Impaired beta-cell function in the presence of reduced insulin sensitivity determines glucose tolerance status in acromegalic patients. - Kasayama,S.; Otsuki,M.; Takagi,M.; Saito,H.; Sumitani,S.; Kouhara,H.; Koga,M.; Saitoh,Y.; Ohnishi,T.; Arita,N. (Clin Endocrinol (Oxf), 2000)