Pineal Gland and Gut Hormones Flashcards
What is the rate-limiting enzyme of melatonin synthesis?
Serotonin N-acetyltransferase (NAT)
Melatonin ______ GnRH secretion in fall breeders and _____ GnRH secretion in spring breeders.
Fall: Melatonin stimulates GnRH (LH and FSH)
Spring: Melatonin inhibits GnRH (LH and FSH)
In mammals, how are light signals delivered to the pineal gland?
- Suprachiasmatic nucleus in hypothalamus
- Superior cervical ganglion (synapse)
- Postganglionic axons to pineal gland
Describe the gross histology of the pineal gland
Outer capsule of connective tissue
Septae divide interior
Describe pinealocytes
Large round nuclei w/ 1-2 nucleoli
Found in clumps
Describe astrocytes (glial cells of pineal gland)
Oval heterochromatic nuclei
Which 4 cell types may be found within pineal gland?
- Pinealocytes
- Astrocytes
- Melanocytes (sometimes)
- Endothelial cells (around capillaries; may not be visible in every slide)
The bands in the corpora arenacea consist of _____ created by ______.
Calcium deposits; exocytosis of carrier proteins
Which gut hormones produce satiety?
- Leptin
- MSH from the intermediate part of the anterior pituitary
- CCK
- Peptide YY
- Glucagon-like peptide 2
What are the consequences of elevated sympathetic activity (due to elevated leptin) in obese individuals?
- Increased salt retention (RAS system activation)
2. Hypertension
Which cell type produces ghrelin?
Parietal cells (in the stomach)
Which adipokines promote angiogenesis?
- Leptin
2. Vascular endothelial growth factor
What are the functions of adiponectin?
- Decrease TG synthesis
- Sensitizes body to insulin
- INHIBITS angiogenesis
What is the relationship between body fat and adiponectin?
More body fat = less adiponectin
In adult animals, elevated GH has what effect(s)?
Enlarged cranium, jaw/teeth, organs
*Long bones do NOT respond to GH after puberty
