抄録
The success of transsphenoidal adenomectomy in 10 patients with Cushing's disease was judged by the residual adenohypophysial function. Surgery was indicated mainly by endocrinological results. Radiologically, the sella turcica was slightly enlarged in three cases, which had all macroadenomas with the diameter of more than 10 mm. The other seven had microadenomas 3-7 mm in diameter with normal-sized sella. In two cases, localized bulging of the floor was confirmed by polytomography. In one case the adenoma was far away from the midline and was completely buried in the It-lateral wing. All the others were located in the center of the adenohypophysis. Complete adenomectomy involving adjacent normal tissue resulted in amazing clinical improvement with hypoadrenocortisolism in all cases except one in which the surgical maneuvers appeared incomplete.
The preoperative basal levels of plasma ACTH were 135.6±27.5 pg/ml (M±S.E.) and responsiveness to insulin hypoglycemia was absent in all cases with a loss of diurnal rhythmicity, whereas conspicuous ACTH responsiveness to 8-lysine vasopressin (LVP) was observed in most cases, as shown by the increase from 107.8±23.8 to 362.5±98.7 pg/ml. The postoperative basal plasma ACTH levels dropped to 24.6±11.3 pg/ml and their responses to LVP became blunted in most cases with a peak value of 57.0±21.4 pg/ml, whereas hypoglycemic responses became positive in most cases, as shown by the peak value of 62.7±12.6 pg/ml. The diurnal rhythmicity of plasma ACTH and cortisol became apparent in all five cases examined 6 months after surgery.
Preoperative plasma GH responses to insulin hypoglycemia were impaired in all cases and the peak value did not exceed 10 ng/ml in any case. Postoperatively, the peak value significantly increased at an average of 7.9±3.9 ng/ml (M±S.D.) and in four cases it exceeded 10 ng/ml. TSH responses to TRH and LH to LH-RH were also significantly improved postoperatively. FSH responses to LH-RH and PRL to TRH did not change significantly.
These results support the concept that ACTH hypersecretion of pituitary adenoma is the primary abnormality in Cushing's disease and hypothalamic CRF activity is suppressed by long-standing hypercortisolism. Furthermore, the hypothalamic-pituitary functions of other anterior pituitary hormones such as GH, TSH and LH are impaired by hypercortisolism and could be returned to normal by selective transsphenoidal adenomectomy. We conclude that this operation is the first choice of treatment of Cushing's disease for clinical and endocrinological improvements.
