Etiological considerations for the growth of stroma in benign prostatic hyperplasia

The finding that human benign prostatic hyperplasia (BPH) consisted primarily of fibromuscular tissue has led to basic research into the hormonal control of the growth of male accessory sex organ smooth muscle. By using the separated epithelium and muscle layers of the guinea pig seminal vesicle, it was determined that the epithelium exhibited only reversible androgen-induced growths, whereas the muscle proved to be a target tissue for both androgen and estrogen, and exhibited irreversible growth responses. It was of particular interest that the normal androgen-dependent pubertal development of the muscle involved an approximate twofold increase in DNA, followed by the development of a complete and relatively selective androgenic insensitivity in this parameter. An understanding of the factors leading to this apparently normal androgen-dependent loss of the proliferative response in muscle may allow for the development of specific hypotheses for the reawakened stromal growth in BPH. Research on other organ systems focusing on the various factors and mechanisms involved in muscle growth regulation is briefly discussed.     

Suppression of 125I-vasoactive Intestinal Polypeptide Binding Sites in Arteries of the Hamster Seminal Vesicle Following Castration

The presence and distribution of 125I-vasoactive intestinal polypeptide (VIP) binding sites in blood vessels supplying the hamster seminal vesicle was studied using a receptor autoradiographic technique before and following castration. 125I-VIP binding was studied in intact animals, in animals under a 15-day period of castration and in animals under the same period of castration but submitted to a further 15-day period of testosterone treatment.Our results show that, in the seminal vesicle, VIP-binding sites are localized in the gland smooth muscle coat and arterial smooth muscle. A 15-day castration period abolishes 125I-VIP binding to vascular smooth muscle but has no effect on 125I-VIP binding to the gland smooth muscle coat. Treatment with testosterone restores 125I-VIP binding to the vascular smooth muscle, completely reversing the effect of castration.Our results indicate that VIP-binding sites in the smooth muscle wall of arteries supplying the hamster seminal vesicle are under androgenic control and are more sensitive to androgen deprivation that VIP-binding sites associated to the gland smooth muscle coat.     

Roles of prepubertal androgen, estrogen or androgen plus prolactin on androgen-induced proliferative response of seminal vesicles in adult mice

Male mice castrated on day 0 after birth were pretreated daily with testosterone propionate (TP, 4 micrograms/g body weight), 17 beta-estradiol (E2, 0.2 micrograms/g body weight) or vehicle for 21 days starting from day 20. In another experiment, male mice were castrated on day 25; two pituitaries from 60-day-old females were immediately grafted under the capsule of the left kidney in one group. The castrated mice with or without grafts were pretreated daily with TP (4 or 20 micrograms/g body weight) for 36 days starting from day 25, and the left kidney was removed on day 60. Daily TP injections (4 micrograms/g body weight) were started again at 30 days after the end of pretreatments to examine androgen-induced proliferation, and incorporation of 5-[125I]iodo-2'-deoxyuridine into the whole seminal vesicles was used as an index of proliferation. In the neonatally castrated mice, both TP and E2 pretreatments given during the prepubertal period significantly increased seminal vesicle weight even long after the end of the pretreatments. However, androgen-induced proliferative response found in the neonatally castrated adult mice (poor response; long duration with a low peak) was changed to that found in mice castrated at adulthood (good response; short duration with a high peak) by the TP pretreatment only but not at all by the E2 pretreatment. In the mice castrated on day 25, a pharmacological dose of TP or TP plus hyperprolactin could not enhance or change the adult castration type of androgen-induced proliferation induced by physiological prepubertal androgens, although both treatments significantly enhanced the prepubertal growth of the seminal vesicles.     

Roles of neonatal and prepubertal testicular androgens on androgen-induced proliferative response of seminal vesicle cells in adult mice

Male mice were castrated at 0, 10, 20, 30, 40 and 60 days of age; daily injections of testosterone propionate (TP, 4 micrograms/g b. wt) were started from day 90. On various days after starting the TP injections, the incorporation of 5-[125I]iodo-2'-deoxyuridine into the whole seminal vesicles was determined as an index for proliferation. The seminal vesicle cells in mice castrated on days 0 and 20 were characterized by low weight (0.5-1 mg) before TP injection, long duration of androgen-induced proliferation (greater than 20 days) with a low peak, and involvement of both epithelial and fibromuscular cells (neonatal castration type). The seminal vesicle cells in mice castrated on days 60 and 40 were characterized by relatively high weight (5-10 mg) before TP injection, short duration of androgen-induced proliferation (10 days) with a high peak, and involvement of only the epithelial cells (adult castration type). In mice castrated on days 0 and 20, the neonatal castration type of androgen-induced proliferation was completely changed to the adult castration type when TP pretreatment (2 micrograms/g b. wt per 12 h) had been given from day 20 to day 40. However, the TP pretreatment given from day 90 to day 110 instead of days 20-40 had no such effect in 140-day old mice castrated on day 0. The present findings suggest that testicular androgens secreted from day 20 to day 40 play an indispensable role in the induction of irreversible proliferative response of the mouse seminal vesicle. The activity of the prepubertal androgens may not be completely compensated by androgen activity at adulthood.     

Proliferative response of seminal vesicle cells to androgen in mice castrated neonatally and pretreated with estrogen or androgen at adulthood

Seminal vesicle cells of neonatally castrated adult mice show poor response to androgen, compared to those of mice castrated at adulthood; effects of pretreatment with androgen or estrogen at adulthood on androgen-induced proliferation of the seminal vesicle cells were examined in neonatally castrated mice. Male mice castrated at day 0 after birth were pretreated with daily injections of testosterone propionate (TP, 100 micrograms/mouse), 17 beta-estradiol (E2, 5 micrograms/mouse) or vehicle for 20 days starting from day 60; daily TP injections (100 micrograms/mouse) for 30 days were started again from day 110 in all the pretreated mice to examine androgen-induced proliferation by incorporation of 5-[125I]iodo-2'-deoxyuridine into the whole seminal vesicles. Both TP and E2 pretreatments significantly increased the seminal vesicle weight found before TP treatment. However, androgen-induced proliferation of the seminal vesicle found in neonatally castrated mice (poor response; long duration with a low peak on day 3) was changed at least in part to that found in mice castrated at adulthood (good response; short duration with a high peak on day 3) only following the TP pretreatment but not at all following the E2 pretreatment. The E2 pretreatment induced poor androgen-induced proliferation with a low peak on day 7.     

Effect of androgen pretreatments at adulthood on androgen-induced proliferative response of seminal vesicles in neonatally castrated mice

Male mice were castrated on days 0 and 60 after birth. The majority of the neonatally castrated mice were pretreated with androgen; the mice were given daily injections of testosterone propionate (TP; 4 or 8 micrograms/g body wt) for 20 or 30 days starting from day 60. Daily injections of TP (4 micrograms/g body wt) to examine androgen-induced proliferation were started from day 30 or 60 after the end of TP pretreatments or from day 60 after castration; on various days after starting TP injections, the weight and the incorporation of 5-[125I]iodo-2'-deoxyuridine into the whole seminal vesicles were determined as indices for proliferation. The seminal vesicles of neonatally castrated adult mice were characterized by long duration of androgen-induced proliferation (greater than 20 days) with a low peak (neonatal castration type), whereas the seminal vesicles of adult castrated mice were characterized by short duration of proliferation (10 days) with a high peak (adult castration type). In neonatally castrated adult mice, the neonatal castration type of androgen-induced proliferation was changed largely to the adult castration type when pretreatment with 8 micrograms/g body wt of TP had been given for 30 days. However, this effect gradually disappeared when the mice had been pretreated with decreasing amounts of TP for a shorter period. The present findings suggest that the defect in the androgen-induced proliferative response of mouse seminal vesicles induced by the absence of neonatal and prepubertal testicular androgens can be compensated by androgens given in adulthood, if enough androgen is given for a sufficiently long time.     

Induction of functional cytodifferentiation in the epithelium of tissue recombinants. I. Homotypic seminal vesicle recombinants

Functional cytodifferentiation of seminal vesicle epithelium was investigated in tissue recombinants. Neonatal rat and mouse seminal vesicles were separated into epithelium and mesenchyme using trypsin. Epithelium and mesenchyme were then recombined in vitro to form interspecific rat/mouse homotypic recombinants. Growth as renal grafts in adult male athymic mice resulted in seminal vesicle morphogenesis in 70% of the recombinants (the remaining 30% failed to grow). Functional cytodifferentiation was judged by the expression of the major androgen-dependent secretory proteins characteristic of the seminal vesicles of adult rats and mice. Antibodies specific for each of these proteins were used to screen tissue sections by immunocytochemistry and to probe protein extracts by immunoblotting techniques. The heterospecific recombinants synthesized the full range of seminal vesicle secretory proteins that typifies the species providing the epithelium of the recombinant, not the mesenchyme. There was little functional variation between individual recombinants. The time course of development corresponded to that of intact neonatal seminal vesicles grown under the same conditions. Morphogenesis and functional cytodifferentiation were not evident after one week, but were well advanced after two weeks. Seminal vesicle recombinants grown for three weeks were indistinguishable morphologically and functionally from normal adult seminal vesicles. In addition, the ability of adult seminal vesicle epithelium to be induced to proliferate was examined. In association with neonatal seminal vesicle mesenchyme, the epithelium of the adult seminal vesicle proliferated and retained its normal functional activity. Thus, seminal vesicle functional cytodifferentiation can be faithfully reproduced in homotypic tissue recombinants. The methods used in this study will be used to investigate seminal vesicle development in instructive inductions of heterotypic epithelia.     

3':5'-AMP-dependent phosphorylation of muscular membrane proteins and calcium transport

The data are presented concerning the role of cAMP-dependent phosphorylation of sarcoplasmic reticulum and sarcolemma proteins in the transport of Ca2+ through the cardiac skeletal and smooth muscle membranes. Phosphorylation of membrane proteins by soluble and membrane-bound cAMP-dependent protein kinases is shown to have a regulating effect on Mn2+-, Ca2+-ATPase activity and to change membrane permeability for Ca2+. The molecular mechanisms and the character of the interaction between the transport systems and the phosphorylating protein substrates have not been yet established.     

Immunoelectron microscopic evidence for different compartments in the secretory vacuoles of the rat seminal vesicles

Summary Immunoelectron microscopy of the rat seminal vesicle was performed using specific antibodies to secretory proteins. Proteins were precipitated from rat seminal vesicle secretion and were separated by SDS—polyacrylamide gel electrophoresis. Among the great number of bands the two most prominent bands were selected and designated SVS II and IV. Their apparent molecular weights were 48 kDa and 16.5 kDa respectively. The bands were excised from the gels and used for antibody production in rabbits. The respective antisera were used for immunohistochemical studies both at the light and electron microscopic levels in the rat seminal vesicle and the different prostatic lobes in infantile, adult and castrated animals. A positive immunoreaction was observed in seminal vesicle and lateral prostatic epithelium of the intact adult rat, while it was lacking in prepubertal and castrated animals. The subcellular distribution of both proteins was clearly different: SVS II was exclusively confined to the electron dense core of the secretory vacuoles, while SVS IV was detected only in the clear halo surrounding the central granule. It is suggested that the spatial arrangement of both proteins in the seminal vesicle secretion vacuole reflects a particular functional significance of each of these proteins. These proteins may serve as a tool in the study of regulation of androgendependent protein synthesis.     

Mechanisms involved in desensitization of particulate guanylyl cyclase in human airway smooth muscle: the role of protein kinase C

We recently showed that cultured human airway smooth muscle cells (HASMC) express both soluble and particulate guanylyl cyclases (GC) and that long term treatment with atrial natriuretic peptide (ANP) causes homologous desensitization of particulate GC. Here we determine if protein kinase C (PKC) activation would desensitize particulate GC and probe the role of PKC in particulate GC desensitization. Pretreatment of HASMC with phorbol 12-myristate 13-acetate (PMA), a PKC activator led to time and concentration-dependent desensitization of ANP-stimulated cGMP accumulation. GF109203X, a selective PKC inhibitor, blocked the PMA-induced desensitization, but did not block ANP-induced desensitization. In addition, desensitization by PMA and ANP showed an additive effect. These results suggest that PKC activation can desensitize particulate GC but that the desensitization induced by ANP is PKC-independent.     

Cyclic AMP-dependent protein kinase in Paramecium tetraurelia. Its purification and the production of monoclonal antibodies against both subunits

Two soluble cAMP-dependent protein kinases were purified from the cytoplasm of Paramecium tetraurelia. Both kinases consisted of a 40-kDa catalytic subunit and a 44-kDa regulatory subunit. The two forms of the enzyme were separated by anion-exchange chromatography. Affinity chromatography on cAMP-Sepharose separated the regulatory subunit (retained by the column) from the cAMP-independent catalytic subunit (not retained). Four classes of monoclonal antibodies were generated. One class was specific for the catalytic subunit of both cAMP-dependent protein kinases, and three classes recognized the regulatory subunit of both forms of the enzyme. Subunits of 40 and 44 kDa were detected on immunoblots of purified cilia and of crude cell extracts. In addition, one class of antibodies specific for the regulatory subunit detected a ciliary protein with a molecular mass of 48 kDa. The monoclonal antibodies did not recognize type I or type II cAMP-dependent protein kinase from rabbit muscle nor did they cross-react with proteins from several unicellular eucaryotes, with one exception: antibodies specific for the catalytic subunit recognized a 40-kDa protein of Tetrahymena pyriformis.     

Testicular protein kinases. Characterization of multiple forms and ontogeny.

Protein phosphokinase activity from the cytosol (105,000 X g soluble fraction) of testes from sexually mature rats has been resolved be DEAE-cellulose chromatography in three forms of protein kinase, cAMP-dependent protein kinases I and II and cAMP-independent protein kinase III. Adenosine 3':5'-monophosphate-binding activity (cAMP-binding activity) was associated with protein kinases I and II but not with protein kinase III. Protein kinases I, II, and III exhibited different pH optima, cyclic nucleotide dependency, and relative substrate specificity. Protein kinases I and II were inhibited by a heat-stable protein inhibitor from rat skeletal muscle, whereas protein kinase III was not inhibited. According to previously established criteria (Traugh, J. A., Ashby, C.D., and Walsh D. A. (1974) Methods Enzymol. 38, 290-299) protein kinases I and II can be classified as cAMP-dependent holoenzymes consisting of regulatory and catalytic subunits. Protein kinase III is a cAMP-independent protein kinase.     

Cyclic nucleotide-dependent protein kinases in airway smooth muscle

Because of the potential importance of cyclic nucleotide-dependent protein kinases in the regulation of airway smooth muscle tone, we have examined some of the characteristics of these enzymes in the soluble fraction of canine trachealis homogenates. In the absence of added cAMP, the heat-stable cAMP-dependent protein kinase inhibitor (PKI) abolished only a half of the 32P incorporation into mixed histones. The remaining activity appeared to be contributed by a cyclic nucleotide-independent enzyme. Phosphotransferase activity was enhanced 5-fold by 5 microM cAMP but only 70% of the cAMP-stimulated activity could be inhibited by PKI. The sensitivity of the cyclic nucleotide-dependent, PKI-resistant enzyme to cAMP, cGMP, and Mg2+ indicated that it was cGMP-dependent protein kinase. Because of the large amount of cyclic nucleotide-independent activity, and the ability of cAMP to activate cGMP-dependent protein kinase, the traditional "-cAMP/+cAMP" ratio did not provide an accurate assessment of the in vivo activation state of cAMP-dependent protein kinase. However, a modified assay was developed which allowed the precise measurement of cAMP-dependent, cGMP-dependent, and cyclic nucleotide-independent protein kinase activities. Using this new method, the cAMP-dependent protein kinase activity ratio of 0.239 in untreated trachealis strips was increased to 0.355 and 0.386 by prior exposure of the intact tissue to the smooth muscle relaxants isoproterenol and prostaglandin E2, respectively. The results of this study are consistent with the proposed role of cAMP-dependent protein kinase in the regulation of smooth muscle contractile function.     

Direct inhibitory effect of adrenomedullin, calcitonin gene-related peptide, calcitonin, and amylin on cholecystokinin-induced contraction of guinea-pig isolated caecal circular smooth muscle cells

We recently reported the direct inhibitory effect of adrenomedullin on caecal circular smooth muscle cells via cAMP system. This study was designed to determine whether the structurally related peptides to adrenomedullin (i.e.; calcitonin gene-related peptide (CGRP), calcitonin, and amylin) can inhibit the cholecystokinin octapeptide (CCK-8)-induced contractile response by exerting a direct action on guinea-pig caecal circular smooth muscle cells, and to compare the inhibitory potency of these peptides. In addition, to elucidate each intracellular mechanisms, the effects of an inhibitor of cAMP-dependent protein kinase, inhibitors of particulate or soluble guanylate cyclase on the each peptide-induced relaxation were investigated. Adrenomedullin, CGRP, calcitonin, and amylin inhibited the contractile response produced by CCK-8 in a dose-dependent manner, with IC50 values of 0.14 nM, 0.37 nM, 5.4 nM, and 160 nM, respectively. An inhibitor of cAMP-dependent protein kinase significantly inhibited the relaxation produced by all of these peptides. On the contrary, inhibitors of particulate or soluble guanylate cyclase did not have any significant effect on the relaxation produced by these peptides. In this study, we demonstrated the direct inhibitory effects of the structurally related peptides to adrenomedullin (i.e.; CGRP, calcitonin, and amylin) on the isolated caecal circular smooth muscle cells via cAMP system. The order of potency was as follows; adrenomedullin falling dots CGRP > calcitonin > amylin.     

Soluble precursor of membrane-associated protein kinase in uterine smooth muscle cells

Incubation of smooth muscle strips from rat uterus with isoproterenol resulted in redistribution of protein kinase activity between the cytosol and a 20,000 to 50,000g membrane fraction. Similarities in the elution properties of the cytosolic and membrane-associated forms of the enzyme on DEAE-cellulose ion exchange chromatography further suggested the two forms were the same. The nature of membrane binding of the soluble enzyme was investigated using smooth muscle microsomal and cytosol fractions. Membranes readily bound the soluble enzyme when the two subcellular compartments were reconstituted and incubated at 30 °C for 10 min. The extent of binding was proportional to the ratio of membranes to cytosol and was characterized by the inhibition of soluble enzyme activity toward exogenous substrates in a Triton X-100 reversible manner. In marked contrast to the binding of soluble protein kinase to heart particulate fractions, binding of the cytosol enzyme to smooth muscle cell membranes was unaffected by ionic strength or cAMP. The latter property indicated holoenzyme was bound in a manner similar to the free catalytic subunit of cAMP-dependent protein kinase and suggested the enzyme was bound by association between the membrane and the catalytic subunit. Binding of cytosol protein kinase to the membranes rendered the enzyme insensitive to trypsin digestion and the capacity of the smooth muscle cell membranes to bind the soluble enzyme exceeded that of other rat tissue fractions. Resistance to salt extraction and proteolysis, as well as its detergent dependence, suggested the soluble enzyme became an integral or intrinsic membrane protein following association with the membrane. The ability of membranes to incorporate [γ-³²P]ATP into phosphoprotein was lost on detergent extraction of protein kinase and restored in an apparently specific manner when extracted and washed membranes were reconstituted with soluble enzyme. The intrinsic nature of membrane protein kinase and the apparent specificity with which the soluble enzyme was hound by membranes further indicated that, in myometrium. hormone-induced translocation of protein kinase is an important mechanism by which enzyme activity is increased in the vicinity of its in situ substrates.     

Altered properties of cAMP-dependent protein kinase in H-ras-transformed NIH3T3 cells

cAMP-dependent protein kinase activity in the soluble fraction was decreased in both v-H-ras-transformed and activated-c-H-ras-transformed NIH3T3 cells as compared with that in NIH3T3 cells. Both of the elution profile of type II cAMP-dependent protein kinase from DEAE-cellulose and the electrophoretic behavior of its regulatory subunits in the particulate fraction of H-ras-transformed cells are different from those of control NIH3T3 cells. These results suggest that ras protein causes the alterations of some properties of cAMP-dependent protein kinases.     

The cyclic nucleotide-dependent phosphorylation of aortic smooth muscle membrane proteins

Membrane proteins of Mr 240,000, 130,000, and 85,000 (GS-proteins) were rapidly and selectively phosphorylated in particulate fractions of rabbit aortic smooth muscle in the presence of [Mg-32P]ATP and low concentrations of cGMP (Ka = 0.01 microM) or cAMP (Ka = 0.2 microM). The effects of both cyclic nucleotides in this preparation were mediated entirely by an endogenous, membrane-bound form of cGMP-dependent protein kinase (G-kinase). The GS-proteins were also phosphorylated by the soluble form of G-kinase purified from bovine lung; this effect was most evident following removal of endogenous G-kinase from the membranes using Na2CO3 and high salt washes. The membrane-bound and cytosolic forms of G-kinase phosphorylated the Mr 130,000 GS-protein with the same specificity as determined by two-dimensional peptide mapping. Despite this functional homology between the two forms of G-kinase, only the particulate enzyme appears to play a role in phosphorylating the GS-proteins. Although little endogenous cAMP-dependent protein kinase (A-kinase) activity was detected in washed aortic smooth muscle membranes, the GS-proteins could be phosphorylated when purified A-kinase catalytic subunit was added to this preparation. Peptide mapping of the Mr 130,000 GS-protein indicated that A-kinase phosphorylated a subset of the same peptides labeled by the two forms of G-kinase. The endogenous A-kinase of rabbit aortic smooth muscle homogenates was also found to phosphorylate the GS-proteins. Since the intracellular concentrations of cGMP or cAMP can be selectively elevated by different stimuli, these results suggest several possible mechanisms by which the phosphorylation state of the GS-proteins may be regulated by cyclic nucleotides: activation of the membrane-bound G-kinase by cGMP or cAMP; and activation of cytosolic A-kinase by cAMP.     

Effects of α-difluoromethylornithine, an enzyme-activated irreversible inhibitor of ornithine decarboxylase, on testosterone-induced regeneration of prostate and seminal vesicle in castrated rats

1. Castration of adult rats markedly decreases the amounts of polyamines (putrescine, spermidine and spermine) and of RNA and DNA in the ventral prostate and the seminal vesicle. 2. Daily injections of testosterone propionate to rats castrated 7 days previously increase polyamine and nucleic acid contents more rapidly in the seminal vesicle than in the ventral prostate. 3. After 7 days of androgen treatment, polyamine and nucleic acid contents of the seminal vesicle are significantly higher than those of intact animals. Nucleic acid, but not polyamine, contents return to normal values during the next 4 days of continued treatment. In the prostate, androgen treatment increases polyamine and nucleic acid contents to, but not above, normal values. 4. Repeated doses of alpha-difluoromethylornithine, a potent enzyme-activated irreversible inhibitor of ornithine decarboxylase, totally blocked the testosterone-induced increase of putrescine and spermidine in the ventral prostate and of putrescine in the seminal vesicle. They slowed significantly the accumulation of spermine in the ventral prostate and of spermidine in the seminal vesicle. alpha-Difluoromethylornithine also retarded the testosterone-induced accumulation of RNA in the ventral prostate. However, no clear correlation was apparent between accumulation of polyamines and of nucleic acids in the two organs. 5. alpha-Difluoromethylornithine markedly slows the testosterone-induced weight gain of the prostate, but not of the seminal vesicle. Cytological studies suggest that this effect on the prostate is due to inhibition of the androgen-induced restoration of the secretion content of prostatic acini.     

Regulation of l-ornithine decarboxylase and S-adenosyl-l-methionine decarboxylase in rat ventral prostate and seminal vesicle

1. The activities of l-ornithine decarboxylase (EC 4.1.1.17) and S-adenosyl-l-methionine decarboxylase (EC 4.1.1.50) were dramatically enhanced in both the ventral prostate and the seminal vesicle of castrated rats in response to androgenic stimulation. The time course of the stimulation of ornithine decarboxylase together with the quantitatively different response of adenosylmethionine decarboxylase to testosterone treatment in the prostate gland and seminal vesicle indicated that the enhancement in polyamine synthesis in the ventral prostate may reflect both cellular proliferation and the restoration of the secretory functions of the organ. In the seminal vesicle, however, the stimulation of the polyamine-biosynthetic pathway more closely resembled the pattern found in other rat tissues, such as regenerating liver, undergoing compensatory growth. 2. Ornithine decarboxylase activity in the ventral prostate and especially in the seminal vesicle of sexually mature rat was diminished in vivo by various short-chain diamines such as 1,2-diaminoethane, 1,3-diaminopropane and putrescine (1,4-diaminobutane). These diamines had no direct effect on the enzyme activity in vitro. 3. In contrast with the marginal decrease in ornithine decarboxylase activity produced by diaminoethane in the ventral prostate of non-castrated animals, repeated injections of the latter amine completely prevented the intense stimulation of the enzyme activity in the ventral prostate and seminal vesicle of castrated rats at 24h after the commencement of testosterone treatment. 4. The decrease in ornithine decarboxylase activity observed after injections of diamines (putrescine) in the ventral prostate was apparently associated with a similar decrease in the amount of immunoreactive protein as revealed by immunotitration of the enzyme with antiserum to rat ornithine decarboxylase.     

Protein-bound male urinary pheromones: differential responses according to age and gender

The attractive properties of male urinary pheromones were tested on adult or prepubertal male and female mice. An androgen-dependent protein is present in adult male urine (major urinary protein, MUP) which has been suggested to be a pheromone-binding protein. We tested the pheromonal properties of the protein-bound volatiles in a test of attractiveness. These molecules, that co-purify with MUP, attract females and repel adult males. In prepubertal animals, females are repelled and males are attracted by the same stimuli. These results are similar to those obtained by others with adult male whole urine. Therefore MUP binds molecules with a pheromonal activity, and these molecules are sufficient to act as male signals.