The Danish pediatrician C.E. Bloch hypothesized its existence based on the 
The Danish pediatrician C.E. Bloch hypothesized its existence based on the work of E.V. McCollum. The carboxylic acid formed from this vitamin is conjugated to glucuronide and secreted into bile, and its esters can be stored in Ito cells or more generalized hepatocytes. Sperm production requires an adequate amount of this vitamin, and deficiency in it can lead to decreased thyroid hormone synthesis, while its aldehyde is a key component of rhodopsin. For 10 points, beta-carotene is a provitamin for what compound also called retinol, whose deficiency can also lead to night blindness?
The Danish pediatrician C.E. Bloch hypothesized its existence based on the work of E.V. McCollum.
Vitamin {A} [accept {retinol} before it is read]