BIOL 1260 Lecture 14: Endocrinology
2 Dec 2016
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Actually two glands, protrusion off bottom of hypothalamus. Anterior pituitary adenopypophysis : originates from rathke"s pouch (pharyngeal epithelium, neurons from hypothalamus secrete releasing factors directly into portal vein regulate pituitary hormone synthesis and release. Posterior pituitary neurohypophysis : originates from neural tissue (extension of hypothalamus, consists of axons of neurons from supraoptic and paraventricular nuclei that deliver hormones to posterior lobe for release anterior pituitary. Hypothalamic releasing hormones regulate anterior pituitary hormones. Anterior pituitary cell types: somatotrophs: gh-secreting cells, make up ~50% cell mass lactotrophs: prl-secreting cells, make up ~10-25% cell mass. Proliferation accounts for increase in pituitary size during pregnancy: thyrotrophs: tsh-secreting cells, make up <10% cell mass, corticotrophs: acth-secreting cells, make p 15-20% cell mass, gonadotrophs: lh and fsh-secreting cells, make up 10- Hypoglycemia, starvation, exercise, stress, sleep: action. Direct: metabolic lipolysis, protein synthesis, insulin resistance indirect: growth igf-i: normal daily secretion: spikes, huge increase at night, normal lifetime secretion: increases during puberty, growth hormone deficiency (dwarfism)
