Induction of benign prostatic hyperplasia in intact dogs by near-physiological levels of 5 alpha-dihydrotestosterone and 17 beta-estradiol.

Benign prostatic hyperplasia was induced in mongrel dogs treated for 60 days with one silastic implant containing 17 beta-estradiol and four containing 5 alpha-dihydrotestosterone. The condition was characterized by (1) a marked increase of the stromal elements, particularly the stromal septa between the individual glands, (2) a slight increase in prostatic volume, and (3) a morphology that resembled spontaneous complex benign prostatic hyperplasia in the dog. Other groups of animals that remained untreated or received only 17 beta-estradiol or only 5 alpha-dihydrotestosterone did not develop this condition. Prostate volumes decreased by 14% in the estrogen-treated dogs, whereas they increased in the androgen-treated animals by 6% compared to pretreatment prostate volumes. The morphology of the epithelium of the prostates of androgen-treated animals was not different from that of controls despite the increase in prostate volume. The serum 17 beta-estradiol and 5 alpha-dihydrotestosterone concentrations were increased from 25 +/- 2 (mean +/- SEM) and 256 +/- 42 pg/mL, respectively, in control dogs to 52 +/- 37 and 562 +/- 37 pg/mL, respectively, in the dogs treated with the hormone combination. Thus, hormone concentrations were two- to three-fold higher than control values, and the ratio of estradiol-17 beta to 5 alpha-dihydrotestosterone was increased by up to 19%. These data demonstrate that treatment of dogs with low levels of estrogen and androgen may be an excellent model for the study of spontaneous complex benign prostatic hyperplasia in aging men.

Regional brain abnormalities in norepinephrine uptake and dopamine beta-hydroxylase activity in the genetically epilepsy-prone rat.

Two markers for noradrenergic neurons: 1) desmethylimipramine sensitive norepinephrine (NE) uptake and 2) dopamine beta-hydroxylase activity were compared in various brain regions of normal and genetically epilepsy-prone rats (GEPR). These studies were designed to characterize further the nature of the noradrenergic deficit in GEPRs, which has been described as a reduction in steady-state NE levels. The high affinity (desmethylimipramine-sensitive) uptake of 3H-NE into crude synaptosomes was found to be significantly reduced in widespread areas of the GEPR forebrain including cortex, hippocampus, amygdala and hypothalamus. GEPRs also displayed a reduced uptake of 3H-NE in synaptosomes from the inferior colliculus, a structure that has been implicated in the audiogenic seizure, but other regions of the brain stem (reticular formation, cochlear nucleus, cerebellum) failed to reveal abnormalities in NE uptake. Reductions in dopamine beta-hydroxylase activity seemed to parallel the reductions in NE uptake regionally (except for the caudate nucleus), and both deficits (uptake and dopamine beta-hydroxylase) were similar in magnitude to the decrements in steady-state NE levels reported previously. The present findings therefore support the concept that there is a reduction in the number of noradrenergic terminals in most structures receiving noradrenergic innervations in the GEPR brain.

Structure-mutagenicity relationships of benzidine analogues.

The mutagenic activities of benzidine, its dihydrochloride salt, and 12 of their analogues were compared in the Ames test using strains TA100 and TA98 with and without rat liver S9 activation. With the exceptions of 4,4'-methylenebis(3-nitroaniline) in both strains and 3,3-dichlorobenzidine in TA98, little or no mutagenicity was observed in the series when tested without S9 activation. All compounds, except tetramethylbenzidine, exhibited some activity in TA100 with S9 activation; dichlorobenzidine and 4-aminobiphenyl were significantly more mutagenic than the other compounds. This was in contrast to the TA98 results where the bridged diphenyl compounds, with the exception of the nitroaniline derivative, were only slightly mutagenic compared to the more planar biphenyl series. Only the nitroaniline compound was mutagenic in both strains in the presence or absence of S9 activation. For benzidine and the 3,3'-disubstituted benzidines (the dimethoxy-, diamino-, and dichloro- compounds), an increase in mutagenicity correlated to a decrease in basicity of the parent anilines in both TA100 and TA98.

The mutagenicity of isoniazid in Salmonella and its effects on DNA repair and synthesis in human fibroblasts.

A commercial sample of the tuberculostatic drug isoniazid (INH) was found to have a weak mutagenic activity towards Salmonella typhimurium strains TA100 and TA1535. The addition of a rat or mouse liver homogenate to the test system decreased the mutagenic effect of INH. Hydrazine, an impurity of the INH sample, was also weakly mutagenic in strains TA100 and TA1535, but not in the extent that could account for the mutagenicity of the INH sample. An inhibition of DNA synthesis in human fibroblasts was observed for INH, this effect being potentiated by the addition of manganese to the test system. There was no induction of unscheduled DNA synthesis in human cells by INH except in the presence of manganese.

A noninvasive technique for monitoring changes in canine prostatic size in vivo.

We describe a procedure for monitoring changes in canine prostatic size. Metal beads were sutured to the surface of the prostate and the interbead distances were derived from two X-rays taken at right angles. Prostatic hyperplasia was induced by castration and injection of 5 alpha-androstane-3 alpha, 17 beta-diol and 17 beta-estradiol. Prostatic regression was caused by castration without further treatment. Although growth of the prostate was nonuniform, changes in prostatic volume were shown to be related to the third power of the distance between appropriate beads. This monitoring technique can be repeated every 2nd day if necessary, and thus has an advantage over procedures that require repeated laparotomies. Significant increases in prostatic volume could be detected within 5 days after steroid injection.

alpha-(2-Pyridine)benzyl aryl ketones as potential hypocholesteremic agents.

A series of alpha-(2-pyridine)benzyl aryl ketones were prepared as potential hypocholesteremic agents. The synthesis of these compounds was by conversion of 2-benzylpyridine to its anion with n-butyllithium and condensation of the anion with selected aromatic esters. The ketones were tested for their hypocholesteremic activity in rats, and those compounds showing activity were further tested for estrogenicity. Only those aryl ketones with substituents in the ortho position showed a statistically significant reduction in serum cholesterol. Of these compounds the tert-butyl derivative had the most favorable hypocholesteremic to estrogenic ratio.

Mutagenicity of aliphatic epoxides.

The mutagenicity of 17 aliphatic epoxides was determined using the specially constructed mutants of Salmonella typhimurium developed by Ames. The activity of these epoxides together with those reported in the literature as mutagens in strains TA100 and TA1535 depended on the degree of substitution around the oxirane ring. Monosubstituted oxiranes were the most potent mutagens in both strains. 1,1-Disubstitution resulted in the complete loss or reduction of mutagenicity, trans-1,2-Disubstituted, and tetrasubstituted oxiranes all lacked mutagenicity, while the cis-1,2-disubstituted oxiranes tested were weakly mutagenic in strain TA100 only. For the monosubstituted compounds the presence of electron-withdrawing substituents increased mutagenicity.

The role of adenosine 3',5'-cyclic monophosphate in the density-dependent regulation of growth and tyrosinase activity of B-16 melanoma cells.

Incubation of cultured B-16 melanoma cells with 1-methyl-3-isobutyl xanthine (MIX) produced a sustained rise in intracellular adenosine 3',5'-cyclic monophosphate (cAMP) which preceded an increase in the specific activity of tyrosinase (EC 1.10.3.1). Cultures of two clones of melanoma cells, one having a mean population doubling time twice that of the other, showed density-dependent inhibition of growth. The tyrosinase activity of each line increased progressively during logarithmic growth, reaching maximal values shortly after the cultures achieved confluence. Intracellular cAMP levels fell during logarithmic growth, being minimal in confluent cultures. The stimulatory effects of MIX and confluence on tyrosinase activity were additive. Cells plated at high density had a lower tyrosinase activity than cells allowed to achieve a similar density by successive division from sparsely planted cultures although the intracellular cAMP levels of such cultures were not different. We support the observations of other investigators that agents which increase intracellular cAMP concentrations can both inhibit cell division and stimulate tyrosinase activity. There are, however, mechanisms for increasing tyrosinase activity and inhibiting cell division which are expressed as B-16 melanoma cells approach confluence and which are not mediated by an increase in intracellular cAMP concentrations.

Dehydrative metabolites of 1-(3-chlorophenyl)-1methyl-2-phenyl-2-(2-pyridine)ethanol as potential hypocholesteremic agents.

The E and Z isomers of 2-[2-(3-chlorophenyl)-1-phenyl-1-propenyl]pyridine (2a,b) and 2-[2-(3-chlorophenyl)-1-(4-hydroxyphenyl)-1-propenyl]pyridine (4a,b) were synthesized and separated as possible metabolites of 1-(3-chlorophenyl)-1-methyl-2-phenyl-2-(2-pyridine)ethanol (1a). Following administration of 1a to rats, a HPLC system was used to examine urine and serum specimens for the less polar metabolites of 1a. Isomers 2a and 2b were not detected but their hydroxylated derivatives 4a and 4b were observed as minor metabolites. Compounds 2a,b and 4a,b exhibited hypocholesteremic activity in rats; compounds 4a and 4b are of special interest because they possessed relatively low estrogenicity.

Metabolic formation and synthesis of 1-(3-chlorophenyl)-2(4-hydroxyphenyl)-1-methyl-2(2 pyridine)ethanol. A potential hypocholesteremic agent.

1-(3-Chlorophenyl)-2-(4-hydroxphenyl)-1-methyl-2(2-pyridine)ethanol (8a) has been synthesized and found to be the major urinary metabolite following intraperitoneal administration of 1-(3-chlorophenyl)-1-methyl-2-phenyl-2-(2-pyridine)ethanol (1) to rats. This metabolite has a hypocholesteremic effect in rats similar to that of the parent drug.

Maturation and differentiation of B16 melanoma cells induced by theophylline treatment.

Recent studies suggested that 3',5'-cyclic AMP (CAMP) may be involved in the regulation of cell proliferation and differentiation. Theophylline, an inhibitor of cyclic nucleotide phosphodiesterase, elevated intracellular cAMP. A melanotic clone of the B16 melanoma was treated with theophylline and studied in vitro and in vivo. With 12 hours after 1.0 mM theophylline was added to growing cultures, the number of cells incorporating tritiated thymidine (3-H-TDR) and the rate of uptake of 3-H-TDR into DNA were significantly reduced. After 7 days, the number of cells in the control cultures increased twenty-four times, whereas theophylline-treated cells increased only sixfold. Compared to the controls, the theophylline-treated cells contained ten times the melanin and an elevated cAMP content. Stimulation of melanogenesis and inhibition of proliferation increased progressively with duration of exposure to theophylline. After 5 days of culture with theophylline, cells were assayed for plating efficiency in theophylline-free medium. Although the number of colony-forming cells was unaffected by previous exposure to theophylline, the colonies were composed of fewer cells inoculated into syngeneic hosts were less tumorigenic than untreated cells. However, theophylline treatment of hosts bearing B16 tumors failed to reduce the tumor growth rate, and theophylline did not potentiate the growth inhibition resulting from treatment with the synthetic polyribonucleotide, polyinosinic-polycytidylic acid.