Unusual MRI finding of multiple adenomas in the pituitary gland: a case report and review of the literature.

The simultaneous occurrence of multiple adenomas in the pituitary gland is a rare event. We report the coexistence of three non functioning pituitary microadenomas in a 37-year-old woman, referred to us for oligomenorrhea and headache. Biochemical evaluation revealed prolactin (131 U/liters), follicle-stimulating hormone (4.

Long-term in vitro exposure to high glucose increases proinsulin-like-molecules release by isolated human islets.

The aim of this study was to determine the effect of long-term in vitro exposure to high glucose on the release and content of proinsulin and insulin in human islets. After 48 h culture in CMRL medium at 5.5 mM (control islets) and 16.

Immunodetection of glycoprotein hormone subunits in nonfunctioning and glycoprotein hormone-secreting pituitary adenomas.

While it is established that nonfunctioning pituitary adenomas (NFPA) produce a spectrum of glycoprotein hormones, the ability of glycoprotein hormone-secreting adenomas to synthesize hormones other than those in vivo hypersecreted has been poorly investigated so far. In this study the immunolocalization of the beta-subunits of LH, FSH, CG and TSH and the common alpha-subunit was investigated in 10 NFPA, 3 gonadotropin-secreting adenomas (Gn-omas, 1 LH-oma, 1 FSH-oma and 1 LH/FSH-oma) and 3 TSH-secreting adenomas (TSH-omas) using an immunohistochemical technique with specific antibodies to glycoprotein subunits. The percentage of positive cells was determined observing at least 5 photograph fields containing about 50 cells.

Mechanism of action of pituitary adenylate cyclase-activating polypeptide (PACAP) in human nonfunctioning pituitary tumors.

Several evidence suggest that pituitary adenylate cyclase activating polypeptides (PACAP-38 and -27) could function as hypophysiotropic factors. Both peptides interact with either the type I receptor, which preferentially binds the two PACAPs and has a much lower affinity for vasoactive intestinal polypeptide (VIP) or the type II receptor, which binds the two PACAPs and VIP with a nearly equal affinity. In addition to the stimulation of adenylyl cyclase (AC) activity, in different cell types PACAP causes an increase of cytosolic calcium levels ([Ca2+]i), consequent to phospholipase-C activation.

Serum levels of beta-subunit of chorionic gonadotropin in patients with pituitary tumors.

Many studies have shown that normal and tumoral pituitary is able to synthesize chorionic gonadotropin (CG). The aim of the present work was to investigate the circulating levels of free beta-subunit of CG (CG-beta) in a large number of patients with pituitary tumors in basal conditions and after thyrotropin-releasing hormone (TRH) injection. The study includes 27 healthy subjects, 23 patients with prolactinoma, 20 with growth hormone-secreting adenoma and 77 with non-functioning pituitary adenoma (NFPA).

Abnormal transduction of dopamine signal in human nonfunctioning pituitary adenomas.

It is well established that dopamine (DA) plays an important role in inhibiting anterior pituitary function. DA receptors present in the pituitary show the pharmacological and biochemical characteristics of the D2 receptor; in fact, they are coupled to the inhibition of both adenylyl cyclase (AC) activity and the reduction of cytosolic free Ca2+ levels ([Ca2+]i) suggesting the involvement of different G-proteins. While the DA receptors present in human PRL-omas display these characteristics, no information is available on the coupling mechanism(s) of DA receptors expressed in nonfunctioning pituitary adenomas (NF-PA).

Abnormal response of luteinizing hormone beta subunit to thyrotrophin-releasing hormone in patients with non-functioning pituitary adenoma.

Objective: It has been suggested that the response of free beta-subunit of LH (LH beta) to TRH is the most useful in-vivo marker of gonadotroph adenomas in patients with non-functioning pituitary adenomas (NFPA). The aim of the present study was to investigate LH beta secretion in patients with NFPA in whom other markers of gonadotroph adenomas, such as supranormal basal concentrations or responses of intact gonadotrophins to TRH, were absent.

Design And Patients: Serum basal levels of LH beta LH and FSH were evaluated in 80 patients with NFPA showing normal levels of intact gonadotrophin, 20 with PRL-secreting adenomas, 25 with GH-secreting adenomas and 58 healthy subjects.

Immunodetection of chorionic gonadotropin and its subunits in human nonfunctioning pituitary adenomas.

Human nonfunctioning pituitary adenomas (NFPA) may produce CG in addition to the classical glycoprotein hormones (LH, FSH, and TSH). The aim of the present study was to localize LH beta, FSH beta, TSH beta, alpha-subunit (alpha SU), CG, and its beta-subunit (beta SU) in NFPA using a highly specific immunohistochemical technique. Nine NFPA, obtained at surgery, were processed for both electron microscopy and immunohistochemistry.

Effects of long-term treatment with the gonadotropin-releasing hormone analog nafarelin in patients with non-functioning pituitary adenomas.

The supposed origin of non-functioning pituitary adenomas (NFPA) from gonadotrophs prompted us to investigate the effects of the gonadotropin-releasing hormone (GnRH) analog nafarelin on hormonal and tumoral parameters in eight patients with NFPA, previously unsuccessfully operated and all hypogonadal. Nafarelin was administered intranasally for 1 year to all patients. Four patients received a dose of 1200 micrograms/day; the remaining four received 800 micrograms/day for 3 months, which was subsequently increased to 1200 micrograms/day.

Immunoelectron microscopy: a new method for detection of insulin antibodies.

The aim of the present study was to set up a sensitive technical alternative to the classical procedures for detection of human insulin antibodies. We developed a method of post-embedding immunoelectron microscopy (IEM) using as the substrate fresh human pancreas, embedded in acrylic resin to maintain its antigenic structure. The antigen was insulin within the mature secretory granule.

In vitro detection of glycoprotein production and secretion by human nonfunctioning pituitary adenomas.

This study, carried out on 9 nonfunctioning pituitary adenomas, was undertaken in order to evaluate the ability of these tumors to synthesize and release gonadotropins and/or free alpha-subunit (alpha-SU) of glycoproteins. The morphological study included electron microscopy and immunofluorescence analysis while hormone release was evaluated by the reverse hemolytic plaque assay (RHPA) and measurements in culture media. By electron microscopy in all tumors (6 null cell adenomas and 3 oncocytomas), it was possible to identify rough endoplasmic reticulum, Golgi apparatus and secretory granules.

[Primary neuroendocrine carcinoma of the skin: histologic, immunohistochemical and ultrastructural study of a case with highly aggressive biological behavior].

We report a histological, immunohistochemical and ultrastructural study of a case of neuroendocrine carcinoma of the skin, which occurred in a 52 years old woman in the dermal, subcutis and soft tissues of the left buttock. Clinically this neoplasm, which was related to intramuscular injections and a to a following abscess, had rapidly reached unusual dimension compared with other cases of neuroendocrine carcinoma of the skin reported in the literature. The patient died three months after presentation with distant metastases.