Biochemical Effects of Recombinant Porcine Somatotropin on Pig Fetal Growth and Metabolism: A Review

Fetal growth is increased when pregnant gilts are treated with recombinant porcine somatotropin. The mechanism for increased fetal growth was examined by measuring the expression of IGF-I and -II and IGF-binding protein-2 (IGFBP-2) mRNA in liver and reproductive tissues of somatotropin- and saline-treated pregnant gilts. Twenty-four pregnant gilts received daily injections of either saline (control; n=12) or 5 mg recombinant porcine somatotropin (n=12) from day 30 to day 43 of gestation. Gilts were slaughtered on day 44 of gestation and liver, ovary, placenta, placental uterus (uterus with adjacent placental tissue) and non-placental uterus (region of the necrotic tip) were collected. The mRNAs for somatotropin receptor, IGFs -I and -II, IGFBP-2 and pregnancy-associated glycoprotein (a marker of trophoblast tissue) were analyzed by Northern blotting or ribonuclease protection assay. Gilts treated with somatotropin had heavier fetuses and placentas. The concentration of mRNA for the components of the IGF system was tissue-dependent. The uterine IGF-I mRNA concentration was greater in non-placental than in placental uterus. The greatest IGF-II mRNA concentration was observed in placenta, and adjacent uterine tissue expressed IGFBP-2 mRNA intensely. In non-placental uterus, IGFBP-2 mRNA was nearly undetectable. Somatotropin-dependent regulation of IGF-I was only observed in liver, where the greatest somatotropin receptor mRNA concentration was found. In the pregnant uterus, somatotropin failed to change the concentration of IGF or IGFBP-2 mRNA. Pregnancy-associated glycoprotein mRNA concentration was decreased by somatotropin. In summary, increased fetal growth in somatotropin-treated pregnant pigs was not associated with changes in IGF or IGFBP-2 mRNA concentration in reproductive tissues. Other mechanisms, therefore, lead to enhanced fetal growth in somatotropin-treated pregnant pigs.

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Effects of recombinant porcine somatotropin on placental size, fetal growth, and IGF-I and IGF-II concentrations in pigs.

Journal of Animal Science ◽

10.2527/1995.73102980x ◽

1995 ◽

Vol 73 (10) ◽

pp. 2980 ◽

Cited By ~ 37

Author(s):

J A Sterle ◽

T C Cantley ◽

W R Lamberson ◽

M C Lucy ◽

D E Gerrard ◽

...

Keyword(s):

Fetal Growth ◽

Porcine Somatotropin ◽

Igf I

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Effects of 5-5'-Diphenyl-2-thiohydantoin (DPTH) and Thyroxine on the Ultrastructure and Chemical Composition of Rat Liver

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066917 ◽

1971 ◽

Vol 29 ◽

pp. 570-571

Author(s):

E. A. Elfont ◽

R. B. Tobin ◽

D. G. Colton ◽

M. A. Mehlman

Keyword(s):

Chemical Composition ◽

Rat Liver ◽

Future Study ◽

Mode Of Action ◽

Liver Mitochondria ◽

Rat Liver Mitochondria ◽

Effective Inhibitor ◽

Biochemical Effects ◽

Glycerophosphate Dehydrogenase ◽

Stimulation Of

Summary5,-5'-diphenyl-2-thiohydantoin (DPTH) is an effective inhibitor of thyroxine (T4) stimulation of α-glycerophosphate dehydrogenase in rat liver mitochondria. Because this finding indicated a possible tool for future study of the mode of action of thyroxine, the ultrastructural and biochemical effects of DPTH and/or thyroxine on rat liver mere investigated.Rats were fed either standard or DPTH (0.06%) diet for 30 days before T4 (250 ug/kg/day) was injected. Injection of T4 occurred daily for 10 days prior to sacrifice. After removal of the liver and kidneys, part of the tissue was frozen at -50°C for later biocheailcal analyses, while the rest was prefixed in buffered 3.5X glutaraldehyde (390 mOs) and post-fixed in buffered 1Z OsO4 (376 mOs). Tissues were embedded in Araldlte 502 and the sections examined in a Zeiss EM 9S.Hepatocytes from hyperthyroid rats (Fig. 2) demonstrated enlarged and more numerous mitochondria than those of controls (Fig. 1). Glycogen was almost totally absent from the cytoplasm of the T4-treated rats.

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