Hervé Degrelle

Y chromosome and aggression in strains of laboratory mice.

Intermale attack behavior differences in laboratory strains of inbred mice have Y chromosome correlates in a small number of strain comparisons. Moreover, the Y correlates interact with autosomal or pseudoautosomal genes. Recent data on the genetics of the Y do not contradict these conclusions. The discovery of several polymorphic loci of the Y could pave the way for a direct confirmation of Y correlates of attack behavior by linkage detection. The involvement of the Y in this behavior has been put forward. Plasmatic testosterone concentration reactivity of some target organs to exogeneous testosterone appears to be correlated with two independent loci of the Y acting in an additive or interactive manner with autosomal or pseudoautosomal loci. However, the association between testosterone action and attack behavior in males needs further evidence, and in any case this association does not underline linear mechanisms.

Genetic Correlation Between Steroid Sulfatase Concentration and Initiation of Attack Behavior in Mice

The pairing region of the X–Y chromosomes recombines at male meiosis. We previously found that offense behavior in male mice, measured by initiation of attack against a conspecific male, was linked to this region. Only one functional gene (coding for steroid sulfatase or Sts) is mapped on this region as of yet, suggesting that it could be a candidate for offense behavior. We estimated the genetic correlation between the concentration of STS protein in the liver and the initiation of attack behavior in 11 strains of inbred mice. The high correlation (close to reliability) coefficient of the behavioral phenotype indicates the implication of STS in offense behavior. Recent investigations have demonstrated the involvement of STS in neurosteroid biochemical pathways, and several lines of evidence indicate that neurosteroids interact with neurotransmitters. These conclusions and our present results support the hypothesis that sulfatation of steroids may be the prime mover of a complex network, including genes shown to be implicated in aggression by mutagenesis.

Linkage between brain serotonin concentration and the sex-specific part of the Y-chromosome in mice

The implication of the sex-specific part of the Y-chromosome (YS-SP) on brain serotonin (5-HT) level was investigated using congenic strains for this chromosomal region. The 5-HT level, which was higher in the NZB than in the CBA/H strain of mice, was depleted by the transfer of the YS-SP from NZB on CBA/H whereas the transfer of the YS-SP from CBA/H on NZB had no effect. The variations of 5-HT levels were not correlated with plasma testosterone concentration which is also dependent of the YS-SP.

Opponent strain effect on eliciting attacks in NZB mice: Physiological correlates

In agonistic encounters between male mice, the characteristics of the opponent may influence the attacking behavior of its partner. The present study shows that the opponents ability to elicit attacking behavior in NZB males is strain dependent. BALB/c opponents elicit attacks more frequently, earlier and more intensively than C57BL/6 males. Plasma testosterone concentration was found to be higher in BALB/c than in C57BL/6 intact males. The weight of seminal vesicles in castrated males of both strains increased with injections of either 10- or 250-micrograms testosterone propionate (TP). This response was greater in BALB/c with the higher TP dose. The submandibular glands reacted to TP only in castrated BALB/c males with the higher dose. Furthermore, BALB/c males produced more marking secretions than C57BL/6 males. These results suggest that for these two strains, a higher testosterone sensitivity and a greater production of secretions are associated with a higher probability of opponents to elicit attacks. Genetic hypotheses on the underlying mechanisms are discussed.

Murine steroid sulfatase (mSTS): Purification, characterization and measurement by ELISA

The murine steroid sulfatase (mSTS) is a microsomal enzyme, important in steroid metabolism. In the mouse, the gene encoding mSTS is pseudoautosomal and thus escapes X-inactivation. We have purified steroid sulfatase approximately 30-fold from mouse liver microsomes and its properties have been investigated. The major steps in the purification procedure included solubilization with Triton X-100, gel filtration chromatography, DEAE-Sephadex chromatography and HPLC gel filtration chromatography. The purified sulfatase showed a relative molecular weight of 128 kDa on HPLC gel filtration, whereas the enzyme migrated as two bands of 60 and 68 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point of steroid sulfatase was estimated to be 6.2 by column chromatofocusing. Polyclonal antibodies to the purified protein were prepared. An Enzyme Linked Immunosorbent Assay (ELISA) was developed using purified monospecific anti-mSTS antibodies labelled with peroxidase. The standard criteria of precision and reproducibility were satisfied. The assay was applicable to routine determination of mSTS samples in research laboratories. Differences in mSTS liver concentrations were used to identify putative alleles for the mSTS gene (Sts). Results in ELISA confirmed the polymorphism previously demonstrated for an enzymatic mSTS activity assay in two inbred mouse strains.

Hormone-associated variation of the glycan microheterogeneity pattern of human sex steroid-binding protein (hSBP)

hSBP is a steroid-binding protein (human) whose serum concentration is increased by estrogens and decreased by androgens. This regulation is independent of a direct effect on the hSBP gene transcription. The purpose of this work was to study the glycan microheterogeneous composition of the mature protein under physiological estrogen stimulation, by means of crossed affinoimmunoelectrophoresis using concanavalin-A. In men hSBP always divided into 2 fractions, both retarded. In women hSBP showed two other components, still more retarded. An explanation for these differences is given and the role of the glycan moiety of hSBP is discussed.

Sex steroid-binding protein: Identification and comparison of the primary product following cell-free translation of human and monkey (Macaca fascicularis) liver RNA

A very close similarity in molecular, steroid-binding and immunological properties have been demonstrated for the sex steroid-binding proteins of plasma from human (hSBP) and monkey (mSBP): both are glycoproteins composed of two similar subunits able to bind one steroid molecule and to cross-react with the same antibodies. After translation of human and monkey (Macaca fascicularis) liver mRNAs by a wheat-germ embryo extract, in the presence of labelled amino-acids, we have characterized in both cases a single radioactive polypeptide immunologically related to SBP, migrating in SDS-PAGE as a single band and having a molecular weight of about 42,000. This protein could be displaced from the antibody by pure unlabelled SBP in excess. The difference in molecular weight between the in vitro translation product and the native SBP sub-unit is probably due to the absence of glycosylation in the neo-synthesized protein. The radioactivity incorporated into mSBP was 4 times higher than the radioactivity incorporated into hSBP, suggesting that the amount of mRNA for SBP is higher in monkey than in human liver. Our results show that the two sub-units of hSBP and mSBP derive from a common precursor, representing respectively 0.0050% and 0.0013% of the total neosynthesized proteins in monkey and in human liver.

Ultradian, Circadian and Seasonal Variations of Plasma Progesterone and Lh Concentrations During the Luteal Phase

The circadian variations in plasma progesterone (P) and LH concentrations were investigated in six women, aged 23-40 years. All were studied in the mid-luteal phase (7 +/- 2 days after LH mid-cycle surge). Experiments were conducted in autumn and in spring. Blood samples were obtained every 15 min for 24 hr. Plasma P and LH concentrations were measured by RIA. Each subjects time-series was analysed using three methods; visual inspection (chronogram), spectral analysis to estimate component periods of rhythms (tau) and cosinor analysis to quantify the rhythms parameters. Marked temporal variations in plasma P concentration were observed in each subject. The maximal variations over a 24-hr period, ranged between 13-58.5 mmol/l. Differences related to sampling time were statistically validated by ANOVA (p less than 0.00001). Significant harmonic periods were detected by spectral analysis but differed among subjects. In all subjects but one, a circadian rhythm was detected. The acrophase location was similar (about 0700 hr) in the four subjects studied in autumn, but ranged from 1940 to 0320 hr in those studied in spring. An ultradian rhythm with tau = 8 hr was also validated in six time-series with similar acrophases (about 0200, 1000, and 1800 hr). Cosinor analysis of pooled data revealed that the 24-hr, 12-hr, and 8-hr rhythms were statistically significant (p = 0.001) in autumn. algebraic sum of these three cosine functions yielded a circadian waveform with peak-times occurring near 0300 and 1130 hr and a trough-time about 2200 hr. In spring, the circadian pattern appeared quite different, and peak-times were found near 0700 and 2000 hr, and trough-times near 0300 and 1500 hr. Furthermore, the 24-hr mean of P was higher in autumn (28.9 +/- 0.4 nmol/l) than in spring (17.2 +/- 0.4 nmol/l), p from ANOVA less than 0.00001. The evidence for a similar circadian LH pattern is not as strong. Seasonal, circadian and ultradian rhythms characterize the physiologic time structure of plasma P concentration in mid-luteal phase.

Regulation of plasma corticosteroid-binding globulin in adult cynomolgus monkey (Macaca fascicularis) during different reproductive states

The plasma concentration of the corticosteroid-binding globulin (mCBG) has been measured in Macaca fascicularis, during different stages of reproduction and under hormonal treatments. The mCBG level was determined by a specific electroimmunoassay. There was no difference between females in the follicular phase and intact males; mCBG concentrations were respectively (mean +/- SEM) 469 +/- 53 and 443 +/- 25.6 nmol/l. The mCBG levels levels were similar during both the luteal (469 +/- 33.5 nmol/l) and the follicular phase (469 +/- 53 nmol/l). Compared to intact males, the mCBG levels were higher (P less than 0.05) in castrated males (527 +/- 6.6 nmol/l). During gestation, no systematic variations were found and the mCBG levels were not statistically different from the values found during the follicular phase. When estradiol benzoate was administered to castrated animals, the mCBG concentrations increased rapidly. In contrast, the values were reduced slightly by testosterone treatment. The sex-steroid action on the mCBG levels was discussed and compared with the mSBP levels. We question also, the mechanisms involved in the regulation of the mCBG levels during pregnancy.

Identification of the primary translation product of the sex steroid-binding protein from monkey liver mRNA in a cell-free system.

The synthesis of monkey (Macaca fascicularis) Sex steroid-Binding Protein (mSBP) in a wheat germ cell-free system in response to liver RNA was demonstrated by use of a specific antiserum raised against purified native human SBP. Antibodies precipitate a single translation product behaving as a 42 kDa protein in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Western blots of monkey sera subjected to SDS-PAGE and immunorevelation show that the native mSBP migrates as 2 molecular species (50 and 53 kDa) present in the approximate ratio of 1:10, respectively. The difference in apparent molecular weights of the primary translation product and the reduced mature mSBP may represent glycosylation that occurs post translationally. We describe for the first time the biosynthesis of mSBP at the molecular level and suggest that both components of mSBP derive from a common differentially processed precursor. Its mRNA is poorly represented, since the neosynthesized mSBP represents about 0.005% of the total proteins encoded by liver mRNA.