Expression of insulin-like growth factor I stimulates normal somatic growth in growth hormone-deficient transgenic mice

RR Behringer, TM Lewin, CJ Quaife, RD Palmiter… - …, 1990 - academic.oup.com
RR Behringer, TM Lewin, CJ Quaife, RD Palmiter, RL Brinster, AJ D'ercole
Endocrinology, 1990academic.oup.com
A line of transgenic mice expressing insulin-like growth factor-I (IGF-I) under the control of
the mouse metallothionien-1 promoter was crossed to a line of dwarf transgenic mice
lacking GH expressing cells that were genetically ablated by diphtheria toxin expression.
Mice generated from this cross that carry both transgenes express IGF-I in the absence of
GH. These mice grew larger than their GH-deficient transgenic littermates and exhibited
weight and linear growth indistinguishable from that of their nontransgenic siblings. These …
A line of transgenic mice expressing insulin-like growth factor-I (IGF-I) under the control of the mouse metallothionien- 1 promoter was crossed to a line of dwarf transgenic mice lacking GH expressing cells that were genetically ablated by diphtheria toxin expression. Mice generated from this cross that carry both transgenes express IGF-I in the absence of GH. These mice grew larger than their GH-deficient transgenic littermates and exhibited weight and linear growth indistinguishable from that of their nontransgenic siblings. These results confirm the suspected role of IGF-I in mediating GH’s stimulation of somatic growth, including that of long bones, and illustrates the essential role of GH and IGF-I in the modulation of postnatal growth. Analysis of differences in organ growth among these mice, however, suggests that GH and IGF-I also have growth promoting actions that are independent of one another; GH appears to be necessary for the attainment of normal liver size, while IGF-I can stimulate brain growth. (Endocrinology127: 1033–1040,1990)
Oxford University Press