Rat Liver Alcohol Dehydrogenase Activity: Effects of Growth Hormone and Hypophysectomy*

Mezey, Esteban; Potter, James J.

doi:10.1210/endo-104-6-1667

Cited by 41 publications

(8 citation statements)

References 38 publications

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“…Rates of cytosolic iV-hydroxyarylamine and hydroxysteroid sulf ations are also differ between the sexes (15,16,33). hepatic proteins in rats (22,23,29,30,34,35). Thus, the effect of pituitary factor on T s sulfotransferase in rat livers was examined.…”

Section: Sulfation Of T and Its Regulation By Gh And T-mentioning

confidence: 99%

Hepatic Triiodothyronine Sulfation and Its Regulation by Growth Hormone and Triiodothyronine in Rats1

Gong

Murayama

Yamazoe

et al. 1992

The Journal of Biochemistry

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The regulatory mechanism of cytosolic sulfation of T3 has been studied in rat liver. Sulfation of T3 is sexually differentiated in adult rats of Sprague-Dawley (SD), Fisher 344, and ACI strains. In SD strain, the male animals showed 4 times higher sulfating activity than did the females. The specific activity was decreased by hypophysectomy of male adult rats, but was not affected in the females. Thus, the sex-difference was abolished in the hypophysectomized condition. Supplement of human GH intermittently twice daily for 7 days, to mimic the male secretory pattern, increased T3 sulfating activity in both sexes of hypophysectomized rats, whereas continuous infusion to mimic a female secretory pattern had no appreciable effect. Cytosolic sulfation of T3 was decreased by 25 to 30% by thyroidectomy or propylthiouracil treatment of male adult rats, and was restored by the supplementation of T3 (50 micrograms/kg daily for 7 days) to thyroidectomized rats. Administration of T3 in hypophysectomized rats almost completely restored the sulfating activity in the males and increased the activity in the females. Cytosolic T3 sulfation was inhibited by the addition of known inhibitors of phenol sulfotransferase, pentachlorophenol or 2,6-dichloro-4-nitrophenol. These results indicate a role of pituitary GH in hepatic sulfation of thyroid hormones in rats. The data obtained also raise the possibility that GH may modify the effect of thyroid hormones on the pituitary by a feed-back mechanism through changing the level of a sex-dominant phenol sulfotransferase(s) in rat livers. T3 was also sulfated in hepatic cytosols of mouse, hamster, rabbit, dog, monkey, and human.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Sulfation Of T and Its Regulation By Gh And T-mentioning

confidence: 99%

Hepatic Triiodothyronine Sulfation and Its Regulation by Growth Hormone and Triiodothyronine in Rats1

Gong

Murayama

Yamazoe

et al. 1992

The Journal of Biochemistry

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“…Some authors have shown that estrogen increased and testosterone decreased hepatic ADH activities, whereas others have found no effect (40,41,52). Growth hormone (GH) has also been shown to be important in regulation of hepatic ADH-specific activity and transcriptional regulation of mRNA in vivo and in vitro, respectively (39,49). Sexual dimorphic expression of hepatic genes in rats is most often due to sexual difference in the GH secretory pattern, which is regulated, in part, by sex steroid hormones (20,54).…”

mentioning

confidence: 99%

Sexual dimorphic expression of ADH in rat liver: importance of the hypothalamic-pituitary-liver axis

Simon

Fortune

Iwahashi

et al. 2002

American Journal of Physiology-Gastrointestinal and Liver Physi

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Hepatic alcohol dehydrogenase (ADH) activity is higher in female than in male rats. Although sex steroids, thyroid, and growth hormone (GH) have been shown to regulate hepatic ADH, the mechanism(s) for sexual dimorphic expression is unclear. We tested the possibility that the GH secretory pattern determined differential expression of ADH. Gonadectomized and hypophysectomized male and female rats were examined. Hepatic ADH activity was 2.1-fold greater in females. Because protein and mRNA content were also 1.7- and 2.4-fold greater, results indicated that activity differences were due to pretranslational mechanisms. Estradiol increased ADH selectively in males, and testosterone selectively decreased activity and mRNA levels in females. Effect of sex steroids on ADH was lost after hypophysectomy; infusion of GH in males increased ADH to basal female levels, supporting a role of the pituitary-liver axis. However, GH and L-thyroxine (T4) replacements alone in hypophysectomized rats did not restore dimorphic differences for either ADH activity or mRNA levels. On the other hand, T4 in combination with intermittent administration of GH reduced ADH activity and mRNA to basal male values, whereas T4 plus GH infusion replicated female levels. These results indicate that the intermittent male pattern of GH secretion combined with T4 is the principal determinant of low ADH activity in male liver.

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“…33 In primary hepatocyte culture, continuous exposure to growth hormone, which mimics the female pattern, increases ADH message and activity, 8 and these effects are initiated at the level of transcription. 13 Hypophysectomy increases ADH activity, 39,40 and, in these rats, steady infusion of growth hormone increases ADH message and activity, whereas intermittent injection reduces the enzyme message and activity. 40 A direct effect of androgens on ADH activity, shown in this study, in hepatocyte culture may also occur in vivo.…”

Section: Discussionmentioning

confidence: 97%

Effect of dihydrotestosterone on turnover of alcohol dehydrogenase in rat hepatocyte culture

1998

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Dihydrotestosterone decreased alcohol dehydrogenase (ADH) activity and enzyme-protein in rat hepatocytes in culture. This effect was observed after the hepatocytes had been exposed to dihydrotestosterone for 3 days at concentrations of 0.5 mol/L or higher. Dihydrotestosterone did not decrease alcohol dehydrogenase messenger RNA (mRNA) but, rather, resulted in small increases in ADH mRNA after 3 days of exposure. To further determine the mechanism for the effects of dihydrotestosterone in decreasing the enzyme, the turnover of ADH was determined after incorporation of Liver alcohol dehydrogenase (ADH; alcohol: nocotinamide adenine dinucleotide oxidoreductase, EC 1.1.1.1) is the principal enzyme responsible for ethanol oxidation. In the rat liver, there is a single class-I ADH, whereas in the liver of both human and animals there are multiple forms. The gene encoding the rat class-I ADH and the enzyme are under hormonal regulation. 1 Castration in male rats increases liver ADH activity and rates of ethanol elimination. 2,3 The enhanced ADH activity is decreased by continuous administration of testosterone. 2,3 Dihydrotestosterone is a more potent androgen than testosterone and is the active form of the hormone in many androgen target tissues. 4 Dihydrotestosterone suppresses ADH activity in primary rat hepatocyte culture 5 ; in addition, dihydrotestosterone is an in vitro inhibitor of class-I ADH in the rat 6 and of the ␥ subunit isoenzymes in man. 7 However, this in vitro inhibition is an unlikely mechanism for the decrease in the enzyme as the inhibitor constant (K i ) for inhibition of ethanol oxidation by the rat enzyme is 11.5 µmol/L 6 which is 10 times higher than the 1 µmol/L concentration which depresses the enzyme activity in hepatocyte culture. 5 The purpose of this study is to determine the mechanism whereby dihydrotestosterone depresses alcohol dehydrogenase in rat hepatocyte culture. MATERIALS AND METHODS Material MethodsHepatocyte Isolation and Cell Culture. Hepatocytes were isolated and cultured from rats weighing 150 to 200 g, as described previously. 8 The cells were cultured in 60 ϫ 15 mm culture dishes which were previously coated with 50 µg of collagen. A total of 3.0 ϫ 10 6 cells in 3.0 mL of culture medium were placed in each dish. The culture medium was serum-free DMEM with dexamethasone (0.1 µmol/L) and the following supplemental growth factors (supplemental growth factor-7, SGF-7): insulin (250 U); epidermal growth factor (10 µg); transferrin (0.5 mg); sodium selenite (5.0 µg); linoleic acid (0.5 mg); fetuin (0.5 mg); and bovine serum albumin (0.5 mg) per liter of DMEM. It also contained penicillin (1 ϫ 10 6 U/L) and streptomycin (0.13 mmol/L). The medium was saturated with 95% O 2 and 5% CO 2 . The cultures were incubated at 37°C in a humidified atmosphere of 95% O 2 and 5% CO 2 .ADH Activity. Dihydrotestosterone was added to the culture medium 14 to 16 hours after starting the cultures and was omitted from Abbreviations: mRNA, messenger RNA; ADH, alcohol dehydrogenase; DMEM, Dulbecco' s...

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Rat Liver Alcohol Dehydrogenase Activity: Effects of Growth Hormone and Hypophysectomy*

Cited by 41 publications

References 38 publications

Hepatic Triiodothyronine Sulfation and Its Regulation by Growth Hormone and Triiodothyronine in Rats1

Hepatic Triiodothyronine Sulfation and Its Regulation by Growth Hormone and Triiodothyronine in Rats1

Sexual dimorphic expression of ADH in rat liver: importance of the hypothalamic-pituitary-liver axis

Effect of dihydrotestosterone on turnover of alcohol dehydrogenase in rat hepatocyte culture

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