Wingfield 2 - NPB101,Autumn2008 Endocrinology2...

Info icon This preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
NPB 101, Autumn 2008 Endocrinology 2 Hypothalamo‐pituitary unit Anterior pituitary
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Hypothalamus Anterior pituitary Posterior pituitary Neurosecretory neurons Systemic arterial inflow Hypothalamic-hypophyseal portal system System venous outflow = Hypophysiotropic = Anterior pituitary hormone Fig. 18‐9, p. 667
Image of page 2
Hormones of the Pars distalis Growth hormone and prolactin (polypeptides) Glycoproteins: thyroid-stimulating hormone (TSH), luteinizing hormone (LH) follicle-stimulating hormone (FSH) Proopiomelanocortin (POMC): adrenocorticotropin (ACTH), melanocyte-stimulating hormone (MSH) and endorphin
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Immunocytochemical staining of pituitary cells Growth hormone ACTH ProlacDn Growth hormone FSH LH
Image of page 4
Growth hormone Prolactin GH and PRL comparisons. Both have considerable overlap in amino acids. GH has two disulphide bonds and PRL has three
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Prolactin Prolactin is synthesized as a prohormone. Following cleavage of the signal peptide, the length of the mature hormone is between 194 and 199 amino acids, depending on species Structure is stabilized by three intramolecular disulfide bonds It is secreted by so-called lactotrophs in the anterior pituitary Prolactin is secreted by a broad range of other cells in the body, most prominently various immune cells, the brain and the decidua of the pregnant uterus
Image of page 6
AcDons of prolacDn Over 300 known Actions related to reproduction Somatotropic effects (e.g. growth) Osmoregulation Actions on the integument and its derivatives Interactions with steroid hormones Interactions with the immune system
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Signal transduction pathways involved in prolactin regulation Positive regulators of prolactin release include vasoactive intestinal peptide (VIP), estrogen, and thyrotropin- releasing hormone (TRH) VIP exerts its effects by G-protein mediated activation of adenylate cyclase (AC) and its downstream effectors cAMP and protein kinase A (PKA). These activate a protein kinase cascade that culminates in gene expression and subsequent release of prolactin. TRH induces prolactin secretion through activation of the phospholipase C (PLC) signaling pathway. Activation of PLC cleaves phosphatidylinositol 4,5-phosphate (PIP) to form diacylglycerol (DAG) and inositol-1,4,5-triphosphate (IP3). These release intracellular calcium from endoplasmic reticulum (ER) and release of prolactin by exocytosis.
Image of page 8
Signal transduction pathways involved in prolactin regulation Negative regulators include dopamine and thyroid hormone Dopamine binds to the D2 dopamine receptor and decreases AC activity. Thyroid hormone can directly inhibit the prolactin promotor again through a genomic receptor.
Image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 10
Growth, growth hormone and growth factors
Image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
G O G 1 S G 2 M The mammalian cell cycle. Go = a fully mature cell (specialized or resDng), not dividing. G1 is the growth phase preparatory to S, the syntheDc stage when DNA is duplicated. G2 is of short duraDon (only 3 ‐ 4 hours and involving protein synthesis), and M is the mitoDc phase. Cells then may re‐enter the proliferaDon cycle or may become resDng or specialized Go cells. The control point appears to be the transiDon from Go to G1 phases (both direcDons).
Image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern