Radioreceptor Assay for Prolactin and Other Lactogenic Hormones

Abstract

A radioreceptor assay with a sensitivity of 5 nanograms per milliliter has been developed for mammalian and avian pituitary prolactin, placental lactogenic hormones, and humnan growth hormone, using a membrane receptor preparation isolated from rabbit mammary glands. Prolactin preparations inhibited the binding of [(125)I]prolactin to receptors in direct proportion to the biological potency of these preparations. Thus, the radioreceptor assay provides a convenient and simnple assay for hormones which have lactogenic activity.

Circulating levels of prolactin in human breast cancer

“…Mittra, Hayward and McNeilly (1974) also did not find a difference in mean basal plasma prolactin levels in breast cancer patients and control women. Shiu et al (1973a) were unable to find elevations in serum lactogenic activity in a group of breast cancer patients by using a sensitive radioreceptor assay (Shiu, Kelly and Friesen, 1973b). These results correlated well with radioimmunoassay measurements in the same sera .…”

The effects of monoclonal antibodies against human growth hormone on hormone—receptor interactions

“…It was of interest therefore to determine whether these antibodies could interfere with the interaction between labelled hGH and receptors from rabbit liver or mammary gland. The mammary gland receptors are specific for lactogenic hormones such as prolactin and human (but not non-primate) growth hormone [4], whereas the liver receptors bind prolactins and growth hormones from several different species [ 51, but show a species specificity that does not accord well with the biological actions of the hormone [6,7]. These results show that 2 of the 4 monoclonal antibodies tested can block receptor binding almost comhGH was a gift from the National Institute of Biological Standards and Control (Hampstead) and was labelled with Na"'I (obtained from the Radiochemical Centre, Amersham, Bucks) by the 'iodogen' method [8] as in [7].…”

Insulin receptors in human cancer

“…Sixty-seven tissue samples were ob- (Holdaway & Friesen, 1977) of the method of Shiu & Friesen (Shiu et al, 1973). In brief, tissue was homogenized in cold 0-3M sucrose with a polytron homogenizer and centrifuged at 15,000 g for 20 min at 4°C.…”