human biology - Pituitary giants - is the fusing of growth plates dependent on amount of growth hormone in blood?

I wanted to ask a couple questions related to pituitary giants (people who are giants because of some anomaly, such as a tumor, in their pituitary gland).

Some of these giants seem to keep growing and growing until the tumor (or the gland) is removed. Is this because the fusing of the growth plates is controlled by the amount of growth hormone in blood?

The reason for this question is that many of the giants have been described to grow past when the growth plates should probably have fused. For example (all heights in meter, m):

• Bernard Coyne This giant is described as having been 2.36m at the age of 20, but 2.54m at the time of his death at the age of 23.



• Edouard Beaupré At the age of 17, this giant was measured as 2.16m tall and at the age of 21, he was measured at 2.50m tall. At the time of his death, at the age of 23, he was listed (in his death certificate) as having been 2.51m tall and "still growing".


• Väinö Myllyrinne This giant was 2.22m at the age of 21 but is described as having "experienced a second phase of growth in his late thirties", attaining a height of 2.51m by the time of his death at 54.


• Adam Rainer This giant was, unusually enough, a "dwarf" at the age of 18, reaching a height of 1.22m. However he had a growth spurt afterwards, reaching a height of 2.18m at the age of 30 and 2.34m by the time of his death at age 49.

Also, in some cases the giant individuals facial (bone) structure changes as he/she ages. Considering that the human skull does not have any growth plates, or anything that would (as far as I know) put a stop to the skull bones response to growth hormone, can changes in face structure also happen to "regular" people who take growth hormones?

Answer

Gigantism is caused by too much growth hormone (GH) and causes increased growth in kids (healthline website). After adulthood, increased GH leads to acromegaly which leads to continuing growth of fingers, feet, forehead, jaw, nose, and lips (UCLA Health website). Note that structures like the nose and ears also keep on growing in healthy folks.

Hence, GH does not prevent closure of the growth plates, which happens normally as far as I am aware.

Taking GH during childhood will likely lead to gigantism, and to acromegaly in healthy individuals.

EDIT: In answer to the QUESTION EDIT: the comment by @Raoul is interesting here, as the first guy Bernard Coyne was an eunich. Perhaps that was why his plates never fused as he will have had no testosterone production. I couldn't find specifics in the other 3 cases, but my guess is they are also exceptional cases (otherwise they wouldn't have made it in the record books). As to the question title I dare say that GH is not involved in plate fusion.