NEW YORK - In a city where dogs command their own shrinks and fashion designers, perhaps pet ambulances were inevitable. With names like Pet Taxi, Pet Chauffeur and Paw Mobile, these companies offer to take your ailing pet to an animal hospital, sometimes on a pint-size stretcher complete with oxygen mask.

But unless the dog has a generous health insurance policy, the costs can be steep.

Take the case of Dr. Ross Friedman, an Upper East Side physician. In July, his golden retriever, Chutney, collapsed from an inflamed pericardium, the sac around the heart. Friedman called Ambuvet to deliver his dog about 20 blocks to the Animal Medical Center on East 62nd Street.

"This company said they had veterinary technicians and oxygen, and it would cost $55 each way," Friedman said. But the bill came to $310.

Ambuvet, in Astoria, Queens, directed all questions to its lawyer, who disputed Friedman's claim.

"The agreed-upon price was in writing," said John Sandleitner, the company's lawyer. "Dr. Friedman signed a contract with two separate credit card vouchers."

Sandleitner also insisted that Ambuvet did not advertise any medical services. But some of Ambuvet's earlier promotional materials describe the company as "owned and operated by vet techs."

The state agency responsible for issuing veterinary licenses has no records for Ambuvet or its owner, Don Montes.

Pet advocates, while praising some companies, are already calling for the new industry to be regulated.

"This seems to be uncharted waters for anyone to get a van and charge whatever they want," said Jane Colton, a flight attendant who spends her spare time publicizing animal causes. "Where are the guidelines for this?"

Nowhere, according to Matthew W. Daus, chairman of the Taxi and Limousine Commission. "These services don't fall under the jurisdiction of the TLC," he said.