Total protein concentration of rat brains determined by Bradford-Protein Assay Kit

Measurement of total protein concentration in total brains of rats was performed using the Bradford Protein Assay Kit (B-Pak) from OZ Biosciences.

This article demonstrate the capacity of the Bradford Protein Assay Kit from OZ Biosciences  to efficiently measure the total protein concentration in rats brains.

Gen Comp Endocrinol. 2013 Jul 9.

Reduced Responsiveness of Kisspeptin Neurons to Estrogenic Positive Feedback Associated with Age-related Disappearance of LH Surge in Middle-Age Female Rats.
Ishii MN, Matsumoto K, Matsui H, Seki N, Matsumoto H, Ishikawa K, Chatani F, Watanabe G, Taya K.

Abstract

Age-related disappearance of the LH surge is one of major biomarkers of reproductive aging in female rats. Kisspeptin neurons in the hypothalamic anteroventral periventricular nucleus (AVPV) are proposed as the critical regulator of the preovulatory LH surge in response to estrogenic positive feedback. Here we investigated the possible involvement of the AVPV kisspeptin neurons in the disappearance of the LH surge in middle-age rats. Middle-age rats exhibiting persistent estrus (M-PE) did not show an LH surge although neither Kiss1 mRNA nor peptide in the AVPV was differentially expressed when compared to young rats exhibiting normal estrous cycles (YN). M-PE released LH in response to exogenous kisspeptin in a similar dose-dependent manner as YN, suggesting that their GnRH neurons still maintained responsiveness to kisspeptin. To investigate the estrogenic positive feedback effect on kisspeptin neurons in the AVPV, rats were ovariectomized and supplemented with estradiol (OVX+E₂). We performed in situ hybridization and immunohistochemistry for Kiss1 mRNA and cFos, respectively, and found that M-PE exhibited a significantly lower percentage of Kiss1 mRNA positive neurons with cFos immunoreactivity, although the total number of kisspeptin neurons was not different from that in cyclic rats. Furthermore, OVX+E₂ M-PE did not show the surge-like LH release under high estradiol administration while YN did. Thus our current study suggests that the reduced responsiveness of the AVPV kisspeptin neurons to estrogenic positive feedback presumably results in the decrease in kisspeptin secretion from neurons and eventually causes the age-related disappearance of the LH surge in middle age female rats.

The Bradford Protein Assay Kit (B-Pak) from OZ Biosciences is a straightforward and rapid procedure for determining the concentration of protein in solution.The B-Pak is based on the binding of Coomassie Brilliant Blue G-250 dye to the proteins and particularly basic and aromatic amino acids residues. The dye exists in three forms: cationic (red), neutral (green) and anionic (blue).