Kerberos token

[m_a_n_j_u_s_k at yahoo.com]

Hi,
I have an application that authenticates against a Proxy server which user Kerberos authentication scheme.
My application is using SSPI library (github/alexbrainman/sspi Golang package to be exact) generate a kerberos token and this token is passed to the Proxy server through Proxy-Authorization header "Proxy-Authorization: Negotiate <kerberos token>"
My query, for the subsequent calls to the proxy do I need to regenerate this key or can I reuse the one generated the first time ? Or is it that each call to the proxy is treated as a session and that Kerberos token is for that session only ?

Thanks for any info.