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Differences in the lateral mobility of receptors for luteinizing hormone in the luteal cell plasma membrane when occupied by ovine luteinizing hormone vs. human chorionic gonadotropin


, : Differences in the lateral mobility of receptors for luteinizing hormone in the luteal cell plasma membrane when occupied by ovine luteinizing hormone vs. human chorionic gonadotropin. Endocrinology 116(1): 164-169

Receptors for LH [luteinizing hormone] are internalized by ovine luteal cells 50 times slower when occupied by hCG [human chorionic gonadotropin] than when occupied by ovine LH (oLH). To determine if differences in the rate of internalization were due to differences in the lateral mobility of the hormone-receptor complexes in the cell membrane, the diffusion coefficients of oLH- and hCG-LH receptors complexes were measured using fluorescence photobleaching recovery methods. Tetramethylrhodamine isothiocyanate (TRITC)-labeled oLH and hCG, which retained full ability to bind to receptor, were bound to LH receptors on enzymatically dispersed ovine luteal cells. Molecules labeled with TRITC within a 3-.mu.m2 region of the cell surface were bleached by a 500-ms pulse of 3 mW laser light at a wavelength of 514.5 nm. The laser beam intensity was then attentuated 20,000-fold; fluorescence from the bleached area was measured by single photon counting as unbleached fluorescent hormone-receptor complexes diffused into the region. Data were analyzed on-line by a NOVA 3/12 computer. The oLH-LH receptor complex had a diffusion coefficient of 1.9 .+-. 1.0 .times. 10-10 cm2/s-1, a value comparable to that of cell surface proteins nonspecifically labeled with succinylated concanavalin A. Fluorescence recovery after photobleaching was 35%. hCG-LH receptor complexes were immobile on the time scale of the experiment, implying that the diffusion coefficient was substantially < 1 .times. 10-11 cm2/s-1. Deglycosylated hCG-TRITC bound to LH receptor had a diffusion coefficient (1.1 .+-. 0.1 .times. 10-10 cm2/s-1) similar to that of receptors occupied by oLH. The carbohydrate portion of the hCG molecule apparently plays a role in decreasing the mobility of the receptor for LH. Apparently the rate of lateral movement of the LH receptor in the plasma membrane of luteal cells appears to be modulated by the nature of the bound hormone.


Accession: 005151356

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Related references

Niswender, G.D.; Roess, D.A.; Sawyer, H.R.; Silvia, W.J.; Barisas, B.G., 1985: Differences in the lateral mobility of receptors for luteinizing hormone (LH) in the luteal cell plasma membrane when occupied by ovine LH versus human chorionic gonadotropin. Receptors for LH are internalized by ovine luteal cells 50 times slower when occupied by hCG than when occupied by ovine LH (oLH). To determine if differences in the rate of internalization were due to differences in the lateral mobility of the ho...

Roess, D.A.; Niswender, G.D.; Barisas, B.G., 1988: Cytochalasins and colchicine increase the lateral mobility of human chorionic gonadotropin-occupied luteinizing hormone receptors on ovine luteal cells. To determine whether cytoskeletal proteins restrict the mobility of LH-receptor complexes occupied by hCG, we measured the rate of lateral diffusion and the fraction of mobile receptor-hormone complexes by fluorescence photobleaching recovery on l...

Huhtaniemi I.T.; Catt K.J., 1981: Differential binding affinities of rat testis luteinizing hormone receptors for human chorionic gonadotropin human luteinizing hormone and ovine luteinizing hormone. Specific binding of hCG [human chorionic gonadotropin], luteinizing hormone (hLH) and ovine [O] LH to LH receptors was analyzed in rat testis homogenate. Equilibration studies with each of the gonadotropins indicated that the 3 hormones bind to a...

Dattatreyamurty, B.; Sheth, A.R.; Purandare, T.V.; Rao, S.S., 1976: Nature of cross reaction between human chorionic gonadotropin and anti ovine luteinizing hormone serum and development of a radio immunoassay to measure human luteinizing hormone specifically in the presence of human chorionic gonadotropin. Immunological cross-reaction between hCG [human chorionic gonadotropin] and anti-oLH [ovine luteinizing hormone] sera was demonstrated using radioimmunoassay techniques. This cross-reaction is incomplete, and the anti-oLH sera used have the abilit...

Jahnsen T.; Purvis K.; Torjesen P.A.; Hansson V., 1981: Temporal relationship between human chorionic gonadotropin induced de sensitization of luteinizing hormone human chorionic gonadotropin responsive adenylate cyclase and down regulation of luteinizing hormone human chorionic gonadotropin receptors in the rat testis. A single s.c. injection of 75 IU of human chorionic gonadotropin (hCG) into adult male rats caused a transient desensitization of the LH[luteinizing hormone, lutropin]/hCG responsive adenylate cyclase (AC) in membrane particles from rat testis. Tw...

Mock, E.J.; Niswender, G.D., 1983: Differences in the rates of internalization of 125I-labeled human chorionic gonadotropin, luteinizing hormone, and epidermal growth factor by ovine luteal cells. The rate of internalization and degradation of radioiodinated hCG, ovine LH (oLH), human LH (hLH), and mouse epidermal growth factor (mEGF) was studied in suspensions of ovine luteal cells. Hormone bound to the plasma membrane was quantified by tr...

Mock E.J.; Niswender G.D., 1983: Differences in the rates of internalization of iodine 125 labeled human chorionic gonadotropin luteinizing hormone and epidermal growth factor by ovine luteal cells. The rate of internalization and degradation of radioiodinated hCG [human chorionic gonadotropin], ovine LH [luteinizing hormone] (oLH), human LH (hLH) and mouse epidermal growth factor (mEGF) was studied in suspensions of ovine luteal cells. Hormo...

Pandian, M.; Bahl, O., 1977: Labeling of bovine corpus luteal plasma membrane human chorionic gonadotropin or luteinizing hormone (hCG. Archives of biochemistry and biophysics: 182 (2) 420-436

Roess D.A.; Barisas B.G.; Niswender G.D., 1986: Lateral diffusion of occupied and unoccupied receptor for luteinizing hormone on ovine luteal cell membranes. Biology of Reproduction 34(SUPPL 1): 138

Bourdage, R.J.; Fitz, T.A.; Niswender, G.D., 1984: Differential steroidogenic responses of ovine luteal cells to ovine luteinizing hormone and human chorionic gonadotropin. Experiments were conducted in vitro on ovine small luteal cells to evaluate their steroidogenic response to ovine luteinizing hormone (oLH) and human chorionic gonadotropin (hCG) administered continuously throughout the experimental period or as a...