Heterogeneity in buffalo pituitary prolactin

A sensitive sandwich ELISA for buffalo prolactin

Two murine monoclonal antibodies have been developed against the buffalo prolactin (buPRL). These were designated as 1501 and 1504. Using two MAbs and anti-buPRL rabbit serum, an analysis was performed for the development of a sandwich ELISA (sELISA). The 1504/buPRL/anti-buPRL rabbit serum system was found feasible for sELISA. The sELISA had a sensitivity of 156 pg/mL. The buffalo serum sample showed a parallelism with the standard curve. The intra- and inter-assay coefficients of variance were 8.4% and 9.06%, respectively. These data proved the validity of the assay.

Enhanced Yield and Homogeneity of Buffalo Growth Hormone by an Improved Chromatographic Protocol

Loss of buffalo Growth Hormone (buGH) in the various side fractions of standard buGH purification protocol has been determined quantitatively by direct binding ELISA and qualitatively by SDS-PAGE and Western blot analysis. Accounting result indicated that there was a considerable loss of buGH in the side fractions. An alternative protocol to prevent loss and to obtain a high yield of buGH has been developed by introducing anion exchange chromatography, QAE-Sephadex. This has resulted in a simple, reproducible three-step protocol. In this protocol, an extract obtained at 250 mM (NH4)2 SO4, pH 5.5, was loaded onto the QAE-Sephadex column in 0.1 M NH4 HCO3. At this salt concentration, the bulk of the buGH came as QAE unbound fraction. Some amount of buGH, together with contaminating proteins, was bound to QAE-Sephadex and these could be eluted with 1 M KCl. The immunopotency of the enriched buGH preparation "QUB" (QAE unbound fraction) in a direct binding ELISA was similar to that of the semi-pure buGH (ECS/APECS) preparation obtained using the standard protocol, but the yield was 4 times higher. The SDS-PAGE data showed that the banding pattern of standard semi-pure buGH and QUB were quite similar and QUB can be loaded onto the Sephacryl S-200 gel filtration chromatography to yield a highly purified buGH. SDS-PAGE and Western blot analyses showed the major band of buGH in QUB at the same position as in the case of standard buGH. It has also been demonstrated here that it is possible to separate buffalo prolactin (buPRL) and buGH on QAE-Sephadex.

Simultaneous isolation of prolactin and growth hormone from "discarded acid pellet" obtained from buffalo pituitaries

An acid pellet, obtained as a side fraction from a conventional gonadotropin purification pathway, has been found to contain the bulk of the pituitary lactogenic hormones (growth hormone or GH and prolactin or PRL). This discarded side fraction has been utilized to obtain buffalo lactogenic hormones (buGH and buPRL), simultaneously, and in bulk. The immunoreactivities of the purified semi-pure buffalo GH and PRL (APECS and APP-I, respectively) preparations were compared by direct binding ELISA with semi-pure standard buGH and PRL (ECS and EP-I, respectively) and were found to be as pure as standard semi-pure buGH and buPRL. When checked by direct binding ELISA using buGH and buPRL antisera, it was observed that APECS and APP-I were not cross-immunoreactive. SDS-PAGE and western blot analysis of APECS and APP-I showed major bands located at the same positions as in the case of standard semi-pure preparations (20 kDa for APECS and 23 kDa for APP-I). The semi-purified buGH and buPRL (APECS and APP-I) were converted to a highly purified preparation by chromatographing them via Sephacryl S-200 gel-filtration chromatography.