Lactogenic hormones

The lactogenic hormone of the pituitary is one that has been known for a relatively long time and has been purified. The hormonal control of lactation and of the development of the mammary glands is complicated by several endocrine interactions, but the lactogenic hormone is a potent and highly important agent. 

Lactogenic hormone lactogen galactin mammotropin) Develops mammary glands in female... 

Binding sites for prolactin and other lactogenic hormones are widely distributed in mammalian tissues [26,27]. Discrimination by such binding sites between GH and prolactin is not always complete, and the frequent use of 125I-labelled human GH... 

The Nb2 cell line was derived from a rat lymphoma and can be grown in vitro indefinitely. Its growth is dependent on the presence of serum in particular, in the presence of 10% horse serum and 10% fetal calf serum, proliferation of Nb2 cells is rapid, but if the fetal calf serum is omitted proliferation almost ceases. A series of studies showed that the requirement for fetal calf serum could be replaced by prolactin or other lactogenic hormones (human GH has frequently been used) [105], It is not clear that the component in fetal calf serum that provides the stimulant for growth of the cell line actually is prolactin [106], but it is established that under appropriate conditions (presence of horse serum) lactogenic hormones act as specific mitogens for the line (Fig. 8). The response is very sensitive, 1 ng/ml giving a max-... 

A possible involvement of polyamines in the response has been suggested. Prolactin stimulated ornithine decarboxylase activity in Nb2 cells [109]. A specific inhibitor of this enzyme partially blocked the actions of lactogenic hormones on Nb2 cell proliferation [110], and addition of polyamines (putrescine, spermidine or spermine) restored normal growth. However, polyamines alone had no effect on Nb2 cell proliferation, suggesting that they are not the sole or major factors involved in mediating the actions of prolactin on cell growth. 

Gerder, A., Grosclaude, J., Strasburger, C. J., Nir, S., and Djiane, J. (1996). Real-time kinetic measurements of the interactions between lactogenic hormones and prolactin-receptor extracellular domains from several species support the model of hormone-induced transient receptor dimerization. J. Biol. Ghent. 271(40), 24482-24491. 

Shiu R, Kelly P, Friesen H. Radioreceptor assay for prolactin and other lactogenic hormones. Science 1973 180 968-71. 

Tanalta T, Shiu RP, Gout PW, Beer C% Noble RL, Friesen HG. A new sensitive and specific assay for lactogenic hormones Measurement of prolactin and growth hormones in human serum. J Clin Endocrinol Me tab 1980 51 1058-63. 

K5. Koenig, V. L., and King, E., Extraction studies of sheep pituitary gonadotropic and lactogenic hormones in alcoholic acetate buffers. Arch. Biochem. Biophys. 26, 219-229 (1950). 

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