scholarly journals LIGHT MICROSCOPIC LOCALIZATION OF BINDING SITES FOR HUMAN CHORIONIC GONADOTROPHIN IN LUTEINIZED RAT OVARIES BY A PEROXIDASE-LABELED ANTIBODY METHOD

1973 ◽  
Vol 21 (3) ◽  
pp. 279-282 ◽  
Author(s):  
P. PETRUSZ ◽  
A. UHLARIK
Keyword(s):  
Binding Sites ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Microscopic Localization ◽  
Antibody Method

ISOLATION OF RAT LEYDIG CELLS BY DENSITY GRADIENT CENTRIFUGATION

1982 ◽  
Vol 92 (2) ◽  
pp. 293-NP ◽  
Author(s):  
J. S. GALE ◽  
J. ST J. WAKEFIELD ◽  
H. C. FORD
Keyword(s):  
Density Gradient ◽  
Binding Sites ◽  
Leydig Cells ◽  
Interstitial Cell ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Collagenase Treatment

A rapid method for preparing Leydig cells from rat testes is described. An interstitial cell suspension, prepared by collagenase treatment of decapsulated testes, was centrifuged for 10 min over a cushion of 60% (v/v) Percoll to remove red blood cells, and then centrifuged for 20 min in a 0–60% linear density gradient of Percoll. Seventy-four per cent of the cells present in that fraction of the gradient comprising 35–50% Percoll were Leydig cells; the yield from each testis was about 1·5 × 106 cells. The Leydig cells appeared viable, excluded Trypan blue, possessed high-affinity binding sites for human chorionic gonadotrophin (hCG) and synthesized increased quantities of testosterone in response to hCG. The cells could be stored overnight in 20% (v/v) glycerol at −20 °C, with only minimal effect on the specific activities of a number of enzymes used as markers of subcellular components. Testosterone production in vitro by the cells after storage for 20 h was greater than that of hCG-stimulated fresh cells and was not further increased by hCG.

Effects of intrauterine instillation of antiserum to hCG during early pregnancy in mice

1984 ◽  
Vol 107 (2) ◽  
pp. 268-274 ◽  
Author(s):  
Narendra J. Joshi ◽  
Tarala D. Nandedkar
Keyword(s):  
Binding Sites ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Mouse Embryos ◽  
Rabbit Serum ◽  
Normal Rabbit Serum ◽  
Cytotoxicity Test ◽  
Implantation Sites ◽  
Immunohistochemical Techniques

Abstract. Human chorionic gonadotrophin (hCG)-like activity has been reported in mouse and rabbit blastocysts. The presence of this hCG-like activity seems to be essential for nidation of the pre-implantation embryo. Binding sites for hCG were localised on day 4 mouse embryos by immunohistochemical techniques. Presence of hCG-like activity was confirmed by cytotoxicity test. The number of implantation sites was significantly reduced on day 8 of pregnancy. Prior treatment to day 4 mouse embryos with hCG antiserum, for 1 h in utero or in vitro and their subsequent transfer to uteri of synchronised pseudopregnant mice resulted in impaired implantation of embryos, compared to controls treated with normal rabbit serum (NRS). These results suggest that hCG-like activity present on the pre-implantation embryo may have a significant role in implantation of the embryo.

Specific binding sites for epidermal growth factor and its effect on human chorionic gonadotrophin secretion by cultured tumour cell lines: comparison between trophoblastic and non-trophoblastic cells

1982 ◽  
Vol 101 (2) ◽  
pp. 281-286 ◽  
Author(s):  
Yukio Hirata ◽  
Satoru Sueoka ◽  
Masahito Uchihashi ◽  
Yoshio Yoshimoto ◽  
Takuo Fujita ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cell Lines ◽  
Binding Sites ◽  
Specific Binding ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Specific Binding Sites ◽  
Epidermal Growth ◽  
Tumour Cell Lines

Abstract. Using human trophoblastic (SCH) and non-trophoblastic (HeLa S3) tumour cell lines, specific binding sites for epidermal growth factor (EGF), a potent stimulator of growth in many tissues, and its effect on secretion of human chorionic gonadotrophin (hCG) and/ or its subunits were compared between these two tumour cells. Both SCH and HeLa S3 cells possessed two populations of specific binding sites for 125I-labelled EGF: the high affinity (Kd ∼10−10m) and the low affinity (Kd ∼ 7 × 10−10 m) system. Tetradecanoyl phorbol acetate (TPA), a tumour promotor, showed a potent competitor of labelled tracer binding to its receptor sites in both cell lines. EGF stimulated both hCG-α and hCG and/or hCG-β secretion in a dose-responsive manner from SCH cells, whereas it had no effect on hCG-α secretion from HeLa S3 cells. In contrast, dibutyryl cyclic AMP plus theophylline, a phosphodiesterase inhibitor, enhanced hCG-α secretion from both cells, while TPA had no effect in either cells. These data suggest that EGF may play a physiological role in hCG secretion from trophoblastic tissues and that the mechanism by which hCG and/or its subunits are secreted may differ between trophoblastic and non-trophoblastic tumour cells.

Arachidonic acid release from rat Leydig cells depends on the presence of luteinizing hormone/human chorionic gonadotrophin receptors

1997 ◽  
Vol 154 (2) ◽  
pp. 201-209 ◽  
Author(s):  
P F Moraga ◽  
M N Llanos ◽  
A M Ronco
Keyword(s):  
Arachidonic Acid ◽  
Luteinizing Hormone ◽  
Dose Response ◽  
Binding Sites ◽  
Leydig Cells ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Receptor Interaction ◽  
Dependent Manner ◽  
Membrane Phospholipids

Abstract In this work, the involvement of arachidonic acid (AA) in the luteinizing hormone and human chorionic gonadotrophin (LH/hCG) action on Leydig cells was studied. Experiments were first designed to evaluate [14C]AA incorporation into membrane phospholipids. Subsequently, time-course, pulse-chase and dose–response studies of the effect of hCG on [14C]AA release were performed. Results indicated that 4 h was optimal for maximal incorporation of [14C]AA into membrane phospholipids of viable Leydig cells. Pulse-chase experiments and studies performed to evaluate the effect of different doses of hCG on [14C]AA release demonstrated that this hormone stimulates [14C]AA release in a dose–response and time-dependent manner. Furthermore, using a desensitised animal model, a link between the presence of LH/hCG receptors and LH/hCG-stimulated [14C]AA release in Leydig cells could be established. In fact, the amount of [14C]AA released was significantly dependent on, and directly proportional to, the concentration of LH/hCG binding sites. Thus [14C]AA released from intact rat Leydig cells decreased when animals had been previously injected with a high single dose of hCG (desensitised animals), which is known to cause a dramatic decrease in the number of LH/hCG binding sites. These results demonstrate that the mechanism of AA release in Leydig cells depends on LH/hCG–receptor interaction and also suggest that AA could act as an additional intracellular messenger associated with the hormonal action of LH/hCG. Journal of Endocrinology (1997) 154, 201–209

Luteinizing hormone increases the number of ova shed in the cyclic hamster and guinea-pig

1984 ◽  
Vol 101 (3) ◽  
pp. 289-298 ◽  
Author(s):  
F. Garza ◽  
M. A. Shaban ◽  
P. F. Terranova
Keyword(s):  
Guinea Pig ◽  
Binding Sites ◽  
Follicular Development ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Serum Concentrations ◽  
Sustained Development ◽  
Antral Follicles ◽  
Preovulatory Follicles ◽  
Pregnant Mare Serum Gonadotrophin

ABSTRACT Osmotic minipumps containing 400 μg ovine LH installed subcutaneously on day 1 (oestrus) of the cycle in the hamster induced superovulation of 30·0 ± 2·1 ova (n=5) at the next expected oestrus. Controls ovulated 12·0 ± 0·8 ova (n = 6). Bovine LH, human LH, porcine LH, human chorionic gonadotrophin and pregnant mare serum gonadotrophin were effective in approximately doubling the number of ova spontaneously shed in the hamster. Ovine FSH (200 μg/pump) was most effective in increasing the number of ova spontaneously shed (55 ± 6, n=5) in the hamster. Infusion of ovine LH on days 1–4 prevented the reduction of the number of antral follicles that occurs normally between days 3 and 4 of the 4-day cycle. Since this reduction in follicular numbers in control cyclic hamsters is due to atresia, the exogenous LH might prevent atresia of the developing follicles. In the hamster, exogenous ovine LH significantly increased the serum concentrations of androstenedione, oestradiol and LH but not of FSH. Hamsters were hypophysectomized on the day of oestrus, given immediate LH (400 pg) or FSH (200 μg) replacement therapy and autopsied on day 4. Ovarian histology revealed that immediate LH treatment after hypophysectomy sustained development of histologically normal preovulatory follicles but had no effect on the number of smaller sizes of follicles. Immediate FSH treatment after hypophysectomy increased only the number of smaller sized follicles. Since LH did not increase the smaller sized follicles, no 'FSH-like' effect on follicular development was observed. In the hamster, the ability of various preparations of LH to induce superovulation did not correlate with their ability to displace 125I-labelled ovine FSH from its ovarian binding sites. The superovulatory action of LH required the presence of the pituitary gland, indicating that LH might synergize with FSH and/or prolactin (or hamster LH) for spontaneous superovulation and it appears that exogenous LH might induce superovulation by prevention of atresia. Infusion of LH into the guinea-pig beginning on day 12 of the cycle (day 1 is the day of ovulation) doubled the ovulation rate whereas in the cyclic rat and mouse LH treatment throughout the cycle was ineffective in increasing the number of ova shed. J. Endocr. (1984) 101, 289–298

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