Title

Thyroxine modifies the effects of growth hormone in Ames dwarf mice

Authors

Authors

A. Do; V. Menon; X. Zhi; A. Gesing; D. S. Wiesenborn; A. Spong; L. Sun; A. Bartke;M. M. Masternak

Comments

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Abbreviated Journal Title

Aging-US

Keywords

growth hormone; insulin; thyroxine; Ames dwarf; longevity; LONG-LIVED MICE; CALORIC RESTRICTION; INSULIN SENSITIVITY; SKELETAL-MUSCLE; LIFE-SPAN; HEALTHY CENTENARIANS; GH RESISTANCE; AGING-PROCESS; IGF-I; EXPRESSION; Cell Biology

Abstract

Ames dwarf (df/df) mice lack growth hormone (GH), thyroid stimulating hormone and prolactin. Treatment of juvenile df/df mice with GH alone stimulates somatic growth, reduces insulin sensitivity and shortens lifespan. Early-life treatment with thyroxine (T4) alone produces modest growth stimulation but does not affect longevity. In this study, we examined the effects of treatment of juvenile Ames dwarf mice with a combination of GH + T4 and compared them to the effects of GH alone. Treatment of female and male dwarfs with GH + T4 between the ages of 2 and 8 weeks rescued somatic growth yet did not reduce lifespan to match normal controls, thus contrasting with the previously reported effects of GH alone. While the male dwarf GH + T4 treatment group had no significant effect on lifespan, the female dwarfs undergoing treatment showed a decrease in maximal longevity. Expression of genes related to GH and insulin signaling in the skeletal muscle and white adipose tissue (WAT) of female dwarfs was differentially affected by treatment with GH + T4 vs. GH alone. Differences in the effects of GH + T4 vs. GH alone on insulin target tissues may contribute to the differential effects of these treatments on longevity.

Journal Title

Aging-Us

Volume

7

Issue/Number

4

Publication Date

1-1-2015

Document Type

Article

Language

English

First Page

241

Last Page

255

WOS Identifier

WOS:000354036900005

ISSN

1945-4589

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