Related Experiment Video
Updated: Aug 14, 2026
12:10
Protocols for Visualizing Steroidogenic Organs and Their Interactive Organs with Immunostaining in the Fruit Fly Drosophila melanogaster
Published on: April 14, 2017
Summary
Insect Malpighian tubules secrete a KCl-rich primary urine, regulated by diuretic hormones (DH) and chloride transport-stimulating hormone. These neuropeptides control fluid and salt transport via cyclic AMP (cAMP) for waste excretion after feeding.
Area of Science:
- Insect physiology
- Renal function
- Neuropeptide signaling
Background:
- Insect Malpighian tubules produce a primary urine, isoosmotic and rich in KCl, with low solute concentrations.
- Diuretic hormones (DH) are neuropeptides that stimulate tubular secretion significantly upon water loading, like after feeding.
- Rectal reabsorption processes determine the final urine's osmotic concentration, which can be hypo- or hyperosmotic.
Purpose of the Study:
- To elucidate the mechanisms of insect urinary fluid and salt transport.
- To describe the roles of neuropeptide diuretic hormones and chloride transport-stimulating hormone in regulating insect osmoregulation.
- To discuss the control of diuretic hormone release and its impact on tubular secretion.
Main Methods:
- Investigated the action of neuropeptides on Malpighian tubules.
- Analyzed the role of cyclic AMP (cAMP) in mediating hormonal effects on salt transport.
- Examined the rectal reabsorption mechanisms and the influence of diuretic and antidiuretic factors.
Main Results:
- Diuretic hormones (DH) stimulate secretion via cAMP without altering osmotic permeability.
- A novel neuropeptide, chloride transport-stimulating hormone, controls salt reabsorption in the rectum via cAMP.
- This hormone stimulates K+-dependent, electrogenic Cl- transport, enhancing passive K+ absorption.
Conclusions:
- Insect osmoregulation involves complex interplay between Malpighian tubules and the rectum, controlled by neuropeptides.
- Cyclic AMP (cAMP) is a key second messenger in regulating both secretion and reabsorption processes.
- The Malpighian tubule-rectal system facilitates the excretion of metabolic wastes and excess substances after feeding.
Related Concept Videos
01:40Hormonal Regulation
Hormones regulate a significant portion of digestion through activation of the neuroendocrine system. The neuroendocrine system of digestion contains many different hormones all with multiple functions that are both, directly and indirectly, involved in digestion.
01:33Hormonal Regulation
The renin-aldosterone system is an endocrine system which guides the renal absorption of water and electrolytes, thus managing blood pressure and osmoregulation. Activation of the system begins in the kidneys with a small cluster of cells adjacent to the afferent and efferent blood vessels of the renal corpuscle. As the nephrons are filtering blood, juxtaglomerular cells monitor blood pressure. If they detect a decrease in pressure, they release the hormone renin into the bloodstream.
01:47Osmoregulation in Insects
Malpighian tubules are specialized structures found in the digestive systems of many arthropods, including most insects, that handle excretion and osmoregulation. The tubules are typically arranged in pairs and have a convoluted structure that increases their surface area.
01:17Hormonal Regulation of Blood Pressure
Endocrinal or hormonal intervention in the cardiovascular system is predominantly exerted by the catecholamines - epinephrine and norepinephrine, as well as a slew of hormones that interact with renal function to modulate blood volume.
Epinephrine and Norepinephrine
The adrenal medulla releases epinephrine and norepinephrine, catecholamines that enhance and extend the sympathetic or "fight or flight" physiological response. These hormones escalate heart rate and the force of contraction while...
Epinephrine and Norepinephrine
The adrenal medulla releases epinephrine and norepinephrine, catecholamines that enhance and extend the sympathetic or "fight or flight" physiological response. These hormones escalate heart rate and the force of contraction while...
01:13Introduction to Urinary System
The urinary system consists of two kidneys, two ureters, the urinary bladder, and the urethra.
The kidneys are bean-shaped organs located in the retroperitoneal space, on either side of the vertebral column, between the T12 and L3 vertebrae. They are partially protected by the rib cage and surrounded by perirenal fat, which provides cushioning. They are responsible for urine formation and play critical roles in regulating blood pressure, electrolyte levels, and hormone production. The ureters...
The kidneys are bean-shaped organs located in the retroperitoneal space, on either side of the vertebral column, between the T12 and L3 vertebrae. They are partially protected by the rib cage and surrounded by perirenal fat, which provides cushioning. They are responsible for urine formation and play critical roles in regulating blood pressure, electrolyte levels, and hormone production. The ureters...
01:30Hormonal Control of the Ovarian Cycle
The ovarian cycle is meticulously regulated by the hypothalamic-pituitary-gonadal axis. This cycle orchestrates the release of a mature oocyte, essential for reproduction.
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...