Plasma testosterone in the male, progesterone and estradiol-17β in the female, and Δ5-3β-hydroxysteroid dehydrogenase (3β-HSD) activity in the testis ovary of the Snell dwarf mouse

Plasma testosterone levels in males and plasma progesterone and estradiol-17β levels in females were measured in the Snell dwarf mouse and phenotypically normal controls in an immature 30-day-old group and a mature 90-day-old group of animals. Plasma testosterone levels in males were significantly lower in dwarfs at 30 days of age, but increased to control levels at 90 days of age. The estradiol-17β levels were found to be significantly lower in female dwarfs than controls in both age groups studied whereas the progesterone levels were found to be significantly lower in female dwarfs only in the 90-day-old animals. The progesterone levels were associated with the lack of corpora lutea in the ovaries of the dwarf mice. Compared with levels in control animals, Δ⁵-3β-hydroxysteroid dehydrogenase (3β-HSD) activity, using pregnenolone as a precursor, was found to be significantly lower in ovaries and testes in dwarf mice at 90 days of age.