G. Giustina

Effect of somatostatin on blood glucose, plasma growth hormone, insulin, and free fatty acids in normal subjects and acromegalic patients

Abstract Synthetic growth-hormone-release inhibitory hormone (GRIH, somatostatin) infused in seven acromegalics significantly lowered plasma growth hormone (GH) and immunoreactive insulin (IRI) levels, did not have any effect on blood glucose, and significantly increased plasma free fatty acids (FFA). Somatostatin, when infused in three normal subjects during an arginine test, inhibited plasma GH and IRI responses. Hypoglycemia-induced GH release was also blocked by somatostatin in two normal subjects thus tested.

Spontaneous remission of Cushing syndrome after termination of pregnancy.

A 27-year-old women developed Cushing syndrome during pregnancy. The course of pregnancy was characterized by abnormally low urine and plasma estrogen levels despite the presence of a living fetus. The signs and symptoms of Cushing syndrome disappeared spontaneously within 2 months after delivery. Hormonal studies, however, suggested the presence of an adrenal tumor. An adrenocortical adenoma was found at surgery and removed.

Plasma Cortisol response to ACTH does not accurately indicate the state of hypothalamic-pituitary-adrenal axis

The hypothalamic-pituitary-adrenal function was studied in 55 patients with various pituitary disorders. In particular, the consistency between the responses of plasma Cortisol to exogenous ACTH and to insulin hypoglycemia was investigated in 5 patients in whom Cortisol response to insulin was absent; four of these patients showed a Cortisol response to ACTH of variable degree. These 4 patients had surgical or functional hypothalamus-pituitary disconnection and showed a preserved Cortisol response to lysine vasopressin. These data demonstrate the unreliability of ACTH test in assessing hypothalamic-pituitary-adrenal function in hypopituitary patients.

Dose-response study of the inhibiting effect of somatostatin on growth hormone and insulin secretion in normal subjects and acromegalic patients

A dose-response study of the effect of somatostatin on plasma growth hormone (GH) and immunoreactive insulin (IRI) levels was performed in normal subjects and acromegalic patients. In normal subjects 150 mug of somatostatin completly suppressed GH and IRI responses to arginine, while with 75 and 37.5 mug only a partial suppression was usually observed. Basal levels of plasma IRI were significantly lowered within 15 min from the start of somatostatin injection at each of the three dose levels. In three acromegalics the doses of 150 and 75 mug of somatostatin were effective in lowering both GH and IRI levels; the dose of 37.5 mug was still effective in lowering plasma IRI levels, while GH levels were not significantly modified. A dose of somatostatin inhibiting GH secretion without affecting insulin secretion has not been found either in acromegalics and in normals. It was concluded that the effects of somatostatin on GH and IRI secretion cannot be easily dissociated.

Radioimmunoassayable plasma luteinizing hormone in primary amenorrhea

n Plasma luteinizing hormone (LH) was detectable by radioimmunoassay in 35 patients, all with female external genitalia, who had never menstruated spontaneously. Patients were grouped as follows: 11 with hypogonadotropic hypogonadism (1 pituitary dwarf, all with normal sex chromatin) 16 with gonadal dysgenesis (5 XO, 5 XX, 2 XY, 3 mosaics), and 8 with uterovaginal atresia (normal karyotypes.) Radioimmunoassay was performed with rabbit anti-human chorionic gonadotropin labeled with iodine-125, by the polystyrene tube method, on plasma samples taken at 9-11 a.m. Hypogonadism patients had mean 9.1 mI.U. LH (range 0-18); gonadal dysgenesis patients had mean 61.5 (range 23-103); uterovaginal atresia patients had 11.9 (0-35). It was noteworthy that no overlap was observed between primary gonadal failure (gonadal dysgensis), and secondary (hypogonadism), and that LH values in 2 other patients with polycystic ovaries, LH was 16 and 34 mI.U. and FSH was not increased.n

Inhibitory effect of somatostatin on dibutyryl cyclic AMP-induced insulin and growth hormone release in human subjects

The effect of somatostatin on the responses of blood glucose, plasma immunoreactive insulin (IRI), growth hormone (GH), and free fatty acids (FFA) to the injection of dibutyryl cyclic AMP (DBC) was studied in six normal volunteers. DBC, when injected alone, induced a rapid increase in blood glucose and plasma IRI levels, while GH concentrations showed a less marked and more delayed increase and plasma FFA showed a clear downtrend. Somatostatin infusion suppressed the GH and IRI release induced by DBC, potentiated its hyperglycemic effect and changed the pattern of FFA. These results suggest that somatostatin inhibits hormone secretion distal to the generation of cyclic AMP.

Plasma gonadotropin and ovarian steroid levels in uterovaginal atresia: A case report

Abstract The pituitary-ovarian relationship was studied in a 26-year-old patient with uterovaginal atresia. The plasma levels of luteinizing hormone, follicle-stimulating hormone, progesterone, and estradiol were determined daily for a months period. They showed cyclic variations similar to those of normally menstruating women.

Variability of gonadotropin response to luteinizing hormone-releasing hormone in amenorrheic women

Abstract Plasma gonadotropin response to luteinizing hormone-releasing hormone (LH-RH) (200 μg intravenously) has been evaluated in a group of amenorrheic women. Eleven of them had primary amenorrhea due to isolated gonadotropin deficiency. Fifteen had secondary functional amenorrhea; this group included patients with anorexia nervosa, polycystic ovary, amenorrhea-galactorrhea, idiopathic amenorrhea. Most patients showed a significant elevation of gonadotropin plasma levels after LH-RH injection. However, a marked variability in luteinizing hormone (LH) and follicle-stimulating hormone (FSH) rise was observed. The two groups included both patients with normal LH response and patients with blunted LH response. An evident FSH elevation has been found in the great majority of subjects. A frequent pattern of anomalous response observed in amenorrheic women was the occurrence of a blunted LH response associated with a markedly elevated FSH response.