The National Trainers Federation has admitted it is "shocked" at the news of positive tests for steroids on horses trained by Mahmood Al Zarooni.
The trainers' professional body says it fully endorses the British Horseracing Authority's regime of testing in training.
In a statement, NTF chief executive Rupert Arnold said: "Like everyone else in the sport of horseracing, the NTF is shocked at the news of these positive tests at the stable of Mahmood Al Zarooni.
"The Godolphin management, for whom Mr Al Zarooni trains, is a byword for the highest levels of professionalism, integrity and sportsmanship.
"News reports so far suggest this case is an aberration and is not indicative of wider use of anabolic steroids in British horseracing.
"We fully endorse the British Horseracing Authority's testing in training regime and all efforts to prevent the use of any prohibited substance to gain an unfair advantage.
"Without wanting to diminish the seriousness of this case, in some ways it is a positive message that the presence of these substances was detected so the sport is kept clean."
Al Zarooni is to face a BHA disciplinary panel hearing after samples taken from 11 horses in his care in Newmarket were found to contain traces of anabolic steroids.
"I deeply regret what has happened. I have made a catastrophic error" - Al Zarooni
Al Zarooni, who won the Ladbrokes St Leger at Doncaster last year with Encke, as well as the richest race in the world, the Dubai World Cup, with Monterosso, has trained a whole host of big-race winners since joining Sheikh Mohammed's operation.
The BHA said that on 9 April this year samples were obtained from 45 horses trained by Al Zarooni at Moulton Paddocks Stables and that on Monday afternoon it had received written advice from the Horseracing Forensic Laboratory that upon analysis 11 of the samples had present in them prohibited substances, namely ethylestranol and stanozolol.
Certify, unbeaten in four career outings and winner of the Shadwell Stud Fillies' Mile at Newmarket in September, was one of the seven horses whose sample tested positive for ethylestranol.
She had been ante-post favourite through the winter months for the Guineas, and only recently lost that position to the Henry Cecil-trained Hot Snap.
Ascot Gold Cup runner-up Opinion Poll was one of four horses testing positive for stanozolol.
Some bookmakers reacted quickly by deciding to refund ante-post bets on the affected Al Zarooni-trained horses.
Kate Miller, head of William Hill's PR team, tweeted: "Godolphin horses William Hill will refund ALL AP bets on; 1000 Guineas, Certify & Desert Blossom. 2000 Guineas; Artigiano/Restraint Of Trade."
Al Zarooni's only intended runner today, Press Room, was taken out of the 10-furlong at Yarmouth. The horse was reported to be coughing.
"I deeply regret what has happened. I have made a catastrophic error," Al Zarooni said on Godolphin's website (www.godolphin.com).
"Sheikh Mohammed was absolutely appalled when he was told" - Godolphin racing manager Simon Crisford
"Because the horses involved were not racing at the time, I did not realise that what I was doing was in breach of the rules of racing. I can only apologise for the damage this will cause to Godolphin and to racing generally."
Godolphin racing manager Simon Crisford said the discovery marked a "dark day" for Godolphin.
"His Highness Sheikh Mohammed was absolutely appalled when he was told and this is completely unacceptable to him. We will await the outcome of the BHA inquiry before taking any further internal action.
"Sheikh Mohammed has instructed me to begin an urgent review of all of our procedures and controls. That is already underway and we will take advice from the BHA in completing it."