50 Years Ago in CORR: The Parathyroid Hormone and Bone Franklin C. McLean, MD CORR 1957;9:46–60

Excerpt

The effects of hormones on bone have been long known. Guyer in 1922 commented, “And if there is a serum-borne agent in the case of compensatory hypertrophy, may there not also be one in that of the ordinary physiological hypertrophy of the exercised muscle or stressed bone!” [4] (Exclamation mark from Guyer.) In the article we highlight this month, Dr. Franklin McLean (1888–1968), an eminent physiologist in the Department of Physiology at the University of Chicago, cited two earlier reports from 1929 [1] and 1932 [5] postulating distinct mechanisms by which parathyroid hormone might influence bone. In the first by Albright and Ellsworth, the observation of an increased serum calcium and increase in urinary phosphate excretion with the administration of parathyroid extract would indirectly lead to changes in bone metabolism [1]. In the second, Thomson and Pugsley suggested parathyroid hormone directly acted on bone by influencing osteoclast activity [5]. (The use of the term “parathormone” appears to have been first used in 1926 by Davies, reporting on the properties of the parathyroid hormone, which at the time had not been completely isolated and characterized [3]; even at the time of McLean’s article in 1957 the hormone had “not been prepared in pure form.”) McLean reviewed a considerable amount of evidence including his own to support the notion that parathyroid hormone indeed had direct actions on bone leading to resorption and in fact it was the mobilization of bone mineral that led to the increase in serum calcium which in fact provided a feedback mechanism to the parathyroid glands. (Feedback loops as they applied to biological organisms were established in the 1920’s and 30’s by a number of individuals but primarily by Gustav Embden and Oscar Myerhof in establishing the glycolytic pathway we know by their names.) …