Studies on equine lipid metabolism. 1. A fluorometric method for the measurement of lipolytic activity in isolated adipocytes of rats and horses.

This research introduces a novel method for monitoring the release of free fatty acids from fat cells in rats and horses, highlighting species-specific responses to lipolysis stimulators and inhibitors.

Method Development

• The research presents a simple and sensitive method for monitoring the release of free fatty acids (FFAs) from isolated fat cells. This method employs a pH-sensitive change in the fluorescent intensity of seminaphthofluorescein (SNAFL-1) to measure the FFA release.
• The method requires a small number of adipocytes (fat cells) isolated from fat pads of rats or biopsy samples from horses. They could determine decreasing pH in fat cell suspensions as FFA get released into the incubation medium.

Species-specific Differences in Lipolysis

• The study found species-specific differences in lipolysis, the process by which fats are broken down in the body. They examined the response of rat and horse adipocytes to various stimulators and inhibitors of lipolysis.
• It was found that norepinephrine (NE), a hormone that facilitates lipolysis, stimulated lipolysis in rat fat cells. In contrast, horse fat cells required the combined presence of NE and either adenosine deaminase (ADA) or 8-Phenyltheophylline (8-PT) to exhibit a measurable release of FFAs.
• The researchers also found that the application of NE and ADA to horse adipocytes did not affect the anti-lipolytic response to insulin. Insulin is known to inhibit lipolysis, suggesting that the procedure used to stimulate lipolysis in horse cells does not interfere with the hormone’s anti-lipolytic effect.

Implication of the Method

• This newly developed method, as described in the study, allows for micro-scaled in vitro studies on the lipolytic activity of adipocytes.
• This could significantly accelerate and enhance research into metabolism in different species, potentially contributing to advancements in the field of veterinary medicine, disease prevention, and animal health.