Isolated Disorders of Pituitary Hormone Secretion	

Isolated disorders of pituitary hormone secretion can occur in the absence of structural lesions of either the hypothalamus or pituitary. Thus, GH, or LH and FSH deficiency, can occur as isolated phenomena. These disorders result from isolated defects in hypothalamic hormone secretion: GH deficiency is due to a congenital deficiency of GHRH; and LH andFSH deficiency results from deficient gonadotrophin-releasing hormone (GnRH) secretion (Kallmann' syndrome). 
Isolated TSH and ACTH deficiencies occur less commonly and are presumably associated with deficient thyrotrophin-releasing hormone (TRH) or corticotrophin-releasing hormone (CRH) secretion, respectively.