Uptake of 125I-labelled prolactin by bullfrog kidney tubules: an autoradiographic study

1982 ◽  
Vol 93 (1) ◽  
pp. 133-NP ◽  
Author(s):  
Ophelia Gona
Keyword(s):  
Growth Hormone ◽  
Specific Binding ◽  
Autoradiographic Study ◽  
Receptor Density ◽  
Kidney Tubules ◽  
Radioactive Label ◽  
Intracardiac Injection ◽  
Distal Tubules ◽  
Ovine Prolactin ◽  
Premetamorphic Tadpole

The uptake of 125I-labelled ovine prolactin in the bullfrog kidney was studied by autoradiography. Five minutes after the intracardiac injection of 125I-labelled prolactin, no labelling was detected in the kidneys of premetamorphic tadpoles or in animals whose forelimbs had just emerged (climax tadpoles). After 15 min, a few isolated tubules were labelled in the premetamorphic tadpole kidneys and many kidney tubules were labelled in climax tadpoles. In the froglet kidneys, extensive labelling was seen by 5 min after injection, and only distal tubules seemed to be consistently unlabelled. The radioactive label was displaced by an excess of unlabelled ovine prolactin, but not by ovine growth hormone or bovine LH. These findings provide the first morphological demonstration of specific binding of prolactin by the nephric tubules of an amphibian. They show that the receptors, present in small numbers in the premetamorphic stage, proliferate during the later stages of metamorphosis. The change in receptor density involves both an increase in the number of tubules having receptors and in the density of receptors per tubule.

Specific binding sites for ovine prolactin in three amphibian cell lines

1985 ◽  
Vol 248 (1) ◽  
pp. C80-C87 ◽  
Author(s):  
M. Dunand ◽  
M. L. Aubert ◽  
J. P. Kraehenbuhl ◽  
B. C. Rossier
Keyword(s):  
Growth Hormone ◽  
Cell Lines ◽  
Binding Sites ◽  
Binding Capacity ◽  
Specific Binding ◽  
Human Growth ◽  
Functional Differentiation ◽  
Water Metabolism ◽  
Ovine Prolactin ◽  
Follicle Stimulating Hormones

Established cell lines (TB-6c and TB-M) obtained by continuous culture of epithelial cells from toad Bufo marinus urinary bladder, which, in culture, maintained a high degree of functional differentiation, exhibited a significant number of high-affinity (KA = 1-2 X 10(10) M-1) binding sites detected both with radioiodinated (125I) ovine prolactin (oPRL) and human growth hormone (hGH). Binding capacity was higher in the case of TB-6c cells (7,573 +/- 581 sites/cell) than with the TB-M cells (1,160 +/- 87). Similarly, binding sites for oPRL were characterized on Xenopus laevis kidney-derived cell line A6. With oPRL used both as tracer and standard, significant cross-reaction was observed with hGH, less with human or rat prolactin (PRL), and none with human chorionic somatomammotropin, bovine growth hormone, and rat luteinizing hormone or follicle-stimulating hormones. B. marinus pituitary extracts completely displaced the binding of 125I-oPRL to toad bladder binding sites. This finding of specific sites for PRL on amphibian bladder and kidney cells confirms that PRL exerts specific biological actions for the control of electrolyte and water metabolism in the amphibians.

scholarly journals An investigation of sites that bind human somatotropin (growth hormone) in the liver of the pregnant rabbit

1981 ◽  
Vol 198 (3) ◽  
pp. 605-614 ◽  
Author(s):  
H F Cadman ◽  
M Wallis
Keyword(s):  
Growth Hormone ◽  
Binding Sites ◽  
Specific Binding ◽  
Bovine Somatotropin ◽  
Scatchard Analysis ◽  
Single Class ◽  
Pregnant Rabbit ◽  
Membrane Bound ◽  
Ovine Prolactin ◽  
Triton X

The binding of 125I-labelled human somatotropin (growth hormone) to a crude membrane preparation from the liver of pregnant rabbit, and to receptors solubilized from this fraction by Triton X-100, was dependent on time, temperature and receptor concentration. At 4 degrees C a steady state was reached after 20 h, and maximum specific binding (as a percentage of total tracer added) was approx. 50% for both membrane-bound and solubilized receptors. Solubilization did not significantly affect the binding properties of the receptor at low concentrations of Triton X-100 (less than 0.05%, v/v, in the assay tube). However, at higher concentrations (approx. 0.1%, v/v), the detergent lowered the ability of some hormones, for example ovine prolactin, to displace 125I-labelled human somatotropin, but did not affect other hormones such as bovine somatotropin. Some somatogenic hormones, such as bovine somatotropin, and some lactogenic hormones, such as ovine prolactin, displaced 125I-labelled human somatotropin from membrane-bound and solubilized receptor preparations. Furthermore, 85% of 125I-labelled bovine somatotropin was displaced from membrane-bound receptors by ovine prolactin, and 125I-labelled ovine prolactin was almost completely displaced by bovine somatotropin. Scatchard analysis of the binding data for human somatotropin suggested a single class of binding sites in the membrane-bound receptor preparation, with an affinity (Ka) of 1.9 X 10(9) M-1 and a capacity of 1726 fmol/mg of protein; these values were slightly increased by solubilization (Ka = 3.2 X 10(9) M-1, capacity = 2103 fmol/mg of protein). Scatchard analysis of binding to membrane-bound receptors also indicated a single class of high-affinity binding sites for bovine somatotropin (Ka = 4.8 X 10(9) M-1, capacity = 769 fmol/mg) and for ovine prolactin (Ka = 6.1 X 10(9) M-1, capacity = 187 fmol/mg).

DA1 dopamine receptors in renal cortical collecting duct

1991 ◽  
Vol 261 (5) ◽  
pp. F890-F895 ◽  
Author(s):  
K. Ohbu ◽  
R. A. Felder
Keyword(s):  
Adenylate Cyclase ◽  
Specific Binding ◽  
Collecting Duct ◽  
Sch 23390 ◽  
Receptor Density ◽  
Cortical Collecting Duct ◽  
Tightly Coupled ◽  
Renal Dopamine ◽  
Dissociation Constant Kd ◽  
Stimulation Of

Renal dopamine DA1 receptors are linked to the regulation of sodium transport. We have previously reported the presence of DA1 receptors in the proximal convoluted tubule (PCT) but not in the distal convoluted tubule. However, the DA1 receptor in the collecting duct, the final determinant of electrolyte transport, has not been studied. DA1 receptors were studied in the microdissected cortical collecting duct (CCD) of rats by autoradiography with use of the selective DA1 radioligand 125I-Sch 23982 and by measurement of adenylate cyclase (AC) activity. Specific binding of 125I-Sch 23982 to CCD was saturable with radioligand concentration. The dissociation constant (Kd) was 0.46 +/- 0.08 nM (n = 5), and the maximum receptor density (Bmax) was 1.41 +/- 0.43 fmol/mg protein (n = 5). The DA1 antagonist Sch 23390 was more effective than the DA1 agonist fenoldopam in competing for specific 125I-Sch 23982 binding. Fenoldopam stimulated AC activity in CCD in a concentration-dependent (10(-9)-10(-6) M) manner. The ability of fenoldopam to stimulate AC activity was similar in CCD and PCT even though DA1 receptor density was 1,000 times greater in the CCD than in the PCT. In additional studies, fenoldopam stimulation of AC activity did not influence vasopressin-stimulated AC activity. We conclude that the DA1 receptor in rat CCD is tightly coupled to AC stimulation and that there is no interaction between DA1 agonist-stimulated and vasopressin-stimulated AC activity in the CCD.

Relationship between potency of L-isoprenaline and β-adrenoceptor density estimated in single cells from tracheal smooth muscles of guinea pigs of different ages

1992 ◽  
Vol 70 (4) ◽  
pp. 458-461 ◽  
Author(s):  
Issei Takayanagi ◽  
Mitsutoshi Satoh ◽  
Noriko Kokubu ◽  
Teruko Kato
Keyword(s):  
Guinea Pig ◽  
Guinea Pigs ◽  
Dissociation Constants ◽  
Specific Binding ◽  
Single Cells ◽  
Regression Line ◽  
Smooth Muscles ◽  
Receptor Density ◽  
Age Related ◽  
Β Receptor

An age-related change in potency of L-isoprenaline in the presence of ascorbic acid, desmethylimipramine, corticosterone, pargyline, and phentolamine was obtained in tracheal strips from guinea pigs of differing ages between 6 and 40 weeks. The potency in the strips from 100-week-old guinea pigs did not significantly differ from that in strips from 40-week-old animals. Single cells were prepared from the tracheal muscles of 6-, 10-, 40-, and 100-week-old guinea pigs. The specific binding of [3H]dihydroalprenolol to the single cells was saturable. The dissociation constants of [3H]dihydroalprenolol were in good agreement with those of the membrane fractions from the guinea-pig tracheal muscles, and did not change with age. An excellent relationship between the potency of L-isoprenaline and the maximum binding of [3H]dihydroalprenolol estimated in the preparations from 6- to 40-week-old guinea pigs was found, suggesting that the increase in the potency of L-isoprenaline is due to the increase in the maximum binding or receptor density. The value in the preparations from 100-week-old guinea pigs deviated significantly from the regression line. This suggests the possibility that the decrease in potency in the strips from 100-week-old animals is due to a change in post β-receptor processes in responsiveness.Key words: guinea-pig trachea, single cells, β-receptor density, ageing, dissociation constant.

Specific binding sites for growth hormone in cultured mouse thymic epithelial cells

Life Sciences ◽  
1991 ◽  
Vol 48 (22) ◽  
pp. 2141-2148 ◽  
Author(s):  
Elisabeth Ban ◽  
Marie-Claude Gagnerault ◽  
Hélène Jammes ◽  
Marie-Catherine Postel-Vinay ◽  
France Haour ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Epithelial Cells ◽  
Binding Sites ◽  
Specific Binding ◽  
Thymic Epithelial Cells ◽  
Specific Binding Sites

Receptors for lactogenic hormones in the ovine corpus luteum. III: Inhibition of 125I-labelled human growth hormone binding by a high molecular weight factor in ovine corpus luteum cytosol

1987 ◽  
Vol 114 (3) ◽  
pp. 383-389 ◽  
Author(s):  
T. A. Bramley ◽  
G. S. Menzies ◽  
A. S. McNeilly ◽  
H. G. Friesen
Keyword(s):  
Molecular Weight ◽  
Corpus Luteum ◽  
Metal Ion ◽  
Specific Binding ◽  
Human Growth ◽  
Gel Chromatography ◽  
Hormone Binding ◽  
Cytosol Fraction ◽  
Dose Dependent Fashion ◽  
Ovine Prolactin

ABSTRACT Ovine luteal cytosol fractions inhibited the specific binding of 125I-labelled human GH and ovine prolactin (oPRL) to ovine luteal microsomes in a dose-dependent fashion. Inhibition was dependent on divalent cation concentrations, and was abolished by divalent metal ion chelating agents or by boiling. Inhibition was not due to ionic strength or salt effects on hormone binding, the release of endogenously bound oPRL into the cytosol fraction during tissue disruption and fractionation, or the presence of a soluble (or solubilized) lactogenic receptor in ovine cytosol preparations. Gel chromatography of cytosol fractions gave a molecular weight for the inhibitor of approximately 50 000. J. Endocr. (1987) 114, 383–389

Dependence of tonin activity in rat submaxillary gland on growth hormone and testosterone.

1977 ◽  
Vol 232 (5) ◽  
pp. E522
Author(s):  
M Lis ◽  
R Boucher ◽  
M Chrétien ◽  
J Genest
Keyword(s):  
Growth Hormone ◽  
Angiotensin Ii ◽  
Specific Activity ◽  
Specific Binding ◽  
Combined Treatment ◽  
Submaxillary Gland ◽  
Female Rats ◽  
Male Rats ◽  
Angiotensin I ◽  
Sharp Drop

Tonin, an enzyme present in rat submaxillary gland, converts angiotensin I to angiotensin II and is able to form angiotensin II directly from renin substrates. This enzyme was previously shown to be different from renin, tissue isorenins, and angiotensin I converting enzyme. The specific activity of tonin in rat submaxillary gland increases with the age of the animal and is much higher in male than in female rats; this sex difference is apparent from 60 to 70 days of age. There is a sharp drop of tonin activity in hypophysectomized animals, whereas adrenalectomy, thyroidectomy, and gonadectomy have have little effect. The marked increase in tonin activity was observed in animals bearing MtT-F4 transplantable tumors known to produce ACTH, prolactin, and growth hormone. Tonin specific activity in hypophysectomized male rats is restored to control levels by combined treatment with growth hormone and testosterone. Prolactin alone or in combination with testosterone, as well as transplanted pituitaries, has no effect in hypophysectomized animals. There is a significant specific binding of 125I-labeled growth hormone to isolated membranes of rat submaxillary gland.

Dopamine1 receptors in rat kidneys identified with 125I-Sch 23982

1988 ◽  
Vol 255 (5) ◽  
pp. F970-F976 ◽  
Author(s):  
R. A. Felder ◽  
P. A. Jose
Keyword(s):  
Room Temperature ◽  
Specific Binding ◽  
Rat Kidney ◽  
Sch 23390 ◽  
Receptor Density ◽  
Single Class ◽  
Apparent Dissociation Constant ◽  
High Affinity ◽  
High Affinity Binding Site ◽  
Inhibition Constants

Dopamine1 receptors were studied in rat kidney using the selective dopamine1 antagonist 125I-labeled Sch 23982. The specific binding of 125I-Sch 23982 (defined by 5 microM Sch 23390) to renal cortical homogenates incubated at room temperature was rapid, saturable with time and ligand concentration, and reversible. Analysis of Rosenthal plots revealed a single class of receptors with an apparent dissociation constant of 12.2 +/- 1.9 nM and maximum receptor density of 1.03 +/- 0.15 pmol/mg protein (n = 6). However, competition experiments with the dopamine1 antagonist Sch 23390 revealed a low- and high-affinity binding site with inhibition constants of 1 x 10(-6) and 1 x 10(-8) M, respectively. The competition experiments were also indicative of dopamine1 receptors with stereoselectivity noted for dopamine1 but not for dopamine2 antagonists. The inhibition constants for dopamine1 antagonists and agonists were two orders of magnitude greater in renal cortical than striatal homogenates. Different buffers affected striatal but not renal cortical binding. Autoradiographic studies revealed 125I-Sch 23982 binding in renal cortical but not medullary tissue. These studies confirm the presence of dopamine1 receptors in the cortex of the rat kidney.

PROLACTIN RECEPTORS IN THE MAMMARY GLAND, CORPUS LUTEUM AND OTHER TISSUES OF THE TAMMAR WALLABY, MACROPUS EUGENII

1979 ◽  
Vol 83 (1) ◽  
pp. 79-89 ◽  
Author(s):  
C. SERNIA ◽  
C. H. TYNDALE-BISCOE
Keyword(s):  
Mammary Gland ◽  
Corpus Luteum ◽  
Specific Binding ◽  
Tammar Wallaby ◽  
Binding Activity ◽  
Breeding Cycle ◽  
Macropus Eugenii ◽  
Lactating Mammary Gland ◽  
The Mean ◽  
Ovine Prolactin

SUMMARY Specific binding of radio-iodinated ovine prolactin to subcellular tissue fractions of the tammar wallaby (Macropus eugenii) was investigated. Specific binding was found, in order of decreasing binding activity, in the lactating mammary gland, corpus luteum, corpus albicans, adrenal gland and ovary. Specific binding was absent in kidney, liver, brain and inactive mammary gland. The mean association constant (Ka at 23 °C) was determined as 0·90 × 109, 2·20 × 109, 2·44 × 109, 3·38 × 109 and 10·98 × 1091/mol for mammary gland, adrenal, corpus albicans, corpus luteum and ovary respectively. The mean receptor concentration (N) varied from 92·87 × 10−14 mol/mg protein for the mammary gland to 1·03 × 10−14 mol/mg protein for the ovary. The concentration in the corpus luteum varied between tissue pools collected at different times of the annual breeding cycle. The specificity for prolactin was shown in the mammary gland and corpus luteum by the failure of ovine FSH, LH, GH and TSH to displace 125I-labelled ovine prolactin, whereas it was displaced readily by both ovine and bovine prolactin.

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