Alan Wui Tze Lim

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Inhibin is a gonadal glycoprotein hormone that regulates the production of follicle-stimulating hormone (FSH) by the anterior pituitary gland and exhibits intragonadal actions as well. The present study shows that inhibin-like immunoreactivity (inhibin-LI) is present in cells of the cytotrophoblast layer of human placenta at term and in primary cultures of(More)
An understanding of the regulation of CRF secretion in rats is currently incomplete, in part due to the lack of sensitive in vitro models available for studying this neuropeptide. In particular, the effects of catecholamines on CRF secretion, and the receptor subtypes mediating these actions have long been the subject of much debate. A cultured cell model(More)
Cell culture and biochemical procedures were used to identify and study the possible mechanisms regulating the secretion of GnRH-like immunoreactivity (GnRH-LI) from human placenta. Monolayer primary cultures of trophoblasts were established after mechanical and enzymatic dispersion of normal human term placenta. The cultured cells stained(More)
Using radioimmunoassay and immunofluorescence with antibodies to beta-endorphin (beta EP) and ACTH, we have shown that a subpopulation of mouse spleen cells, expressing Mac-1, a marker of macrophage differentiation, contains immunoreactive (ir)-beta EP, ir-ACTH, and smaller amounts of presumptive higher molecular weight forms of both. Neither nonadherent(More)
The tissue-specific processing of proopiomelanocortin (POMC), the precursor of ACTH, beta-endorphin, and their related peptides, is currently of considerable interest. We report a patient with a large aggressive pituitary tumor, Cushing's syndrome, and hyperpigmentation managed by transsphenoidal hypophysectomy, bilateral adrenalectomy, and sellar(More)
Whereas progesterone and dopamine share a common central pathway to modulate sexual behavior in female rats, the way in which estrogen is involved remains unclear. In a long-term rat hypothalamic cell culture system, atrial natriuretic factor-producing neurons were identified as candidate sites for integration of sex steroid action. Estrogen induces the(More)
Controversies remain whether atrial natriuretic factor (ANF) may play a role in modulating the release of POMC derived peptides from pituitary corticotrophs. Employing AtT-20 mouse pituitary tumour cells, we report here the effects of rat ANF(1-28) and sodium nitroprusside (SNP), both of which augment cellular levels of cGMP through activating particulate(More)
The brain is thought to exert a predominantly stimulatory action on ACTH secretion mediated mainly by corticotrophin-releasing factor-41 (CRF-41) and arginine vasopressin (AVP). Several data, however, also point to the existence of an ACTH-inhibiting factor. Atrial natriuretic peptide (ANP), at concentrations found in hypophysial portal blood, inhibits ACTH(More)
L-Glutamate, a major excitatory amino acid of the central nervous system, plays important roles as neurotransmitter and neuromodulator in the brain. Increasing evidence suggests that glutamate may also involve in the regulation of the neuroendocrine system at the hypothalamus. Employing long term monolayer hypothalamic cell cultures prepared from neonatal(More)
Aberrant responses to dopamine consequent to a reduction of D1-like receptors in critical regions of the brain have been implicated in schizophrenia. Whereas estrogen may protect against the onset and incidence of psychosis in the illness, the neurobiological effects of the ovarian steroid remain unclear. Recently we have shown that estrogen augments the(More)