In an attempt to determine whether the decreased number of insulin's receptors in obesity is a result of downregulation of the receptors, diazoxide (5 mg/kg/d) was given to 10 obese subjects. Insulin's suppression by diazoxide in these 10 subjects resulted in a mild glucose intolerance and an increase in insulin's receptors in seven of the 10 subjects. The subjects could be divided into three groups by analyzing the Scatchard plots of their insulin receptor studies before and after diazoxide. Four subjects exhibited an increase in both high affinity and low affinity receptors, three showed an increase only in high affinity receptors, and three failed to demonstrate any change in receptors in response to diazoxide. These studies support the concept that the decreased number of insulin's receptors observed in obesity is a result of the downregulation of the receptors and is not the primary, underlying cause of insulin resistance in obesity, although a contributory role cannot be ruled out.

Forty-five patients with galactorrhea-amenorrhea were followed during a period of 1 to 8 years (mean 3.1) after transsphenoidal prolactinoma removal. The ratios of patients who appear to be cured to the total numbers treated were 20 patients of 27 with grade I tumors; six of 10 with grade II; two of five with grade III; and none with grade IV tumors. Six patients with normal prolactin levels one week postoperatively had relapse later, as did three with normal prolactin levels 2 months postoperatively. A normal prolactin level 6 months postoperatively predicted ultimate cure. The 19 pregnancies that occurred in 15 patients, four with high prolactin levels, were uneventful. Prolactin rose normally with pregnancy and returned to prepregnancy level in all but one patient. Prolactin responses to stimulation tests were blunted for 6 months after successful tumor removal. By 1 year, responses to thyrotropin releasing hormone and metoclopramide tests were returning to normal, although responses to chlorpromazine and hypoglycemia remained blunted. The postoperative inhibition of normal lactotropes for 6 months is suggested. Ultimate cure cannot be determined before 6 months and conception should be deferred until then.

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