Steroid-Protein Binding: from Circulating Blood to Target Cell Nucleus

Szego, Clara M.

doi:10.1159/000301388

Cited by 13 publications

(2 citation statements)

References 67 publications

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“…Both LH and hCG have been shown to promote acute labilization of ovarian lysosomes, with enhanced release of marker enzymes above basal values (16,35,52), as well as delayed increases in numbers of lysosomes (19) and total cellular hydrolases (17,19). Recent experiments have also revealed decreased latency of acid phosphatase and cathepsin B, in lysosome-enriched fractions of preovulatory rat ovaries in response to in vitro addition of LH, whereas post-ovulatory preparations, presumably having released a portion of their lysosomal enzyme complement in response to the endogenous gonadotropin surge, were lower in total enzymes and less sensitive to exogenous LH .3 Similarly, the tachyphylaxis exhibited toward LH by lysosomes of late-proestrous oocytes after GVB may reflect depletion of receptors of the oocyte :follicular cell complex during prior exposure in vivo to preovulatory levels of active hormone.…”

Section: Discussionmentioning

confidence: 99%

Luteinizing hormone-accelerated redistribution of lysosome-like organelles preceding dissolution of the nuclear envelope in rat oocytes maturing in vitro.

Ezzell¹,

Szego²

1979

The Journal of Cell Biology

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Maturation of the mammalian oocyte is characterized in part by dissolution of the nuclear envelope, or germinal vesicle breakdown (GVB) . By fluorescence microscopy after vital uptake of acridine orange (AO), redistribution and perinuclear accumulation of organelles corresponding to lysosomes occur before GVB in rat oocytes undergoing meiotic maturation in vitro . In follicle-enclosed oocytes explanted during the preovulatory gonadotropin surge (GS) and individually cultured as such in chemically defined medium at -22°C, lysosomes aggregated into disperse clusters after 30 min ; by 60 min, perinuclear concentration of lysosomes and their essential disappearance from the cortical ooplasm were observed . GVB occurred within 120 min . In contrast, follicle-enclosed oocytes explanted before the GS displayed a generally homogeneous distribution of lysosomes and an intact GV for up to 5 h in culture .In oocytes aspirated from follicles before the GS, partially denuded of granulosa cells, and cultivated without added hormone, most lysosomes concentrated around the GV within 60 min, with GVB occurring generally by 120 min . Luteinizing hormone (LH) added in vitro to the isolated preparation at 3 or 30 x 10 -8 M sharply accelerated these events . The effects of LH, not seen with 1 .5 x 10-8 M hormone, were blocked by anti-LH IgG . Up to 60 x 10-8 M folliclestimulating hormone or 80 x 10-8 M prolactin were ineffective in accelerating lysosome redistribution or GVB .After GVB, lysosomes became once again uniformly dispersed and unresponsive, even to 60 x 10-8 M added LH, a finding consistent with tachyphylaxis of target cells by independent criteria . The present data, all statistically significant at P < 0 .05, demonstrate that mobilization of lysosomes before GVB is a specific response to factors that promote resumption of meiotic maturation of rat oocytes .KEY WORDS rat oocytes -meiotic maturation -nuclear envelope -luteinizing hormone -lysosome translocation -acridine orange -fluorescence microscopy Maturation of the mammalian oocyte is arrested at the diplotene stage of the first meiotic division . Meiosis resumes before ovulation upon exposure to appropriate hormone levels and proceeds to J. CELL BIOLOGY C The Rockefeller University Press

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Section: Discussionmentioning

confidence: 99%

Luteinizing hormone-accelerated redistribution of lysosome-like organelles preceding dissolution of the nuclear envelope in rat oocytes maturing in vitro.

Ezzell¹,

Szego²

1979

The Journal of Cell Biology

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“…4, 5 but cf. [6][7][8] or in equilibrium between the cytoplasm and nucleus (9). However, results of a variety of studies (10,11) suggested that unoccupied and occupied estrogen receptors (ERs) and progestin receptors (PRs) are present almost exclusively in cell nuclei, and they suggested that the unoccupied receptors typically found in cytosol after cell fractionation and differential centrifugation result from tissue disruption.…”

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confidence: 99%

Colchicine‐lnduced Accumulation of Estrogen Receptor and Progestin Receptor Immunoreactivity in Atypical Areas in Guinea‐Pig Brain

Blaustein

Olster

1993

J Neuroendocrinology

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Using immunocytochemical techniques, cells containing estrogen and progestin receptors have been observed in many discrete regions of the guinea-pig forebrain, including the mediobasal hypothalamus and preoptic area. While most reaction product is located within cell nuclei, we have reported abundant reaction product in perikaryal cytoplasm and neuronal processes as well. Ultrastructural analysis has revealed the presence of estrogen and progestin receptors in atypical subcellular sites within the hypothalamus, including dendrites and axon terminals. In order to determine if microtubule-dependent intracellular transport is involved in intraneuronal transport of steroid hormone receptors, ovariectomized guinea-pigs were injected intracerebroventricularly with the microtubule inhibitor, colchicine, and brain sections at the level of the hypothalamus were immunostained for estrogen receptors. This treatment resulted in the appearance of estrogen receptor immunoreactivity in the paraventricular and mediodorsal thalamic region, areas typically devoid of estrogen receptor-immunoreactive cells in guinea-pigs. In a second study on progestin receptors, we observed the colchicine-induced accumulation of progestin receptor immunoreactivity in the paraventricular thalamic, mediodorsal thalamic and lateral dorsal thalamic areas as well as in the medial amygdala, all areas typically devoid of progestin receptor immunoreactivity. While estradiol injection induced progestin receptor immunoreactivity in the hypothalamus and preoptic area as described previously, it had no effect on the colchicine-induced accumulation in the thalamus and amygdala. These results provide evidence that in some neurons, progestin receptors and estrogen receptors are transported intracellularly, apparently at a rapid enough rate that they do not ordinarily accumulate within the perikaryon.

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Parallels in the Modes of Action of Peptide and Steroid Hormones: Membrane Effects and Cellular Entry

Szego

1978

Structure and Function of the Gonadotropins

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Steroid-Protein Binding: from Circulating Blood to Target Cell Nucleus

Cited by 13 publications

References 67 publications

Luteinizing hormone-accelerated redistribution of lysosome-like organelles preceding dissolution of the nuclear envelope in rat oocytes maturing in vitro.

Luteinizing hormone-accelerated redistribution of lysosome-like organelles preceding dissolution of the nuclear envelope in rat oocytes maturing in vitro.

Colchicine‐lnduced Accumulation of Estrogen Receptor and Progestin Receptor Immunoreactivity in Atypical Areas in Guinea‐Pig Brain

Parallels in the Modes of Action of Peptide and Steroid Hormones: Membrane Effects and Cellular Entry

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