Obesity and dehydroepiandrosterone/dehydroepiandrosterone sulfate relationships in lean, obese, and meat-type cross-bred boars: responses to porcine growth hormone.
As so many variables can affect obesity (age, genetics, health status), new directions, other than reducing or altering diet, are being pursued in controlling obesity in our society. Both dehydroepiandrosterone (DHEA) and GH have reported antiobesity effects; thus, the possible interaction of these hormones was investigated in genetically lean, obese, and meat-type cross-bred male pigs (boars) administered implants that released 0, 2, or 4 mg/day recombinant porcine GH (pGH) for 42 days. Subcutaneous fat was determined by measurement of back fat depth at 2-week intervals, and blood samples were obtained 0, 7, 14, 28, and 42 days post-implant. The weight of perinephrenic fat, an index of abdominal fat, was obtained at death. The obese line had higher DHEA/DHEA sulfate (DHEA-SO4) serum concentrations than the lean and cross-bred boars. Treatment with pGH reduced sc and perinephrenic fat in all lines at both doses (P < 0.01). There was no relationship between day 42 concentrations of DHEA/DHEA-SO4 and indexes of obesity. Concentrations of DHEA/DHEA-SO4 were decreased by pGH treatment (P < 0.01) by days 7-14 in all genetic lines. Concentrations of insulin-like growth factor I, insulin-like growth factor II, and insulin were increased with pGH treatment in all lines (P < 0.01). The a priori hypothesis that increases in these peptides would stimulate gonadal steroidal synthesis (as demonstrated in vitro) and result in elevated DHEA/DHEA-SO4 concentrations and reduced obesity was not supported by pGH-induced decreases in DHEA/DHEA-SO4. Insulin concentrations were elevated 7-14 days postimplant in all lines (P < 0.01), then declined in the later stages of the trial. Insulin concentrations and DHEA/DHEA-SO4 concentrations were inversely related (r = -0.59; P < 0.05); this may indicate that with elevated insulin levels, DHEA/DHEA-SO4 is decreased and has a limited opportunity to affect obesity. Although the administration of DHEA may reduce obesity, the lipolytic action of pGH does not appear to be through increased circulating concentrations of DHEA/DHEA-SO4.
Wise
T
T
U.S. Department of Agriculture, Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, Nebraska 68933-0166, USA.
Klindt
J
J
Buonomo
F C
FC
D000822:Animal Husbandry; D000818:Animals; D003687:Dehydroepiandrosterone / Q000031:analogs & derivatives* / Q000097:blood*; D019314:Dehydroepiandrosterone Sulfate; D013006:Growth Hormone / Q000494:pharmacology; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D008297:Male; D008460:Meat; D009765:Obesity / Q000097:blood*; D012016:Reference Values; D013552:Swine / Q000097:blood* / Q000235:genetics
D007328:Insulin; D003687:Dehydroepiandrosterone; D019314:Dehydroepiandrosterone Sulfate; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013006:Growth Hormone