Hormonal effect on the formation of lipid-saccharide intermediates for N-linked glycoprotein biosynthesis of lactating bovine mammary gland in organ culture: Evidence of inhibitory action of hydrocortisone.

Abstract

The effects of prolactin (P), hydrocortisone (F), and insulin (I) on the formation of lipid-saccharide intermediates concerned in the N-linked glycoprotein biosynthesis of lactating bovine mammary explants in organ culture were examined using radioactive mannose (Man). The response of F was fast ( 72 hr). F at concentrations varied from 10−3 to 10 μg/ml decreased the incorporation of radioactivity from [14C]Man into the lipid-linked saccharides (C/M), lipid-linked oligosaccharides (C/M/W), and protein fractions by about 25~30%. On the other hand, at the range of 10−4 to 5 μg/ml, I had a stimulatory effect and P did not affect the N-glycosylation of mammary explants. The stimulatory effect of I, however, was negated by with F. Partial inhibition of F was shown by even 10 ng/ml. The inclusion of F into the pre-incubation medium significantly inhibited the [14C]Man incorporation in the C/M/W and protein fractions rather than in the C/M fraction. The results sugges...