THE HOUSSAY PHENOMENON IN MAN

The phenomenon of clinical improvement of diabetes mellitus after occu rrence of pituitary insufficiency has been reported occasionally in th e medical literature, as a human counterpart of Houssay's experiment w ith hypophysectomized diabetic animals. We report the case of a 76-yea r-old woman who developed diabetes in 1928, at the age of 14, and was treated with low doses of insulin. At the age of 29, during the 7th mo nth of her second pregnancy, she suddenly developed severe headaches a nd soon afterwards an intense polyuria which subsided under treatment with posterior pituitary extract. Her pregnancy followed to term but u terine stimulants had to be used at delivery because of lack of contra ctions. She was unable to nurse her baby and a permanent amenorrhea en sued. She continued using the posterior pituitary powder for several y ears, after which she discontinued it without adverse effects. The dos e of insulin was decreased gradually until its replacement by chloropr opamide in 1967 and glybenclamide in 1970. The present dose of glybenc lamide is 2.5 mg daily, on which she has occasional mild hypoglycemic reactions. When the medication was discontinued for 5 days glycemia ro se to 450 mg/dl but responded immediately to 2.5 mg of the drug with a mild hypoglycemia. She never required thyroid hormone therapy. Glucoc orticoid substitution was instituted recently because of evidence of m ild adrenocortical insufficiency. Basal hormone levels were normal for thyroxin, thyrotropin, FSH, LH, prolactin, hGH and cortisol; the resp onses to pituitary stimulation with TRH and LHRH were subnormal or nil . Cortisol stimulation with ACTH was normal. Insulin levels rose moder ately after stimulation with glucagon, and with glybenclamide, with si multaneous marked decrease in glycemia. There were no changes visible on the radiographs as well as on CT scan of the sella turcica. Ophthal mological and neurologic examinations failed to show any evidence of c hronic diabetic complications, 60 years after onset of the disease. Pe digree analysis revealed presence of diabetes in the patient's materna l grandmother, mother and daughter, the latter with an unusually benig n course. We conclude that our patient is an example of diabetes melli tus of onset in childhood but with benign course (probably of the type MODY), who developed a partial pituitary necrosis at the age of 29, d uring a pregnancy, and completed 60 years of her disease without chron ic complications and with a marked sensitivity to insulin, characteris tics of the phenomenon described by Houssay in 1930.