Hormonal and metabolic effects of genistein and daidzein in male rat

Abstract

Genistein and daidzein belong to a large group of compounds called phytooestrogens present in several plants consumed by animals. Apart from oestrogenic activity, these compounds influence on many different processes in the organism. Their effect on metabolic processes was previously observed, however, it is poorly understood. In the performed experiment the effect of genistein (5 mg/kg BW) or daidzein (5 mg/kg BW) administered intragastrically for three days to growing male rats was studied and compared to oestradiol (0.1 mg/kg BW). Both phytooestrogens and oestradiol caused slight increase in blood glucose content with concomitant drop in insulin level. Blood cholesterol and HDL-cholesterol were not statistically altered. However, a slight reduction in total cholesterol with simultaneous slight rise in HDL-cholesterol in rats receiving oestradiol and phytooestrogens caused that HDL-cholesterol/total cholesterol ratio was significantly higher in these animals. The tested substances had no influence on blood free fatty acids and triglycerides. All these compounds caused substantial diminution in muscle triglycerides content. Liver glycogen, triglycerides and cholesterol contents were augmented only by daidzein.Our results indicate that genistein and daidzein evoked many similar metabolic changes. These changes were comparable to those caused by oestradiol and to changes induced by genistein and observed previously in ovariectomized rats.

The influence of genistein on insulin, leptin, thyroid hormones and metabolic parameters in mature rats

“…It was demonstrated that genistein (5 mg/kg BW for seven days) diminished the blood leptin level in immature female rats . Similar results were observed in adult male rats receiving genistein at the same dose (5 mg/kg BW) but only for 3 days (Szkudelska et al, 2003). Also, blood leptin levels were reduced in adult male rats consuming a diet enriched in isoflavones (Lephart et al, 2004).…”

“…HDLcholesterol was assayed in serum after separation of high density lipoproteins using polyethylene glycol. Liver and muscle glycogen was extracted and hydrolysed by amyloglucosidase (Szkudelska et al, 2003). Liver and muscle triglycerides and cholesterol content were determined similarly as in serum after extraction of total lipids using the method of Folch et al (1975).…”

“…There are many results that support such an activity of the investigated phytoestrogen. Szkudelska et al (2003) demonstrated that genistein may effectively modulate insulin concentrations. This phytoestrogen at a dose of 5 mg/kg BW administered for 3 days diminished blood insulin levels in adult male rats (Szkudelska et al, 2003).…”

“…Szkudelska et al (2003) demonstrated that genistein may effectively modulate insulin concentrations. This phytoestrogen at a dose of 5 mg/kg BW administered for 3 days diminished blood insulin levels in adult male rats (Szkudelska et al, 2003). A similar effect was observed in immature female rats after 7 days of treatment with genistein ).…”

“…Nogowski et al (1998) found that genistein decreased the triglyceride concentration in blood and skeletal muscle in ovariectomized rats fed a diet with genistein for 14 days. In an experiment performed on male rats receiving the tested compound, serum HDL-cholesterol also tended to be increased (Szkudelska et al, 2003). Moreover, this isoflavone has an influence on metabolism of isolated rat adipocytes.…”