. Sairam ◽  
G. N. Bhargavi ◽  
B. R. Downey ◽  
A. Srikandakumar
Keyword(s):  
Granulosa Cells ◽  
Follicular Fluid ◽  
Binding Sites ◽  
Cell Receptor ◽  
Binding Activity ◽  
Human Chorionic Gonadotrophin ◽  
Supernatant Fraction ◽  
Receptor Binding Activity ◽  
Membrane Bound ◽  
Hcg Receptor

ABSTRACT The follicular fluid is an important milieu for the growing and maturing oocyte and granulosa cells. In this study we investigated: (1) the properties of gonadotrophin-binding sites in the supernatant fraction of porcine follicular fluid (pFF) and compared them with those of membrane-bound receptors, and (2) the relative changes that occur in pFF and granulosa cell receptor-binding activity following hormone priming of gilts. 125I-Labelled human chorionic gonadotrophin (hCG) and 125I-labelled ovine FSH (oFSH) binding to particulate and supernatant fractions of pFF were hormone-specific and saturable. The concentration of 125I-labelled hCG-binding sites was roughly 50-fold higher in particulate than in supernatant fractions of pFF. However, 30–40% of the total 125I-labelled hCG-binding activity in pFF was present in the supernatant fraction of commercial batches of pFF. 125I-Labelled oFSH binding to pFF membranes was markedly higher than to supernatant fractions. Binding of 125I-labelled hCG and 125I-labelled oFSH to granulosa cells and supernatants of pFF showed a time-dependent variation in response to hormone priming. The results suggest that gonadotrophin-binding sites in the supernatant fraction of pFF have properties similar to those of their membrane-bound counterparts. 125I-Labelled hCG-binding activity in the supernatant fraction of pFF was shown to be more stable than detergent-solubilized LH/hCG receptors, even in glycerol-preserved preparations. Based on a number of criteria, we have speculated that pFF may have components which may be similar in structure to the extracellular domain of the LH/hCG receptor. Journal of Endocrinology (1990) 124, 485–494

The Estimation of the Number of Binding Sites for Antibody on Antigen Molecules with Reference to Factor VIII and its Antibody

1976 ◽  
Vol 35 (02) ◽  
pp. 274-288 ◽  
Author(s):  
Judith Pool ◽  
Rosemary Biggs ◽  
R. G Miller
Keyword(s):  
Factor Viii ◽  
Binding Sites ◽  
Theoretical Basis ◽  
Human Antibody ◽  
Rabbit Antibody ◽  
Number Of Binding Sites ◽  
Theoretical Considerations

SummaryThe theoretical basis for determining the number of antibody sites on antigen molecules is examined. The theoretical considerations are applied to factor VIII molecules. Examples based on data available at the Oxford Haemophilia Centre are calculated to illustrate the approach. It is concluded that there are few sites on each factor VIII molecule for human antibody. The three antibodies for which reasonable data were available suggest 1–3 sites for human antibody. The data for rabbit antibody suggest 5–6 sites per factor VIII molecule.

Abnormal Platelet Serotonin Uptake and Binding Sites in Myeloproliferative Disorders

1984 ◽  
Vol 51 (03) ◽  
pp. 349-353 ◽  
Author(s):  
C Caranobe ◽  
P Sié ◽  
F Fernandez ◽  
J Pris ◽  
S Moatti ◽  
...  
Keyword(s):  
Binding Sites ◽  
High Capacity ◽  
Specific Inhibitor ◽  
Myeloproliferative Disorders ◽  
Normal Subjects ◽  
Binding Data ◽  
Full Explanation ◽  
Number Of Binding Sites ◽  
5 Ht Uptake ◽  
Kinetics Of

SummaryA simultaneous investigation of the kinetics of serotonin (5 HT) uptake and of binding sites was carried out in the platelets of normal subjects and of 10 patients affected with various types of myeloproliferative disorders (MD). The 5 HT uptake was analysed according to the Lineweaver-Burk and the Eadie-Hofstee methods. With the two methods, the patient’s platelets exhibited a dramatic reduction of the Vi max and of the Km; in some patients the Eadie-Hofstee analysis revealed that a passive diffusion phenomenon is superimposed on the active 5 HT uptake at least for the higher concentration used. The binding data were analysed with the Scatchard method. Two classes of binding sites (high affinity - low capacity, low affinity - high capacity) were found in normal subjects and patients. Pharmacological studies with imipramine, a specific inhibitor of 5 HT uptake, suggested that both the sites are involved in 5 HT uptake. The number of both binding sites was significantly decreased in patient’s platelets while the affinity constants of these binding sites were not significantly reduced in comparison with those of the control subjects. No correlations were found between Vi max, Km and the number of binding sites. These results suggest that a reduction in the number of platelet membrane acceptors for 5 HT commonly occurs in myeloproliferative disorders but does not provide a full explanation of the uptake defect.

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