Serum S-Klotho levels in subjects with active acromegaly were significantly higher than that in subjects with hypopituitarism, who were receiving complete hormone replacement therapies for all pituitary deficits (n=11): 2291 ng/l (488–6823) (mean (range)) vs 574 ng/l (341–1084); P=0.0009 (Fig. 1). Here, KL is linked to hypopituitarism.