Partial (selective) deficiency of pituitary hormones

Partial deficiency of pituitary hormones may be an early signal for the development of a more generalized pathology of the pituitary gland. Patients should undergo a screening to determine the deficiency of other hormones in the pituitary gland, and the area of the Turkish saddle with appropriate intervals for the detection of a pituitary tumor should be examined during visualization.

[1], [2], [3], [4], [5], [6], [7], [8]

Forms

Isolated growth hormone deficiency

Isolated deficiency of growth hormone (GH) is the cause of many cases of pituitary Nanism. And, although there are isolated cases of autosomal dominant inheritance of a complete GH deficiency associated with damage to the structural GH gene, such gene defects are probably the minimum number of cases.

[9], [10], [11]

Isolated gonadotropin deficiency

Isolated gonadotropin deficiency occurs in both sexes and should be differentiated with primary hypogonadism. As a rule, patients have an eunuchoid physique. Patients with primary hypogonadism have elevated levels of luteinizing (LH) and follicle-stimulating (FSH) hormones, whereas levels of these same hormones with a deficiency of gonadotropins are at the lower limit of the norm, low or not measurable at all. Although most cases of hypogonadotropic hypogonadism include deficiency of both LH and FSH, in rare cases, the secretion of only one of them is impaired. Isolated gonadotropin deficiency should be differentiated with secondary hypogonadotropic amenorrhea, which develops as a result of physical overload, diet or neuropsychological stress disorders. And, although the clarification of the anamnesis in both cases can help in establishing the diagnosis, in some cases, differential diagnosis may be difficult.

Specific deficiency of gonadotropin-releasing hormone

In Kallman's syndrome, the specific deficiency of gonadotropin-releasing hormone (gonadoliberin) is associated with middle defects of the facial skull, including anosmia and splitting of the upper or lower lip and palate, and loss of color vision. Embryological studies have shown that neurons that produce gonadoliberin develop in a special way in the epithelium of the olfactory placode [local thickening of the embryonic nutrient layer, which forms primordial cell clusters, from which cell structures develop and then migrate to the septal-preoptic region of the hypothalamus at an early stage of its development. At least in a few cases, with the X-linked form of the disease, defects of the gene localized on the X chromosome, called the KALIG-1 gene (Kallmann syndrom interval gene 1), were found, this gene encodes adhesion proteins that facilitate neuronal migration. Gonadoliberin is not indicated in this case.

Isolated ACTH deficiency

Isolated ACTH deficiency is rare. Weakness, hypoglycemia, weight loss and decreased hairiness in the armpits and the pubic area suggest a diagnosis. Low levels of steroid hormones in blood plasma and urine are found, which return to normal only in the treatment of ACTH. There are no short-term laboratory signs of deficiency of other hormones. Treatment is a substitution therapy with cortisol, as in the case  of Addison's disease.

Isolated thyroid-stimulating hormone deficiency of the pituitary gland 

Isolated thyroid-stimulating hormone deficiency (TTG) is likely when there are clinical signs of hypothyroidism, plasma TSH levels are not increased and there is no deficiency of other pituitary hormones. Plasma TSH levels measured by the enzyme immunoassay are not always below normal, indicating that TSH secretion is biologically inactive.

Isolated deficiency of prolactin 

Isolated deficiency of prolactin is rarely recorded in women who have stopped lactation after delivery. Low levels of prolactin are recorded, which do not increase after stimulation (carrying out provocative tests), such as a test with thyrotropin-releasing hormone. The purpose of prolactin in this case is not shown.