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.

Endothelin ETA and ETB receptors in postnatal intestine

2001 ◽  
Vol 280 (4) ◽  
pp. G555-G562 ◽  
Author(s):  
Craig A. Nankervis ◽  
David J. Dunaway ◽  
Charles E. Miller
Keyword(s):  
Binding Sites ◽  
Specific Binding ◽  
Ischemia Reperfusion ◽  
Age Groups ◽  
Scatchard Analysis ◽  
Binding Assays ◽  
Site Model ◽  
Number Of Binding Sites ◽  
Competitive Binding Assays

We aimed to characterize endothelin (ET) receptors in the swine intestinal vasculature and to determine ischemia-reperfusion (I/R) effects on these receptors. Saturation and competitive binding assays were performed on mesenteric artery protein membranes from 1- and 40-day-old animals, both control and those subjected to 1 h of partial ischemia followed by 6 h of reperfusion in vivo. Scatchard analysis of saturation binding with 125I-labeled ET-1 in membranes from endothelium-denuded (E−) vessels revealed that the maximum number of binding sites was greater in younger animals. Competitive125I-ET-1 binding was significant for a one-site model with ET-1, ET-3, and sarafotoxin S6c (S6c) in membranes from endothelium-intact (E+) and E− vessels in both age groups. The maximum number of ET-1 binding sites was significantly greater in younger animals. In the presence of the ETAreceptor antagonist BQ-123, competitive 125I-ET-1 binding was significant for a one-site model with ET-1 and S6c in membranes from E+ vessels in both age groups. The maximum number of ET-1 binding sites was significantly greater in younger animals. After I/R, the maximum number of ET-1 binding sites was unchanged. In the presence of BQ-123, specific binding by ET-1 and S6c was eliminated in both age groups after I/R. These results suggest that both ET receptor populations are expressed to a greater degree in younger animals and I/R significantly affects the ETB receptor.

The Binding Of 125I-Von Willebrand Factor To Human Platelets In The Presence Of Ristocetin

1981 ◽  
Author(s):  
P Silber ◽  
T H Finlay
Keyword(s):  
Von Willebrand Factor ◽  
Binding Sites ◽  
Binding Constant ◽  
Specific Binding ◽  
Human Platelets ◽  
Scatchard Analysis ◽  
Binding Data ◽  
Number Of Binding Sites ◽  
Von Willebrand ◽  
Willebrand Factor

The effect of ristocetin on the binding of 125I-porcine von Willebrand factor to human platelets was studied. Previously, we had shown that 125I-porcine von Willebrand factor binds to human platelets in the absence of ristocetin. The present work demonstrates that binding is stimulated by ristocetin and this stimulation is maximal at a ristocetin concentration of 2 mg/ml. At a ristocetin concentration of 0.5 mg/ml, Scatchard analysis indicates a binding constant of 5.18 × 10-9M and the presence of 105,000 binding sites. This compares with our previous finding, in the absence of ristocetin, of a binding constant of 2.92 × 10-7M and 4760 binding sites. These binding data assume the porcine von Willebrand factor to be a tetramer with a molecular weight of 9 × 105. This study indicates that ristocetin causes tighter binding and increases the number of binding sites on human platelets for porcine von Willebrand factor. Unlabelled porcine von Willebrand factor competitively inhibits the specific binding of the labelled protein and gives a binding constant of 0.17 × 10-9M. Similar results were obtained using human von Willebrand factor.

CONCENTRATION OF PROSTAGLANDIN F2α AND STEROIDS IN THE HUMAN CORPUS LUTEUM

1977 ◽  
Vol 73 (1) ◽  
pp. 115-122 ◽  
Author(s):  
I. A. SWANSTON ◽  
K. P. McNATTY ◽  
D. T. BAIRD
Keyword(s):  
Menstrual Cycle ◽  
Corpus Luteum ◽  
Luteal Phase ◽  
Prostaglandin F2α ◽  
Corpora Lutea ◽  
Progesterone Concentration ◽  
Late Luteal Phase ◽  
Prostaglandin F ◽  
Human Corpus Luteum

SUMMARY The concentration of prostaglandin F2α (PGF2α), progesterone, pregnenolone, oestradiol-17β, oestrone, androstenedione and testosterone was measured in corpora lutea obtained from 40 women at various stages of the menstrual cycle. The concentration of PGF2α was significantly higher in corpora lutea immediately after ovulation (26·7 ± 3·9 (s.e.m.) ng/g, P < 0·005) and in corpora albicantia (16·3 ± 3·3 ng/g, P < 0·005) than at any other time during the luteal phase. There was no correlation between the concentration of PGF2α and that of any steroid. The progesterone concentration was highest in corpora lutea just after ovulation (24·9 ± 6·7 μg/g) and in early luteal groups (25·7 ± 6·8 μg/g) but declined significantly (P < 0·05) to its lowest level in corpora albicantia (1·82 ± 0·66 μg/g). The concentration of oestradiol-17β in the corpus luteum and luteal weight were significantly greater during the mid-luteal phase than at any other stage (concentration 282 ± 43 ng/g, P < 0·05; weight 1·86 ± 0·18 g, P < 0·005). The results indicate that regression of the human corpus luteum is not caused by a rise in the ovarian concentration of PGF2α in the late luteal phase of the cycle.

Comparison of growth hormone binding and metabolic response in rat adipocytes of epididymal, subcutaneous, and retroperitoneal origin

1985 ◽  
Vol 110 (1) ◽  
pp. 50-55 ◽  
Author(s):  
Stephen LaFranchi ◽  
Cheryl E. Hanna ◽  
Toni Torresani ◽  
Eugen Schoenle ◽  
Ruth Illig
Keyword(s):  
Growth Hormone ◽  
Binding Sites ◽  
Metabolic Response ◽  
Specific Binding ◽  
Human Growth ◽  
Scatchard Analysis ◽  
Rat Adipocytes ◽  
Significant Difference ◽  
Glucose Incorporation ◽  
Number Of Binding Sites

Abstract. We undertook a comparison of human growth hormone (hGH) binding and metabolic responses in rat adipocytes of epididymal, subcutaneous, and retroperitoneal origin to determine whether the site of fat depot biopsy might affect the response to hGH stimulation. The results showed highest specific binding in epididymal (3.6%), followed by subcutaneous (2.3%) and retroperitoneal adipocytes (1.5%); half-maximal binding was achieved at 14–18 ng/ml hGH for the three sites. Scatchard analysis of the binding data from each site was linear; there was no significant difference in binding affinities (2.1 to 3.3 × 109, m−1), but the number of binding sites was statiticially higher in epididymal (9.8 × 103) as compared to subcutaneous (7.5 × 103, P < 0.05) and retroperitoneal cells (3.3 × 103, P < 0.01). Stimulation with 5 to 2500 ng pituitary hGH produced a dose-related increase in glucose incorporation, with the largest increase in epididymal fat cells (31%, P <0.05) followed by subcutaneous cells (18%, P < 0.05); no significant increase was seen with retroperitoneal cells. Biosynthetic hGH produced a similar pattern of glucose incorporation in the three sites. Addition of hGH antibodies blocked the glucose incorporation in epididymal adipocytes using both pituitary-derived and biosynthetic hGH. It seems clear that this insulin-like effect is caused by hGH, not an insulin-like impurity. We conclude that the number of binding sites, perhaps related to adipose cell size, differs in adipose tissue from different locations and this influences the metabolic response to hGH stimulation.

Characteristics of atrial natriuretic hormone receptors in human pheochromocytomas

1990 ◽  
Vol 122 (6) ◽  
pp. 740-744 ◽  
Author(s):  
J. Eurin ◽  
A. Carayon ◽  
M. A. Zongazo ◽  
F. Masson ◽  
C. Barthelemy ◽  
...  
Keyword(s):  
Binding Sites ◽  
Hormone Receptors ◽  
Scatchard Analysis ◽  
Binding Assays ◽  
Single Class ◽  
Natriuretic Hormone ◽  
Number Of Binding Sites ◽  
Normal Human ◽  
Atrial Natriuretic Hormone ◽  
Atrial Natriuretic

Abstract. The presence of functional receptors for human atrial natriuretic hormone in human pheochromocytomas was recently reported. The present study reports the binding of hANH as measured by Scatchard analysis in 4 human adrenal glands and in 5 human pheochromocytomas. Binding assays using [3H]ANH revealed a single class of high-affinity binding sites for hANH in both tissues. Human pheochromocytomas present a lower number of binding sites than normal human adrenal gland (Bmax of 7.1±2.1 vs 33.6±6.9 fmol/mg protein, respectively). However, the decreased number of ANH receptors was not paralleled by modifications of tissular cyclic GMP (cGMP). Moreover, plasma hANH concentrations in 7 patients with pheochromocytomas (20.2±2.7 pmol/l) were statistically higher than those obtained in 25 normal control humans (8.1±0.6 pmol/l, p<0.001). We also demonstrated the presence of immunoreactive ANH in the tumour itself.

scholarly journals Characterization of a thyroid-hormone-binding site on nuclear envelopes and nuclear matrices of the male-rat liver

1984 ◽  
Vol 219 (3) ◽  
pp. 1001-1007 ◽  
Author(s):  
Y A Lefebvre ◽  
J T Venkatraman
Keyword(s):  
Rat Liver ◽  
Binding Sites ◽  
Intact Animal ◽  
Binding Capacity ◽  
Specific Binding ◽  
Male Rat ◽  
Scatchard Analysis ◽  
Specific Binding Sites ◽  
Number Of Binding Sites

Nuclear envelopes and nuclear matrices were isolated from the male-rat liver. Incubation of 125I-labelled 3,3′,5-tri-iodothyronine (T3) with the nuclear-envelope fraction resulted in specific binding of T3 to the membranes. Maximum specific binding occurred at 30 degrees C after 2h incubation. Storage for 1 week at -80 degrees C resulted in no loss of binding. Scatchard analysis revealed a class of binding sites with KD 86 nM. 3,3′,5′-Tri-iodothyronine was as effective a competitor of [125I]T3 binding to nuclear envelopes as was L-T3 itself, and tri-iodothyroacetic acid was 70% as potent as T3. L- and D-thyronine did not compete for [125I]T3 binding. Incubation of nuclear envelopes with 0.6 M-NaCl before addition of T3 resulted in the complete loss of specific binding sites, whereas exposure of the membranes to 2.0 M-NaCl after incubation with T3 did not extract binding sites. Nuclear matrices, after incubation with [125I]T3 under the same conditions, were shown to possess a class of binding sites with a similar KD but with approx. 30% of the maximum binding capacity. Nuclear envelopes from hypothyroid animals may possess slightly lower numbers of binding sites compared with nuclear envelopes from the intact animal, whereas nuclear matrices from hypothyroid animals have the same number of binding sites as do nuclear envelopes from the intact animal. In conclusion, nuclear envelopes and nuclear matrices have a class of binding sites with relatively high affinity for T3. It is distinct from nuclear and cytosolic binding sites.

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.

RECEPTORS FOR GONADOTROPHIN AND PROSTAGLANDIN F2α IN BOVINE CORPORA LUTEA OF EARLY, MID AND LATE LUTEAL PHASE

1979 ◽  
Vol 91 (3) ◽  
pp. 529-537 ◽  
Author(s):  
Ch. V. Rao ◽  
V. L. Estergreen ◽  
F. R. Carman ◽  
G. E. Moss
Keyword(s):  
Luteal Phase ◽  
Specific Binding ◽  
Prostaglandin F2α ◽  
Progressive Increase ◽  
Corpora Lutea ◽  
Apparent Dissociation Constant ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
Late Luteal Phase ◽  
Dissociation Constant Kd

ABSTRACT A total of 15 corpora lutea representing early (day 3), mid (day 13) and late luteal phase (days 20 and 21–24) were obtained by ovariectomy on cycling cows. The luteal weights and peripheral plasma progesterone levels just prior to ovariectomy, were consistent with the above luteal phases. The specific binding of [125I]human chorionic gonadotrophin to membranes prepared from corpora lutea was significantly higher (P < 0.01) for days 13 and 20 than for days 3 and 21–24. The binding in day 21–24 corpora lutea was higher (P < 0.01) than day 3. Although there was no difference either in number or affinity (apparent dissociation constant (Kd) = 0.04 nm) of gonadotrophin receptors in days 13 and 20 corpora lutea, only in the former did the binding correlate well with plasma progesterone levels. The specific binding of [3H]prostaglandin (PG)F2α to the membranes of these same corpora lutea showed a progressive increase (P < 0.01) from day 3, reached the highest value at a time when corpora lutea were actively regressing (day 20) and then declined (P < 0.01) by day 21–24. Although a considerable number of PGF2α receptors existed at day 13, the affinity of these same receptors was 203 times lower (Kd = 3458 nm) than the affinity of receptors in day 20 corpora lutea (Kd = 17 nm). In summary, the above results show that gonadotrophin receptors correlate with luteotrophic, whereas PGF2α receptors correlate with luteolytic phases in bovine corpora lutea.

Growth hormone receptors in the liver and osmoregulatory organs of rainbow trout: characterization and dynamics during adaptation to seawater

1991 ◽  
Vol 130 (3) ◽  
pp. 425-433 ◽  
Author(s):  
T. Sakamoto ◽  
T. Hirano
Keyword(s):  
Growth Hormone ◽  
Rainbow Trout ◽  
Binding Sites ◽  
Chum Salmon ◽  
Hormone Receptors ◽  
Sea Water ◽  
Specific Binding ◽  
Head Kidney ◽  
Scatchard Analysis ◽  
Single Class

ABSTRACT Specific binding sites for chum salmon growth hormone (sGH) were identified in the membranes obtained from tissues of rainbow trout. Specific binding of 125I-labelled sGH (% per mg protein) was found in the liver (37%), ovary (6%), brain (6%), gill (4%), intestine (4%) and posterior body kidney (4%). Specific binding was not significant in head kidney, anterior body kidney, spleen, heart, skeletal muscle or skin. Scatchard analyses demonstrated the presence of a single class of high-affinity low-capacity receptors in the liver, gill, intestine and kidney. The association constants for the membranes from liver, gill, intestine and kidney were of the same order (1 litre/nmol). Chum salmon prolactin did not inhibit the binding of 125I-labelled sGH to receptors in the liver, gill, intestine and kidney. Transfer of rainbow trout from fresh water to 80% seawater evoked a rise in plasma concentration of GH and a significant decrease in the GH binding to the liver membranes after 1 day. Binding in the gill and kidney was not altered significantly. Membranes were treated with 4 mol MgCl2/l to remove bound GH from the receptors, and the results indicated that the reduction in binding in the liver after transfer to sea-water was probably due to receptor occupancy by increased endogenous GH. The occupancy of liver GH-binding sites was maximal 4 days after transfer. Total (MgCl2-treated) binding sites in the liver increased significantly 14 days after transfer. Scatchard analysis indicated that receptors were altered in capacity without changes in binding affinity. Although GH may also directly affect osmoregulatory organs through their GH receptors, the present results indicate the likelihood of at least partial mediation by the liver of the seawater-adapting action of GH in the rainbow trout. Journal of Endocrinology (1991) 130, 425–433

Binding sites for interferons on ovine and human endometrial membranes

1993 ◽  
Vol 5 (2) ◽  
pp. 219 ◽  
Author(s):  
DL Russell ◽  
GG Manalo ◽  
JK Findlay ◽  
LA Salamonsen
Keyword(s):  
Binding Sites ◽  
Luteal Phase ◽  
Binding Capacity ◽  
Specific Binding ◽  
Major Product ◽  
Human Endometrium ◽  
Scatchard Analysis ◽  
Ovarian Steroids ◽  
Steroid Dependence ◽  
Proliferative Phase

In the ewe, the major product of the preimplantation blastocyst is ovine trophoblast protein-1 (oTP-1), which is now classified as an omega-interferon (IFN). Receptors for IFN are present on sheep endometrium and vary cyclically, presumably modified by the actions of ovarian steroids. This study examined whether or not IFN receptors were present on human endometrium at any stage during the menstrual cycle. In addition, the steroid dependence of ovine endometrial IFN receptors was determined. Specific binding of 125I-labelled IFN (125I-IFN) to ovine endometrial membranes was substantially higher than binding to membranes derived from bovine spleen, human placenta or pooled human endometrium (relative specific binding 100:33:36:20). Human endometrial membrane preparations from proliferative-phase tissue showed very little specific binding (mean 0.8 +/- 0.3%, n = 4) in contrast to luteal-phase endometrium (2.1 +/- 0.3%, n = 8). Treatment of ovariectomized ewes with oestradiol-17 beta (E) resulted in significantly increased binding (117 +/- 7%) of 125I-IFN to endometrial tissues compared with tissue from ovariectomized (OvX, 75 +/- 7%), progesterone (P)-treated (69 +/- 7%), or (E + P)-treated (81 +/- 8%) groups (P < 0.05); all were compared with binding to pooled ovine luteal-phase tissue, 100%. There were no differences between the other three groups. Scatchard analysis showed binding affinity of the same order for the sheep and human receptors (Kd = 10(-10) mol L-1) but binding capacity was considerably lower for human (6.0 fmol mg-1) than for sheep (47-123 fmol mg-1) endometrium.(ABSTRACT TRUNCATED AT 250 WORDS)

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