Parenteral Linoleic and -Linolenic Acids Ameliorate the Gross Effects of Zinc Deficiency

Publisher Website
Google Scholar
Abstract
Zn deficiency and essential fatty acid deficiency in rats have similar gross effects. Zn, prostaglandin [PG] E1 and dihomo-.gamma.-linolenic acid (PG E1 precursor) have similar effects on rat vascular smooth muscle. Zn deficiency has no consistent effect on tissue Zn or Zn enzymes. The mechanism by which Zn deficiency affects growth and metabolism may be via inhibition of PG synthesis from essential fatty acids [EFA]. This hypothesis was examined using Zn deficient rats supplemented with oils containing various concentrations of EFA. Male Wistar rats were maintained on a Zn deficient diet for 5 wk and supplemented daily with one of 3 oils containing different concentrations of essential fatty acids: olive oil (mainly oleic acid), safflower oil (mainly linoleic acid) or evening primrose oil (mainly linoleic and .gamma.-linolenic acids). The oliver oil treated rats did not benefit from this treatment. Dermal lesions were actually worse in this group than in the untreated Zn deficient rats. Safflower oil supplementation significantly inhibited the development of dermal lesions but was of only marginal benefit with respect to growth. Evening primrose oil supplementation blocked the development of dermal lesions and restored growth to 50% of control. A primary defect of Zn deficiency is to inhibit essential fatty acid metabolism to Pg by blocking linoleic acid desaturation to .gamma.-linolenic acid or by inhibiting mobilization of dihomo-.gamma.-linolenic acid from tissue membrane stores.