PRL and Central hypothyroidism: Endocrine evaluation was notable for a mildly elevated prolactin of 51.1 ng/ml (normal range: 4.8-23.3 ng/mL), felt to be due to stalk effect, and decreased free T4 of 0.63 ng/dL (normal range: 0.80-1.70 ng/dL), the latter suggesting central hypothyroidism.