Anterior pituitary receptor

Perrin MH, Haas Y, Rivier JE, Vale WW (1986) Corticotropinreleasing factor binding to the anterior pituitary receptor is modulated by divalent cations and guanyl nucleotides. Endocrinology 118 1171-9... 

Clomiphene (Clomid) is a synthetic nonsteroidal compound that binds to estrogen receptors, decreasing the amount of available estrogen receptors and causing the anterior pituitary to increase secretion of FSH and LH. It is used to induce ovulation in anovulatory (nonovulating) women. 

The precise role of melatonin in sleep and waking is uncertain but it seems to act as a go-between for the light and biological cycles and evidence suggests that it has a reciprocal relationship with the SCN (Fig. 22.3). Its actions are mediated by (MLi) receptors which are found predominantly in the SCN as well as thalamic nuclei and the anterior pituitary. These are G protein-coupled receptors, with seven transmembrane domains, that inhibit adenylyl cyclase. Their activation by melatonin, or an MLi agonist such as 2-iodomelatonin, restores the impaired circadian cycle in aged rats. 

Prolactin is an essential hormone for normal production of breast milk following childbirth. It also plays a pivotal role in a variety of reproductive functions. Prolactin is regulated primarily by the hypothalamus-pituitary axis and secreted solely by the lactotroph cells of the anterior pituitary gland. Under normal conditions, secretion of prolactin is predominantly under inhibitory control by dopamine and acts on the D2 receptors located on the lactotroph cells. Increase of hypothalamic thyrotropin-releasing hormone (TRH) in primary hypothyroidism can stimulate the release of prolactin. 

The acute CNS effects of MDMA administration are mediated by the release of monoamine transmitters, with the subsequent activation of presynaptic and postsynaptic receptor sites.40 As specific examples in rats, MDMA suppresses 5-HT cell firing, evokes neuroendocrine secretion, and stimulates locomotor activity. MDMA-induced suppression of 5-HT cell firing in the dorsal and median raphe involves activation of presynaptic 5-HT1A autoreceptors by endogenous 5-HT.4142 Neuroendocrine effects of MDMA include secretion of prolactin from the anterior pituitary and corticosterone from the adrenal glands 43 Evidence supports the notion that these MDMA-induced hormonal effects are mediated via postsynaptic 5-HT2 receptors in the hypothalamus, which are activated by released 5-HT. MDMA elicits a unique profile of locomotor effects characterized by forward locomotion and elements of the 5-HT behavioral syndrome such as flattened body posture, Straub tail, and forepaw treading.44 6 The complex motor effects of MDMA are dependent on monoamine release followed by activation of multiple postsynaptic 5-HT and DA receptor subtypes in the brain,47 but the precise role of specific receptor subtypes is still under investigation. 

Scully KM, Gleiberman AS, Lindzey J, Lubhan DB, Korach KS, Rosenfeld MG (1997) Role of estrogen receptor-a in the anterior pituitary gland. Mol Endocrinol 11 674-681... 

Szabo M, Kilen SM, Nho SJ, Schwartz NB (2000) Progesterone receptor A and B messenger ribonucleic acid levels in the anterior pituitary of rats are regulated by estrogen. Biol Reprod 62 95-102... 

In the brain, the effects of AVP are mediated through G protein-coupled receptors, which have been classified as Via and Vlb subtypes, the former being expressed—inter alia—at the level of the amygdala, septum and hypothalamus (Ostrowski et al. 1992 Tribollet et al. 1999). While the Vlb receptor is primarily locahzed in the anterior pituitary, it has also been detected in various brain areas, including the amygdala, the hypothalamus and the hippocampus (Lolait... 

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