#glucagon

Sugar High

Insulin is the star of the show when it comes to controlling your blood sugar levels. But it’s part of a tag team with another hormone called glucagon. When you haven't eaten in a while, islet cells in your pancreas release glucagon to increase your blood sugar levels. Conversely, just after eating, glucagon is suppressed. However, in type-1 diabetics, this goes wrong — glucagon is too high after eating and too low after going without food. Researchers now investigate what controls glucagon release using fluorescence microscopy of human pancreases, focusing on the sympathetic nervous system, which is best known for controlling ‘fight or flight’ responses. Projections from sympathetic nerve cells (red) matched up to glucagon-producing islet cells (green) in both diabetic and non-diabetic pancreases. However, RNA analysis of islet cells showed changes in nerve cell signalling proteins in diabetics. This suggests that something’s gone awry in the sympathetic nerves regulating glucagon in diabetics.

Written by Lux Fatimathas

Image from work by Martha Campbell-Thompson and colleagues

Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in Scientific Reports, March 2021

Hama Bead Molecules Pt.1 - Insulin

A patient came in after taking a 60 day supply of 25mg Carvedilol. He presented with a heartrate in the 50's, and a blood pressure, well, also in the 50's. 50/30 was the lowest. He was drifting in and out of consciousness, so we pushed atropine, the first line drug for bradycardia, to no effect.

You know it's gonna be fun when you call poison control, you tell them what's going on, and their first response is "ooooo that's not good." Poison control recommended Glucagon, 5-15mg IV push followed by a drip of 5-15mg every hour. This comes in 1mg vials, so we had to mix and draw up a lot of these vials. (See below)

He did respond. His pulse was now around 80, and we kept his blood pressure between 95 and 105 systollic. He was placed on a drip of 10mg/hr. I feel sorry for the pharmacist that had to mix the bag of 30mg of Glucagon. Central pharmacy also told us they only had 6 more glucagons in stock after making this bag, so if he wasn't better in 3 hours, we would have a problem.. but that was a problem for ICU to handle (I love you, ICU nurses)!

Glucagon has inotropic effects that bypass the beta blockade, this allows it to increase heartrate and blood pressure even in the presence of beta blockage. Glucagon also counteracts the negative effects of the beta blockade on a patients blood sugar.

Part 4 (last part)

In this chapter we're going to talk about:

1. Thyroid Hormones.

2. Insulin & Glucagon.

Thyroid Hormones:

T4 or Thyroxine

T3 or Triiodothyronine

Calcitonin.

T4 & T3 :

T4 and T3 are tyrosine based hormones. Produced by the follicular cells (thyrocytes).

Synthesis:

Iodide (I-) is taken from the bloodstream by follicular cells to the colloid where it gets oxidized to iodine (I) then it combines with thyroglobulin to form MIT (monoiodotyrosine) and DIT (diiodotyrosine) .

Two DIT molecules combine to form T4 while MIT & DIT combine to form T3.

Iodinated thyroglobulin is transported back to the follicular cells and is cleaved by lysosomes.

T4 & T3 are then released into the circulation through MCT transporter.

Regulation:

TRH ➡ TSH ➡ THYROID ➡T4 & T3

➡ By:

⏫Iodide pumping

⏫ Iodination

⏫Thyroglobulin synthesis.

⏫ release of thyroid hormone.

T4 & T3 bind in the plasma to plasma proteins such as:

TBG or Thyroxine binding globulin

Albumin

Transthyretin.

The bound form is the inactive form. While free T3 & T4 form the active form that works on cells.

Note that inside the cell T4 is coverted to T3 by 5-Iodinase.

Effects:

⏫ Basal metabolic rate.

⏫Activation of sympathetic nervous system.

⏫long bone growth

⏫Hair follicle growth

Regulation of body temperature & weight.

Brain development.

Insulin:

Is a peptide hormone produced and secreted by Beta cells which are cells in the islets of langerhans

Synthesis:

Single polypeptide (preproinsulin) ➡ proinsulin (which has 3 chains : peptide A, peptide B and peptide C in between.

Proinsulin gets cleaved on two positions leaving the C chain alone (AWW :-( )

Two disulfide bonds connect The B chain and the A chain to form INSULIN

Effects:

⏬⏬ Blood sugar levels.

How :

In the liver:

Activates the formation of glycogen

(glucose ➡ glycogen)

In adipose tissue:

Activates glycolysis

In skeletal muscles :

stimulates amino acids and glucose uptake into muscle cells ➡ protein production and muscle growth.

Inhibites:

▶ Gluconeogenesis

▶ lipolysis.

Glucagon:

A hormone produced by alpha cells which are cells in the islets of langerhans.

Works by ⏫⏫ blood suger ▶ in situations like: fasting.

And it does that by:

▶ activation of gluconeogenesis & glycogenolysis

▶ activation of lipolysis.

Glucagon is a catabolic hormone which means it promotes the breaking down of large storage molecules inside certain tissues into small energy molecules in the blood.

Glucagon stimulators:

▶ low blood suger

▶ adrenaline

▶ cholecystokinin

Glucagon inhibitors:

▶ high blood sugar

▶ somatostatin

▶GH

Part 1

Part 2

Part 3

🌸- 🌸-🌸-🌸-🌸-🌸-🌸-🌸-🌸

Hello 🌸🍃

With this we're done with a good part of endocrine physiology!Next, we're going to start with clinical cases and diseases related to the endocrine system (aka we're gonna get serious SERIOUS xD) I hope you find this helpful in reviewing or studying ☺

Thank you so much🌸🍃

On that academic grind📚📖📝 💻

Guys, be nice to your pancreas and try your best to stay healthy. If you’re like me and you love sweets, I advice you to eat it in moderation. And make sure to stay active.

It’s so tempting to be lazy, but the exam period is here and there’s no time to waste. Even though I would much rather lay back and chill, I have to work. I hope you choose to make the most out of this time too!