Lindane-induced modifications to membrane lipid structure: Effect on membrane fluidity after subchronic treament

1992 ◽  
Vol 12 (4) ◽  
pp. 303-311 ◽  
Author(s):  
M. T. Gutierrez-Ocaña ◽  
S. Senar ◽  
M. A. Perez-Albarsanz ◽  
M. N. Recio

Chronic lindane intoxication by injecting subcutaneously the toxicant, resulted in an altered lipid pattern in rat ventral prostate membranes. An increase of membrane fluidity was also observed using a fluorescence polarization technique. When in vitro experiments were carried out with both treated and untreated rats, an interesting lack of parallelism was found, which could indicate the development of a resistance to membrane disordering by lindane. The observed changes in cholesterol and phospholipid composition are also consistent with the hypothesis that lindane perturbs the lipid matrix of membranes, possibly inducing complex compensatory changes in the membrane lipid composition.

1970 ◽  
Vol 65 (3) ◽  
pp. 517-524 ◽  
Author(s):  
Olav Unhjem

ABSTRACT The ability of various steroids and metabolic inhibitors to influence the binding of androgen to soluble macromolecules in the rat ventral prostate was evaluated in vitro. The results obtained revealed some structural requirements of steroids for binding to the macromolecules. An androstane skeleton with the α-configuration of the hydrogen atom at position 5 seemed to be essential for binding as well as a keto group at position 3. N-ethylmaleimide, Na-iodoacetate and p-hydroxymercuribenzoate inhibited the binding of androgen to macromolecules. The androgen-macromolecular complexes appeared to be rather stable at temperatures below 5°C.


1970 ◽  
Vol 17 (6) ◽  
pp. 453-458 ◽  
Author(s):  
JUN SHIMAZAKI ◽  
JIN SATO ◽  
HISAKO NAGAI ◽  
KEIZO SHIDA

In Vitro ◽  
1984 ◽  
Vol 20 (3) ◽  
pp. 216-228 ◽  
Author(s):  
Frederick B. Merk ◽  
Paul W. L. Kwan ◽  
Stanley Spilman ◽  
Louis Terracio ◽  
William H. J. Douglas

1990 ◽  
Vol 10 (3) ◽  
pp. 263-270 ◽  
Author(s):  
J. Pascal Zimmer ◽  
Hans A. Lehr ◽  
Christoph Hübner ◽  
Stephan G. Lindner ◽  
Ralf Ramsperger ◽  
...  

Although most non-human primates, except the chimpanzee and the gibbon in vivo are not infectible by HIV-1, lymphocytes of several of these species can be infected by HIV-1 in vitro.In order to investigate whether the in vitro infectibility of primate lymphocytes might be attributed to plasma membrane adaptation processes or to serum factors, we compared HIV-1 infectibility of cultivated peripheral blood lymphocytes of macaques and of baboons on day one and on day ten of cultivation. These data were correlated to plasma membrane lipid composition and membrane fluidity.We found a correlation between increased HIV-1 in vitro infectibility and changes in plasma membrane lipid composition resulting in decreased membrane fluidity of cultured primate lymphocytes.


Author(s):  
Paula Piccolo Maitan ◽  
Elizabeth G. Bromfield ◽  
Romy Hoogendijk ◽  
Miguel Ricardo Leung ◽  
Tzviya Zeev-Ben-Mordehai ◽  
...  

Classical in vitro fertilization (IVF) is still poorly successful in horses. This lack of success is thought to be due primarily to inadequate capacitation of stallion spermatozoa under in vitro conditions. In species in which IVF is successful, bicarbonate, calcium, and albumin are considered the key components that enable a gradual reorganization of the sperm plasma membrane that allows the spermatozoa to undergo an acrosome reaction and fertilize the oocyte. The aim of this work was to comprehensively examine contributors to stallion sperm capacitation by investigating bicarbonate-induced membrane remodelling steps, and elucidating the contribution of cAMP signalling to these events. In the presence of capacitating media containing bicarbonate, a significant increase in plasma membrane fluidity was readily detected using merocyanine 540 staining in the majority of viable spermatozoa within 15 min of bicarbonate exposure. Specific inhibition of soluble adenylyl cyclase (sAC) in the presence of bicarbonate by LRE1 significantly reduced the number of viable sperm with high membrane fluidity. This suggests a vital role for sAC-mediated cAMP production in the regulation of membrane fluidity. Cryo-electron tomography of viable cells with high membrane fluidity revealed a range of membrane remodelling intermediates, including destabilized membranes and zones with close apposition of the plasma membrane and the outer acrosomal membrane. However, lipidomic analysis of equivalent viable spermatozoa with high membrane fluidity demonstrated that this phenomenon was neither accompanied by a gross change in the phospholipid composition of stallion sperm membranes nor detectable sterol efflux (p > 0.05). After an early increase in membrane fluidity, a significant and cAMP-dependent increase in viable sperm with phosphatidylserine (PS), but not phosphatidylethanolamine (PE) exposure was noted. While the events observed partly resemble findings from the in vitro capacitation of sperm from other mammalian species, the lack of cholesterol removal appears to be an equine-specific phenomenon. This research will assist in the development of a defined medium for the capacitation of stallion sperm and will facilitate progress toward a functional IVF protocol for horse gametes.


1970 ◽  
Vol 63 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Olav Unhjem

ABSTRACT Following incubation of rat ventral prostate slices with [1,2-3H]testosterone in vitro, radioactive material is found to be associated with the nuclei. Sodium chloride extraction of the nuclei removes macromolecules which might at least partially be responsible for this association. These macromolecules are probably components of the nuclear chromatin. Analyses of the radioactive material indicate that the major portion consists of dihydrotestosterone* and to a lesser extent of testosterone. All the radioactive material is linked non-covalently to the nuclear components responsible for the association.


2001 ◽  
Vol 26 (3) ◽  
pp. 175-184 ◽  
Author(s):  
D Marcantonio ◽  
LE Chalifour ◽  
MA Alaoui-Jamali And H T Huynh ◽  
MA Alaoui-Jamali ◽  
MA Alaoui-Jamali ◽  
...  

Steroid-sensitive gene-1 (SSG1) is a novel gene we cloned, found regulated by 17beta-estradiol in the rat uterus and mammary gland, and over-expressed in 7,12-dimethylbenz(a)anthracene-induced rat mammary tumors. We show here that SSG1 mRNA and protein expression are regulated by androgens in the rat ventral prostate. Increases in SSG1 mRNA levels were detected by Northern blotting after 24 h and reached a 27-fold peak 96 h following castration, relative to SSG1 mRNA expression in sham-operated rats. Dihydrotestosterone or testosterone supplementation of castrated rats prevented this rise in SSG1 mRNA. In contrast with SSG1 mRNA expression, SSG1 protein was decreased 16-fold 2 weeks following castration but was at control levels in the prostates of castrated rats receiving dihydrotestosterone or testosterone. Although SSG1 is regulated by androgens in vivo, treatment of LnCap cells with dihydrotestosterone, cyproterone acetate or flutamide did not result in the regulation of SSG1 protein levels in vitro. Immunofluorescence studies show that SSG1 is mainly expressed in prostatic smooth muscle cells. These results indicate that SSG1 is an androgen-regulated gene that is expressed in the smooth muscle component of the rat ventral prostate in vivo.


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