1,25 (OH)2 vitamin D3 modifies growth and contractile function of vascular smooth muscle of spontaneously hypertensive rats.

The effects of 1,25 (OH)2 vitamin D3 on growth of cultured vascular myocytes and on the contractile response of isolated resistance arteries to norepinephrine was examined using tissue derived from 12-week-old spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats. 1,25 (OH)2 vitamin D3 (214 pg/mL) stimulated the growth of superior mesenteric artery myocytes cultured from the SHR and increased the sensitivity of isolated mesenteric resistance arteries to norepinephrine. These effects were not observed in tissue of the WKY. It is concluded that 1,25 (OH)2 vitamin D3 modulates vascular growth and contractility in the SHR, but apparently not the WKY. Possible mechanisms of action are discussed.