The aim of this paper is to investigate the initial-boundary value problem of a possibly degenerate reaction-diffusion system over \(\Omega \subset \mathbb {R}^n\) with \(n\ge 1\) of the following form \(\begin{aligned} \left\{ \begin{aligned}&\partial _tm_i-\kappa \Delta m_i+|m_i|^{\gamma -2}m_i=(\partial _{x_i}p)^2,\\&-\nabla \cdot [\textbf{m}\nabla p]=S, \end{aligned} \right. \end{aligned}\) with \(\textbf{m}=\textrm{diag} (m_1,\cdots ,m_n)\) , the diffusivity \(\kappa >0\) , the metabolic exponent \(\gamma \ge 2\) and the given function S. When \(\kappa =0\) , this system was introduced by Haskovec, Kreusser and Markowich as a continuous version of the discrete Hu-Cai model for biological transport networks. In this work, our result asserts that whenever the random fluctuations of the conductance in the medium were considered, i.e., \(\kappa >0\) , then for general large data the corresponding initial-boundary value problem possesses a global weak solution.