Elution and rebinding of gonadotropins to receptors in corpora lutea: comparisons among treatments and species.

Several treatment regimens have been used to dissociate bound gonadotropins from their target tissues to quantify numbers of occupied receptors. To compare the efficacy of these methods, we evaluated the ability of a number of treatments to elute bound gonadotropins from corpora lutea of various species. In addition, we examined the capacity of luteal tissue to rebind gonadotropins after efficacious elution (greater than 90% dissociation of bound gonadotropin). Particulate (20,000 g) preparations of luteal tissue from pseudopregnant rats and from nonpregnant pigs and rhesus monkeys were incubated with 125I-labeled human luteinizing hormone (hLH, NIH-LH-11) or 125I-labelled chorionic gonadotropin (hCG, CR119) for 20 h at 25 degrees C to occupy gonadotropin receptors. Heat treatment (60 degrees C) eluted greater than 80% of bound 125I-hLH from rat tissue within 30 min, but similar treatment dissociated only 35% of 125I-hLH bound to porcine tissue (p less than 0.01). Likewise, heat treatment eluted only 57% of 125I-hLH bound to macaque tissue. At 4 degrees C, the following treatments dissociated greater than 90% of specifically bound 125I-hLH from porcine and rat luteal particulates within 5 min: acetic acid (pH 2.3), formic acid (pH 2.3), propionic acid (pH 2.3), acetic acid: HCl (pH 2.3 and 3.3), and MgCl2 (4 M). After 1-2 h at 4 degrees C, exposure to urea (4 M) or acetic acid:HCl (pH 4.3) also eluted greater than 90% of bound 125I-hLH.(ABSTRACT TRUNCATED AT 250 WORDS)

[1]  R. Stouffer,et al.  Receptors for chorionic gonadotropin in the corpus luteum of the rhesus monkey during simulated early pregnancy: lack of down-regulation. , 1986, Endocrinology.

[2]  R. Stouffer,et al.  Characterization of corpora lutea in monkeys after superovulation with human menopausal gonadotropin or follicle-stimulating hormone. , 1986, The Journal of clinical endocrinology and metabolism.

[3]  K. Tsutsui,et al.  Developmental changes in the binding of follicle-stimulating hormone (FSH) to testicular preparations of mice and the effects of hypophysectomy and administration of FSH on the binding. , 1985, Endocrinology.

[4]  R. Stouffer,et al.  Evidence for two populations of masked gonadotropin-binding sites in the corpus luteum of the rhesus monkey (Macaca mulatta). , 1985, Endocrinology.

[5]  M. F. Smith,et al.  Changes and interrelationships among luteal LH receptors, adenylate cyclase activity and phosphodiesterase activity during the bovine estrous cycle. , 1985, Journal of animal science.

[6]  R. Stouffer,et al.  Investigation of binding sites for follicle-stimulating hormone and chorionic gonadotropin in human ovarian cancers. , 1984, The Journal of clinical endocrinology and metabolism.

[7]  R. Stouffer,et al.  Changes in available gonadotropin receptors in the corpus luteum of the rhesus monkey during simulated early pregnancy. , 1984, Endocrinology.

[8]  M. Ascoli.  Internalization and degradation of receptor-bound human choriogonadotropin in Leydig tumor cells. Fate of the hormone subunits. , 1982, The Journal of biological chemistry.

[9]  J. Cameron,et al.  Gonadotropin receptors of the primate corpus luteum. I. Characterization of 125I-labeled human luteinizing hormone and human chorionic gonadotropin binding to luteal membranes from the rhesus monkey. , 1982, Endocrinology.

[10]  A. Flint,et al.  Luteal LH receptors during the oestrous cycle and early pregnancy in the pig. , 1980, Journal of reproduction and fertility.

[11]  Y. Salomon,et al.  Studies on the receptor for luteinizing hormone in a purified plasma membrane preparation from rat ovary. , 1980, Endocrinology.

[12]  G. Niswender,et al.  Validation of methods and quantification of luteal receptors for LH throughout the estrous cycle and early pregnancy in ewes. , 1978, Biology of reproduction.

[13]  J. Halme,et al.  Gonadotropin receptors of human corpus luteum during menstrual cycle and pregnancy. , 1978, American journal of obstetrics and gynecology.

[14]  Y. D. Chen,et al.  Regulation of testicular LH receptors by homologous hormone: in vitro studies on receptor occupancy and receptor loss. , 1977, Biochemical and biophysical research communications.

[15]  J. Bockaert,et al.  Adenylyl cyclase activities in ovarian tissues. I. Homogenization and conditions of assay in graafian follicles and corpora lutea of rabbits, rats, and pigs: regulation by ATP, and some comparative properties. , 1976, Endocrinology.

[16]  H. Behrman,et al.  Rapid block of gonadotropin uptake by corpora lutea in vivo induced by prostaglandin F2alpha. , 1976, Prostaglandins.

[17]  M. M. Bradford.  A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. , 1976, Analytical biochemistry.