Altered electrolyte and taurine levels in milk from nursing hypertensive rats

To examine whether milk factors play a role in the development of hypertension in the spontaneously hypertensive rat (SHR) of the Okamoto strain we have examined the levels of electrolytes and the amino acid taurine in milk from nursing SHR, Wistar Kyoto (WKY) and the stroke prone substrain of the SHR (SHR-SP). The Na + concentration of SHR milk was significantly higher than that of the WKY and SHR-SP. The K + concentration of SHR milk tended to be lower than that of WKY and SHR-SP and thus the Na/K ratio of SHR milk was significantly higher than that of both the SHR-SP and WKY. While taurine levels of SHR and SHR-SP milk were 29% and 28% higher than that of WKY respectively, these differences were only of borderline significance (p=0.07). The blood pressure of offspring at 8 and 12 weeks failed to correlate with milk factors within any strain. Thus while the altered levels of electrolytes in milk from SHR may play a role in the development of its hypertension the results for the SHR-SP suggests that these differences are not invariably associated with high blood pressure.