Sex-dependent Protein Research Articles

Comparison of some sex-dependent proteins in the adult male rat

An hepatically synthesized sex-dependent protein ( α 2u), isolated from male rat urine, has been compared with other similarly designated rat proteins. Using a specific antiserum prepared against α 2u, immunological analysis revealed no cross reaction with a sex-dependent protein prepared from unsonicated rat liver homogenates. An α-globulin separated from urine by molecular sieving and chromatography on CM-cellulose was shown to be immunologically identical with α 2u. This α-globulin exhibited only a single electrophoretic band (acrylamide gel) whereas α 2u contained multiple species of protein having different isoelectric points. The single isoelectric form obtained from CM-cellulose migrated electrophoretically as did the major α 2u (5.2) component. Further studies showed that CM-cellulose could be used to separate the various isoelectric species of α 2u. Antisera to murine, urinary sex-dependent proteins have been shown to cross react with some urinary proteins in the rat. However, an antiserum to α 2u did not cross react with any murine urinary proteins.

Multiple forms of α2u, a sex-dependent urinary protein of the adult male rat

A sex-dependent protein ( α 2u) which exists as multiple isoelectric forms in the urine of adult male rats has also been partially purified from the liver, blood serum and kidneys. Only one electrophoretic form of the protein was observed in liver and serum, which corresponded to the major urinary component α 2u (5.2). The kidneys, on the other hand, contained several forms of α 2u, one of which is not found in the urine. In addition, at least one urinary species of the protein has not been identified in the kidneys. A possible explanation for the differences in the multiple forms of α 2u is discussed.

Further studies on the isolation and characterization of a sex-dependent protein from the urine of male rats

The major urinary protein (α 2u) of the adult male rat has been isolated by a combination of (NH 4) 2SO 4 fractionation, gel filtration on Sephadex G-100, and isoelectric focusing. The final preparation was carbohydrate-free, had a molecular weight of 20 000–21 000, an N-terminal glutamyl or glutaminyl residue, and consisted of a family of species varying in isoelectric points from pH 5.0 to 5.8. These species were immunologically identical among themselves and also with a product produced by an earlier procedure.

Synergistic effect of glucocorticoids and androgens on the biosynthesis of a sex-dependent protein in the male rat

Castration of male rats reduced the urinary excretion of sex-dependent α 2u-globulin by 50%. Replacement therapy with testosterone, dihydrotestosterone, androstenedione, and dehydroepiandrosterone increased the urinary excretion of α 2u. To determine if adrenal androgen contributions to the excretion of α 2u, especially in castrated rats, some animals were adrenalectomized. Adrenalectomy, however, almost abolished the excretion of the protein, an effect which could be reversed with glucocorticoid but not androgen or aldosterone. When male rats were adrenalectomized and castrated, then the excretion of α 2u was obtained only following therapy with both androgen and glucocorticoid. It is suggested that the glucocorticoid is required in a synergistic or permissive sense for the androgen-dependent excretion of α 2u.

Androgenic induction of alpha-2-u-globulin in the rat: requirement of an intact pituitary.

A SEX dependent urinary protein in the rat has been described by Roy and Neuhaus1–4. This protein is an α2-globulin (α2U) of hepatic origin and has a molecular weight of 26,400 (refs. 2 and 3). It is rapidly excreted in the urine3. The level of α2U in blood is therefore very low (< 3 mg per 100 ml. blood)3. This protein is absent in females and immature male rats. The synthesis of α2U is very sensitive to hormonal manipulations4. Treatment with testosterone of the spayed females induces its synthesis whereas treatment of adult male rats with oestradiol brings about a complete repression4. A quantitative immunological method for the assay of α2U has been described3. All of these above mentioned properties make α2U a very convenient system for studying the possible hormonal control of gene action in the mammalian system. In this communication we report our studies on the requirement of the pituitary gland for the androgenic induction of α2U in spayed rats.

Androgenic control of a sex-dependent protein in the rat.

PROTEINURIA in the adult male rat has been recognized as a sex characteristic since 19331. At first the source of the sex-related proteins was considered to be the prostate gland1, but more recently evidence has suggested the kidneys2,3. These sites are likely because of the known anabolic effects of androgens on prostatic and renal tissues4,5.

Proof of the hepatic synthesis of a sex-dependent protein in the rat

An α 2-globulin ( α 2u), previously purified from the urine of male rats, has been identified immunologically in the liver, kidneys and serum. This protein was associated with the microsomal fraction of the liver but not that of the kidneys. Total nephrectomy yielded in 6 h a 30-fold accumulation of α 2u above the normal plasma concentration of 3 mg per 100 ml. Simultaneous partial hepatectomy or administration of puromycin inhibited its accumulation. The perfusion of rat liver in vitro with blood containing [ 14C]glycine led to the production of radioactively labeled α 2u. These studies demonstrate the hepatic synthesis of the sex-related α 2-globulin originally isolated from male rat urine.