The effects of long-term administration of methyltestosterone on the development of liver lesions in BALB/c mice

Characterization of Androgen Receptor Complex Associated Protein (ARCAP) in hepatocellular carcinoma and liver

BACKGROUND

Hepatocellular carcinoma (HCC) ranks many tasks in clinical oncology due to possibly developing a general tumor in men and, usually lead to malignant to death within years. Researches had reported about major factors for being HCC was male sex and HCC associated with cirrhosis in childhood was found more common in males than females. In certain mouse strains as studied, breeding with testosterone significantly increases the development of HCC. Furthermore, castration of male mice diminished the frequency of the development of liver tumors. Meanwhile male hepatitis B virus transgenic mice have a greater occurrence of HCC than females.

METHODS

We apply degenerate priming PCR to observe the expression of various steroid receptors in livers. Yeast-two hybrid screening to search a novel RNA fragment helps to find a new full-length gene by RACE experiment. RT-PCR is applied to detect various expressions in tissues and cell lines. In situ hybridization detects DNA in Chromosome mapping. GFP-constructs transfection proves the gene localization in cells. Immunoprecipitation pulldown assay verifies protein interaction. Gene transfection followed with luciferase assay demonstrates the interaction of genes within cellular signaling. Genomic alignment analysis for observing sequences data perform from NCBI database website (http://www.ncbi.nim.nih.gov/genebank/).

RESULTS

The androgen receptor (AR) expression level is found at the highest level among the steroid receptors families detected in liver tumors. By yeast-two hybrid screening, we cloned an Androgen Receptor Complex Associated Protein (ARCAP), of 95 Kd in molecular weight and its cDNA. ARCAP locates at Chromosome 1. Our findings indicate ARCAP is highly expressed in hepatoma cell lines and liver tumors and their adjacent tumors as observed. Yeast two-hybrid assay and in vitro immunoprecipitation assays demonstrated an interaction between AR and ARCAP.

CONCLUSION

We aim to search for different types and levels of steroid receptors expressed within human HCCs and in the adjacent liver tissues. To verify possible molecular mechanisms by which AR might affect hepatoma cells, we had characterized a novel protein ARCAP which functions as a coregulator to interact with AR within liver. The ligand-dependent AR with its cofactor, ARCAP, can induce a signal cascade by transactivation.

Effects of synthetic androgens on liver function using the rabbit as a model

The objective of this study was to determine whether the rabbit was a suitable model to test new synthetic androgens for potential liver toxicity within a short dosing interval. Adult male rabbits were dosed orally daily on days 0-13 with 17α-methyltestosterone (MT) as a positive control and testosterone (T) as a negative control to validate this model. Synthetic androgens tested were: 7α-methyl-19-nortestosterone (MENT), dimethandrolone-undecanoate (DMAU), and 11β-methyl-19-nortestosterone-17β-dodecylcarbonate (11β-MNTDC). Serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma glutamyl transpeptidase (GGT), and sorbitol dehydrogenase (SDH), as well as clearance of intravenous injected bromsulfonphthalein (BSP) from serum on days 0, 7, and 14, were determined. As expected, T (10 mg/kg/d) did not adversely affect BSP retention or serum liver enzymes. MT (10 mg/kg/d) increased BSP retention, and AST, ALT, GGT, and SDH levels, indicating that this model could detect androgens known to be hepatotoxic. DMAU and MENT (10 mg/kg/d) increased BSP retention and all 4 serum liver enzymes as well, but the effects were less than those observed with MT at the same dose. All parameters returned to baseline 2 weeks after cessation of dosing. 11β-MNTDC at 10 mg/kg/d did not have an effect on BSP retention or liver enzymes, but a slight increase in serum GGT levels was observed in rabbits treated with 25 mg/kg/d. For the androgens that exhibited liver toxicity at 10 mg/kg/d (MT, DMAU, and MENT), a no-observed-effect level of 1 mg/kg/d was established. Overall ranking of the synthetic androgens from most to least hepatotoxic on the basis of percent BSP retention was: MT & DMAU > MENT > 11β-MNTDC. Hence, the rabbit appears to be a promising model for detection of potential liver toxicity by synthetic androgens using BSP clearance and serum liver enzyme levels as early indicators of injury.

Liver pathology associated with the use of anabolic-androgenic steroids

This review examines the liver-damaging side effects of anabolic-androgenic steroids (AAS). It seems that AAS can cause development of peliosis hepatis, subcellular changes of hepatocytes, hepatocellular hyperplasia and hepatocellular adenomas. On the other hand, it has not been convincingly proved that AAS can cause development of hepatocellular carcinomas when used in the usual therapeutic doses. Tumours reported as hepatocellular carcinomas caused by AAS seems to be hyperplastic lesions of a benign nature able to regress with withdrawal of the putative agent. The effects of untraditional combinations and high-dose AAS are not yet known, leaving the possibility of a carcinogenic effect in those cases.

Experimental treatment of thioacetamide-induced liver cirrhosis by metenolone acetate. A morphological and biochemical study

The influence of metenolone acetate (1 mg/kg b.m. orally) on intact and chronically thioacetamide-injured rat liver (experimental liver cirrhosis) was investigated over 14 d. Histological examination revealed nodular transformation of liver structure according to cirrhosis like lesions with hepatocellular and cholangiocellular proliferations. These structural alterations were more serious in the group treated with metenolone compared with the group without metenolone. Metanolone administration to animals with thioacetamide-induced experimental liver cirrhosis led to an increase in liver injury. This treatment seems to promote hepatic preneoplastic lesions induced by thioacetamide reflected by histology and induction of gamma-glutamyltranspeptidase and 7-ethoxycoumarin O-deethylase in injured livers. Metenolone did not interfere directly with the processes of connective tissue synthesis and degradation after thioacetamide pretreatment. Only little changes of the investigated biochemical parameters were seen after metenolone administration to animals with intact liver function: increases in serum cholinesterase and tissue N-acetyl-beta-D-glucosaminidase activity; decreases in N-acetyl-beta-D-glucosaminidase in serum, liver hydroxyproline content and hepatic gamma-glutamyltranspeptidase activity. The observed changes reflect hepatic adaption processes under the influence of metenolone. The results of this study indicate that the risk of anabolic steroids in adjuvant therapy of liver cirrhosis cannot be calculated at present.

Sex hormones and neoplasia: liver tumors in rodents

The association of liver tumors in women and men with the use of oral contraceptives and anabolics, respectively, has drawn attention to the hepatotumorigenic effects of sex hormones. The available evidence from long-term carcinogenicity studies in various strains of mice, rats and hamsters indicates that sex hormones are hepatotumorigenic agents, although the incidence of liver tumors is, in general, low even at doses exceeding human exposure by a factor of one hundred or more. Among the three rodent species, mice appear to be the least sensitive. Under certain modulating conditions, however, a 100% incidence of hepatocellular carcinomas can be obtained with some estrogens in male Syrian golden hamsters. The mechanism of the hepatotumorigenic effect of sex hormones is far from being clear. Whereas their tumor promoting activity is generally recognized, there is recent evidence suggesting that some sex hormones may also have initiating potential. Although the incomplete understanding of the mechanisms responsible for sex hormone induced liver neoplasia seriously hampers the assessment of the human risk, it appears to be clear that sex hormones are important modulating factors determining the incidence of hepatic tumors in rodents and possibly in humans.

Liver lesions in BALB/C mice induced by an anabolic androgen (Decadurabolin), with and without pretreatment with diethylnitrosamine

Male BALB/C mice were treated with the anabolic androgen Decadurabolin (17 beta-hydroxy-19-nor-androst-4-ene-17 beta-n-decanoate) (DecaD) with and without pretreatment with diethylnitrosamine (DEN). Treatment with DEN alone caused development of severe hepatocytic dysplasia in all animals; 11/11 had cystadenomas and 3/11 haemangiomas, both of which were benign. Mice treated with DecaD alone developed only moderate to severe hepatocytic dysplasia. Treatment with DecaD after DEN induced neoplasms in the livers; 15/15 had severe dysplasia; 14/15 had cystadenomas, 2/15 had haemangiomas, and 4/15 developed nodular proliferation. Single hepatomas were seen in 4/15 livers, two of which also had multiple hepatomas. Control animals had normal liver histology. We conclude that DecaD enhances the hepatocarcinogenicity of DEN, especially with respect to neoplastic lesions in hepatocytes.