Endogenous substances are those that originate from within an organism, tissue, or cell.Endogenous retroviruses are caused by ancient infections of germ cells in humans, mammals and other vertebrates. Their proviruses remain in the genome and are passed on to the next generation.

Endogenous processes include the self-sustained circadian rhythms of plants and animals.

In some biological systems, endogeneity refers to the recipient of DNA (usually in prokaryotes). However, due to homeostasis, discerning between internal and external influences is often difficult.

Endogenous transcription factors refers to those that are manufactured by the cell, as opposed to cloned transcription factors.

The word endogenous (pronounced /ɛnˈdɒdʒɪnəs/) derives from the Greek: ενδογενής, meaning "proceeding from within" ("ενδο"=inside "-γενής"=coming from), the complement of exogenous (Greek: εξωγενής exo, "έξω"= outside) "proceeding from outside".

Patti Rothberg (born May 4, 1972) is a New York-based singer, songwriter, recording artist, multi-instrumentalist, and painter/artist.

Born in New York City Rothberg grew up in Scarsdale, NY, playing piano from the age of 3 and writing songs by the age of 15, joining a high school Rod Stewart cover band.

Rothberg played all the guitar and bass parts on her debut album, Between the 1 and the 9, which was released on April 2, 1996. The album went on to sell over 250,000 copies in the US and another 200,000 in Europe and Japan. The first single, "Inside", reached number 25 on Billboard's Alternative Songs Chart.

During this time, two of Rothberg's songs appeared in movies: a cover of "Kung Fu Fighting" in Beverly Hills Ninja (1997) and "Inside" in The Misadventures of Margaret (1998).

Rothberg's third album, Double Standards, was released by indie label Megaforce on May 13, 2008. The release show was at the Blender Theater in NYC on May 22, 2008.

Lorraine Leckie is a NYC based singer/songwriter. She performs solo and with her band, Lorraine Leckie and her Demons.

Leckie (Nee Turansky) was born and raised in Whitby, Ontario, near Toronto With sister Brenda Turansky and brother Paul Turansky(deceased). She married Steve Leckie, of The Viletones, at the age of 18, but later left Toronto and the marriage and moved to NYC. She still returns to Toronto to perform with local musicians and Steve Leckie.

Her most recent solo album, "Martini Eyes," was released in Toronto on Aug 12, 2010 and was released in NYC on Sept 29, 2010. Her last full band album, "Four Cold Angels," was on the Pazz and Jop 2008 as a rated album, and the song Ontario was on Pazz & Jop 2009.

Lorraine Leckie & Her Demons is a folk rock band based in New York City. The band consists of Lorraine Leckie on guitar, vocals, piano; Hugh Pool on electric guitar; Paul Triff on drums; George Jackson on Bass; and the guest demons are Buddy Cage on pedal steel, and Alexa Wilding on vocals. They performed at the Bowery Ballroom June 1, 2009 and June 17, 2010.