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The hormonal control of protein N-glycosylation in the developing rabbit mammary gland and its effect upon transferrin synthesis and secretion

1985; Elsevier BV; Volume: 847; Issue: 3 Linguagem: Inglês

10.1016/0167-4889(85)90040-0

1879-2596

Judith P. Bradshaw, J. Hatton, David A. White,

Growth Hormone and Insulin-like Growth Factors

Pregnant rabbit mammary gland explants cultured with insulin, prolactin and cortisol, synthesise and secrete transferrin radiolabelled with [3H]leucine or [3H]mannose. Omission of prolactin from the culture medium inhibited the incorporation of [3H]leucine into casein but not transferrin. Total transferrin secreted under these conditions was approx. 75% of the control (+ prolactin) value measured by rocket immunoelectrophoresis. Little incorporation of [3H]mannose into transferrin was seen in the absence of prolactin suggesting a lack of glycosylation of the protein. Dual label experiments with [3H]mannose and [14C]leucine confirmed this. The decreased incorporation of [3H]mannose into dolichol linked intermediates suggests a general effect on protein N-glycosylation in the absence of prolactin. Thus, while the synthesis of the polypeptide backbone of transferrin does not require prolactin its glycosylation does.