INDUCTION OF LIPID-SYNTHESIS IN MAMMARY ORGAN-CULTURES FROM MATURE VIRGIN AND PREGNANT GOATS

  • 1 January 1978
    • journal article
    • research article
    • Vol. 27  (1) , 53-59
Abstract
The hormones needed to induce lipogenesis in mammary organ cultures from mature virgin and pregnant goats were studied. In tissues from both mature virgin goats and goats at wk 10 of pregnancy, cultivated in Waymouth medium without hormones, the rate of the incorporation of [1-14C]-acetate into the lipids was low and decreased throughout culture. In the presence of insulin, the rate of acetate incorporaton was maintained at a higher level. Cortisol acted synergistically with insulin, to produce a rate of lipid synthesis higher than that using insulin alone. The further addition of prolactin had little effect on the incorporation of acetate into the lipids of mammary explants from mature virgin goats, but markedly stimulated it in tissue from animals at wk 9-10 of pregnancy. The maximum increase in the rate of lipid synthesis was achieved in the presence of 0.5 .mu.g prolactin/ml, whereas with growth hormone 50 .mu.g/ml was needed for the maximum effect. The initial rate of acetate incorporation into mammary explants from goats at wk 13 and 18 of pregnancy was high. It was not stimulated by the hormones during culture, however, and decreased more rapidly in the absence of hormones than in their presence. The rate of acetate incorporation into the lipids was in agreement with the histological evaluation of the secretory response of the mammary explants after cultivation. The secretory response to prolactin and the rate of the incorporation of acetate into the lipids were highest in goats at wk 9-10 of pregnancy while in tissues from goats at wk 13 and 18 were not stimulated and decreased during culture.