Sexual Differentiation of Gonadotropin Patterns

The original experiments, done by Witschi and his associates,on sexual differentiation of pituitary gonadotropins weie interpietedas demonstrating the contrasting effects of testes on the subsequentoutput of luteimzing hormone (LH) and interstitial cell stimulatinghormone (ICSH). The subsequent demonstration that these twohormones were identical has led to a theory that testes alterthe hypothala mic centeis which control the cyclic release ofLH "Masculinization of the female hypothalamic pituitary axishas been claimed following neonatal treatment with steroids".However, true sex reversal of gonadotiopin patterns has neitherbeen demon stiated, the male pattern has not yet been clearlydenned Consistent high levels of blood and pituitary folliclestimulating hormone (FSH) appear to be at least two characteristicsof the male pattern, and neither can be induced in lemales byneonatal treatment with testosterone propionate. Furthermore,castration of males at bnth with concomitant ovanan implinldtion,does not appear to remove the male pattern of high FSH. Consideringthat we understand so little regarding gonadotropin patternsin males, we cannot assume that this pattern can be inducedsimply by pie or postnatal steroid trealment. Considerably moredata on the positive and negative feedback effects of steroids,and steroid combinations, on TSH, LH, and piolictin in bothmales and females, will be requned before a meaningful conceptof sexual differentiation cin be formulated