Interrelationships of porcine X and Y chromosomes with pituitary gonadotropins and testicular size.
Endocrine and testicular responses to unilateral castration on 1, 10, 56, or 112 days of age were characterized in 132 Chinese Meishan (MS) x White composite (WC) crossbred boars in which testicular size associates with a quantitative trait locus (QTL) on X chromosome. At 220 days of age, testicles of boars unilaterally castrated on Day 1 or 10 weighed more and had greater total daily sperm production (DSP) than one testicle of bilaterally intact boars (P < 0.05); compensation did not double these two responses. Boars with MS alleles at the X chromosome QTL had smaller testicles, darker colored parenchyma, and lower total DSP than boars with WC alleles (P < 0.05). The MS alleles engendered greater (P < 0.05) plasma FSH and LH during puberty than WC alleles. Plasma FSH increased (P < 0.05) within 48 h of unilateral castration on Days 1, 10, and 56. Subsequent increases occurred earlier during puberty (P < 0.05) after unilateral castration at younger ages than after unilateral castration at older ages. Pubertal increases in plasma FSH and LH were greater (P < 0.05) in boars with MS alleles than in those with WC alleles for the X chromosome QTL. Breed of Y chromosome had no effect on testicular traits, FSH, testosterone, or estrone. For LH, boars with an MS Y chromosome had greater (P < 0.01) plasma LH across all ages than boars with a WC Y chromosome. We conclude that a gene or groups of genes that reside on the porcine X chromosome regulate testicular development and pubertal gonadotropin concentrations.
Ford
J J
JJ
USDA, ARS, RLH U.S. Meat Animal Research Center, State Spur 18D, Clay Center, Nebraska 68933, USA. ford@email.marc.usda.gov
Wise
T H
TH
Lunstra
D D
DD
Rohrer
G A
GA
D000375:Aging; D000483:Alleles; D000818:Animals; D000831:Animals, Newborn; D001947:Breeding; D004822:Epididymis / Q000033:anatomy & histology; D005640:Follicle Stimulating Hormone / Q000097:blood; D005838:Genotype; D006065:Gonadotropins, Pituitary / Q000502:physiology*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D009919:Orchiectomy; D009929:Organ Size; D010641:Phenotype; D012741:Sexual Maturation; D013045:Species Specificity; D013091:Spermatogenesis / Q000235:genetics; D013552:Swine; D013737:Testis / Q000033:anatomy & histology*; D014960:X Chromosome; D014998:Y Chromosome
D006065:Gonadotropins, Pituitary; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone