The sources, who spoke on the condition of anonymity, did not provide details about the incident but confirmed that police were called about 1:20 p.m. The case turned into a "medical emergency" and was handed off from the LAPD to the Los Angeles Fire Department, the sources said.
The incident occurred at the home of West's personal trainer, the sources said.
West agreed to seek medical treatment, according to a law enforcement source, and he was treated for stress and exhaustion at Ronald Reagan UCLA Medical Center.
An LAFD spokesman said that paramedics and police responded to an address in Beverly Grove, just south of West Hollywood, after a 911 call was made from the location.
Paramedics eventually took a "medically stable" man to the hospital for further assessment, said Brian Humphrey, a spokesman for the department.
Humphrey said he was bound by privacy laws from disclosing the man's identity.
The incident comes at a turbulent period for West, who walked off the stage three songs into his Saturday night concert in Sacramento and canceled Sunday's at the Forum three hours before showtime.
On Saturday, West ranted about a few longtime friends and acquaintances, including Jay Z, Beyoncé and Facebook Chief Executive Mark Zuckerberg.
"I've been sent here to give y'all my truth, even at the risk of my own life," West said on Saturday night. "At the risk of my own success. I'll give y'all the truth. Jay Z, call me, you still ain't called me.… Jay Z, I know you got killers. Please don't send them at my head. Just call me. Talk to me like a man."
On Thursday during his concert in San Jose, West editorialized about racism and the Black Lives Matter movement before praising President-elect Donald Trump.
West, who is married to Kim Kardashian West, has indicated that he may run for president in 2020.
Realty TV star Kris Jenner, who is West's mother-in-law, told Vanity Fair on Monday night that West was "exhausted" but doing "good."
West's representatives have not made any officials comments about his condition or when he might leave the hospital. UCLA Medical Center has also not released any information.
West's hospitalization was first reported by NBC News.
12:30 p.m.: This article was updated with additional details about West's hospitalization and his personal trainer.
6:50 a.m., Nov. 22: This article was updated with comments from Kris Jenner.
9:05 p.m.: This article was updated with additional details.
7:30 p.m.: This article was updated with comments from the Los Angeles Fire Department.
6:15 p.m.: This article was updated with confirmation that West agreed to seek medical treatment.