It may have been the hottest new offering in Wall Street history.

Genentech Inc., one of a handful of firms in the exotic genetic-engineering industry and the first to sell shares to the public, saw the price of its stock skyrocket within minutes from the initial offering price of $35 to $80 a share.

The sale of 1 million shares of the San Francisco-based company was eagerly awaited by investors anxious to get in on the ground floor of the nas-cent gene-splicing industry that promises to revolutionize the production of drugs -- from insulin to Interferon, the antiviral substance that holds promise in fighting some forms of cancer.

Investors were buying only a promise.

Since Genetech was founded four years ago by a young business school graduate and a leading microbiologist, the company has lost $1 million. It only began to earn a profit, and a small one, early last year.

During the first six months of 1980, the company earned $80,000 on sales of $3.4 million.

Wall Street veterans said the frenzy that surrounded the Genentech offering was reminiscent of the late 1960s and early 1970s when small technology companies sold shares in themselves for prices that were hundreds of times higher than their earnings.

But John C. Whitehead, cochairman of the big brokerage firm Goldman Sachs, said he could not recall "a new issue having such a meteroic rise." He said that the "extreme demand" should be construed as a "danger signal" that Wall Street could move toward some of the excesses apparent in the late 1960s and early 1970s that eventually sent stock prices down sharply -- a decline that ended only in the last few years.

Thomas Perkins, whose venture capital firm injected the initial $200,000 that got Genentech off the ground, also is concerned over the sharp jump in the stock's price.

"We thought $25 to $30 a share was a realistic value for the company, but when there was such terrific interest we raised it to $35," Perkins said. "But I am absolutely amazed at what happened."

Perkins is a partner in Kleiner & Perkins, a San Francisco company that specializes in obtaining capital for new companies that need funds to get started. The firms owns 938,800 shares in Genentech as a result of that initial investment.

The cofounders of the company, who own 925,000 shares each, are the president, Robert A. Swanson, and a University of California professor, Herbert W. Boyer, who did the original research in gene-splicing (called recombinant DNA) that attracted the attention of Kleiner & Perkins. Swanson was working for Kleiner & Perkins at the time.

Public investors own only 1 million of the 7.5 million shares in Genentech.

Besides Swanson, Boyer and Kleiner & Perkins, the rest of the shares are owned by Lubrizol Corp. (1,555,200) and other officers, directors and staff of Genentech.

The underwriting was handled by Blyth Eastman Paine Webber and the San Francisco securities firm Hambrecht & Quist.

Only about a half dozen firms specialize in recombinant DNA technology, and most of the capital invested in the industry has been to fund basic research. That is why Genentech only began to show a small profit last year. rSome large companies, however, do large amounts of their own research into recombinant DNA.

Eli Lilly & Co, the giant pharmaceuticals firm, has been experimenting with a Genetech-developed bacterium to produce human insulin.

So-called genetic engineering is a process in which scientists take a gene from one organism and transplant in to a bacterium. The gene then directs the bacterium to produce a substance -- such as insulin.

Interest in Genentech remained strong all today. Although the price finally subsided to about $71.50 (from a peak of near $87), it closed more than twice as high as what initial investors paid for it. According to the National Association of Securities Dealers, 528,768 shares of Genentech were traded today, which means that more than half of the shares purchased by initial investors were resold on the day the stock became public.

Peter Rawlings, who headed the syndicate for Paine Webber, noted that "we've got to see where the stock trades three months, or three years from now." He pointed out that the old stockholders own more than 80 percent of the company for an investment of about $12 million, while the new stockholders own less than 1 4 percent for an investment of $35 million.