分泌する

The Japanese verb 分泌する (bunpi suru) is a technical yet common term that translates to 'to secrete' in English. It is primarily used in biological, medical, and physiological contexts to describe the process where a gland, cell, or organism produces and releases a specific chemical substance. While you might encounter it in a high school biology textbook, it is also a staple in daily conversations regarding health, skincare, and even emotional responses. For instance, when you discuss how exercise makes you feel good, you are talking about the brain's ability to secrete endorphins. Understanding this word requires a grasp of both the physical act of production and the subsequent release of substances like hormones, enzymes, sweat, or saliva. It is a Suru-verb, meaning it combines the noun 分泌 (secretion) with the helper verb する (to do).

Biological Context

This word is most frequently used to describe internal bodily functions. For example, the pancreas secreting insulin or the salivary glands secreting saliva during a meal. It implies a controlled, purposeful release by the body's systems.

Skincare and Health

In the beauty industry, you will often hear about the secretion of sebum (皮脂). If your skin is oily, a dermatologist might say your skin is secreting too much oil. Similarly, in health contexts, doctors discuss the secretion of stress hormones like cortisol.

Botany and Nature

Plants also perform this action. Flowers secrete nectar to attract bees, and certain trees secrete resin to protect themselves from insects or damage. The word remains the same regardless of the species doing the secreting.

When using this word, it is important to distinguish it from simple 'leaking' or 'coming out.' While 出る (deru) is a general word for 'to come out,' 分泌する implies a biological mechanism. If water leaks from a pipe, you use 漏れる (moreru), not 分泌する. The latter is reserved for the sophisticated chemical factories of living organisms. In B1 level Japanese, you are expected to move beyond simple verbs and use these specific terms to describe processes accurately. This word often appears in the passive voice 分泌される because we often talk about the substance being secreted rather than the gland doing the action. For example, 'Insulin is secreted' is more common than 'The pancreas secretes insulin' in general conversation.

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Formal and Scientific. It is used in news reports, doctor consultations, and academic papers. Using it in casual conversation makes you sound very precise and educated.

In summary, use 分泌する whenever you are talking about a living thing producing a liquid or chemical. Whether it is sweat during a marathon, hormones during puberty, or sap from a pine tree, this is the precise verb to use. It bridges the gap between everyday physiological experiences and scientific understanding, making it a vital addition to the vocabulary of an intermediate Japanese learner seeking to discuss health and biology.

Mastering the usage of 分泌する (bunpi suru) involves understanding its grammatical particles and its passive form. Since it is a transitive verb in its core meaning (A secretes B), it often takes the particle を (o). However, in many contexts, especially scientific ones, we focus on the substance itself, leading to the use of the passive される (sareru) or the intransitive-like usage where the substance is the subject with が (ga). Let's look at the primary patterns.

Pattern 1: [Organ] + が + [Substance] + を + 分泌する

This is the most direct way to describe the action. Example: 'The stomach secretes gastric acid.' (胃が胃液を分泌する). This emphasizes the source of the secretion.

Pattern 2: [Substance] + が + 分泌される

This is the passive form and is extremely common. It translates to '[Substance] is secreted.' This is used when the focus is on the chemical or liquid rather than the gland. Example: 'Adrenaline is secreted.' (アドレナリンが分泌される).

Another important aspect is the use of adverbs to describe the amount or frequency of secretion. Words like 過剰に (kajou ni - excessively), 活発に (kappatsu ni - actively), and 抑制する (yokusei suru - to suppress/inhibit) are frequent companions to this verb. For instance, 'Hormone secretion is suppressed' would be ホルモンの分泌が抑制される. Notice here that we used the noun form 分泌 followed by the particle が. This is a very common way to treat the entire process as a single noun phrase.

In medical settings, you might hear about 内分泌 (naibunpi - endocrine/internal secretion) and 外分泌 (gaibunpi - exocrine/external secretion). While these are more advanced, knowing that 'bunpi' is the core helps you understand these complex terms. In a B1 context, you should be able to explain how your body reacts to things. Instead of just saying 'I sweat,' saying 'Sweat is secreted' (汗が分泌される) demonstrates a higher level of linguistic sophistication and biological awareness. Also, remember that this verb is almost never used for inanimate objects like machines or leaky faucets. For those, use 流出する (ryuushutsu suru - to leak/outflow) or 出る (deru).

Common Subjects

Hormones (ホルモン), Enzymes (酵素), Saliva (唾液), Sweat (汗), Gastric Acid (胃液), Nectar (蜜), Sebum (皮脂).

Finally, consider the timing. Use 分泌し始める (begin secreting) or 分泌し続ける (continue secreting) to describe ongoing biological processes. For example, 'The body continues to secrete insulin throughout the day.' This verb is highly versatile within its scientific domain, allowing for nuanced descriptions of how living things function internally.

You might think 分泌する (bunpi suru) is restricted to science labs, but it is surprisingly ubiquitous in Japanese daily life, media, and professional environments. Understanding where you'll hear it will help you recognize its importance beyond mere 'textbook Japanese.' Here are the most common scenarios where this word takes center stage.

Television and Documentaries

Health-themed variety shows are huge in Japan. Programs like 'Gatten!' or health segments on morning news frequently discuss how certain foods or habits affect the 'bunpi' of hormones. You'll hear phrases like 'Eat this to increase the secretion of growth hormones!'

Hospitals and Clinics

If you go for a check-up or a blood test, the doctor might explain your results using this word. 'Your insulin secretion is a bit low' (インスリンの分泌が少し少ないです) or 'We need to check your thyroid secretion.' It is the standard professional term used by healthcare providers.

Beauty and Cosmetics Commercials

Skincare ads often target 'excessive sebum secretion' (過剰な皮脂の分泌). They promise products that control or inhibit this secretion to prevent acne or oily skin. Listen for it in commercials for face washes and lotions.

In schools, from elementary biology onwards, students are taught about the endocrine system using this word. It's part of the basic scientific literacy in Japan. Furthermore, in the news, whenever there is a story about a new medical discovery or a health crisis (like diabetes or hormonal imbalances), 分泌する will appear in the headlines and scripts. It is also found in psychological discussions, such as how 'oxytocin' (the love hormone) is secreted when people hug or interact with pets.

Academic Contexts

University lectures in biology, chemistry, and medicine use this word constantly. It's an essential term for anyone studying life sciences in Japanese.

Lastly, you might see it in gardening or agricultural contexts. Farmers might discuss the secretion of substances from roots that affect soil quality or the secretion of pheromones used in pest control. While the word feels 'heavy' because of its kanji, its application is incredibly broad, touching everything from the sweat on your brow to the complex chemical signals that keep our ecosystems functioning. Hearing 分泌する is a sign that the conversation has moved into a more detailed, factual, or professional territory.

While 分泌する (bunpi suru) is a precise term, its specificity often leads to confusion with other similar-sounding or similar-meaning verbs. For English speakers, the distinction between 'secrete,' 'excrete,' 'discharge,' and 'leak' can be tricky when translated into Japanese. Avoiding these common pitfalls will make your Japanese sound much more natural and accurate.

Mistake 1: Confusing with 排出する (haishutsu suru)

This is the most common error. 分泌 (bunpi) is 'secretion' (producing something useful or functional, like hormones). 排出 (haishutsu) is 'excretion' or 'exhaust' (getting rid of waste, like CO2 or urine). You wouldn't say the body 'secretes' exhaust gas; you say it 'excretes' or 'emits' it.

Mistake 2: Using it for Non-living Objects

As mentioned before, 分泌する is strictly biological. You cannot say a machine 'secretes' oil. For machines, use 漏れる (moreru - leak) or 出る (deru - come out). Using 'bunpi' for a car engine sounds like the car is a living creature, which might be funny but is technically incorrect.

Another mistake involves the confusion between 分泌 (bunpi) and 放出 (houshutsu). While 'houshutsu' means 'release' or 'emission,' it is often used for energy, heat, or radiation. For example, a radioactive substance 'emits' (houshutsu) radiation, it doesn't 'secrete' it. 'Bunpi' always implies a liquid or chemical substance produced by a gland. Also, be careful with the reading. While the kanji 泌 looks like it might be read as 'hitsu' (as in 'hitsu-you' - necessary), in this word it is always pi (or hi in older texts). Saying 'bun-hitsu' is a common reading error for beginners.

Mistake 3: Over-relying on the Active Voice

In English, we might say 'The body secretes sweat.' In Japanese, while 'Karada ga ase o bunpi suru' is correct, it often sounds more natural to say 'Ase ga bunpi sareru' (Sweat is secreted). Using the passive voice helps you sound more like a native speaker when discussing biological processes where the 'actor' (the body) is implied.

Finally, don't confuse 分泌 (bunpi) with 分離 (bunri - separation). They look somewhat similar and both start with 'bun' (divide), but they describe completely different actions. 分離 is about taking things apart, while 分泌 is about producing and releasing a substance. Keeping these distinctions in mind will ensure your scientific and health-related Japanese remains accurate and professional.

To truly master 分泌する (bunpi suru), you should know the words that surround it in the same semantic field. Depending on the context—whether it's casual, medical, or environmental—there might be a better or more common alternative. Let's compare 分泌する with its closest relatives.

出る (Deru)

The most common and casual alternative. Instead of 'Ase ga bunpi sareru,' most people in daily life just say 'Ase ga deru' (Sweat comes out). Use 'deru' for casual talk and 'bunpi suru' for technical or formal explanations.

排出する (Haishutsu suru)

Meaning 'to excrete' or 'to discharge.' As discussed, this is for waste products. If the body is getting rid of something it doesn't need (like toxins), use 'haishutsu.' If it's creating something it *does* need (like saliva), use 'bunpi.'

放出する (Houshutsu suru)

Meaning 'to release' or 'to emit.' This is used for energy, heat, or large quantities of gas. It's also used for 'releasing' things into the environment, like 'releasing water from a dam' or 'releasing CO2 into the air.'

Other technical terms include 漏出する (roushutsu suru - to leak out) and 滲出する (shinshutsu suru - to ooze out/exude). 'Shinshutsu' is particularly close to 'bunpi' but implies a slower, more passive 'oozing' through a membrane or from a wound, whereas 'bunpi' is an active physiological function of a gland. For instance, fluid oozing from a scrape is 'shinshutsu,' but sweat from a pore is 'bunpi.'

Producing vs. Releasing

If you want to focus on the *production* part, you might use 生成する (seisei suru - to generate/produce). 'Bunpi' includes both the production and the release. If a gland makes a hormone but doesn't release it yet, that's 'seisei.' Once it enters the bloodstream, that's 'bunpi.'

In casual conversation, you might also hear ドバドバ出る (dobadoba deru), an onomatopoeic way to describe something coming out in large quantities, like sweat or adrenaline. While 'bunpi' is the academic term, 'dobadoba' is the visceral, everyday way to describe a massive secretion. Knowing both allows you to navigate everything from a scientific journal to a chat with a friend after a workout.