Human Chorionic Gonadotropin increases Chromatin Solubility in Isolated Bovine and Human Luteal Nuclel1

Oechsli, Malgorzata; Rao, Ch.V.; Chegini, Nasser

doi:10.1095/biolreprod41.4.753

Cited by 6 publications

(1 citation statement)

References 25 publications

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“…Whether this apparent perinuclear immunostaining is due to the natural thickness of the cells in the nuclear region and/or intrinsic receptor distribution is not known. However, previous studies have demonstrated that functional LH/hCG receptors are also present in part in the nucleus of the target cells [27][28][29][30][31]. Preabsorption of the receptor antibody with excess corresponding receptor peptide resulted in an absence of immunostaining (Fig.…”

Section: Resultsmentioning

confidence: 98%

Neurons from Fetal Rat Brains Contain Functional Luteinizing Hormone/Chorionic Gonadotropin Receptors1

Al-Hader

Lei

Rao

1997

Biology of Reproduction

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Adult and neonatal rat brains contain functional LH/hCG receptors. These findings have led us to hypothesize that the fetal rat brain may also contain these receptors. To test this hypothesis, we isolated neurons from 19-day-old fetal rat brains and cultured them in chemically defined serum-free medium. The reverse transcription polymerase chain reaction amplified an expected 256-base pair size LH/hCG receptor fragment that could hybridize with a full-length LH/hCG receptor cDNA in Southern blotting. Northern blotting demonstrated that neurons contained a major 2.6 kilobase (kb) and a minor 4.3 kb transcript. Immunocytochemistry demonstrated that the neurons contained LH/hCG receptor immunostaining. Western immunoblotting showed that neurons contained an 80-kDa receptor protein that increased to a maximal level on Day 3 of culture and then gradually decreased until the 9th day of culture. Culturing neurons for 3 days in the presence of highly purified hCG resulted in a dose-dependent increase in the outgrowth of neurite processes and total cellular protein and a decrease in DNA fragmentation as compared to values in the corresponding controls. At the maximally effective hCG concentration, the number of neurite-bearing cells was increased by 53% and the total cellular protein by 60%, and DNA fragmentation decreased by 31%. In summary, this is the first study to demonstrate the presence of LH/hCG receptors and neurotrophic effects of hCG in fetal rat brain neurons. These findings imply that locally produced gonadotropins may possibly play a role in the growth and development of the fetal brain.

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Section: Resultsmentioning

confidence: 98%

Neurons from Fetal Rat Brains Contain Functional Luteinizing Hormone/Chorionic Gonadotropin Receptors1

Al-Hader

Lei

Rao

1997

Biology of Reproduction

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Nuclear volume and chromatin conformation of small and large bovine luteal cells: effect of gonadotropins and prostaglandins and dependence on luteal phase

1991

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Change in nuclear volume and chromatin conformation are generally considered to reflect altered gene expression in eukaryotic cells. The present studies were undertaken to investigate whether these nuclear parameters of luteal cells can be altered by hormone treatment in vitro or change during the estrous cycle. The nuclear volume of small luteal cells was significantly lower than that of large luteal cells during the cycle and pregnancy. The nuclear volumes of small and large luteal cells from pregnancy did not change during incubation without any hormone or with 10 nM prostaglandin (PG)F 2 alpha. However, incubation with 1 nM human chorionic gonadotropin (hCG) or 10 nM PGE1 resulted in a significant increase of nuclear volume of small luteal cells by 4 h and that of large luteal cells by 6 h. Small luteal cells were more responsive to hCG than large luteal cells. The nuclear volumes of small and large luteal cells also significantly increased from early to mid luteal phase with no further change in late luteal phase. hCG and PGE1, as well as PGF2 alpha, treatment resulted in a change of chromatin conformation of small and large luteal cells. Dibutyryl cyclic AMP (10 mM) mimicked the hormones by increasing nuclear volumes and changing the chromatin conformation of small and large luteal cells. Chromatin conformation of small and large luteal cells also changed from early to mid luteal phase and mid to late luteal phase. In conclusion, in vitro, hCG and PGs can regulate nuclear volume and/or chromatin conformation of small as well as large bovine luteal cells.(ABSTRACT TRUNCATED AT 250 WORDS)

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Role of luteal cell nucleus in the expression of gonadotropin action

Bibbins

Rao

Carman

et al. 1991

J Endocrinol Invest

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Gonadotropin receptors are not only present in cell membranes, but also in nuclei of bovine and human luteal cells. hCG/hLH can directly regulate several nuclear functions. To further investigate the role of luteal cell nucleus in the expression of gonadotropin action, the effect of enucleation of luteal cells on gonadotropin receptors and gonadotropin response was studied. Luteal cytoplasts were prepared by colchicine treatment of purified whole luteal cells followed by centrifugation at 37 C in a Percoll gradient. The cytoplasts were 85 to 90% pure with a recovery of about 57%. Cytoplasts were viable as determined by trypan blue exclusion (87%) and metabolically competent as determined by 3H-leucine incorporation into proteins. On the day of preparation, the viability and metabolic competency of cytoplasts were similar to control cells, i.e. untreated and colchicine treated whole luteal cells. In addition, cytoplasts and control cells showed a similar decline in number and viability during storage at 4 C. While control cells continue to be metabolically competent, cytoplasts showed a dramatic decline by 48 h of storage at 4 C. Neither the cytoplasts nor control cells degraded 125I-hCG. The kinetics of 125I-hCG association and dissociation, specificity and affinity of binding to cytoplasts were similar to control cells. However, the number of available gonadotropin receptors in cytoplasts was significantly lower than in control cells. Cytoplasts contained lower progesterone levels and more importantly, they could not be stimulated by 10 nM hCG or 10 mM dibutyryl cyclic AMP to produce more progesterone. Controls cells, on the other hand, contained higher progesterone levels and responded to hCG and dibutyryl cyclic AMP stimulation. In summary, removal of nuclei from luteal cells results in a partial loss of gonadotropin receptors and complete loss of steroidogenic response to hCG and dibutyryl cyclic AMP.(ABSTRACT TRUNCATED AT 250 WORDS)

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Human Chorionic Gonadotropin increases Chromatin Solubility in Isolated Bovine and Human Luteal Nuclel1

Cited by 6 publications

References 25 publications

Neurons from Fetal Rat Brains Contain Functional Luteinizing Hormone/Chorionic Gonadotropin Receptors1

Neurons from Fetal Rat Brains Contain Functional Luteinizing Hormone/Chorionic Gonadotropin Receptors1

Nuclear volume and chromatin conformation of small and large bovine luteal cells: effect of gonadotropins and prostaglandins and dependence on luteal phase

Role of luteal cell nucleus in the expression of gonadotropin action

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