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Testosterone (T) exerts negative feedback on the hypothalamo-pituitary (GnRH-LH) unit, but the relative roles of the CNS and pituitary are not established. We postulated that relatively greater LH responses to flutamide (brain-permeant antiandrogen) than bicalutamide (brain-impermeant antiandrogen) should reflect greater feedback via CNS than pituitary/ peripheral androgen receptor-dependent pathways. To this end, 24 healthy men ages 20-73 yr, BMI 21-32 kg/[m.sup.2], participated in a prospective, placebo-controlled, randomized, double-blind crossover study of the effects of antiandrogen control of pulsatile, basal, and entropic (pattern regularity) measurements of LH secretion. Analysis of covariance revealed that flutamide but not bicalutamide 1) increased pulsatile LH secretion (P = 0.003), 2) potentiated the agerelated abbreviation of LH secretory bursts (P = 0.025), 3) suppressed incremental GnRH-induced LH release (P = 0.015), and 4) decreased the regularity of GnRH-stimulated LH release (P = 0.012). Furthermore, the effect of flutamide exceeded that of bicalutamide in 1) raising mean LH (P = 0.002) and T (P = 0.017) concentrations, 2) accelerating LH pulse frequency (P = 0.013), 3) amplifying total (basal plus pulsatile) LH (P = 0.002) and T (P < 0.001) secretion, 4) shortening LH secretory bursts (P = 0.032), and 5) reducing LH secretory regularity (P < 0.001). Both flutamide and bicalutamide elevated basal (nonpulsatile) LH secretion (P < 0.001). These data suggest the hypothesis that topographically selective androgen receptor pathways mediate brain-predominant and pituitary-dependent feedback mechanisms in healthy men. leuteinizing hormone; testosterone; pulsatile; secretion; human; approximate entropy doi: 10.1152/ajpendo.00300.2010.

DESCRIPTION of CASE A 52-year-old female presented to an otolaryngologist with a hoarse voice. An endocrine opinion was sought to exclude an underlying endocrinopathy. She had been investigated three years [...]

Byline: S. Bhaskar, B. Mallanna, Chetana. Arun, D. Srinivasalu Sir, We report the anaesthetic management of an 11-year-old male patient with multiple pituitary hormone deficiency (MPHD) posted for laparoscopic appendicectomy [...]

Context.--The sellar region is the site of frequent pathology. The pituitary is affected by a large number of pathologic entities arising from the gland itself and from adjacent anatomical structures including brain, blood vessels, nerves, and meninges. The surgical pathology of this area requires the accurate characterization of primary adenohypophysial tumors, craniopharyngiomas, neurologic neoplasms, germ cell tumors, hematologic malignancies, and metastases as well as nonneoplastic lesions such as cysts, hyperplasias, and inflammatory disorders. Objective.--To provide a practical approach to the diagnosis of pituitary specimens. Data Sources.--Literature review and primary material from the University of Toronto. Conclusions.--The initial examination requires routine hematoxylin-eosin to establish whether the lesion is a primary adenohypophysial proliferation or one of the many other types of pathology that occur in this area. The most common lesions resected surgically are pituitary adenomas. These are evaluated with a number of special stains and immunohistochemical markers that are now available to accurately classify these tumors. The complex subclassification of pituitary adenomas is now recognized to reflect specific clinical features and genetic alterations that predict targeted therapies for patients with pituitary disorders. (Arch Pathol Lab Med. 2008;132:1231-1240), A number of pathologic processes occur in the region of the pituitary gland. They include primary pituitary lesions that are unique to this site, as well as disorders arising in [...]