Vitamin D and DBP: The free hormone hypothesis revisited

“Bound” to Work: The Free Hormone Hypothesis Revisited

Megalin is a member of the low-density lipoprotein receptor-related protein (LRP) family. The plasma membrane-anchored LRPs serve as receptors for a wide variety of extracellular ligands, promoting their entry into cells by endocytosis of the receptor-ligand complex. In this issue of Cell, Hammes et al. (2005) show that resistance (insensitivity) to sex steroid hormones is encountered in animal...

Vitamin D: the alternative hypothesis.

Early studies on vitamin D showed promise that various forms of the "vitamin" may be protective against chronic disease, yet systematic reviews and longer-term studies have failed to confirm these findings. A number of studies have suggested that patients with autoimmune diagnoses are deficient in 25-hydroxyvitamin D (25-D) and that consuming greater quantities of vitamin D, which further eleva...

Sex Steroids and the Free Hormone Hypothesis

In their research article published in the September 9, 2005 issue of Cell, Hammes et al. (2005) investigated the role of megalin (an endocytic receptor in a variety of tissues) and SHBG (sex hormone binding globulin) on the cellular uptake of sex steroid hormones in mice. In plasma, androgens and estrogens can circulate bound tightly to SHBG, bound loosely to albumin, unbound, or free. Althoug...

Vitamin D: the tricky hormone.

Parathyroid hormone and vitamin D.

Along with many others of my generation at the Yale School of Medicine and the New Haven Hospital, I owe a great debt to Grover Powers as an inspiring teacher, friend, and benefactor. The invitation to give the Grover Powers lecture at Yale had a special emotional significance, therefore, and it is with a sense of great privilege that I address you this afternoon. I do not consider the primary ...