PRL and familial hyperprolactinemia: The PRL levels in the normal group, mild, moderate, and severe HPRL groups were 264.70 ± 125.4 mIU/L, 771.63 ± 171.73 mIU/L, 1,487.22 ± 289.69 mIU/L, and 3,233.66 ± 1,001.98 mIU·L-1, respectively.