Extraction of rat pituitary prolactin for radioimmunoassay
- 8 Downloads
The bulk of Prolactin (PRL) in rat pituitary gland stored as big molecular forms in secretory granules is mostly excluded from radioimmunoassay (RIA) determinations because secretory granules remain intact after tissue homogenization. Also big PRL is little immunoreactive and must be deaggregated to monomers to allow a complete detection by RIA. Different dissociating agents, used to render PRL monomers soluble, were tested at various temperatures and pH conditions. Incubations of pituitary homogenates in buffers at neutral pH yield consistent levels of PRL, but the sole alkalinization of the media increases significantly the radioimmunoassayable PRL content. No significant increase was detected with EDTA and thiols. The 2.5 M urea was the most effective extraction agent increasing about 7-fold the quantification of PRL by RIA. Extraction of PRL with urea was enhanced at pH 9.0 and at 4 C and this combination constitutes the method of choice for a complete extraction of pituitary PRL.
Key-wordsProlactin extraction RIA pituitary gland PRL polymers
Unable to display preview. Download preview PDF.
- 1.Torres A.I., Haggi, E.S., Aoki A. Isolation of two different pools of pituitary prolactin. Acta Endocrinol. (Copenh.) 107: 25, 1984.Google Scholar
- 3.Haggi E., Aoki A. Prolactin content in rat pituitary gland, RIA of prolactin after different extraction procedures. Acta Endocrinol. (Copenh.) 97: 338, 1981.Google Scholar
- 10.Jacobs L.S., Lorenson M.Y. Extractability of rat pituitary prolactin: rat and bovine prolactins are stored differently. In: Mac Leod R.M., Thorner M.O., Scapagnini U. (Eds.), Prolactin basic and clinical correlates. Liviana Press, Padova, 1985, p. 455.Google Scholar