Hydroxycarboxylic acid receptor 1
protein-coding gene in the species Homo sapiens
Hydroxycarboxylic acid receptor 1 (HCA1), formerly known as G protein-coupled receptor 81 (GPR81), is a protein that in humans is encoded by the HCAR1 gene. HCA1, like the other hydroxycarboxylic acid receptors HCA2 and HCA3, is a Gi/o-coupled G protein-coupled receptor (GPCR). The primary endogenous agonist of HCA1 is lactic acid (and its conjugate base, lactate). More recently, 3,5-dihydroxybenzoic acid has been reported to activate HCA1.
Lactate was initially found to activate HCA1 on fat cells and thereby to inhibit these cells lipolysis i.e., break-down of their fats into free fatty acids and glycerol. Subsequent studies have found that in addition to fat cells, HCA1 is expressed on cells in the brain, skeletal muscle, lymphoid tissue, uterus, kidney, liver, and pancreas as well as on immune cells such as macrophages and antigen-presenting cells. In the brain, HCA1 acts to dampen neuron excitation and may also function to promote neurogenesis (the production of neurons from neural stem cells) and angiogenesis (the formation of new blood vessels from pre-existing blood vessels). The functions of HCA1 in non-fat and non-neural tissues have not been fully defined but in many cases appear to involve promoting the survival of cells, including various types of cancer cells.
The public source identifies “Hydroxycarboxylic acid receptor 1” as protein-coding gene in the species Homo sapiens. This brief keeps that definition visible, then builds a research path around Hydroxycarboxylic, acid and receptor.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Hydroxycarboxylic acid receptor 1”, the useful work is to connect “protein-coding gene in the species Homo sapiens” to the records capable of establishing context and consequence.
Datasets, specimens, observations and peer-reviewed methods provide the appropriate test for the technical claims summarized here. The source revision retrieved here is dated Sep 30, 2025. The linked authority identifier is Q18038714. None of the 0 selected statements returned an explicit reference.
Current terminology should not be projected backward without checking the classification used when the underlying evidence was created. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Check terminology, classification and the date of the cited evidence. Scientific names and technical consensus can change while older records retain historical value.
- Current terminology
- Classification context
- Finding cited technical literature
Primary datasets, specimen catalogues, standards bodies and the most recent peer-reviewed literature.
Three-step research path
- Establish the record: confirm the title “Hydroxycarboxylic acid receptor 1”, its source revision and the description used here.
- Expand the search: follow Hydroxycarboxylic acid receptor 1 primary sources, Hydroxycarboxylic acid receptor 1 archive and Hydroxycarboxylic research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Hydroxycarboxylic acid receptor 1”?
- Which observation, specimen, dataset or publication supports the account?
- Has classification or technical consensus changed since the cited source?
Search terms from this dossier
This entry incorporates text from “Hydroxycarboxylic acid receptor 1” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.