scholarly journals Properties of follicle-stimulating-hormone receptor in cell membranes of bovine testis

1975 ◽  
Vol 149 (1) ◽  
pp. 123-132 ◽  
Author(s):  
K W Cheng
Keyword(s):  
Plasma Membranes ◽  
Specific Binding ◽  
Follicle Stimulating Hormone ◽  
Binding Activity ◽  
Receptor Protein ◽  
Temperature Dependent ◽  
Irreversible Damage ◽  
Simple Method ◽  
Testicular Receptor ◽  
Stimulating Hormone

A simple method for preparing plasma membranes from bovine testes is described. Bovine testicular receptor has a high affinity and specificity for 125I-labelled human FSH (follicle-stimulating hormone). The specific binding of 125I-labelled human FSH to the plasma membranes is a saturable process with respect to the amounts of receptor protein and FSH added. The association and dissociation of 125I-labelled human FSH are time- and temperature-dependent, and the binding of labelled human FSH to bovine testicular receptor is strong and not readily reversible. Scatchard [Ann. N.Y. Acad. Sci. (1949) 51, 660-672] analysis indicates a dissociation constant, Kd, of 9.8 ×10-11M, and 5.9 × 10-14mol of binding sites/mg of membrane protein. The testicular membrane receptor is heat-labile. Preheating at 40°C for 15 min destroyed 30% of the binding activity. Specific binding is pH-dependent, with an optimum between pH 7.0 and 7.5. Brief exposure to extremes of pH caused irreversible damage to the receptors. The ionic strength of the incubation medium markedly affects the association of 125I-labelled human FSH with its testicular receptor. Various cations at concentrations of 0.1M inhibit almost completely the binding of 125I-labelled human FSH. Nuclectides and steroid hormones at concentrations of 1mM and 5 μg/ml respectively have no effect on the binding of FSH to its receptor. Incubation of membranes with and chymotrypsin resulted in an almost complete loss of binding activity, suggesting that protein moieties are essential for the binding of 125I-labelled human FSH. Binding of 125I-labelled human FSH to bovine testicular receptor does not result in destruction or degradation of the hormone.

EVALUATION OF THE BOVINE TESTICULAR RADIORECEPTOR ASSAY FOR PITUITARY FOLLICLE-STIMULATING HORMONE

1979 ◽  
Vol 82 (2) ◽  
pp. 253-262 ◽  
Author(s):  
M. R. SAIRAM
Keyword(s):  
Biological Activities ◽  
Follicle Stimulating Hormone ◽  
Radioreceptor Assay ◽  
In Vitro Assays ◽  
Receptor Interactions ◽  
Testicular Receptor ◽  
Pregnant Mare Serum Gonadotrophin ◽  
Stimulating Hormone

SUMMARY A modified bovine testicular receptor was used to evaluate highly purified follicle-stimulating hormone (FSH) from a number of species. The particulate receptor obtained from adult bovine testes could be stored frozen or lyophilized for long periods without appreciable decrease in the binding of the ligand facility or in loss of specificity. The bovine testis receptor binds twice as much 125I-labelled ovine FSH as 125I-labelled human hormone. When FSH from different species was compared against NIH-FSH-S10, using various FSH ligands, the ovine hormone was clearly the most active, although many had comparable in-vivo biological potencies. The results suggest that there is probably some species specificity in the hormone–receptor interactions. As the ovine hormone is structurally closer to the bovine, from which the receptor was derived, it appears to have the highest activity in vitro. Marked differences in the biological activities of the different preparations between the human chorionic gonadotrophin-augmentation test and the in-vitro assays have been observed. In the in-vitro assays, all preparations, with the exception of the porcine hormone preparation, were less active and the ratio of bioassay/radioreceptor assay varied widely. In the radioreceptor assays, all FSH preparations except pregnant mare serum gonadotrophin (PMSG) showed parallel inhibition curves. The three different PMSG preparations examined gave inhibition lines that were parallel to each other.

SPECIFIC RECEPTORS FOR PROLACTIN IN THE OVARY

1975 ◽  
Vol 80 (1) ◽  
pp. 126-137 ◽  
Author(s):  
Tokuko Saito ◽  
Brij B. Saxena
Keyword(s):  
Protein Concentration ◽  
Plasma Membranes ◽  
Ovarian Function ◽  
Specific Binding ◽  
Receptor Protein ◽  
Tissue Homogenate ◽  
Mammary Tissue ◽  
Number Of Binding Sites ◽  
Specific Receptors

ABSTRACT A role of prolactin (PRL) in ovarian function has been suggested in several species, but not unequivocally established except in the rat. We, therefore, examined the presence of specific receptor for PRL in ovaries of rat, cow, and human. Human PRL (hPRL) labelled with 125I by the lactoperoxidase method was shown to be capable of specific binding to rat mammary tissue homogenate. Human, cow, and rat ovarian homogenates and/or partially purified plasma membranes were also shown to specifically bind 125I-hPRL. Binding was a saturable phenomenon and was dependent on receptor protein concentration. Optimal binding was observed at pH 7.0 and at 37°C. Binding was reversibly inhibited by exposure of membranes to pH 10.0 and irreversibly destroyed by exposure to pH 3.0. Bound 125I-hPRL was displaceable by unlabelled human, ovine, and bovine PRL but not by FSH or LH. However, human chorionic somatomammotrophin (hCS) and hGH showed some competition with 125I-hPRL. Number of binding sites/mg protein was lowest (0.8 × 10−12 m) during metoestrus and increased during dioestrus (11 × 10−12 m) reaching the maximum number at pro-oestrus (24.6 × 10−12 m). These results demonstrate that presence of specific PRL receptor in the ovaries and are consistent with a role of PRL at the ovarian level.

scholarly journals The Testicular Receptor for Follicle Stimulating Hormone: Structure and Functional Expression of Cloned cDNA

1990 ◽  
Vol 4 (4) ◽  
pp. 525-530 ◽  
Author(s):  
Rolf Sprengel ◽  
Thomas Braun ◽  
Karoly Nikolics ◽  
Deborah L. Segaloff ◽  
Peter H. Seeburg
Keyword(s):  
Follicle Stimulating Hormone ◽  
Functional Expression ◽  
Testicular Receptor ◽  
Cloned Cdna ◽  
Stimulating Hormone

scholarly journals Human somatotropin binding to rabbit kidney microsomal fraction

1981 ◽  
Vol 200 (2) ◽  
pp. 257-264 ◽  
Author(s):  
L P Roguin ◽  
S H Sánchez ◽  
J S Bonifacino ◽  
A C Paladini
Keyword(s):  
Binding Capacity ◽  
Specific Binding ◽  
Binding Activity ◽  
Rabbit Kidney ◽  
Scatchard Analysis ◽  
Temperature Dependent ◽  
Binding Reaction ◽  
Dissociation Equilibrium ◽  
Microsomal Membranes ◽  
Kidney Microsomes

Specific binding of 125I-labelled human somatotropin was demonstrated in microsomal membranes (microsomes) from rat and rabbit kidneys. Female rabbit kidney microsomes showed the highest binding activity and were used for further study. The association of 125I-labelled human somatotropin was time- and temperature-dependent and the binding reaction was reversible. Scatchard analysis of saturation data indicated a dissociation equilibrium constant, KD, of 56 pM and a binding capacity of 37 fmol per mg of protein. Similar results were obtained from competition experiments. Binding of 125I-labelled human somatotropin to the microsomes was specifically inhibited by hormones with lactogenic activity. The binding sites, as well as 125I-labelled human somatotropin, were not inactivated on incubation. Treatment of the microsomes with trypsin and chymotrypsin decreased the specific binding by over 90%. Preheating of the microsomes at 55 degrees C for 15 min abolished 50% of the specific binding activity.

BINDING OF GONADOTROPHIN RELEASING HORMONE (GnRH) BY BOVINE ANTERIOR PITUITARY PLASMA MEMBRANES AND PURIFIED GnRH RECEPTOR PROTEIN (GnRH.R)

1978 ◽  
Vol 89 (2) ◽  
pp. 232-239 ◽  
Author(s):  
Joseph C. Zolman ◽  
Lubomir J. Valenta
Keyword(s):  
Concentration Dependence ◽  
Anterior Pituitary ◽  
Plasma Membranes ◽  
Polyacrylamide Gel Electrophoresis ◽  
Fold Increase ◽  
Binding Activity ◽  
Gnrh Receptor ◽  
Receptor Protein ◽  
Single Protein ◽  
Binding Curves

ABSTRACT [125I]-(GnRH) concentration dependence binding curves using isolated bovine anterior pituitary plasma membranes, intact and solubilized, and purified GnRH receptor protein, are compared. In all instances the concentration dependence binding curves had a stepwise character here interpreted as multisigmoid, with several steep increases and plateaus. These curves are compatible with the existence of several binding sites for GnRH. Purification of the GnRH receptor protein (GnRH.R) resulted in about 500 000-fold increase of binding activity and yielded a single protein species on polyacrylamide gel electrophoresis in SDS, of estimated molecular weight 60 000. Similarity of GnRH binding by the purified protein with that of intact and solubilized plasma membranes suggested that a single protein was responsible for the binding in each instance. Thus heterogeneity of GnRH binding is likely attributable to phase transitions of a single receptor protein into different allosteric forms. The data suggest that positive cooperativity is involved in the studied system.

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