Hereditary Isolated Somatotropin Deficiency: Effects of Human Growth Hormone Administration

The clinical and laboratory appraisal of a familial isolated growth hormone deficiency is reported. The lack of consanguinity and the absence of other short members in the family speak for the occurrence of a mutation in the father which he then transmitted as a dominant trait to four of his seven children. Growth hormone administration not only resulted in an increase in linear growth in those members of the family whose epiphyses were not closed, but also the rapid appearance of secondary sexual characteristics in the 18-year-old sexually infantile female and an increase of body hair and libido in both the father and the 21-year-old sexually mature, staturally retarded sister. These observations strengthen the contention that the diagnosis of hypopituitarism cannot be excluded on the basis of eventual sexual development in individuals whose statural growth is retarded. It is concluded that induction of sexual maturation during growth hormone therapy is not related to increased pituitary gonadotropin release. Growth hormone administration appeared to have no effect on thyroid function or on adrenal responsiveness to administered ACTH and metyrapone. An antiinsulinogenic effect of growth hormone was demonstrated during both oral and intravenous glucose tolerance tests.