The hyperinsulinemia produced by concanavalian A in rats is opioid-dependent and hormonally regulated
Braz. j. med. biol. res
;
31(5): 697-703, May 1998. tab, graf
Artigo
em Inglês
| LILACS
| ID: lil-212410
RESUMO
The present study examines the effect of concanavalin A (Con A) on the blood insulin and glucose levels of rats. Male and female rats treated with Con A (62.5-500 mug/kg) for three days showed a dose-and time-dependent hyperinsulinemia that lasted more than 48 h. Male rats were more sensitive to Con A. Thus, 6 h after treatment with Con A the circulating insulin levels in male rats had increased by 85 percent (control 10.2 + 0.9 mU/l and Con A-treated 18.8 + 1 mU/l) compared to only 38 percent (control 7.5 + 0.2 mU/l; Con A-treated 10.3 + mU/l) in females. An identical response was seen after 12 h. Con A (250 mug/kg) produced time-dependent hypoglycemia in both sexes but more pronounced in males. There was no correlation between the hypoglycemia and hyperinsulinemia described above. The Con A-induced hyperinsulinemia in rats of both sexes was abolished in gonadectomized animals (intact males +101 + 17 percent vs orchiectomized males -5 + 3 percent; intact females +86 + 23 percent vs ovariectomized females -18 + 7.2 percent). Pretreating intact male and female rats with human chorionic gonadotropin also significantly inhibited the Con A-induced hyperinsulinemia. Estradiol (10 mug/kg, im) significantly blocked the Con A-induced increase in circulating insulin in male rats (101 + 17 percent for controls vs 32 + 5.3 percent for estradiol-treated animals, P<0.05) while testosterone (10 mg/kg, im) had no similar effect on intact female rats. Pretreating Con A-injected rats with opioid antagonists such as naloxone (1 mg/kg, sc) and naltrexone (5 mg/kg, sc) blocked the hyperinsulinemia produced by the lectin in males (control +101 + 17 percent vs naloxone-treated +5 + 14 percent, or naltrexone-treated -23 + 45 percent) and females (control +86 + 23 por cent vs naloxone-treated +21 + 20 percent, or naltrexone-treated -18 + 11 percent). These results demonstrate that Con A increases the levels of circulating insulin in rats and that this response is opioid-dependent and hormonally regulated.
Texto completo:
DisponíveL
Índice:
LILACS (Américas)
Assunto principal:
Concanavalina A
/
Hormônios
/
Hiperinsulinismo
/
Antagonistas de Entorpecentes
Limite:
Animais
Idioma:
Inglês
Revista:
Braz. j. med. biol. res
Assunto da revista:
Biologia
/
Medicina
Ano de publicação:
1998
Tipo de documento:
Artigo
/
Congresso e conferência
/
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