Biotin Deficiency and Cryptorchidism in Rats. ∗

Abstract

A form of cryptorchidism attributed to biotin deficiency was recently reported in rats ( 1 ). The reproductive anomaly was produced in 8 rats in 2 experiments involving a diet rich (66%) in spray-dried egg white, containing avidin, a protein which combines with biotin within the intestine in a non-absorbable complex( 2 ). The cause of the cryptorchidism was suggested as due to the contracture of the cremaster muscle which completely surrounds the testicle in the rat. Biotin deficiency symptoms have been described in detail in the rat( 3 ) and fowl ( 4 ), and the biochemical action of this vitamin in carboxylase and deaminase systems has been reported in bacteria and mammalian tissues 5 6 . Although other vitamin deficiencies, for example, A and E, have been involved in male reproductive disorders, the claim that biotin deficiency may specifically cause testicular ascent is of unusual interest. In the absence of details pertaining to biotin therapy, contractility of the cremaster muscle, or growth and weight changes in the experimental animals, we have attempted to repeat and elaborate on this work.

Five experiments, involving 98 male weanling albino rats, were conducted to test the specific effect of biotin deficiency in causing cryptorchidism, as well as possible factors mediating or counteracting the reproductive disorder. Rats of the University of Massachusetts and the Carworth Farms strains were used in all tests. The animals were isolated in wire screen cages with screen bottoms and fed weighed quantities of food: 10 to 15 g/rat/day or as much as each animal would eat, with water supplied ad libitum. Litter mate controls were used where possible. Weanling weights, however, varied considerably, between 29 and 48 g. The experiments and conclusions are summarized in Table I.