Effect of castration on the synthesis of seminal vesicle secretory protein IV in the rat

Abstract

The effects of castration on the synthesis (accumulation) of a major seminal vesicle secretory protein (SVS IV) were examined in young adult rats. In vitro incorporation of labeled amino acids into SVS IV by minced tissue was monitored by immunological methods. Castration resulted in a large decrease in the differential synthesis of SVS IV. A significant decrease in the relative incorporation of isotope into SVS IV was evident within 3 days of castration, and by 4 weeks relative incorporation dropped some 30-fold. These changes took place in the presence of a large generalized decline in protein synthesis so that incorporation into SVS IV on an organ basis decreased by over 200-fold. SVS IV messenger RNA levels were estimated by RNA excess solution hybridization using a cloned cDNA probe. Relative message levels declined after castration in harmony with the declines in SVS IV synthesis. SVS IV mRNA was decreased by a relative factor of approximately 20 and an absolute factor of approximately 200 in long-term (40-day) castrates. Accordingly, the seminal vesicle conforms to the general pattern of steroid regulated systems in which hormone withdrawal leads to differential decreases in the steady-state pool size for specific mRNAs. The seminal vesicle is unusual, however, in that a prolonged period is required for maximum differential effects to occur.

Protease-nexin I as an androgen-dependent secretory product of the murine seminal vesicle.

“…Also, the possibility that PN-I mRNA processing or stability might be affected by androgens should be considered (Higgins and Hemingway, 1991). The rodent seminal vesicle has long been known to be exquisitely sensitive to the androgenic status of the animals, and a number of its secretory products have been shown to be under testosterone control (Ostrowski et al, 1982;Brooks et al, 1986;Chen et al, 1987;Mills et al, 1987;Schifman et al, 1988;Harris et al, 1990;Higgins and Hemingway, 1991). A comparison of the genes coding for these different products, which now include PN-I, should yield valuable information regarding the mechanism of androgen regulation in the male genital tract.…”

Use of a cloned double stranded cDNA coding for a major androgen dependent protein in rat seminal vesicle secretion: the effect of testosterone in gene expression

“…The insert size together with the result of the hybridization of insert fragments to 32P-cDNA probes and the sequencing data prove that the insert corresponds to an almost full-length structural gene coding for a precursor to SVS protein IV. It is well established that the synthesis of SVS protein IV is controlled by testosterone (4). In this report we have used the cloned structural gene to determine the concentration of mRNAIV after administration of testosterone to rats castrated for five weeks.…”

“…SVS protein IV has been described (1,2,3,4) and the amino acid sequence has been deduced (13). The biological function of protein IV is still unknown but considering that this protein represents 25-30% of the seminal vesicle protein-synthetic output an important role in reproduction seems very likely.…”

“…In rat seminal vesicle there is a small set of polypeptides representing 30-50% of the proteins synthesized by the vesicle and the synthesis of these proteins is controlled by androgens (1,2,3,4). The abundant class of poly(A+)RNA coding for these polypeptides has been isolated and characterized (5).…”

A novel gene family encoding proteins with highly differing structure because of a rapidly evolving exon

“…The rat seminal vesicle secreted protein SVSIV and SVSV are small (-10 kDa) androgen-regulated proteins [9,10]. They are expressed from genes that are organized in a way similar to the semenogelin (Sg) genes, with one exon encoding the signal peptide, a second encoding the secreted protein and a third encompassing 3' non-translated nucleotides [11,12] It has previously been shown that the 3' non-translated nucleotides of cDNAs for human SgI and rat SVSIV are similar in sequence [7].…”