Gonadotropin Receptors in Rat Ovarian Tissue. II. Subcellular Localization of LH Binding Sites by Electron Microscopic Radioautography<sup>1</sup>

Han, Seong S.; Rajaniemi, Hannu; Cho, Moon I.; Hirshfield, Anne N.; Midgley, A. Rees

doi:10.1210/endo-95-2-589

Cited by 60 publications

(13 citation statements)

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“…However, their observations could not be confirmed by following the distribution of radioactivity and subcellular organelles by sucrose-gradient centrifugation since a good separation was not achieved between the plasma membrane and lysosomal fractions [29]. A similar mechanism was also proposed to explain the interaction of epidermal growth factor with cultured human fibroblasts [30].…”

Section: Discussionmentioning

confidence: 98%

Intracellular uptake and catabolism of lutropin by testicular tissue in vivo

Ascoli

Puett

1977

FEBS Letters

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Section: Discussionmentioning

confidence: 98%

Intracellular uptake and catabolism of lutropin by testicular tissue in vivo

Ascoli

Puett

1977

FEBS Letters

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“…Highly purified hCG 12,800 international units (IU)/mg], rat FSH, and pregnant mare serum gonadotropin were kindly provided by the National Institutes of Health (Bethesda, MD). Goat anti-rabbit IgG conjugated to fluorescein was obtained from Hyland (Costa Mesa, CA).…”

Section: Introductionmentioning

confidence: 99%

“…Hertz and Hisaw demonstrated (11) that pituitary extracts, containing gonadotropic hormones such as follitropin (follicle-stimulating hormone; FSH), play an important role in the regulation of ovarian development. It is now known that gonadotropic hormones have receptors on the plasma membrane of ovarian target cells (12) and that they exert their effect via activation of a hormone-sensitive adenylate cyclase (13,14).…”

mentioning

confidence: 99%

Aggregation of luteinizing hormone receptors in granulosa cells: a possible mechanism of desensitization to the hormone.

Amsterdam¹,

Berkowitz²,

Nimrod³

et al. 1980

Proc. Natl. Acad. Sci. U.S.A.

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The temporal relationship between redistribution of receptors to lutropin (luteinizing hormone)/human chorionic gonadotropin in cultured rat ovarian granulosa cells and the cellular response to hormonal challenge were studied. Visualization of receptor-bound human chorionic gonadotropin by indirect immunofluorescence, with hormone-specific antibodies after fixation with 2% formaldehyde, revealed the existence of small clusters around the entire cell circumference 5-20 min after exposure to the hormone at 370C. Such small receptor aggregates were also evident if hormone incubation was at 40C or if cells were fixed with 2% formaldehyde before incubation. Larger clusters were evident after prolonged incubation with the hormone (2-4 hr) at 370C. The later change coincided with diminished cyclic AMP accumulation in response to challenge with fresh hormone. When the fixation step was omitted and antibodies to human chorionic gonadotropin were applied after hormonal binding, acceleration of both receptor clustering and the desensitization process was observed. This maneuver also induced capping of the hormone receptors. In contrast, monovalent Fab' fragments of the antibodies were without effect. Internalization of the bound hormone in lysosomes, and subsequent degradation, was evident 8 hr after hormonal application and was not accelerated by the antibodies. It is suggested that clustering of the luteinizing hormone receptors may play a role in cellular responsiveness to the hormone. Massive aggregation of the receptors may desensitize the cell by interfering with coupling to adenylate cyclase.Since the observation by Frye and Edidin (1) of lateral mobility of membrane proteins, movement and clustering have been demonstrated for receptors to immunoglobulins (2) and lectins (3) as well as receptors to hormones and neurotransmitters (4-7). Moreover, it was recently suggested that receptors associated with the plasma membrane can be internalized after binding specific ligands (8-10). However, the biological significance of such a receptor redistribution is not fully understood.Hertz and Hisaw demonstrated (11) that pituitary extracts, containing gonadotropic hormones such as follitropin (follicle-stimulating hormone; FSH), play an important role in the regulation of ovarian development. It is now known that gonadotropic hormones have receptors on the plasma membrane of ovarian target cells (12) and that they exert their effect via activation of a hormone-sensitive adenylate cyclase (13,14).Prolonged exposure of ovarian tissue to lutropin (luteinizing hormone; LH) or human chorionic gonadotropin (hCG), which bind to the same receptor, causes prompt stimulation of adenylate cyclase followed by desensitization of the enzyme to renewed challenge with the hormone in vmvo and in vitro (13-16). A similar phenomenon was also described in other systems where hormones exert their effects via activation of adenylate cyclase (17, 18). The mechanism responsible for this refractoriness is not clear. Several explanations have b...

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“…From measurements in vitro of the affinity and the concentration of insulin receptors on liver cells, heart muscle, lymphocytes, adipocytes, and other tissues, we estimate that in vivo about one-half of the extrapancreatic hormone is actually bound to receptors2'3 ' The receptor for luteinizing hormone and human chorionic gonadotropin in ovaries has been extensively studied by both in vivo and in vitro procedures (5)(6)(7). 2 For our calculations, the hepatocyte has a volume of _ 1.2 x 104 ,um3 and has 2.3 x 105 surface insulin receptors per cell (11).…”

Section: Introductionmentioning

confidence: 99%

Demonstration of the insulin receptor in vivo in rabbits and its possible role as a reservoir for the plasma hormone.

Zeleznik¹,

Roth²

1978

J. Clin. Invest.

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A B S T R A C T Based on studies of the interaction of' insulin with its receptors in vitro, we calculated that a receptor compartment should be measurable directly in vivo. For this purpose, rabbits were injected intravenously with a labeled insulin that has low affinity for receptors in combination with a radioiodinated insulin that has high affinity for receptors. Plasma concentrations of labeled insulins were measured at selected intervals after injection. Apparent volumes of distribution were calculated by extrapolation of plasma disappearance curves; high affinity insulins consistently distributed into spaces that were two-three times greater than those of the low affinity insulins.Injections of unlabeled pork insulin before tracer insulins decreased the distribution space of the high affinity insulin in a dose-dependent manner while having little or no effect on the distribution space of the low affinity labeled insulin. When unlabeled insulin was injected after the tracer insulins, there was an immediate rise in the plasma concentration of the high affinity insulin with only a slight change in the plasma concentration of the low affinity insulin.These results demonstrate that high affinity insulins distribute into a body compartment which has many properties of the insulin receptor previously studied in vitro. This receptor compartment: (a) recognizes insulins based on their biological potencies; (b) is saturated by elevated concentrations of insulin; and (c) instulin bound to receptors is in equilibrium with free hormone in plasma. Further, the bound to free ratios for hormone, calculated from these data, suggest that in vivo >50% of the extrapancreatic insulin is bound to receptors during normal physiological states.

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Gonadotropin Receptors in Rat Ovarian Tissue. II. Subcellular Localization of LH Binding Sites by Electron Microscopic Radioautography¹

Cited by 60 publications

References 0 publications

Intracellular uptake and catabolism of lutropin by testicular tissue in vivo

Intracellular uptake and catabolism of lutropin by testicular tissue in vivo

Aggregation of luteinizing hormone receptors in granulosa cells: a possible mechanism of desensitization to the hormone.

Demonstration of the insulin receptor in vivo in rabbits and its possible role as a reservoir for the plasma hormone.

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Gonadotropin Receptors in Rat Ovarian Tissue. II. Subcellular Localization of LH Binding Sites by Electron Microscopic Radioautography1

Cited by 60 publications

References 0 publications

Intracellular uptake and catabolism of lutropin by testicular tissue in vivo

Intracellular uptake and catabolism of lutropin by testicular tissue in vivo

Aggregation of luteinizing hormone receptors in granulosa cells: a possible mechanism of desensitization to the hormone.

Demonstration of the insulin receptor in vivo in rabbits and its possible role as a reservoir for the plasma hormone.

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Gonadotropin Receptors in Rat Ovarian Tissue. II. Subcellular Localization of LH Binding Sites by Electron Microscopic Radioautography¹