PHY3181 Lecture 9: Pituitary Gland
10 Feb 2019
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26/03/2018: gonadotropes (lh + fsh) only 5-10, lactotropes (prolactin, somatotropes (gh, thyrotropes (trh, corticotropes (acth) Doesn"t affect blood supply to pituitary still capable of secreting hormones. Immediately lh secretion stops: due to inhibin genitive feedback regulator of fsh. Inverse relationship between gnrh pulse frequency and lh pulse amplitude: gnrh frequency = rapid small lh pulses (low amplitude, gnrh frequency = infrequent big lh pulses (high amplitude) Relationship present in both males + females except in late follicular phase. Lh is packaged into dense core secretory granules: because it is actively secreted. Fsh is packaged into constitutive vesicles: diffuse secretory profile not pulsatile. Make sure lh vesicles are docked to the membrane ready to be secreted. Gnrh works via multiple intracellular second messenger signalling pathways pcreb pathway. Phosphorylation of creb (pcreb) drives altered transcription. Erk leads to induction of fos marker of neuronal activation. Acute estrogen administration causes negative feedback at pituitary.
