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Partial hepatectomy induces delayed hepatocyte proliferation and normal liver regeneration in ovariectomized mice.

Umeda M, Hiramoto M, Imai T - Clin Exp Gastroenterol (2015)

Bottom Line: Both E2 administration and PH induced the gene expression of estrogen receptor α (ERα).The transcripts of ERα were detected specifically in periportal hepatocytes after E2 administration and PH.Moreover, the E2 concentrations and hepatocyte proliferation rates were highest in the proestrus period of the estrous cycle.

View Article: PubMed Central - PubMed

Affiliation: Department of Aging Intervention, National Center for Geriatrics and Gerontology, Obu, Aichi, Japan.

ABSTRACT
Estrogens play central roles in sexual development, reproduction, and hepatocyte proliferation. The ovaries are one of the main organs for estradiol (E2) production. Ovariectomies (OVXs) were performed on the female mice, and hepatocyte proliferation was analyzed. The ovariectomized mice exhibited delayed hepatocyte proliferation after partial hepatectomy (PH) and also exhibited delayed and reduced E2 induction. Both E2 administration and PH induced the gene expression of estrogen receptor α (ERα). The transcripts of ERα were detected specifically in periportal hepatocytes after E2 administration and PH. Moreover, the E2 concentrations and hepatocyte proliferation rates were highest in the proestrus period of the estrous cycle. Taken together, these findings indicate that E2 accelerated ERα expression in periportal hepatocytes and hepatocyte proliferation in the female mice.

No MeSH data available.


Related in: MedlinePlus

Delayed elevations of circulating E2 and ERα expression after PH were observed in the ORC and OVX mice.Notes: (A and B) PH increased circulating E2 concentrations. Sham-operated control (male mice, A, open squares; female mice, B, open circles), ORC (A, gray inverted triangles with dotted lines), and the OVX (B, filled triangles with dotted lines) B6 mice underwent PH operations, and the concentrations of E2 were analyzed. The values are expressed as the mean ± SEM (n=5). *P<0.05. (C) Possible model of the PH-induced E2 production.Abbreviations: E2, estradiol; ERα, estrogen receptor α; PH, partial hepatectomy; ORC, orchiectomy; OVX, ovariectomy; SEM, standard error of the mean.
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f1-ceg-8-175: Delayed elevations of circulating E2 and ERα expression after PH were observed in the ORC and OVX mice.Notes: (A and B) PH increased circulating E2 concentrations. Sham-operated control (male mice, A, open squares; female mice, B, open circles), ORC (A, gray inverted triangles with dotted lines), and the OVX (B, filled triangles with dotted lines) B6 mice underwent PH operations, and the concentrations of E2 were analyzed. The values are expressed as the mean ± SEM (n=5). *P<0.05. (C) Possible model of the PH-induced E2 production.Abbreviations: E2, estradiol; ERα, estrogen receptor α; PH, partial hepatectomy; ORC, orchiectomy; OVX, ovariectomy; SEM, standard error of the mean.

Mentions: Previous studies indicate that PH induces E2 concentration in human beings, rats, and male mice (Figure 1).9,11,12,20 E2 is converted from testosterone by aromatase, and the highest expression of aromatase is observed in the ovary and the testis; however, other tissues (eg, the gonads, placenta, adipose tissue, etc) also weakly produce aromatase.21,22 These observations suggested that no PH-induced E2 production was observed in orchiectomized (ORC) mice. So, the male mice were operated with ORC, and then, these ORC mice were operated with PH. After PH, plasmas were collected, and circulating E2 concentrations were measured (Figure 1A). Plasma E2 was strongly elevated after 6–48 hours in the control mice after PH (open squares) and was also induced after 24–48 hours in the ORC mice (filled triangles with dotted lines), which indicates that the E2 induction following PH was delayed and reduced in the ORC mice. PH-induced E2 concentrations were mainly from testes (of control mice) and majorly from nontestes organs (of ORC mice, eg, gonads, adipose tissue; Figure 1C).


Partial hepatectomy induces delayed hepatocyte proliferation and normal liver regeneration in ovariectomized mice.

Umeda M, Hiramoto M, Imai T - Clin Exp Gastroenterol (2015)

Delayed elevations of circulating E2 and ERα expression after PH were observed in the ORC and OVX mice.Notes: (A and B) PH increased circulating E2 concentrations. Sham-operated control (male mice, A, open squares; female mice, B, open circles), ORC (A, gray inverted triangles with dotted lines), and the OVX (B, filled triangles with dotted lines) B6 mice underwent PH operations, and the concentrations of E2 were analyzed. The values are expressed as the mean ± SEM (n=5). *P<0.05. (C) Possible model of the PH-induced E2 production.Abbreviations: E2, estradiol; ERα, estrogen receptor α; PH, partial hepatectomy; ORC, orchiectomy; OVX, ovariectomy; SEM, standard error of the mean.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494181&req=5

f1-ceg-8-175: Delayed elevations of circulating E2 and ERα expression after PH were observed in the ORC and OVX mice.Notes: (A and B) PH increased circulating E2 concentrations. Sham-operated control (male mice, A, open squares; female mice, B, open circles), ORC (A, gray inverted triangles with dotted lines), and the OVX (B, filled triangles with dotted lines) B6 mice underwent PH operations, and the concentrations of E2 were analyzed. The values are expressed as the mean ± SEM (n=5). *P<0.05. (C) Possible model of the PH-induced E2 production.Abbreviations: E2, estradiol; ERα, estrogen receptor α; PH, partial hepatectomy; ORC, orchiectomy; OVX, ovariectomy; SEM, standard error of the mean.
Mentions: Previous studies indicate that PH induces E2 concentration in human beings, rats, and male mice (Figure 1).9,11,12,20 E2 is converted from testosterone by aromatase, and the highest expression of aromatase is observed in the ovary and the testis; however, other tissues (eg, the gonads, placenta, adipose tissue, etc) also weakly produce aromatase.21,22 These observations suggested that no PH-induced E2 production was observed in orchiectomized (ORC) mice. So, the male mice were operated with ORC, and then, these ORC mice were operated with PH. After PH, plasmas were collected, and circulating E2 concentrations were measured (Figure 1A). Plasma E2 was strongly elevated after 6–48 hours in the control mice after PH (open squares) and was also induced after 24–48 hours in the ORC mice (filled triangles with dotted lines), which indicates that the E2 induction following PH was delayed and reduced in the ORC mice. PH-induced E2 concentrations were mainly from testes (of control mice) and majorly from nontestes organs (of ORC mice, eg, gonads, adipose tissue; Figure 1C).

Bottom Line: Both E2 administration and PH induced the gene expression of estrogen receptor α (ERα).The transcripts of ERα were detected specifically in periportal hepatocytes after E2 administration and PH.Moreover, the E2 concentrations and hepatocyte proliferation rates were highest in the proestrus period of the estrous cycle.

View Article: PubMed Central - PubMed

Affiliation: Department of Aging Intervention, National Center for Geriatrics and Gerontology, Obu, Aichi, Japan.

ABSTRACT
Estrogens play central roles in sexual development, reproduction, and hepatocyte proliferation. The ovaries are one of the main organs for estradiol (E2) production. Ovariectomies (OVXs) were performed on the female mice, and hepatocyte proliferation was analyzed. The ovariectomized mice exhibited delayed hepatocyte proliferation after partial hepatectomy (PH) and also exhibited delayed and reduced E2 induction. Both E2 administration and PH induced the gene expression of estrogen receptor α (ERα). The transcripts of ERα were detected specifically in periportal hepatocytes after E2 administration and PH. Moreover, the E2 concentrations and hepatocyte proliferation rates were highest in the proestrus period of the estrous cycle. Taken together, these findings indicate that E2 accelerated ERα expression in periportal hepatocytes and hepatocyte proliferation in the female mice.

No MeSH data available.


Related in: MedlinePlus